Drip irrigated with fulvic acid improves soil environment and enhances fruit yield and quality of fragrant pear planted in saline-alkali land

Drip irrigated with fulvic acid improves soil environment and enhances fruit yield and quality of fragrant pear planted in saline-alkali land | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Drip irrigated with fulvic acid improves soil environment and enhances fruit yield and quality of fragrant pear planted in saline-alkali land Hao Liu, Jun Wang, Jiusheng Li, Dezhao Liu, Long Wang, Taofeng Luo, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8199859/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Soil salinization restricts the sustainable development of agriculture, organic amendments can ameliorate the saline–alkali soil environment, and appropriate irrigation interval reduced the root zone soil salinity by leaching salt into deeper soil. While, it remains unclear how the application of soluble amendments under drip irrigation affects the soil environment, which is crucial for understanding their role in the yield and quality formation of deep-rooted crops such as fruit trees. A two-year experiment was conducted in a Korla fragrant pear orchard to investigate the effects of irrigation interval, fulvic acid (FA) application rate, and application timing on soil environment indices, i.e., soil water content (SWC), soil salinity, soil nitrate nitrogen content, and thus fruit yield and quality of drip irrigated fragrant pear. The treatments included three irrigation intervals: 10 (P1), 15 (P2) and 20 days (P3), three FA application rates: 0 (H0), 200 (H1) and 400 kg ha − 1 (H2), and two FA application timings: once (T1), three times (T2). In addition, insoluble organic amendment (CK) was used as a control treatment. Compared with the P1 and P3 treatments, the P2 treatment increased the SWC in the root zone by 5.6% and 9.4% and decreased the soil salinity by 8.6% and 13.7%, respectively. FA application increased the SWC and nitrate nitrogen content by 5.7–14.7% and 8.3–35.1%, respectively, and reduced the soil salinity by 7.6–23.5%. With the same organic carbon content, the SWC and nitrate nitrogen content of H2 treatment were 8.5% and 9.2% greater than that of the CK treatment, respectively, and soil salinity was 6.9% lower. Compared with single application, split application of FA resulted in a significant 17.5% increase in soil nitrate nitrogen content. In addition, the overall fruit quality was determined through principal component analysis (PCA) of various fruit quality parameters. The yield and overall quality of fragrant pear initially increased and then decreased with increasing drip irrigation interval, but increased with increasing application rate and number of FA applications. Random forest analysis revealed that the interaction of irrigation interval and FA application rate had significant effects on soil salinity, and the FA application rate was the dominant factor. In summary, the recommended irrigation interval, application rate and number of FA applications were 15 days, 400 kg ha − 1 , and three, respectively, for saline-affected fragrant pear orchards in arid region. organic amendment soil salinity fertigation soil environment random forest analysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 1. Introduction Worldwide, a significant portion of croplands suffer from soil salinization (Sytar et al. 2017 ). By 2024, the total area of saline soils expanded to an alarming 1.381 billion hectares, approximately 10.7% of the Earth’s land surface (FAO, 2024). The climate in the Xinjiang region of China is characterized by low rainfall and high evaporation, which exacerbates the problem of soil salinization (Wang et al., 2022 ). The Korla fragrant pear is a distinctive fruit of the region and a key pillar industry in its main production area, Korla City. Recently, labor-saving intensive planting has been adopted as an novel cultivation approach for fragrant pear in Xinjiang province. However, most orchards are affected by severe soil salinity, with the salt concentration in the surface soil approaching 9 g kg − 1 , posing a direct threat to the sustainable development of fragrant pear trees (Zhang et al., 2022 ). In modern arid-region agricultural systems, drip irrigation has become an indispensable component (Yao et al., 2019 ), as it maintains adequate rooting zone moisture and continuously leaches salts downward, reducing the rooting zone salinity levels (Du et al., 2023 ). In saline soils, the drip irrigation interval is a key technical parameter that regulates the range of water and salt migration, directly affecting the soil desalination efficiency and the root zone environment (Zhang et al., 2019 ). Under the same irrigation quota, low-frequency irrigation, owing to its larger single irrigation volume, promotes the downward movement of salinity-related ions into lower soil horizons (Xiao et al., 2023 ) and results in considerable nitrogen leaching (Wei et al., 2024 ; Feng et al., 2023 ). However, high-frequency drip irrigation can create a continuously moist zone, promoting the downward movement of salts and preventing their build-up at the surface due to capillary action (Liu et al., 2013 ). Moreover, previous studies have shown that high-frequency irrigation effectively reduces salt accumulation in the root zones of annual crops (Zhang et al., 2014 ; Xiao et al., 2024 ; Dai et al., 2024 ) and thus improves yield and quality (Liu et al., 2025 ). However, for fruit trees with deeper root systems, lower single irrigation volumes may not be sufficient to effectively leach salts from the root zone (Aragüés et al., 2014 ). Furthermore, appropriate irrigation intervals for shallow-rooted crops under saline conditions have been well studied, while limited research has explored suitable drip irrigation frequencies for deep-rooted crops such as fruit trees, especially regarding the labor-saving cultivation fragrant pear orchards, which remains a clear knowledge gap. Organic amendments (i.e., manure, lignite bioorganic, biochar, and fulvic acid) have been proposed and documented to improve the soil environment of saline-alkaline land (Mao et al., 2022 ; Li et al., 2025 ; Leogrande et al., 2019). Organic amendments can improve soil structure, facilitate the downward movement of salts, and suppress salinization in surface soils (Lei et al., 2025 ; Nie et al., 2025 ). Cheng et al. ( 2023 ) reported that the organic fertilizers applying significantly increased surface soil porosity and decreased both soil electrical conductivity and the sodium adsorption ratio. In addition, organic amendment application reduces nitrogen leaching and increases total soil nitrogen levels (Rodrigues et al., 2018 ). Chen et al. ( 2025 ) reported that organic amendments significantly increased the soil nitrate nitrogen, phosphorus, and potassium contents, particularly in the surface soil layer. This soil improvement approach can ameliorate the soil environment, there by increasing both the yield and quality of crops in saline soils and promoting sustainable agricultural production (Wang et al., 2023 ; Chen et al., 2023 ). However, the ameliorative effects of farmyard manure and other conventional organic amendments diminish with increasing soil depth (Huang et al., 2022 ), limiting their effectiveness in reducing salinity in the root zones of deep-rooted crops. Fulvic acid (FA), an organic amendment extracted from materials such as lignite or agricultural waste (Goenadi et al., 2021), has excellent water solubility (Mankotia et al., 2024), enabling its delivery to deeper soil layers through drip irrigation systems. Owing to the ability of FA to adsorb salt ions, it has been confirmed to have the potential to reduce soil salinity (Li et al., 2025 ). However, the improvement effect of FA on the soil environment in different soil layers of deep-rooted crops has not been sufficiently studied. Additionally, previous research has indicated that split-dose of chemical fertilizers are more beneficial for enhancing nutrient use efficiency (Yin et al., 2024 ). Due to their low solubility and slow nutrient release, organic amendments are typically applied as basal fertilizers in a single application (Thomas et al., 2019 ). In contrast to insoluble organic amendments, FA has high water solubility, which facilitates multiple applications during the crop growing season through drip irrigation systems. However, the interaction effect between the rate and timing of FA applications and drip-irrigation intervals on the soil environment have not been well studied. In order to bridge the identified research gaps, the objectives of the present study were to (1) evaluate the effects of different drip irrigation intervals, FA application rates, and application timings on soil environment indices, i.e., SWC, soil salinity, and soil nitrate nitrogen content, as well as on the yield and overall quality of fragrant pears; (2) identify the dominant factors affecting the soil environment under varying drip-irrigation intervals and FA application practices; and (3) recommend appropriate drip irrigation intervals, FA application rates, and application timings for Korla fragrant pears in southern Xinjiang. 2. Materials and methods 2.1 Experimental site Field experiments were performed between May and September during the 2023 and 2024 growing seasons in a seven-year-old fragrant pear orchard located in Korla City, Xinjiang, China (41°79′ N, 85°88′ E) (Fig. 1 ), with a planting pattern of 1 m × 4 m. The experimental area has aclimatic aridity, characterized by an average annual temperature of 11.4°C, average annual precipitation of 58.6 mm, and evaporation of 2800 mm. Meteorological data were continuously recorded via a Tianqi Intelligent Ecological Station (INSENTEK, China) installed at the experimental site. Meteorological information for the two growing seasons is illustrated in Fig. 1 . The experimental field had a sandy loam soil texture, with an mean bulk density of 1.57 g cm − 3 within the 0–100 cm depth. The initial contents of salt, organic matter, total nitrogen, and nitrate nitrogen for the 0–100 cm depth were 7.7 g kg − 1 ,15.0 g kg − 1 , 0.6 g kg − 1 , and 13.5 mg kg − 1 , respectively. The physical properties of the soil are summarized in Table 1 . The groundwater table depth was greater than 5 m. Irrigation water was pumped from a well over 70 meters deep, with a salinity of 0.21 dS m − 1 . Table 1 Soil physical properties at the experimental site. Depth (cm) Soil texture Soil textural composition (%) Bulk density (g cm − 3 ) Saturated water Content (%) Field capacity (%) TDS (g kg − 1 ) pH Clay Silt Sand 0–20 silty loam 8.36 75.91 15.73 1.58 27.54 18.53 7.79 7.73 20–40 silty loam 9.94 78.71 11.34 1.52 26.35 19.61 9.95 7.45 40–60 silty loam 12.55 78.1 9.34 1.59 28.31 19.32 9.91 7.34 60–80 silty loam 6.88 66.51 26.61 1.43 29.06 20.15 5.55 7.24 80–100 silty loam 6.54 60.12 33.34 1.38 30.61 21.32 6.03 7.36 # Fig. 1 approximately here# # Fig. 2 approximately here# # Table 1 approximately here# 2.2 Experimental treatments The treatments included three irrigation intervals: 10 (P1), 15 (P2) and 20 days (P3), three FA application rates: 0 (H0), 200 (H1) and 400 kg ha − 1 (H2), and two FA application timings: once (T1), three times (T2). Additionally, a solid organic amendment with low water solubility was used as a control treatment (CK). The experimental treatments are detailed in Table 2 . The application rate of the insoluble solid organic amendments (560 kg ha − 1 ) was calibrated to match the application rate (400 kg ha − 1 ) of FA on the equivalent organic carbon content. Three replicates per treatment were arranged using a blocking design with random assignment. The area of each experimental unit was 80 m 2 , and each was equipped with an independent water meter and valve. Table 2 Experimental treatments in 2023 and 2024. Drip irrigation interval (d) Rate of FA application (kg ha − 1 ) Number of FA applications 2023 2024 10(P1) 0(H0) one time(T1) P1H0T1 P1H0T1 200(H1) P1H1T1 —— 400(H2) P1H2T1 P1H2T1 0(H0) three times(T2) —— —— 200(H1) P1H1T2 P1H1T2 400(H2) P1H2T2 P1H2T2 15(P2) 0(H0) one time(T1) —— P2H0T1 200(H1) —— —— 400(H2) —— P2H2T1 0(H0) three times(T2) —— —— 200(H1) —— P2H1T2 400(H2) —— P2H2T2 20(P3) 0(H0) one time(T1) P3H0T1 P3H0T1 200(H1) P3H1T1 —— 400(H2) P3H2T1 P3H2T1 0(H0) three times(T2) —— —— 200(H1) P3H1T2 P3H1T2 400(H2) P3H2T2 P3H2T2 10(P1) 400(CK) one time(T1) P1CKT1 P1CKT1 # Table 2 approximately here# The organic amendment was potassium fulvate derived from mineral sources provided by Xinjiang Shuanglong Humic Acid Co., Ltd., with the following composition: K 2 O ≥ 12.0%, humic acid ≥ 55%, and fulvic acid ≥ 50%. The insoluble solid organic amendment was a biochemically treated lignite product provided by Apaxfon Bioscience and Technologies Ltd., CO, Baotou, Inner Mongolia, China. For the CK treatment and the single application of FA, the organic amendment was applied together with chemical fertilizer during the fruit-set stage. For the split application of FA, it was applied through drip irrigation during three stages of fragrant pear, on May 10, July 8, and August 2, following a ratio of 2:4:4. The application rates of N, P, and K fertilizers were determined based on the study by Liu et al ( 2025 ) as 300, 200, and 150 kg ha − 1 , respectively. These fertilizers were also applied at three growth stages at a ratio of 2:4:4 together with the organic amendment. Fertigation was conducted following the “1/4 W-1/2 N-1/4 W” strategy (Li et al., 2004 ), via a proportional fertilizer injector (Mis Rite Model 2504, Tefen) to ensure uniform application across all plots. Surface drip irrigation was adopted, with two drip lines per tree row, positioned 40 cm from the tree line on either side. The drip tubes were equipped with an emitter flow rate of 2.4 L h − 1 and spaced at 30 cm intervals. In accordance with the standard Technical Regulation for Micro-irrigation Fertilization of Korla Fragrant Pear (DB65/T 3203 − 2011), all the treatments were irrigated with a quota of 525 mm. Standard orchard management practices such as pruning, pesticide application, and weeding were consistently implemented throughout all plots. 2.3 Sampling and measurements 2.3.1 Soil water content The study by Liu et al. ( 2025 ) showed that the root distribution of 7-year-old Korla fragrant pear trees is primarily located within the 0–100 cm soil depth. Consequently, this depth range was designated as the root zone for this study. The SWC was measured via a Trime-T3 time-domain reflectometer (IMKO, Germany). Two 1.5-meter-long Trime tubes were installed at 40 cm from a representative pear tree at the center of each plot, one along the row and the other perpendicular to it. Soil water content was conducted weekly during the growing period, with a sampling depth of 100 cm. 2.3.2 Soil salinity and nitrate nitrogen content Soil samples were collected from depths of 0–20, 20–40, 40–60, 60–80, and 80–100 cm to measure the concentrations of soil salts and nitrates. Soil samples were collected one day before and one day after fertilization in each plot. For each row of pear trees, sampling was performed at points located 40 cm from the tree trunk, both along and perpendicular to the tree row direction. The soil samples were naturally dried in a shaded cool place, sieved through a 2 mm sieve, and then used to measure the nitrate nitrogen content. This process involved extraction with KCl solution, followed by analysis using an Autoanalyzer (AA500, Bran + Luebbe, Germany). Additionally, the electrical conductivity (EC 1:5 ) of the soil extract was determined using a portable conductivity meter (F3-Standard, Mettler Toledo, Switzerland). The extract was prepared by mixing soil with water at a 1:5 ratio, followed by shaking, settling, and filtering. Finally, the correlation between soil salt content and electrical conductivity was ultimately determined using the residue-drying method: S = 4.719 C (N = 55, R²=0.993) (1) where S represents the soil salinity (g kg − 1 ), and C represents the EC 1:5 (dS m − 1 ) of the soil. 2.3.3 Yield and fruit quality During the mature stage of the fragrant pear, three vigorously growing pear trees were chosen per treatment to measure yield. Fruits from each selected tree were entirely harvested and weighed, and the individual tree fruit counts were accurately recorded. The yield per tree was then calculated by multiplying the average fruit weight by the fruit count. In addition, 15 representative fruit samples were collected from different directions of the trees in each treatment to assess fruit quality. The measurement of soluble solids content was conducted with a digital refractometer (Delixi, China), and the soluble sugar content was determined using the anthrone colorimetric assay with concentrated sulfuric acid. The vitamin C content was measured via 2,6-dichlorophenol titration. The titratable acidity was measured by titration with NaOH, and pear firmness was determined through a firmness meter (Topyunong Technology, China). An overall score of the qualities was subsequently calculated based on principal component analysis (PCA) (Liu et al., 2025 ). 2.4 Statistical analysis The statistical analysis comprised of analysis of variance (ANOVA) along with significance testing, were carried out using R4.4.1 (R Foundation for Statistical Computing, Vienna, Austria). We performed ANOVA using the stats package, and the least significant difference (LSD) was applied for post-hoc comparison via the agricolae package, with a significance threshold of P < 0.05. Three-way ANOVA was applied using the aov function from the stats package to assess the impact of the irrigation interval, FA application rate, and application timings on fruit yield and quality, at significance set at P = 0.05 and 0.01. Random forest is a robust machine learning technique that is extensively applied in both classification and regression problems (Breiman et al., 2001). In random forests, the importance of each feature to model performance is quantified by computing the mean decrease in impurity across all trees attributable to that feature. A higher value indicates a greater contribution of the feature to the prediction results (Tang et al., 2024 ). In this study, feature importance analysis was used to identify the key soil environmental factors driving fragrant pear yield and quality, and to further clarify how the experimental factors influence these soil variables. Random forest analysis was performed with the rfPermute package in R4.4.1. 3. Results 3.1 Changes in soil water content at different soil depths The soil water content (SWC) at different soil depths from 0–100 cm during various growth stages in 2023 and 2024 is shown in Fig. 3 . The average SWC at each of the soil depths was in the range of 0.19–0.31cm 3 cm − 3 , and the SWC of the root zone under each treatment increased initially but then decreased with increasing soil depth during each growing stage. Both the irrigation interval and FA application influenced the SWC at the 0–100 cm soil depth. During the fruit expansion stage in the two-year experiment, the SWC under the 10-day irrigation interval (P1) reached its maximum in the 40–60 cm soil depth, whereas SWC under the 15-day and 20-day intervals (P2 and P3) peaked in the 60–80 cm soil depth. In 2023, the root zone SWC under P1 was 4.7–11.6% greater than that under P3, with significant differences noted throughout the fruit expansion stage. In 2024, the root zone SWC under P2 was 3.4–6.9% and 9.6–16.5% greater than that under P1 and P3, respectively, with a significantly higher SWC compared to P3 throughout the fruit expansion stage. During each growth stage of 2023 and 2024, the SWC under the FA application rates of 200 and 400 kg ha⁻ 1 (H1 and H2) was greater than that in the FA application rates of 0 kg ha⁻ 1 (H0) across all depths, and the SWC generally increased in response to rising application rates of FA. In addition, the SWC at each soil depth under the solid organic amendment (CK) treatment was lower than that under H2. Moreover, the application of FA significantly affected the root zone SWC during both the fruit set and fruit expansion stages in 2023 and 2024 (P < 0.01). During these stages, the root zone SWC in H1 and H2 was 5.7–10.6% and 9.4–14.7% greater than that in H0, respectively. The root zone SWC in CK was 8.5% lower than that in H2. During the whole growth stage of fragrant pear, root zone SWC did not differ significantly between single and split applications of FA (T1 and T2). Whereas, it should be pointed out that the SWC in T1 was 3.8–5.2% greater and 8.7–11.3% lower than that in T2 during the fruit set and expansion stage, respectively. # Fig. 3 approximately here# 3.2 Changes in soil salinity at different soil depths The distributions of soil salinity across soil depths and growth stages in 2023 and 2024 are presented in Fig. 4 . The root zone soil salinity ranged from 5.0 to 11.0 g kg − 1 . The drip irrigation interval affects the salt distribution by influencing soil water movement. As the irrigation interval increases, the soil salt peak gradually moves to greater soil depths. Additionally, the soil salinity in P1 increased with increasing soil depth, whereas in P2 and P3, the soil salinity first decreased but then increased with increasing depth (Fig. 4 ). The drip irrigation interval significantly impacted the root zone average soil salinity (P < 0.05). During the fruit expansion stages in 2023 and 2024, the root zone soil salinity in P3 was significantly (4.6–8.3%) lower than that in P1. In the fruit expansion stages of 2024, the root zone soil salinity in P2 was significantly reduced by 7.5–11.7% and 3.8–9.6% compared to P1 and P3, respectively. During the two-year field experiment, the root zone soil salinity at all soil depths in H1 and H2 was lower than that in H0, and the salinity generally decreased with increasing rates of FA. The FA application at the H2 rate primarily reduced the soil salinity at the 0–80 cm soil depth. In contrast to CK, which increased the soil salinity at the 40–100 cm soil depth. Furthermore, the application of FA significantly impacted the root zone average soil salinity at different growth stages during both years of the experiment (P < 0.05). The soil salinities in H1 and H2 were 7.6–13.8% and 12.7–23.5% lower than those in H0, respectively. In addition, the soil salinity in H2 was 6.9% lower than that in CK. The root zone soil salinity did not differ significantly between FA application timings of T1 and T2 throughout the entire growth stage of fragrant pear. Whereas, the FA application timings had varying effects on the soil salinity at different growth stages. During the fruit set stage, the soil salinity in T1 was 4.1–7.5% lower than that in T2. During the fruit expansion stages, the salinity in T2 remained 4.7–9.2% lower than that in T1. # Fig. 4 approximately here# 3.3 Changes in the soil nitrate nitrogen content at different soil depths The soil NO 3 − -N contents across soil depths and growth stages in 2023 and 2024 are shown in Fig. 5 . The root zone soil NO 3 − -N content ranged from 1.2 to 46.0 mg kg − 1 . During each growth stage in 2023 and 2024, the soil NO 3 − -N content generally tended to decline as soil depth increased. The drip irrigation interval affects the soil NO 3 − -N content at all depths of the root zone by influencing the soil water and salt transport (Fig. 5 ). The NO 3 − -N content under P1 and P2 was mainly concentrated in the 0–60 cm soil depth, whereas under P3, it extended to the 0–80 cm throughout the fruit set stage. This nitrate was then transported downward to the 0–80 cm soil depth throughout the fruit expansion stage. The drip irrigation interval significantly impacted the root zone average soil NO 3 − -N content (P < 0.05). In 2023, the root zone NO 3 − -N content under P1 was 3.7–11.2% greater than that under P3, with significant differences noted throughout the fruit expansion stage. In 2024, the root zone soil NO 3 − -N contents under P2 were 2.8–8.9% and 7.8–16.8% greater than those under P1 and P3, respectively. In 2023 and 2024, the soil NO 3 − -N content at all depths followed the order: H0 < H1 < H2. Compared with the FA application at the H2 rate, CK reduced the NO 3 − -N content in the 0–60 cm depth, whereas increasing it in the 60–100 cm depth. Furthermore, FA application significantly impacted the root zone NO 3 − -N content during the fruit expansion stage (P < 0.01). During this stage, the root zone NO 3 − -N contents in H1 and H2 were 8.3–12.4% and 11.6–35.1% greater than those in H0, respectively. Under single application, the NO 3 − -N content in H2 treatments was 9.2% greater than that in CK. FA application timings produced a significant effect on the root zone NO 3 − -N content in 2023 and 2024 (P < 0.05). The soil NO 3 − -N content under T1 was significantly (11.3–17.2%) higher than that under T2 throughout the fruit set stage. However, the soil NO 3 − -N content under T2 was significantly (3.1–15.8%) higher than that under T1 throughout the fruit expansion and mature stages. # Fig. 5 approximately here# 3.4 Fragrant pear yield under different treatments The pear yields under different treatments in 2023 and 2024 are presented in Fig. 6 . The highest yields were observed under the P3H2T2 and P2H2T2 treatments, reaching 36.3 t ha − 1 and 39.2 t ha − 1 in 2023 and 2024, respectively, whereas the lowest yields in both years were recorded under the P1H0T1 treatment, at 28.7 t ha − 1 and 31.5 t ha − 1 , respectively. The drip irrigation interval significantly influenced pear yield in both 2023 and 2024 (P < 0.05). In 2023, the yield under P3 was 1.7–8.5% greater than that under P1. In 2024, P2 produced the highest yield, which was 5.2–7.5% and 1.7–4.8% greater than those under P1 and P3, respectively. The rate of FA application significantly affected pear yield in both 2023 and 2024 (P < 0.01). The yield under H2 was 10.7–19.5% and 4.1–12.1% greater than that under H0 and H1, respectively. Under the irrigation interval of P1, the yields under H2 were 11.3% and 5.7% greater than those under CK in 2023 and 2024, respectively. FA application timings also significantly influenced pear yield in 2024 (P < 0.05). The split application of FA increased the yield by 3.2–6.3%. The interactive effect of the drip irrigation interval and the FA application rate had a significant effect on pear yield (P < 0.05). Under the split application of FA, the yield under H2 was 9.3% greater than that in H1 under the irrigation interval of P1, whereas the yield was nearly the same between H2 and H1 under the irrigation interval of P3. These results indicate that increasing the FA rate is more effective in enhancing yield under shorter drip irrigation intervals. # Fig. 6 approximately here# 3.5 Fragrant pear quality under different treatments Pear fruit quality across different treatments in 2023 and 2024 is presented in Tables 3 and 4 . The drip irrigation interval had a significant effect on the soluble solids content (SSC), titratable acid, single-fruit weight, and overall quality score in 2023 and 2024. In 2023, P3 increased the SSC, single-fruit weight, and overall quality score by 4.1–10.4%, 3.7–5.2%, and 30.7–339.7%, respectively, relative to P1, whereas the titratable acid decreased by 4.8–14.1%. In 2024, P2 increased the SSC by 6.9–9.1% and 3.2–6.1%, the single-fruit weight by 1.8–5.3% and 1.2–3.8%, and the overall quality score by 29.7–201.6% and 83.6–162.8%, respectively, compared with those of P1 and P3, whereas the titratable acid decreased by 4.7–16.1% and 2.6–10.3%, respectively. Table 3 Effects of the drip irrigation interval, FA application rate, and application timing on fruit quality in 2023. Treatment Soluble solids (%) Total sugar (%) Titratable acid content (%) Vitamin C (mg 100g − 1 ) Peel hardness (kg cm − 2 ) Single fruit Weight (g) Overall Score P1CKT1 11.81 ± 0.31bc 6.81 ± 0.35de 0.96 ± 0.07ab 1.71 ± 0.08c 7.63 ± 0.19cd 107.16 ± 2.64d -2.06 ± 0.16fg P1H0T1 10.04 ± 0.15d 6.40 ± 0.11e 1.28 ± 0.08a 1.53 ± 0.10d 8.00 ± 0.17b 100.07 ± 5.88f -2.57 ± 0.02g P1H1T1 10.61 ± 0.12cd 6.97 ± 0.14d 0.84 ± 0.13b 1.62 ± 0.07c 7.97 ± 0.16b 105.83 ± 5.15de -1.19 ± 0.02f P1H2T1 11.29 ± 0.14c 7.74 ± 0.08c 0.78 ± 0.05bc 1.94 ± 0.15bc 7.80 ± 0.23bc 114.37 ± 2.60b 0.66 ± 0.03d P1H1T2 10.95 ± 0.32c 7.06 ± 0.21d 0.82 ± 0.07b 2.04 ± 0.06bc 7.42 ± 0.24d 110.24 ± 3.02b -0.78 ± 0.01ef P1H2T2 12.96 ± 0.09a 8.35 ± 0.10b 0.65 ± 0.07d 2.37 ± 0.10a 7.26 ± 0.21de 122.11 ± 3.58b 1.74 ± 0.09b P3H0T1 10.25 ± 0.27d 6.51 ± 0.17e 1.12 ± 0.12a 1.67 ± 0.05cd 8.21 ± 0.18a 103.98 ± 2.46e -1.78 ± 0.07fg P3H1T1 11.80 ± 0.38bc 7.07 ± 0.13d 0.83 ± 0.08b 1.93 ± 0.07bc 7.65 ± 0.20c 115.02 ± 3.79b -0.62 ± 0.03e P3H2T1 12.17 ± 0.12b 7.93 ± 0.18c 0.79 ± 0.04bc 2.13 ± 0.06b 7.43 ± 0.21d 119.98 ± 3.15c 0.87 ± 0.03cd P3H1T2 12.21 ± 0.21b 8.11 ± 0.24bc 0.78 ± 0.06bc 2.24 ± 0.08ab 7.72 ± 0.19c 119.83 ± 4.01c 1.02 ± 0.05c P3H2T2 13.12 ± 0.28a 8.83 ± 0.22a 0.67 ± 0.08d 2.45 ± 0.18a 7.20 ± 0.12e 126.67 ± 2.76a 2.33 ± 0.14a ANOVA P *(P = 0.02) NS(P = 0.25) *(P = 0.04) *(P = 0.02) NS(P = 0.30) **(P = 0.00) **(P = 0.00) H **(P = 0.00) *(P = 0.03) *(P = 0.02) NS(P = 0.41) *(P = 0.02) *(P = 0.04) **(P = 0.00) T NS(P = 0.14) NS(P = 0.21) NS(P = 0.32) NS(P = 0.26) *(P = 0.03) *(P = 0.02) *(P = 0.04) P×H *(P = 0.03) NS(P = 0.25) NS(P = 0.15) *(P = 0.02) *(P = 0.02) *(P = 0.04) NS(P = 0.43) P×T NS(P = 0.21) *(P = 0.03) *(P = 0.02) NS(P = 0.41) NS(P = 0.54) NS(P = 0.12) NS(P = 0.32) H×T *(P = 0.04) *(P = 0.03) NS(P = 0.32) NS(P = 0.26) NS(P = 0.13) *(P = 0.02) *(P = 0.04) P×H×T *(P = 0.04) NS(P = 0.25) *(P = 0.04) NS(P = 0.52) NS(P = 0.36) NS(P = 0.61) NS(P = 0.70) Table 4 Effects of the drip irrigation interval, FA application rate, and application timing on fruit quality in 2024. Treatment Soluble solids (%) Total sugar (%) Titratable acid content (%) Vitamin C (mg100 g − 1 ) Peel hardness (kg cm − 2 ) Single fruit Weight (g) Overall Score P1CKT1 11.82 ± 0.21c 6.93 ± 0.16d 0.76 ± 0.03cd 1.94 ± 0.03de 7.64 ± 0.12cd 112.62 ± 2.63e -1.13 ± 0.16de P1H0T1 10.17 ± 0.12e 6.13 ± 0.18e 1.25 ± 0.03a 1.61 ± 0.03ef 8.26 ± 0.31a 99.23 ± 2.68g -2.63 ± 0.16f P1H1T2 11.72 ± 0.17b 6.53 ± 0.13de 0.86 ± 0.03c 1.92 ± 0.02de 7.49 ± 0.29cd 113.88 ± 1.21de -1.38 ± 0.08de P1H2T1 12.02 ± 0.24c 6.96 ± 0.21d 0.81 ± 0.05c 1.98 ± 0.04d 7.74 ± 0.17cd 116.25 ± 3.01d 0.62 ± 0.07bc P1H2T2 12.78 ± 0.16bc 7.62 ± 0.11c 0.78 ± 0.06cd 2.04 ± 0.02d 7.82 ± 0.21c 119.26 ± 2.65cd 1.74 ± 0.06b P2H0T1 11.57 ± 0.21cd 7.04 ± 0.05d 1.06 ± 0.04b 1.80 ± 0.02c 8.06 ± 0.45b 107.21 ± 3.35b -1.85 ± 0.06e P2H1T2 12.67 ± 0.25bc 7.17 ± 0.20cd 0.70 ± 0.04de 2.09 ± 0.05cd 6.77 ± 0.36d 116.98 ± 1.17ab -0.78 ± 0.11d P2H2T1 12.98 ± 0.15b 8.13 ± 0.06bc 0.72 ± 0.07d 2.64 ± 0.06ab 6.40 ± 0.21de 126.79 ± 1.63b 1.87 ± 0.21b P2H2T2 13.63 ± 0.21a 8.87 ± 0.07a 0.63 ± 0.04d 2.72 ± 0.04a 6.46 ± 0.17de 131.55 ± 3.51a 3.12 ± 0.15a P3H0T1 10.75 ± 0.07d 6.67 ± 0.10de 1.18 ± 0.07ab 1.70 ± 0.04e 8.03 ± 0.28b 103.27 ± 2.01f -2.02 ± 0.14e P3H1T2 11.94 ± 0.21c 6.90 ± 0.12d 0.78 ± 0.13cd 1.91 ± 0.05de 7.48 ± 0.21cd 115.55 ± 3.04d -1.14 ± 0.01b P3H2T1 12.39 ± 0.08bc 8.08 ± 0.09bc 0.73 ± 0.04d 2.21 ± 0.06c 7.51 ± 0.20cd 117.68 ± 2.28cd 0.86 ± 0.07bc P3H2T2 12.92 ± 0.09b 8.34 ± 0.09b 0.68 ± 0.03e 2.43 ± 0.03b 6.81 ± 0.25d 122.92 ± 2.32c 2.14 ± 0.15b ANOVA P *(P = 0.04) NS(P = 0.43) *(P = 0.04) NS(P = 0.42) NS(P = 0.13) **(P = 0.00) **(P = 0.00) H *(P = 0.04) *(P = 0.02) *(P = 0.02) NS(P = 0.52) NS(P = 0.14) *(P = 0.02) **(P = 0.00) T NS(P = 0.14) NS(P = 0.21) NS(P = 0.32) NS(P = 0.26) *(P = 0.03) *(P = 0.02) *(P = 0.04) P×H *(P = 0.02) NS(P = 0.41) NS(P = 0.75) *(P = 0.03) NS(P = 0.32) *(P = 0.04) NS(P = 0.27) P×T NS(P = 0.34) NS(P = 0.43) NS(P = 0.52) NS(P = 0.61) NS(P = 0.34) NS(P = 0.25) NS(P = 0.14) H×T NS(P = 0.74) NS(P = 0.64) NS(P = 0.42) NS(P = 0.53) NS(P = 0.23) NS(P = 0.47) NS(P = 0.74) P×H×T *(P = 0.04) NS(P = 0.45) *(P = 0.03) NS(P = 0.62) *(P = 0.02) NS(P = 0.74) NS(P = 0.41) The rate of FA application significantly affected the SSC, soluble sugar content, titratable acid, single-fruit weight, and overall quality score in both 2023 and 2024. Compared to H0 and H1, the FA application at the H2 rate increased the SSC by 11.9–21.6% and 5.6–10.4%, the soluble sugar content by 13.2–21.1% and 3.2–14.3%, the single-fruit weight by 13.9–18.4% and 3.7–10.7%, and the overall quality score by 124.2–201.4% and 31.6–79.1%, respectively, whereas the titratable acid decreased by 21.4–36.5% and 7.9–19.6%, respectively. FA application timings significantly influenced peel hardness, single-fruit weight, and overall fruit quality in both 2023 and 2024. Compared to single application (T1), split application (T2) increased single-fruit weight and overall quality score by 4.3–7.5% and 34.7–163.6%, respectively, whereas the peel hardness decreased by 2.9–6.7%. The interactive effect of the drip irrigation interval and the FA application rate had a significant effect on the SSC, vitamin C content, and single-fruit weight in 2023 and 2024 (Tables 3 and 4 ). Under the irrigation interval of P1, compared with H1, the FA application at the H2 rate increased the SSC, vitamin C content, and single-fruit weight by 9.3%, 19.2%, and 10.7%, respectively, whereas it reduced titratable acid by 18.6%. Under the irrigation interval of P3, H2 resulted in 3.6%, 9.7%, and 4.5% increases in SSC, vitamin C content, and single-fruit weight, respectively, compared with H1, whereas it reduced titratable acid by 4.7%. These results indicate that increasing the FA application rate can improve fruit quality under shorter drip irrigation intervals. Additionally, the interaction among drip irrigation interval, FA application rate, and application timings significantly affected the SSC and titratable acidity during the two-year experiment. When single application of FA under irrigation intervals of P1 and P3, H2 resulted in a 6.4% and 3.2% increase in soluble solids compared to H1, whereas reducing titratable acid by 7.1% and 4.8%, respectively. In cases where split application of FA under the same irrigation intervals of P1 and P3, H2 led to a 19.3% and 7.6% increase in soluble solids compared to H1, whereas a reduction in titratable acid by 20.7% and 14.2%, respectively. # Table 3 approximately here# # Table 4 approximately here# 3.6 Random forest analysis Random forest analysis revealed that the drip irrigation interval, FA application rate, and their interaction significantly affected soil salinity, with increases in the mean squared error (MSE) of 16.3%, 21.6%, and 9.5%, respectively. These findings indicate that the FA application rate was the dominant factor influencing soil salinity. In addition, the drip irrigation interval, FA application rate, application timings, and interactive effect of the drip irrigation interval and FA application rate, the interactive effect of the FA application rate and application timings, and the three-way interactive effect of drip irrigation interval, FA application rate, and application timings significantly influenced the soil NO 3 − -N content, with increases in the MSE of 10.6%, 17.8%, 8.6%, 8.3%, 6.5% and 5.8%, respectively. Among these factors, the FA application rate was determined to be the most important factor influencing the soil NO 3 − -N content. Furthermore, both the soil salinity and the soil NO 3 − -N content significantly affected the yield of Korla fragrant pear, with soil salinity playing a dominant role (Fig. 7 ), with an increase in the MSE of 12.1%. Moreover, soil salinity had a significant effect on overall fruit quality, with an increase in the MSE of 14.2%. Therefore, the FA application rate primarily influenced the soil salinity and nitrate content, followed by yield and overall quality. # Fig. 7 approximately here# 4. Discussion 4.1 Appropriate drip irrigation intervals increased SWC and reduced soil salinity The drip irrigation interval is a major factor influencing the SWC in the root zone (Fig. 7 ). With increasing drip irrigation interval, the SWC initially increases but then decreases (Li et al., 2024 ). In this study, the SWC at 0–100 cm in P2 was 4.6% and 9.1% greater than that in P1 and P3, respectively. Zhang et al. ( 2019 ) reported that higher soil moisture storage in the 0–60 cm layer under a 6-day irrigation interval than under 3-day and 9-day intervals. This could be attributed to the greater volume of water under longer irrigation intervals, which results in deeper water infiltration (Sharmasarkar et al., 2001 ; Liu et al., 2013 ). Additionally, when the irrigation interval is shorter, the surface soil remains moist more frequently, thereby increasing evaporation losses from the soil surface (Minhas et al., 2020 ; Meshkat et al., 2000 ). Drip irrigation intervals alter the soil water distribution, thereby influencing the transport of the root zone soil salinity (Du et al., 2023 ). In this study, the wetting front under irrigation interval of P3 was located at 80–100 cm depth (Fig. 3 ), which resulted in the highest soil salinity occurring at this depth (Fig. 4 ). In addition, the soil salinity at 0–100 cm depth in P3 was 7.9–16.2% lower than that in P1. However, Chauhdary et al. ( 2020 ) reported that high-frequency drip irrigation is more effective in mitigating soil salinity in the corn root zone than low-frequency irrigation is. This discrepancy is likely because high-frequency irrigation is sufficient to leach salts beyond the root zone in shallow-rooted crops (Du et al., 2019 ), whereas in deep-rooted fruit trees, the wetting front formed by frequent irrigation does not reach below the root zone, limiting salt leaching (Dahiya et al., 1984 ). In this study, we found that the wetting front under irrigation interval of P2 was reached a depth of 60–80 cm (Fig. 3 ), which is shallower than that under P3. However, the soil salinity at 0–100 cm depth under P2 was 4.6–12.9% lower than that under P3. This may be attributed to the fact that longer irrigation intervals reduce matric potential in the topsoil, causing salts from deeper layers to migrate upward into the rot zone (Kourgialas et al., 2021; He et al., 2023 ). 4.2 FA reduced root-zone soil salinity and increased soil nitrate nitrogen content The application rate of FA is a dominant factor influencing soil salinity and the soil NO 3 − -N content in the root zone (Fig. 7 ). The application of FA resulted in a significantly reduction of the soil salinity in the root zone, and this effect increased as the application rate of FA increased from 0 kg ha − 1 to 400 kg ha − 1 (Fig. 4 ). Li et al. ( 2025 ) also reported that soil salt content decreases with higher application rates of humic acid, and the lowest soil salinity was observed at the application rate of 350 kg ha − 1 . In our study, solid organic amendments (CK) primarily reduced the salinity across the 0–40 cm soil depth, whereas FA application at the H2 rate reduced the salinity across the 0–100 cm depth (Fig. 4 ). Moreover, throughout the 0–100 cm soil depth, the soil salinity under H2 was 12.9% lower than that under CK. This may be because solid organic amendments have difficulty migrating with water and reduce soil salinity by promoting the leaching and removal of salts in topsoil (Diacono et al., 2015), whereas FA is highly water-soluble and can move to deeper soil layers. Owing to its large specific surface area and the presence of weakly acidic functional groups, it is capable of effectively adsorbing and exchanging salt cations in saline–alkali soils, resulting in a reduction in soil salinity (Zhao et al., 2025 ; Savarese et al., 2021 ). The application of FA can also increase the soil NO 3 − -N content in the rooting zone, and it increases with increasing application rate of FA (Gümüş et al., 2015). Similar to soil salinity, owing to significant differences in the solubility and moisture migration characteristics of solid organic fertilizers and FA, CK and H2 increased the nitrate nitrogen content in the 0–40 cm and 0–100 cm soil depths, respectively. The soil NO 3 − -N content in the 0–100 cm soil depth under H2 was 8.1% greater than that under CK (Fig. 5 ). Hu et al. ( 2022 ) reported that solid organic fertilizers can provide a large amount of organic nitrogen and increase the nitrate nitrogen content in the surface soil through the mineralization process. In contrast, FA increases the soil nitrate nitrogen content by enhancing soil nitrification and microbial nitrogen fixation processes (Jin et al., 2023 ). Additionally, when FA is applied in multiple applications, it can significantly increase the soil nitrate nitrogen content by 12.6%. This is because FA is continuously lost due to microbial degradation, leading to a reduction in its long-term effectiveness (Ma et al., 2022). The application of FA in combination with nitrogen fertilizer enhances its complexing effect with nitrogen, thereby effectively reducing nitrogen loss (Chen et al., 2020 ). 4.3 The effects of drip irrigation interval, FA application rate, and their interaction on the soil environment, pear yield, and quality Random forest analysis revealed that the interactive effect of the drip irrigation interval and FA application rate produced a significant influence on the SWC, soil salinity, and soil nitrate nitrogen content (P < 0.05) (Fig. 7 ). As the drip irrigation interval increased from 10 days to 15 days, the SWC increased by 4.6% and 12.9%, the soil salinity decreased by 4.8% and 24.6%, and the soil nitrate nitrogen decreased by 8.3% and 16.2% at FA application rates of 200 and 400 kg ha − 1 , respectively. Similarly, Sun et al. ( 2019 ) reported that intermittent irrigation coupled with greater biochar amendment (e.g., 5%) may improve the SWC and reduce the soil salt content. Abd-Allah et al. ( 2025 ) reported that an appropriate drip irrigation interval and hydrogel amendments lead to a significant improvement in the soil nitrate nitrogen content. In addition, the drip irrigation interval and FA application rate produced a significant influence on pear yield and overall quality. Since soil salinity is the primary factor influencing pear yield and overall quality in this study and since the FA application rate is the main factor affecting soil salinity (Fig. 7 ), we infer that the FA application rate is a dominant factor influencing pear yield and overall quality. These results are aligned with those of previous research emphasizing the beneficial role of humic substances on crop productivity and fruit quality in saline soils (Liu et al., 2022 ; Chen et al., 2025 ). The interactive effect of the drip irrigation interval and FA application rate produced a significant effect on pear yield and overall quality (Tables 3 and 4 ). Extending the drip irrigation interval from 10 days to 15 days the pear yield showed an increase of 7.3% and 16.9%, and the overall quality showed an increase of 24.8% and 64.6% for HA application rates of 200 and 400 kg ha − 1 , respectively. These findings indicate that the optimal yield and overall quality of fragrant pears were achieved with a 15-day drip irrigation interval and an organic fertilizer applied at 400 kg ha − 1 . Zoghdan et al. (2019) reported that suitable drip irrigation intervals coupled with a high application rate of organic waste compost significantly increased the yield, SSC, and vitamin C content of orange trees. Abdelraouf et al. ( 2019 ) reported that an moderate drip irrigation interval and a high application rate of organic straw (9 tons ha − 1 ) significantly affect yield, water productivity, soluble solids content, and total sugar content in citrus. This research elucidated the contributions of drip irrigation intervals, FA application rates, and application timings in remediating saline soil environments and promoting the yield and quality of fragrant pear, providing a theoretical foundation for soil improvement and sustainable development in saline orchards. However, in this study, FA was applied as an additional soil conditioner in conjunction with the conventional nitrogen fertilizer application rate, without reducing the nitrogen fertilizer rate. Future research will explore the effects of applying FA under reduced nitrogen conditions on improving pear yield and quality to evaluate the potential of FA in optimizing the nitrogen application rate, mitigating soil salinization, and effectively enhancing crop growth and fruit quality. 5. Conclusion In this research, we conducted a two year field experiment to investigate the effects of the irrigation interval, fulvic acid (FA) application rate, and application timing on soil environment indices, i.e., SWC, soil salinity, and soil nitrate nitrogen content, as well as on the yield and overall quality of fragrant pears in saline pear orchards. The main conclusions are as follows: The drip irrigation interval significantly affected the soil water content and further influenced the distribution of soil salinity. Under the 15-day drip irrigation interval treatment, the root zone soil water content reached its highest level, while the soil salinity in the root zone was reduced to its lowest value. Compared with insoluble organic amendments, the application of FA reduced soil salinity in the deeper soil layers. The soil salinity showed a declining trend with the increasing FA application rates, while the soil nitrate nitrogen content increased with increasing application rate and number of applications. The FA application rate of 400 kg ha − 1 with three split times produced a high soil moisture and low soil salinity environment. (3) FA application rate is the dominant factor influencing the yield and quality of fragrant pear. Appropriately increasing the application rate of FA is a primary strategy for reducing soil salinity and improving the soil environment in salt-affected orchards. The optimization of the drip irrigation interval serves as an important complementary approach to increase overall orchard productivity. (4) Taking into account the soil environment, pear yield, and overall quality, a drip irrigation interval of 15 days, an FA application rate of 400 kg ha − 1 , and three split applications are recommended for saline-affected pear orchards. Declarations CRediT authorship contribution statement Hao Liu: Field experiment, Data analysis and curation, and Writing − original draft. Jun Wang: Funding acquisition, Project administration, Formal analysis, Methodology, Conceptualization, Data analysis, Writing − review and editing, and Internal scientific review. Jiusheng Li: Conceptualization, Internal scientific review, and writing − review and editing. Dezhao Liu: Methodology, Field experiment observation. Long Wang: Methodology, Field experimental observation. Taofeng Luo: Field experiment observation. Chaofan Zhang: Field experiment observation. Declaration of Competing Interest The authors declare that there are no financial or personal relationships that could have inappropriately influenced the research presented in this article. Acknowledgments This project was supported by the National Natural Science Foundation of China (52179055 and 52579056), the Science and Technology Program of Xinjiang Production and Construction Corps (2022DB020), and the Key Research Project of Science and Technology in Inner Mongolia Autonomous Region of China (NMKJXM202301). References Abdelraouf RE, Azab A, Tarabye HHH, Refaie KM (2019) Effect of pulse drip irrigation and organic mulching by rice straw on yield, water productivity and quality of orange under sandy soils conditions. Plant Archives 19(2):2613–2621 Abd-Allah A, Mohamed M, Hegab RH, Elmehy AA (2025) Effect of some soil amendments on nutrients uptake and productivity of cowpea/maize intercropping system under water stress in sandy soil. Egypt J Agron 47(1):95–106 Aragüés R, Medina ET, Martínez-Cob A, Faci J (2014) Effects of deficit irrigation strategies on soil salinization and sodification in a semiarid drip-irrigated peach orchard. Agric Water Manage 142:1–9 Breiman L (2001) Random forests. Mach Learn 45:5–32 Chauhdary JN, Bakhsh A, Ragab R, Khaliq A, Engel BA, Rizwan M, Shahid MA, Nawaz Q (2020) Modeling corn growth and root zone salinity dynamics to improve irrigation and fertigation management under semi-aridconditions. Agric Water Manage 230:105952 Chen H, Ruan Y, Jia Z (2025) A meta-analysis of 30 years in china and micro-district experiments shows organic amendment quantification combined with chemical amendment reduction enhances rice yield on saline-alkali land. Rice Sci 32(2):259–272 Chen Q, Li B, Zhang X, Ge S, Jiang Y (2020) Split application of humic acid significantly improves the yield, quality and nitrogen utilization efficiency of ‘Fuji’apple. J Plant Nutr Fertilizers 26(4):757–764 Chen R, Chang H, Wang Z, Lin H (2023) Determining organic-inorganic amendment application threshold to maximize the yield and quality of drip-irrigated grapes in an extremely arid area of Xinjiang, China. Agric Water Manage 276:108070 Cheng Y, Luo M, Zhang T, Yan S, Wang C, Dong QG, Feng H, Zhang T, Kisekka I (2023) Organic substitution improves soil structure and water and nitrogen status to promote sunflower (Helianthus annuus L.) growth in an arid saline area. Agric Water Manage 283:108320 Dahiya IS, Singh M, Richter J, Singh M (1984) Leaching of soluble salt during infiltration and redistribution. Irrig Sci 5(1):15–24 Dai J, Cui Z, Zhang Y, Zhan L, Nie J, Cui J, Zhang D, Xu S, Sun L, Chen B, Dong H (2024) Enhancing stand establishment and yield formation of cotton with multiple drip irrigation during emergence in saline fields of Southern Xinjiang. Field Crops Res 315:109482 Diacono M, Montemurro F (2015) Effectiveness of organic wastes as amendments and amendments in salt-affected soils. Agriculture 5(2):221–230 Du L, Zheng Z, Li T, Zhang X (2019) Effects of irrigation frequency on transportation and accumulation regularity of greenhouse soil salt during different growth stages of pepper. Sci Hort 256:108568 Du Y, Liu X, Zhang L, Zhou W (2023) Drip irrigation in agricultural saline-alkali land controls soil salinity and improves crop yield: Evidence from a global meta-analysis. Sci Total Environ 880:163226 Feng X, Pu J, Liu H, Wang D, Liu Y, Qiao S, Lei T, Liu R (2023) Effect of fertigation frequency on soil nitrogen distribution and tomato yield under alternate partial root-zone drip irrigation. J Integr Agric 22(3):897–907 Food and Agriculture Organization of the United Nations (2024) Global Status of Salt-Affected Soils. FAO Goenadi DH (2021) Fulvic acid–a small but powerful natural substance for agricultural and medical applications. Menara Perkebunan 89(1):73–90 Gümüş İ, Şeker C (2015) Influence of humic acid applications on soil physicochemical properties. Solid Earth 7:2481–2500 He P, Li J, Yu S, Ma T, Ding J, Zhang F, Chen K, Guo S, Peng S (2023) Soil moisture regulation under mulched drip irrigation influences the soil salt distribution and growth of cotton in Southern Xinjiang. China Plants 12(4):791 Hu Y, Zhan P, Thomas BW, Zhao J, Zhang X, Yan H, Zhang Z, Chen S, Shi X, Zhang Y (2022) Organic carbon and nitrogen accumulation in orchard soil with organic fertilization and cover crop management: A global meta-analysis. Sci Total Environ 852:158402 Huang L, Liu Y, Ferreira JF, Wang M, Na J, Huang J, Liang Z (2022) Long-term combined effects of tillage and rice cultivation with phosphogypsum or farmyard manure on the concentration of salts, minerals, and heavy metals of saline-sodic paddy fields in Northeast China. Soil Tillage Res 215:105222 Jin Y, Zhang X, Yuan Y, Lan Y, Cheng K, Yang F (2023) Synthesis of artificial humic acid-urea complex improves nitrogen utilization. J Environ Manage 344:118377 Kourgialas NN, Dokou Z (2021) Water management and salinity adaptation approaches of Avocado trees: A review for hot-summer Mediterranean climate. Agric Water Manage 252:106923 Lei S, Jia X, Zhao C, Shao M (2025) A review of saline-alkali soil improvements in China: Efforts and their impacts on soil properties. Agric Water Manage 317:109617 Leogrande R, Vitti C (2019) Use of organic amendments to reclaim saline and sodic soils: a review. Arid Land Res Manage 33(1):1–21 Li J, Zhang J, Rao M (2004) Wetting patterns and nitrogen distributions as affected by fertigation strategies from a surface point source. Agric Water Manage 67(2):89–104 Li N, Shi X, Zhang H, Shi F, Zhang H, Liang Q, Hao X, Luo H, Wang J (2024) Optimizing irrigation strategies to improve the soil microenvironment and enhance cotton water productivity under deep drip irrigation. Agric Water Manage 305:109095 Li T, Wang S, Liu S, Zhang X, Dong H, Dai S, Chai L, Li H, Lv Y, Li T, Gao Q, Ma X (2025) Trade-offs of organic amendment input on soil quality and crop productivity in saline-alkali land globally: A meta-analysis. Eur J Agron 164:127471 Liu H, Wang J, Li J (2025) The impact of drip irrigation methods and nitrogen application rates on soil salinity and nitrogen distribution, and fruit quality in arid regions of Northwest China. Agric Water Manage 319:109810 Liu M, Yang J, Li X, Liu G, Yu M, Wang J (2013) Distribution and dynamics of soil water and salt under different drip irrigation regimes in northwest China. Irrig Sci 31:675–688 Liu X, Yang J, Tao J, Yao R (2022) Integrated application of inorganic fertilizer with fulvic acid for improving soil nutrient supply and nutrient use efficiency of winter wheat in a salt-affected soil. Appl Soil Ecol 170:104255 Mankotia S (2024) Impact of humic acid on various properties of soil and crop productivity-A review. J Agric Ecol 18:1–6 Mao X, Yang Y, Guan P, Geng L, Ma L, Di H, Liu W, Li B (2022) Remediation of organic amendments on soil salinization: Focusing on the relationship between soil salts and microbial communities. Ecotoxicol Environ Saf 239:113616 Meshkat M, Warner RC, Workman SR (2000) Evaporation reduction potential in an undisturbed soil irrigated with surface drip and sand tube irrigation. Trans ASAE 43(1):79–86 Minhas PS, Ramos TB, Ben-Gal A, Pereira LS (2020) Coping with salinity in irrigated agriculture: Crop evapotranspiration and water management issues. Agric Water Manage 227:105832 Nie Z, Zhang L, Zhang T, Guo L, Zhou J, An F, Ma H, Wang Z, Yang F (2025) Effects of lignite humic acid and lignite humic acid-based combined amendment on soil quality in saline-sodic farmlands in the west liaohe plain, china. Chin Geogra Sci 35(2):401–414 Rodrigues MÂ, Ladeira LC, Arrobas M (2018) Azotobacter-enriched organic manures to increase nitrogen fixation and crop productivity. Eur J Agron 93:88–94 Savarese C, Drosos M, Spaccini R, Cozzolino V, Piccolo A (2021) Molecular characterization of soil organic matter and its extractable humic fraction from long-term field experiments under different cropping systems. Geoderma 383:114700 Sharmasarkar FC, Sharmasarkar S, Miller SD, Vance GF, Zhang R (2001) Assessment of drip and flood irrigation on water and fertilizer use efficiencies for sugarbeets. Agric Water Manage 46(3):241–251 Sun J, Yang R, Zhu J, Pan Y, Yang M, Zhang Z (2019) Can the increase of irrigation frequency improve the rate of water and salt migration in biochar-amended saline soil? J Soils Sediments 19(12):4021–4030 Sytar O, Brestic M, Zivcak M, Olsovska K, Kovar M, Shao H, He X (2017) Applying hyperspectral imaging to explore natural plant diversity towards improving salt stress tolerance. Sci Total Environ 578:90–99 Tang K, Qin M, Han B, Shao D, Xu Z, Sun H, Wu Y (2024) Identifying the influencing factors of soil nitrous acid emissions using random forest model. Atmos Environ 339:120875 Thomas CL, Acquah GE, Whitmore AP, McGrath SP, Haefele SM (2019) The effect of different organic fertilizers on yield and soil and crop nutrient concentrations. Agronomy 9(12):776 Wang X, Li Y, Wang H, Wang Y, Biswas A, Chau HW, Liang J, Zhang F, Bai Y, Wu S, Chen J, Liu H, Yang G, Pulatov A (2022) Targeted biochar application alters physical, chemical, hydrological and thermal properties of salt-affected soils under cotton-sugarbeet intercropping. CATENA 216:106414 Wang Y, Gao M, Chen H, Chen Y, Wang L, Wang R (2023) Organic amendments promote saline-alkali soil desalinization and enhance maize growth. Front Plant Sci 14:1177209 Wei Q, Xu J, Liu Y, Wang D, Chen S, Qian W, He M, Chen P, Zhou X, Qi Z (2024) Nitrogen losses from soil as affected by water and amendment management under drip irrigation: Development, hotspots and future perspectives. Agric Water Manage 296:108791 Xiao C, Ji Q, Zhang F, Li Y, Fan J, Hou X, Yan F, Liu X, Gong K (2023) Effects of various soil water potential thresholds for drip irrigation on soil salinity, seed cotton yield and water productivity of cotton in northwest China. Agric Water Manage 279:108172 Xiao C, Zhang F, Li Y, Fan J, Xu X, Liu X (2024) Optimal drip irrigation leaching amount and times enhance seed cotton yield and its stability by improving soil chemical environment and source-sink relationship. Field Crops Res 317:109531 Yao Z, Yan G, Wang R, Zheng X, Liu C, Butterbach-Bahl K (2019) Drip irrigation or reduced N-amendment rate can mitigate the high annual N 2 O + NO fluxes from Chinese intensive greenhouse vegetable systems. Atmos Environ 212:183–193 Yin R, Gu X, Cheng Z, Li W, Wang Y, Zhao T, Cai W, Du Y, Cai H (2024) Optimizing nitrogen application patterns and amounts to improve maize yield and water-nitrogen use efficiencies in the Loess Plateau of China: A meta-analysis. Field Crops Res 318:109599 Zhang G, Shen D, Ming B, Xie R, Jin X, Liu C, Hou P, Xue J, Chen J, Zhang W, Liu W, Wang K, Li S (2019) Using irrigation intervals to optimize water-use efficiency and maize yield in Xinjiang, northwest China. Crop J 7(3):322–334 Zhang L, Zeng S, Ma J, Liang F, Wang G (2014) The effect of irrigation frequency on soil water and salt distribution and yield of rice under subsurface drip irrigation. Northwest Agricultural J 23(03):74–79 Zhang Y, Liu H, Gong P, He X, Wang J, Wang Z, Zhang J (2022) Irrigation method and volume for korla fragrant pear: Impact on soil water and salinity, yield, and fruit quality. Agronomy. 12 (8), 1980 Zhao W, Wang S, Tang L, Xiao J, Chen G (2025) Combined application of humic acid and attapulgite improves physical structure and nutrients in coastal saline-alkali soils. Land Degrad Dev 36:4415–4424 Zhang Z, Yang P, Zheng W, Liu Y, Guo M, Yang F (2019) Effects of drip irrigation frequency on emitter clogging using saline water for processing tomato production. Irrig Sci 68(3):464–475 Zoghdan MG, Abo El-Enien MMS (2019) Irrigation regime and soil conditioners impact on characteristics of sandy soil and Washington Navel orange trees. J Soil Sci Agricultural Eng 10(4):233–243 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8199859","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":554257162,"identity":"47e69efc-a8e0-438a-86d3-87d738571061","order_by":0,"name":"Hao Liu","email":"","orcid":"","institution":"China Institute of Water Resources and Hydropower Research","correspondingAuthor":false,"prefix":"","firstName":"Hao","middleName":"","lastName":"Liu","suffix":""},{"id":554257163,"identity":"471be215-c465-4ee7-b3a2-0b443d9f34da","order_by":1,"name":"Jun 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2","display":"","copyAsset":false,"role":"figure","size":1942349,"visible":true,"origin":"","legend":"\u003cp\u003eMeteorological data of the experimental site.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8199859/v1/12153498fc2a9c09e87d9e90.png"},{"id":97370789,"identity":"3f56ac61-af30-463e-8bf3-f03b65c1ab80","added_by":"auto","created_at":"2025-12-03 16:27:55","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":661072,"visible":true,"origin":"","legend":"\u003cp\u003eSoil water content in different soil depths during different growth stages in 2023 and 2024.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8199859/v1/1773c12690a880934f2313ad.png"},{"id":97370735,"identity":"839ea2b0-f7a8-4595-b8fe-db73119ad417","added_by":"auto","created_at":"2025-12-03 16:27:50","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":771033,"visible":true,"origin":"","legend":"\u003cp\u003eSoil salinity at different soil depths during different growth stages in 2023 and 2024.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8199859/v1/54db6cccb5c493f46b0dffee.png"},{"id":97369807,"identity":"d49f83a0-1b3f-4185-a9ed-1e999b8a7cc0","added_by":"auto","created_at":"2025-12-03 16:25:50","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":910190,"visible":true,"origin":"","legend":"\u003cp\u003eSoil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003e-N content at different soil depths during different growth stages in 2023 and 2024.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8199859/v1/9c462251eedb75472596427a.png"},{"id":97369983,"identity":"01097791-c6c9-4c72-be75-918bbc81b0b4","added_by":"auto","created_at":"2025-12-03 16:26:18","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":333920,"visible":true,"origin":"","legend":"\u003cp\u003eFragrant pear yield under different treatments in 2023 and 2024.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8199859/v1/69ac3b2c9866d308b8668cae.png"},{"id":97370882,"identity":"cb8d04af-deec-4d2f-ba8b-ed7703ae2524","added_by":"auto","created_at":"2025-12-03 16:28:06","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":498531,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Increase in MSE (%) indicating the impact of the three experimental factors on fruit yield and quality; (b) Increase in MSE (%) showing the contribution of the factors and their interactions to the soil water content; (c) Increase in MSE (%) showing the contribution of the factors and their interactions to the soil salinity; (d) Increase in MSE (%) showing the contribution of the factors and their interactions to the soil nitrate nitrogen content.\u003c/p\u003e\n\u003cp\u003eNote: * indicates that it is significant at the 0.05 level; ** indicates that it is significant at the 0.01 level.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8199859/v1/2a1428a9a1535493e8e9f2ca.png"},{"id":104587503,"identity":"abdcabcb-c7a5-4e10-84ad-220dcf7bb8a3","added_by":"auto","created_at":"2026-03-13 16:10:50","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":9016661,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8199859/v1/b9332105-7af6-48ca-9091-f764a830cc64.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Drip irrigated with fulvic acid improves soil environment and enhances fruit yield and quality of fragrant pear planted in saline-alkali land","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eWorldwide, a significant portion of croplands suffer from soil salinization (Sytar et al. \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). By 2024, the total area of saline soils expanded to an alarming 1.381\u0026nbsp;billion hectares, approximately 10.7% of the Earth\u0026rsquo;s land surface (FAO, 2024). The climate in the Xinjiang region of China is characterized by low rainfall and high evaporation, which exacerbates the problem of soil salinization (Wang et al., \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The Korla fragrant pear is a distinctive fruit of the region and a key pillar industry in its main production area, Korla City. Recently, labor-saving intensive planting has been adopted as an novel cultivation approach for fragrant pear in Xinjiang province. However, most orchards are affected by severe soil salinity, with the salt concentration in the surface soil approaching 9 g kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, posing a direct threat to the sustainable development of fragrant pear trees (Zhang et al., \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn modern arid-region agricultural systems, drip irrigation has become an indispensable component (Yao et al., \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), as it maintains adequate rooting zone moisture and continuously leaches salts downward, reducing the rooting zone salinity levels (Du et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). In saline soils, the drip irrigation interval is a key technical parameter that regulates the range of water and salt migration, directly affecting the soil desalination efficiency and the root zone environment (Zhang et al., \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Under the same irrigation quota, low-frequency irrigation, owing to its larger single irrigation volume, promotes the downward movement of salinity-related ions into lower soil horizons (Xiao et al., \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) and results in considerable nitrogen leaching (Wei et al., \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Feng et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). However, high-frequency drip irrigation can create a continuously moist zone, promoting the downward movement of salts and preventing their build-up at the surface due to capillary action (Liu et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Moreover, previous studies have shown that high-frequency irrigation effectively reduces salt accumulation in the root zones of annual crops (Zhang et al., \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Xiao et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Dai et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) and thus improves yield and quality (Liu et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). However, for fruit trees with deeper root systems, lower single irrigation volumes may not be sufficient to effectively leach salts from the root zone (Arag\u0026uuml;\u0026eacute;s et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). Furthermore, appropriate irrigation intervals for shallow-rooted crops under saline conditions have been well studied, while limited research has explored suitable drip irrigation frequencies for deep-rooted crops such as fruit trees, especially regarding the labor-saving cultivation fragrant pear orchards, which remains a clear knowledge gap.\u003c/p\u003e\u003cp\u003eOrganic amendments (i.e., manure, lignite bioorganic, biochar, and fulvic acid) have been proposed and documented to improve the soil environment of saline-alkaline land (Mao et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Li et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2025\u003c/span\u003e; Leogrande et al., 2019). Organic amendments can improve soil structure, facilitate the downward movement of salts, and suppress salinization in surface soils (Lei et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2025\u003c/span\u003e; Nie et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). Cheng et al. (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) reported that the organic fertilizers applying significantly increased surface soil porosity and decreased both soil electrical conductivity and the sodium adsorption ratio. In addition, organic amendment application reduces nitrogen leaching and increases total soil nitrogen levels (Rodrigues et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Chen et al. (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2025\u003c/span\u003e) reported that organic amendments significantly increased the soil nitrate nitrogen, phosphorus, and potassium contents, particularly in the surface soil layer. This soil improvement approach can ameliorate the soil environment, there by increasing both the yield and quality of crops in saline soils and promoting sustainable agricultural production (Wang et al., \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Chen et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). However, the ameliorative effects of farmyard manure and other conventional organic amendments diminish with increasing soil depth (Huang et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), limiting their effectiveness in reducing salinity in the root zones of deep-rooted crops.\u003c/p\u003e\u003cp\u003eFulvic acid (FA), an organic amendment extracted from materials such as lignite or agricultural waste (Goenadi et al., 2021), has excellent water solubility (Mankotia et al., 2024), enabling its delivery to deeper soil layers through drip irrigation systems. Owing to the ability of FA to adsorb salt ions, it has been confirmed to have the potential to reduce soil salinity (Li et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). However, the improvement effect of FA on the soil environment in different soil layers of deep-rooted crops has not been sufficiently studied. Additionally, previous research has indicated that split-dose of chemical fertilizers are more beneficial for enhancing nutrient use efficiency (Yin et al., \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Due to their low solubility and slow nutrient release, organic amendments are typically applied as basal fertilizers in a single application (Thomas et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). In contrast to insoluble organic amendments, FA has high water solubility, which facilitates multiple applications during the crop growing season through drip irrigation systems. However, the interaction effect between the rate and timing of FA applications and drip-irrigation intervals on the soil environment have not been well studied.\u003c/p\u003e\u003cp\u003eIn order to bridge the identified research gaps, the objectives of the present study were to (1) evaluate the effects of different drip irrigation intervals, FA application rates, and application timings on soil environment indices, i.e., SWC, soil salinity, and soil nitrate nitrogen content, as well as on the yield and overall quality of fragrant pears; (2) identify the dominant factors affecting the soil environment under varying drip-irrigation intervals and FA application practices; and (3) recommend appropriate drip irrigation intervals, FA application rates, and application timings for Korla fragrant pears in southern Xinjiang.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Experimental site\u003c/h2\u003e\u003cp\u003eField experiments were performed between May and September during the 2023 and 2024 growing seasons in a seven-year-old fragrant pear orchard located in Korla City, Xinjiang, China (41\u0026deg;79\u0026prime; N, 85\u0026deg;88\u0026prime; E) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), with a planting pattern of 1 m \u0026times; 4 m. The experimental area has aclimatic aridity, characterized by an average annual temperature of 11.4\u0026deg;C, average annual precipitation of 58.6 mm, and evaporation of 2800 mm.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eMeteorological data were continuously recorded via a Tianqi Intelligent Ecological Station (INSENTEK, China) installed at the experimental site. Meteorological information for the two growing seasons is illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The experimental field had a sandy loam soil texture, with an mean bulk density of 1.57 g cm\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e within the 0\u0026ndash;100 cm depth. The initial contents of salt, organic matter, total nitrogen, and nitrate nitrogen for the 0\u0026ndash;100 cm depth were 7.7 g kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e,15.0 g kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 0.6 g kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, and 13.5 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively. The physical properties of the soil are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The groundwater table depth was greater than 5 m. Irrigation water was pumped from a well over 70 meters deep, with a salinity of 0.21 dS m\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eSoil physical properties at the experimental site.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"10\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eDepth\u003c/p\u003e\u003cp\u003e(cm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eSoil texture\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e\u003cp\u003eSoil textural composition (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eBulk density\u003c/p\u003e\u003cp\u003e(g cm\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eSaturated water\u003c/p\u003e\u003cp\u003eContent (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eField capacity\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eTDS\u003c/p\u003e\u003cp\u003e(g kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003epH\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eClay\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSilt\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eSand\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0\u0026ndash;20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003esilty loam\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e8.36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e75.91\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e15.73\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e1.58\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e27.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e18.53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e7.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e7.73\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e20\u0026ndash;40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003esilty loam\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e9.94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e78.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e11.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e1.52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e26.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e19.61\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e9.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e7.45\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e40\u0026ndash;60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003esilty loam\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e12.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e78.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e9.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e1.59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e28.31\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e19.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e9.91\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e7.34\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e60\u0026ndash;80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003esilty loam\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e6.88\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e66.51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e26.61\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e1.43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e29.06\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e20.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e5.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e7.24\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e80\u0026ndash;100\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003esilty loam\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e6.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e60.12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e33.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e1.38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e30.61\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e21.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e6.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e7.36\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eFig. \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eFig. \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eTable \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Experimental treatments\u003c/h2\u003e\u003cp\u003eThe treatments included three irrigation intervals: 10 (P1), 15 (P2) and 20 days (P3), three FA application rates: 0 (H0), 200 (H1) and 400 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (H2), and two FA application timings: once (T1), three times (T2). Additionally, a solid organic amendment with low water solubility was used as a control treatment (CK). The experimental treatments are detailed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The application rate of the insoluble solid organic amendments (560 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) was calibrated to match the application rate (400 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) of FA on the equivalent organic carbon content. Three replicates per treatment were arranged using a blocking design with random assignment. The area of each experimental unit was 80 m\u003csup\u003e2\u003c/sup\u003e, and each was equipped with an independent water meter and valve.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eExperimental treatments in 2023 and 2024.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDrip irrigation interval (d)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRate of FA application (kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNumber of FA applications\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2023\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2024\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003e10(P1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0(H0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eone time(T1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP1H0T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP1H0T1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e200(H1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP1H1T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e400(H2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP1H2T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP1H2T1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0(H0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003ethree times(T2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e200(H1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP1H1T2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP1H1T2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e400(H2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP1H2T2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP1H2T2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003e15(P2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0(H0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eone time(T1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP2H0T1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e200(H1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e400(H2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP2H2T1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0(H0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003ethree times(T2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e200(H1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP2H1T2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e400(H2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP2H2T2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"5\" rowspan=\"6\"\u003e\u003cp\u003e20(P3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0(H0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eone time(T1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP3H0T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP3H0T1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e200(H1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP3H1T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e400(H2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP3H2T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP3H2T1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0(H0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003ethree times(T2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026mdash;\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e200(H1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP3H1T2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP3H1T2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e400(H2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP3H2T2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP3H2T2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10(P1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e400(CK)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eone time(T1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP1CKT1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP1CKT1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eTable \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe organic amendment was potassium fulvate derived from mineral sources provided by Xinjiang Shuanglong Humic Acid Co., Ltd., with the following composition: K\u003csub\u003e2\u003c/sub\u003eO\u0026thinsp;\u0026ge;\u0026thinsp;12.0%, humic acid\u0026thinsp;\u0026ge;\u0026thinsp;55%, and fulvic acid\u0026thinsp;\u0026ge;\u0026thinsp;50%. The insoluble solid organic amendment was a biochemically treated lignite product provided by Apaxfon Bioscience and Technologies Ltd., CO, Baotou, Inner Mongolia, China. For the CK treatment and the single application of FA, the organic amendment was applied together with chemical fertilizer during the fruit-set stage. For the split application of FA, it was applied through drip irrigation during three stages of fragrant pear, on May 10, July 8, and August 2, following a ratio of 2:4:4. The application rates of N, P, and K fertilizers were determined based on the study by Liu et al (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2025\u003c/span\u003e) as 300, 200, and 150 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively. These fertilizers were also applied at three growth stages at a ratio of 2:4:4 together with the organic amendment. Fertigation was conducted following the \u0026ldquo;1/4 W-1/2 N-1/4 W\u0026rdquo; strategy (Li et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2004\u003c/span\u003e), via a proportional fertilizer injector (Mis Rite Model 2504, Tefen) to ensure uniform application across all plots.\u003c/p\u003e\u003cp\u003eSurface drip irrigation was adopted, with two drip lines per tree row, positioned 40 cm from the tree line on either side. The drip tubes were equipped with an emitter flow rate of 2.4 L h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and spaced at 30 cm intervals. In accordance with the standard Technical Regulation for Micro-irrigation Fertilization of Korla Fragrant Pear (DB65/T 3203\u0026thinsp;\u0026minus;\u0026thinsp;2011), all the treatments were irrigated with a quota of 525 mm. Standard orchard management practices such as pruning, pesticide application, and weeding were consistently implemented throughout all plots.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Sampling and measurements\u003c/h2\u003e\u003cdiv id=\"Sec6\" class=\"Section3\"\u003e\u003ch2\u003e2.3.1 Soil water content\u003c/h2\u003e\u003cp\u003eThe study by Liu et al. (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2025\u003c/span\u003e) showed that the root distribution of 7-year-old Korla fragrant pear trees is primarily located within the 0\u0026ndash;100 cm soil depth. Consequently, this depth range was designated as the root zone for this study. The SWC was measured via a Trime-T3 time-domain reflectometer (IMKO, Germany). Two 1.5-meter-long Trime tubes were installed at 40 cm from a representative pear tree at the center of each plot, one along the row and the other perpendicular to it. Soil water content was conducted weekly during the growing period, with a sampling depth of 100 cm.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section3\"\u003e\u003ch2\u003e2.3.2 Soil salinity and nitrate nitrogen content\u003c/h2\u003e\u003cp\u003eSoil samples were collected from depths of 0\u0026ndash;20, 20\u0026ndash;40, 40\u0026ndash;60, 60\u0026ndash;80, and 80\u0026ndash;100 cm to measure the concentrations of soil salts and nitrates. Soil samples were collected one day before and one day after fertilization in each plot. For each row of pear trees, sampling was performed at points located 40 cm from the tree trunk, both along and perpendicular to the tree row direction. The soil samples were naturally dried in a shaded cool place, sieved through a 2 mm sieve, and then used to measure the nitrate nitrogen content. This process involved extraction with KCl solution, followed by analysis using an Autoanalyzer (AA500, Bran\u0026thinsp;+\u0026thinsp;Luebbe, Germany). Additionally, the electrical conductivity (EC\u003csub\u003e1:5\u003c/sub\u003e) of the soil extract was determined using a portable conductivity meter (F3-Standard, Mettler Toledo, Switzerland). The extract was prepared by mixing soil with water at a 1:5 ratio, followed by shaking, settling, and filtering. Finally, the correlation between soil salt content and electrical conductivity was ultimately determined using the residue-drying method:\u003c/p\u003e\u003cp\u003eS\u0026thinsp;=\u0026thinsp;4.719 C (N\u0026thinsp;=\u0026thinsp;55, R\u0026sup2;=0.993) (1)\u003c/p\u003e\u003cp\u003ewhere S represents the soil salinity (g kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e), and C represents the EC\u003csub\u003e1:5\u003c/sub\u003e (dS m\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) of the soil.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section3\"\u003e\u003ch2\u003e2.3.3 Yield and fruit quality\u003c/h2\u003e\u003cp\u003eDuring the mature stage of the fragrant pear, three vigorously growing pear trees were chosen per treatment to measure yield. Fruits from each selected tree were entirely harvested and weighed, and the individual tree fruit counts were accurately recorded. The yield per tree was then calculated by multiplying the average fruit weight by the fruit count. In addition, 15 representative fruit samples were collected from different directions of the trees in each treatment to assess fruit quality. The measurement of soluble solids content was conducted with a digital refractometer (Delixi, China), and the soluble sugar content was determined using the anthrone colorimetric assay with concentrated sulfuric acid. The vitamin C content was measured via 2,6-dichlorophenol titration. The titratable acidity was measured by titration with NaOH, and pear firmness was determined through a firmness meter (Topyunong Technology, China). An overall score of the qualities was subsequently calculated based on principal component analysis (PCA) (Liu et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2025\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Statistical analysis\u003c/h2\u003e\u003cp\u003eThe statistical analysis comprised of analysis of variance (ANOVA) along with significance testing, were carried out using R4.4.1 (R Foundation for Statistical Computing, Vienna, Austria). We performed ANOVA using the stats package, and the least significant difference (LSD) was applied for post-hoc comparison via the agricolae package, with a significance threshold of P\u0026thinsp;\u0026lt;\u0026thinsp;0.05. Three-way ANOVA was applied using the aov function from the stats package to assess the impact of the irrigation interval, FA application rate, and application timings on fruit yield and quality, at significance set at P\u0026thinsp;=\u0026thinsp;0.05 and 0.01.\u003c/p\u003e\u003cp\u003eRandom forest is a robust machine learning technique that is extensively applied in both classification and regression problems (Breiman et al., 2001). In random forests, the importance of each feature to model performance is quantified by computing the mean decrease in impurity across all trees attributable to that feature. A higher value indicates a greater contribution of the feature to the prediction results (Tang et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). In this study, feature importance analysis was used to identify the key soil environmental factors driving fragrant pear yield and quality, and to further clarify how the experimental factors influence these soil variables. Random forest analysis was performed with the rfPermute package in R4.4.1.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Changes in soil water content at different soil depths\u003c/h2\u003e\u003cp\u003eThe soil water content (SWC) at different soil depths from 0\u0026ndash;100 cm during various growth stages in 2023 and 2024 is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The average SWC at each of the soil depths was in the range of 0.19\u0026ndash;0.31cm\u003csup\u003e3\u003c/sup\u003e cm\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e, and the SWC of the root zone under each treatment increased initially but then decreased with increasing soil depth during each growing stage. Both the irrigation interval and FA application influenced the SWC at the 0\u0026ndash;100 cm soil depth.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eDuring the fruit expansion stage in the two-year experiment, the SWC under the 10-day irrigation interval (P1) reached its maximum in the 40\u0026ndash;60 cm soil depth, whereas SWC under the 15-day and 20-day intervals (P2 and P3) peaked in the 60\u0026ndash;80 cm soil depth. In 2023, the root zone SWC under P1 was 4.7\u0026ndash;11.6% greater than that under P3, with significant differences noted throughout the fruit expansion stage. In 2024, the root zone SWC under P2 was 3.4\u0026ndash;6.9% and 9.6\u0026ndash;16.5% greater than that under P1 and P3, respectively, with a significantly higher SWC compared to P3 throughout the fruit expansion stage.\u003c/p\u003e\u003cp\u003eDuring each growth stage of 2023 and 2024, the SWC under the FA application rates of 200 and 400 kg ha⁻\u003csup\u003e1\u003c/sup\u003e (H1 and H2) was greater than that in the FA application rates of 0 kg ha⁻\u003csup\u003e1\u003c/sup\u003e (H0) across all depths, and the SWC generally increased in response to rising application rates of FA. In addition, the SWC at each soil depth under the solid organic amendment (CK) treatment was lower than that under H2. Moreover, the application of FA significantly affected the root zone SWC during both the fruit set and fruit expansion stages in 2023 and 2024 (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01). During these stages, the root zone SWC in H1 and H2 was 5.7\u0026ndash;10.6% and 9.4\u0026ndash;14.7% greater than that in H0, respectively. The root zone SWC in CK was 8.5% lower than that in H2.\u003c/p\u003e\u003cp\u003eDuring the whole growth stage of fragrant pear, root zone SWC did not differ significantly between single and split applications of FA (T1 and T2). Whereas, it should be pointed out that the SWC in T1 was 3.8\u0026ndash;5.2% greater and 8.7\u0026ndash;11.3% lower than that in T2 during the fruit set and expansion stage, respectively.\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eFig. \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Changes in soil salinity at different soil depths\u003c/h2\u003e\u003cp\u003eThe distributions of soil salinity across soil depths and growth stages in 2023 and 2024 are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The root zone soil salinity ranged from 5.0 to 11.0 g kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe drip irrigation interval affects the salt distribution by influencing soil water movement. As the irrigation interval increases, the soil salt peak gradually moves to greater soil depths. Additionally, the soil salinity in P1 increased with increasing soil depth, whereas in P2 and P3, the soil salinity first decreased but then increased with increasing depth (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The drip irrigation interval significantly impacted the root zone average soil salinity (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). During the fruit expansion stages in 2023 and 2024, the root zone soil salinity in P3 was significantly (4.6\u0026ndash;8.3%) lower than that in P1. In the fruit expansion stages of 2024, the root zone soil salinity in P2 was significantly reduced by 7.5\u0026ndash;11.7% and 3.8\u0026ndash;9.6% compared to P1 and P3, respectively.\u003c/p\u003e\u003cp\u003eDuring the two-year field experiment, the root zone soil salinity at all soil depths in H1 and H2 was lower than that in H0, and the salinity generally decreased with increasing rates of FA. The FA application at the H2 rate primarily reduced the soil salinity at the 0\u0026ndash;80 cm soil depth. In contrast to CK, which increased the soil salinity at the 40\u0026ndash;100 cm soil depth. Furthermore, the application of FA significantly impacted the root zone average soil salinity at different growth stages during both years of the experiment (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The soil salinities in H1 and H2 were 7.6\u0026ndash;13.8% and 12.7\u0026ndash;23.5% lower than those in H0, respectively. In addition, the soil salinity in H2 was 6.9% lower than that in CK.\u003c/p\u003e\u003cp\u003eThe root zone soil salinity did not differ significantly between FA application timings of T1 and T2 throughout the entire growth stage of fragrant pear. Whereas, the FA application timings had varying effects on the soil salinity at different growth stages. During the fruit set stage, the soil salinity in T1 was 4.1\u0026ndash;7.5% lower than that in T2. During the fruit expansion stages, the salinity in T2 remained 4.7\u0026ndash;9.2% lower than that in T1.\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eFig. \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Changes in the soil nitrate nitrogen content at different soil depths\u003c/h2\u003e\u003cp\u003eThe soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N contents across soil depths and growth stages in 2023 and 2024 are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. The root zone soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content ranged from 1.2 to 46.0 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. During each growth stage in 2023 and 2024, the soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content generally tended to decline as soil depth increased.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe drip irrigation interval affects the soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content at all depths of the root zone by influencing the soil water and salt transport (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content under P1 and P2 was mainly concentrated in the 0\u0026ndash;60 cm soil depth, whereas under P3, it extended to the 0\u0026ndash;80 cm throughout the fruit set stage. This nitrate was then transported downward to the 0\u0026ndash;80 cm soil depth throughout the fruit expansion stage. The drip irrigation interval significantly impacted the root zone average soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). In 2023, the root zone NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content under P1 was 3.7\u0026ndash;11.2% greater than that under P3, with significant differences noted throughout the fruit expansion stage. In 2024, the root zone soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N contents under P2 were 2.8\u0026ndash;8.9% and 7.8\u0026ndash;16.8% greater than those under P1 and P3, respectively.\u003c/p\u003e\u003cp\u003eIn 2023 and 2024, the soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content at all depths followed the order: H0\u0026thinsp;\u0026lt;\u0026thinsp;H1\u0026thinsp;\u0026lt;\u0026thinsp;H2. Compared with the FA application at the H2 rate, CK reduced the NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content in the 0\u0026ndash;60 cm depth, whereas increasing it in the 60\u0026ndash;100 cm depth. Furthermore, FA application significantly impacted the root zone NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content during the fruit expansion stage (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01). During this stage, the root zone NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N contents in H1 and H2 were 8.3\u0026ndash;12.4% and 11.6\u0026ndash;35.1% greater than those in H0, respectively. Under single application, the NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content in H2 treatments was 9.2% greater than that in CK.\u003c/p\u003e\u003cp\u003eFA application timings produced a significant effect on the root zone NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content in 2023 and 2024 (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content under T1 was significantly (11.3\u0026ndash;17.2%) higher than that under T2 throughout the fruit set stage. However, the soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content under T2 was significantly (3.1\u0026ndash;15.8%) higher than that under T1 throughout the fruit expansion and mature stages.\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eFig. \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Fragrant pear yield under different treatments\u003c/h2\u003e\u003cp\u003eThe pear yields under different treatments in 2023 and 2024 are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. The highest yields were observed under the P3H2T2 and P2H2T2 treatments, reaching 36.3 t ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 39.2 t ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in 2023 and 2024, respectively, whereas the lowest yields in both years were recorded under the P1H0T1 treatment, at 28.7 t ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 31.5 t ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe drip irrigation interval significantly influenced pear yield in both 2023 and 2024 (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). In 2023, the yield under P3 was 1.7\u0026ndash;8.5% greater than that under P1. In 2024, P2 produced the highest yield, which was 5.2\u0026ndash;7.5% and 1.7\u0026ndash;4.8% greater than those under P1 and P3, respectively. The rate of FA application significantly affected pear yield in both 2023 and 2024 (P\u0026thinsp;\u0026lt;\u0026thinsp;0.01). The yield under H2 was 10.7\u0026ndash;19.5% and 4.1\u0026ndash;12.1% greater than that under H0 and H1, respectively. Under the irrigation interval of P1, the yields under H2 were 11.3% and 5.7% greater than those under CK in 2023 and 2024, respectively. FA application timings also significantly influenced pear yield in 2024 (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The split application of FA increased the yield by 3.2\u0026ndash;6.3%.\u003c/p\u003e\u003cp\u003eThe interactive effect of the drip irrigation interval and the FA application rate had a significant effect on pear yield (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Under the split application of FA, the yield under H2 was 9.3% greater than that in H1 under the irrigation interval of P1, whereas the yield was nearly the same between H2 and H1 under the irrigation interval of P3. These results indicate that increasing the FA rate is more effective in enhancing yield under shorter drip irrigation intervals.\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eFig. \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\u003ch2\u003e3.5 Fragrant pear quality under different treatments\u003c/h2\u003e\u003cp\u003ePear fruit quality across different treatments in 2023 and 2024 is presented in Tables\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The drip irrigation interval had a significant effect on the soluble solids content (SSC), titratable acid, single-fruit weight, and overall quality score in 2023 and 2024. In 2023, P3 increased the SSC, single-fruit weight, and overall quality score by 4.1\u0026ndash;10.4%, 3.7\u0026ndash;5.2%, and 30.7\u0026ndash;339.7%, respectively, relative to P1, whereas the titratable acid decreased by 4.8\u0026ndash;14.1%. In 2024, P2 increased the SSC by 6.9\u0026ndash;9.1% and 3.2\u0026ndash;6.1%, the single-fruit weight by 1.8\u0026ndash;5.3% and 1.2\u0026ndash;3.8%, and the overall quality score by 29.7\u0026ndash;201.6% and 83.6\u0026ndash;162.8%, respectively, compared with those of P1 and P3, whereas the titratable acid decreased by 4.7\u0026ndash;16.1% and 2.6\u0026ndash;10.3%, respectively.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffects of the drip irrigation interval, FA application rate, and application timing on fruit quality in 2023.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTreatment\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSoluble solids\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTotal sugar\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTitratable\u003c/p\u003e\u003cp\u003eacid content\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eVitamin C\u003c/p\u003e\u003cp\u003e(mg 100g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003ePeel hardness\u003c/p\u003e\u003cp\u003e(kg cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eSingle fruit Weight\u003c/p\u003e\u003cp\u003e(g)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eOverall Score\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP1CKT1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11.81\u0026thinsp;\u0026plusmn;\u0026thinsp;0.31bc\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.81\u0026thinsp;\u0026plusmn;\u0026thinsp;0.35de\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.96\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07ab\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.71\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08c\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7.63\u0026thinsp;\u0026plusmn;\u0026thinsp;0.19cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e107.16\u0026thinsp;\u0026plusmn;\u0026thinsp;2.64d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-2.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16fg\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP1H0T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10.04\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.28\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08a\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.53\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e8.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17b\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e100.07\u0026thinsp;\u0026plusmn;\u0026thinsp;5.88f\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-2.57\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02g\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP1H1T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.97\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.84\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13b\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.62\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07c\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7.97\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16b\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" 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colname=\"c8\"\u003e\u003cp\u003e**(P\u0026thinsp;=\u0026thinsp;0.00)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eT\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.14)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.21)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.32)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.26)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.03)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.02)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.04)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP\u0026times;H\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.03)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.15)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.02)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.02)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.04)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.43)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP\u0026times;T\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.21)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.03)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.02)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.41)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.54)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.12)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.32)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eH\u0026times;T\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.04)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.03)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.32)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.26)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.13)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.02)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.04)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP\u0026times;H\u0026times;T\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.04)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.04)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.52)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.36)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.61)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.70)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEffects of the drip irrigation interval, FA application rate, and application timing on fruit quality in 2024.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTreatment\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSoluble solids\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTotal sugar\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTitratable\u003c/p\u003e\u003cp\u003eacid content\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eVitamin C\u003c/p\u003e\u003cp\u003e(mg100 g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003ePeel hardness\u003c/p\u003e\u003cp\u003e(kg cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eSingle fruit Weight\u003c/p\u003e\u003cp\u003e(g)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eOverall Score\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP1CKT1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11.82\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21c\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.76\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.94\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03de\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7.64\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e112.62\u0026thinsp;\u0026plusmn;\u0026thinsp;2.63e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-1.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16de\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP1H0T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10.17\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03a\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03ef\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e8.26\u0026thinsp;\u0026plusmn;\u0026thinsp;0.31a\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e99.23\u0026thinsp;\u0026plusmn;\u0026thinsp;2.68g\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-2.63\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16f\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP1H1T2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11.72\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17b\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.53\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13de\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.86\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03c\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.92\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02de\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7.49\u0026thinsp;\u0026plusmn;\u0026thinsp;0.29cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e113.88\u0026thinsp;\u0026plusmn;\u0026thinsp;1.21de\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-1.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08de\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP1H2T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.24c\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.96\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.81\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05c\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.98\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e116.25\u0026thinsp;\u0026plusmn;\u0026thinsp;3.01d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.62\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07bc\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP1H2T2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12.78\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16bc\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7.62\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11c\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.78\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.04\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7.82\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21c\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e119.26\u0026thinsp;\u0026plusmn;\u0026thinsp;2.65cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06b\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP2H0T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11.57\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7.04\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04b\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02c\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e8.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.45b\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e107.21\u0026thinsp;\u0026plusmn;\u0026thinsp;3.35b\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-1.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP2H1T2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12.67\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25bc\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7.17\u0026thinsp;\u0026plusmn;\u0026thinsp;0.20cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04de\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05cd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.77\u0026thinsp;\u0026plusmn;\u0026thinsp;0.36d\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e116.98\u0026thinsp;\u0026plusmn;\u0026thinsp;1.17ab\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-0.78\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11d\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP2H2T1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12.98\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15b\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" 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colname=\"c8\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.27)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP\u0026times;T\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.34)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.43)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.52)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.61)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.34)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.14)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eH\u0026times;T\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.74)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.64)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.42)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.53)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.23)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.47)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.74)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eP\u0026times;H\u0026times;T\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.04)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.45)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.03)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.62)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e*(P\u0026thinsp;=\u0026thinsp;0.02)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.74)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNS(P\u0026thinsp;=\u0026thinsp;0.41)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe rate of FA application significantly affected the SSC, soluble sugar content, titratable acid, single-fruit weight, and overall quality score in both 2023 and 2024. Compared to H0 and H1, the FA application at the H2 rate increased the SSC by 11.9\u0026ndash;21.6% and 5.6\u0026ndash;10.4%, the soluble sugar content by 13.2\u0026ndash;21.1% and 3.2\u0026ndash;14.3%, the single-fruit weight by 13.9\u0026ndash;18.4% and 3.7\u0026ndash;10.7%, and the overall quality score by 124.2\u0026ndash;201.4% and 31.6\u0026ndash;79.1%, respectively, whereas the titratable acid decreased by 21.4\u0026ndash;36.5% and 7.9\u0026ndash;19.6%, respectively.\u003c/p\u003e\u003cp\u003eFA application timings significantly influenced peel hardness, single-fruit weight, and overall fruit quality in both 2023 and 2024. Compared to single application (T1), split application (T2) increased single-fruit weight and overall quality score by 4.3\u0026ndash;7.5% and 34.7\u0026ndash;163.6%, respectively, whereas the peel hardness decreased by 2.9\u0026ndash;6.7%.\u003c/p\u003e\u003cp\u003eThe interactive effect of the drip irrigation interval and the FA application rate had a significant effect on the SSC, vitamin C content, and single-fruit weight in 2023 and 2024 (Tables\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Under the irrigation interval of P1, compared with H1, the FA application at the H2 rate increased the SSC, vitamin C content, and single-fruit weight by 9.3%, 19.2%, and 10.7%, respectively, whereas it reduced titratable acid by 18.6%. Under the irrigation interval of P3, H2 resulted in 3.6%, 9.7%, and 4.5% increases in SSC, vitamin C content, and single-fruit weight, respectively, compared with H1, whereas it reduced titratable acid by 4.7%. These results indicate that increasing the FA application rate can improve fruit quality under shorter drip irrigation intervals. Additionally, the interaction among drip irrigation interval, FA application rate, and application timings significantly affected the SSC and titratable acidity during the two-year experiment. When single application of FA under irrigation intervals of P1 and P3, H2 resulted in a 6.4% and 3.2% increase in soluble solids compared to H1, whereas reducing titratable acid by 7.1% and 4.8%, respectively. In cases where split application of FA under the same irrigation intervals of P1 and P3, H2 led to a 19.3% and 7.6% increase in soluble solids compared to H1, whereas a reduction in titratable acid by 20.7% and 14.2%, respectively.\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eTable \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eTable \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003e3.6 Random forest analysis\u003c/h2\u003e\u003cp\u003eRandom forest analysis revealed that the drip irrigation interval, FA application rate, and their interaction significantly affected soil salinity, with increases in the mean squared error (MSE) of 16.3%, 21.6%, and 9.5%, respectively. These findings indicate that the FA application rate was the dominant factor influencing soil salinity. In addition, the drip irrigation interval, FA application rate, application timings, and interactive effect of the drip irrigation interval and FA application rate, the interactive effect of the FA application rate and application timings, and the three-way interactive effect of drip irrigation interval, FA application rate, and application timings significantly influenced the soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content, with increases in the MSE of 10.6%, 17.8%, 8.6%, 8.3%, 6.5% and 5.8%, respectively. Among these factors, the FA application rate was determined to be the most important factor influencing the soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content. Furthermore, both the soil salinity and the soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content significantly affected the yield of Korla fragrant pear, with soil salinity playing a dominant role (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e), with an increase in the MSE of 12.1%. Moreover, soil salinity had a significant effect on overall fruit quality, with an increase in the MSE of 14.2%. Therefore, the FA application rate primarily influenced the soil salinity and nitrate content, followed by yield and overall quality.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e#\u003c/b\u003eFig. \u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e \u003cb\u003eapproximately here#\u003c/b\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003e4.1 Appropriate drip irrigation intervals increased SWC and reduced soil salinity\u003c/h2\u003e\u003cp\u003eThe drip irrigation interval is a major factor influencing the SWC in the root zone (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). With increasing drip irrigation interval, the SWC initially increases but then decreases (Li et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). In this study, the SWC at 0\u0026ndash;100 cm in P2 was 4.6% and 9.1% greater than that in P1 and P3, respectively. Zhang et al. (\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) reported that higher soil moisture storage in the 0\u0026ndash;60 cm layer under a 6-day irrigation interval than under 3-day and 9-day intervals. This could be attributed to the greater volume of water under longer irrigation intervals, which results in deeper water infiltration (Sharmasarkar et al., \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Liu et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Additionally, when the irrigation interval is shorter, the surface soil remains moist more frequently, thereby increasing evaporation losses from the soil surface (Minhas et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Meshkat et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2000\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eDrip irrigation intervals alter the soil water distribution, thereby influencing the transport of the root zone soil salinity (Du et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). In this study, the wetting front under irrigation interval of P3 was located at 80\u0026ndash;100 cm depth (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), which resulted in the highest soil salinity occurring at this depth (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). In addition, the soil salinity at 0\u0026ndash;100 cm depth in P3 was 7.9\u0026ndash;16.2% lower than that in P1. However, Chauhdary et al. (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) reported that high-frequency drip irrigation is more effective in mitigating soil salinity in the corn root zone than low-frequency irrigation is. This discrepancy is likely because high-frequency irrigation is sufficient to leach salts beyond the root zone in shallow-rooted crops (Du et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), whereas in deep-rooted fruit trees, the wetting front formed by frequent irrigation does not reach below the root zone, limiting salt leaching (Dahiya et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1984\u003c/span\u003e). In this study, we found that the wetting front under irrigation interval of P2 was reached a depth of 60\u0026ndash;80 cm (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), which is shallower than that under P3. However, the soil salinity at 0\u0026ndash;100 cm depth under P2 was 4.6\u0026ndash;12.9% lower than that under P3. This may be attributed to the fact that longer irrigation intervals reduce matric potential in the topsoil, causing salts from deeper layers to migrate upward into the rot zone (Kourgialas et al., 2021; He et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003e4.2 FA reduced root-zone soil salinity and increased soil nitrate nitrogen content\u003c/h2\u003e\u003cp\u003eThe application rate of FA is a dominant factor influencing soil salinity and the soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content in the root zone (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). The application of FA resulted in a significantly reduction of the soil salinity in the root zone, and this effect increased as the application rate of FA increased from 0 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e to 400 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Li et al. (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2025\u003c/span\u003e) also reported that soil salt content decreases with higher application rates of humic acid, and the lowest soil salinity was observed at the application rate of 350 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. In our study, solid organic amendments (CK) primarily reduced the salinity across the 0\u0026ndash;40 cm soil depth, whereas FA application at the H2 rate reduced the salinity across the 0\u0026ndash;100 cm depth (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Moreover, throughout the 0\u0026ndash;100 cm soil depth, the soil salinity under H2 was 12.9% lower than that under CK. This may be because solid organic amendments have difficulty migrating with water and reduce soil salinity by promoting the leaching and removal of salts in topsoil (Diacono et al., 2015), whereas FA is highly water-soluble and can move to deeper soil layers. Owing to its large specific surface area and the presence of weakly acidic functional groups, it is capable of effectively adsorbing and exchanging salt cations in saline\u0026ndash;alkali soils, resulting in a reduction in soil salinity (Zhao et al., \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2025\u003c/span\u003e; Savarese et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe application of FA can also increase the soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content in the rooting zone, and it increases with increasing application rate of FA (G\u0026uuml;m\u0026uuml;ş et al., 2015). Similar to soil salinity, owing to significant differences in the solubility and moisture migration characteristics of solid organic fertilizers and FA, CK and H2 increased the nitrate nitrogen content in the 0\u0026ndash;40 cm and 0\u0026ndash;100 cm soil depths, respectively. The soil NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e-N content in the 0\u0026ndash;100 cm soil depth under H2 was 8.1% greater than that under CK (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Hu et al. (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) reported that solid organic fertilizers can provide a large amount of organic nitrogen and increase the nitrate nitrogen content in the surface soil through the mineralization process. In contrast, FA increases the soil nitrate nitrogen content by enhancing soil nitrification and microbial nitrogen fixation processes (Jin et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Additionally, when FA is applied in multiple applications, it can significantly increase the soil nitrate nitrogen content by 12.6%. This is because FA is continuously lost due to microbial degradation, leading to a reduction in its long-term effectiveness (Ma et al., 2022). The application of FA in combination with nitrogen fertilizer enhances its complexing effect with nitrogen, thereby effectively reducing nitrogen loss (Chen et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cb\u003e4.3 The effects of drip irrigation interval, FA application rate, and their interaction on the soil environment, pear yield, and quality\u003c/b\u003e\u003c/p\u003e\u003cp\u003eRandom forest analysis revealed that the interactive effect of the drip irrigation interval and FA application rate produced a significant influence on the SWC, soil salinity, and soil nitrate nitrogen content (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). As the drip irrigation interval increased from 10 days to 15 days, the SWC increased by 4.6% and 12.9%, the soil salinity decreased by 4.8% and 24.6%, and the soil nitrate nitrogen decreased by 8.3% and 16.2% at FA application rates of 200 and 400 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively. Similarly, Sun et al. (\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) reported that intermittent irrigation coupled with greater biochar amendment (e.g., 5%) may improve the SWC and reduce the soil salt content. Abd-Allah et al. (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2025\u003c/span\u003e) reported that an appropriate drip irrigation interval and hydrogel amendments lead to a significant improvement in the soil nitrate nitrogen content.\u003c/p\u003e\u003cp\u003eIn addition, the drip irrigation interval and FA application rate produced a significant influence on pear yield and overall quality. Since soil salinity is the primary factor influencing pear yield and overall quality in this study and since the FA application rate is the main factor affecting soil salinity (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e), we infer that the FA application rate is a dominant factor influencing pear yield and overall quality. These results are aligned with those of previous research emphasizing the beneficial role of humic substances on crop productivity and fruit quality in saline soils (Liu et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Chen et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). The interactive effect of the drip irrigation interval and FA application rate produced a significant effect on pear yield and overall quality (Tables\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Extending the drip irrigation interval from 10 days to 15 days the pear yield showed an increase of 7.3% and 16.9%, and the overall quality showed an increase of 24.8% and 64.6% for HA application rates of 200 and 400 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively. These findings indicate that the optimal yield and overall quality of fragrant pears were achieved with a 15-day drip irrigation interval and an organic fertilizer applied at 400 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Zoghdan et al. (2019) reported that suitable drip irrigation intervals coupled with a high application rate of organic waste compost significantly increased the yield, SSC, and vitamin C content of orange trees. Abdelraouf et al. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) reported that an moderate drip irrigation interval and a high application rate of organic straw (9 tons ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) significantly affect yield, water productivity, soluble solids content, and total sugar content in citrus.\u003c/p\u003e\u003cp\u003eThis research elucidated the contributions of drip irrigation intervals, FA application rates, and application timings in remediating saline soil environments and promoting the yield and quality of fragrant pear, providing a theoretical foundation for soil improvement and sustainable development in saline orchards. However, in this study, FA was applied as an additional soil conditioner in conjunction with the conventional nitrogen fertilizer application rate, without reducing the nitrogen fertilizer rate. Future research will explore the effects of applying FA under reduced nitrogen conditions on improving pear yield and quality to evaluate the potential of FA in optimizing the nitrogen application rate, mitigating soil salinization, and effectively enhancing crop growth and fruit quality.\u003c/p\u003e\u003c/div\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eIn this research, we conducted a two year field experiment to investigate the effects of the irrigation interval, fulvic acid (FA) application rate, and application timing on soil environment indices, i.e., SWC, soil salinity, and soil nitrate nitrogen content, as well as on the yield and overall quality of fragrant pears in saline pear orchards. The main conclusions are as follows:\u003c/p\u003e\u003cp\u003e\u003col\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eThe drip irrigation interval significantly affected the soil water content and further influenced the distribution of soil salinity. Under the 15-day drip irrigation interval treatment, the root zone soil water content reached its highest level, while the soil salinity in the root zone was reduced to its lowest value.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003eCompared with insoluble organic amendments, the application of FA reduced soil salinity in the deeper soil layers. The soil salinity showed a declining trend with the increasing FA application rates, while the soil nitrate nitrogen content increased with increasing application rate and number of applications. The FA application rate of 400 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with three split times produced a high soil moisture and low soil salinity environment.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e\u003cp\u003e(3) FA application rate is the dominant factor influencing the yield and quality of fragrant pear. Appropriately increasing the application rate of FA is a primary strategy for reducing soil salinity and improving the soil environment in salt-affected orchards. The optimization of the drip irrigation interval serves as an important complementary approach to increase overall orchard productivity.\u003c/p\u003e\u003cp\u003e(4) Taking into account the soil environment, pear yield, and overall quality, a drip irrigation interval of 15 days, an FA application rate of 400 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, and three split applications are recommended for saline-affected pear orchards.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCRediT authorship contribution statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eHao Liu:\u003c/strong\u003e Field experiment, Data analysis and curation, and Writing \u0026minus; original draft. \u003cstrong\u003eJun Wang:\u003c/strong\u003e Funding acquisition, Project administration, Formal analysis, Methodology, Conceptualization, Data analysis, Writing \u0026minus; review and editing, and Internal scientific review. \u003cstrong\u003eJiusheng Li:\u003c/strong\u003e Conceptualization, Internal scientific review, and writing \u0026minus; review and editing. \u003cstrong\u003eDezhao Liu:\u0026nbsp;\u003c/strong\u003eMethodology, Field experiment observation. \u003cstrong\u003eLong Wang:\u0026nbsp;\u003c/strong\u003eMethodology, Field experimental observation. \u003cstrong\u003eTaofeng Luo:\u003c/strong\u003e Field experiment observation. \u003cstrong\u003eChaofan Zhang:\u003c/strong\u003e Field experiment observation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of Competing Interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that there are no financial or personal relationships that could have inappropriately influenced the research presented in this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis project was supported by the National Natural Science Foundation of China (52179055 and 52579056), the Science and Technology Program of Xinjiang Production and Construction Corps (2022DB020), and the Key Research Project of Science and Technology in Inner Mongolia Autonomous Region of China (NMKJXM202301).\u003c/p\u003e "},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAbdelraouf RE, Azab A, Tarabye HHH, Refaie KM (2019) Effect of pulse drip irrigation and organic mulching by rice straw on yield, water productivity and quality of orange under sandy soils conditions. Plant Archives 19(2):2613\u0026ndash;2621\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAbd-Allah A, Mohamed M, Hegab RH, Elmehy AA (2025) Effect of some soil amendments on nutrients uptake and productivity of cowpea/maize intercropping system under water stress in sandy soil. Egypt J Agron 47(1):95\u0026ndash;106\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eArag\u0026uuml;\u0026eacute;s R, Medina ET, Mart\u0026iacute;nez-Cob A, Faci J (2014) Effects of deficit irrigation strategies on soil salinization and sodification in a semiarid drip-irrigated peach orchard. Agric Water Manage 142:1\u0026ndash;9\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBreiman L (2001) Random forests. Mach Learn 45:5\u0026ndash;32\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChauhdary JN, Bakhsh A, Ragab R, Khaliq A, Engel BA, Rizwan M, Shahid MA, Nawaz Q (2020) Modeling corn growth and root zone salinity dynamics to improve irrigation and fertigation management under semi-aridconditions. Agric Water Manage 230:105952\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChen H, Ruan Y, Jia Z (2025) A meta-analysis of 30 years in china and micro-district experiments shows organic amendment quantification combined with chemical amendment reduction enhances rice yield on saline-alkali land. Rice Sci 32(2):259\u0026ndash;272\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChen Q, Li B, Zhang X, Ge S, Jiang Y (2020) Split application of humic acid significantly improves the yield, quality and nitrogen utilization efficiency of \u0026lsquo;Fuji\u0026rsquo;apple. J Plant Nutr Fertilizers 26(4):757\u0026ndash;764\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChen R, Chang H, Wang Z, Lin H (2023) Determining organic-inorganic amendment application threshold to maximize the yield and quality of drip-irrigated grapes in an extremely arid area of Xinjiang, China. Agric Water Manage 276:108070\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCheng Y, Luo M, Zhang T, Yan S, Wang C, Dong QG, Feng H, Zhang T, Kisekka I (2023) Organic substitution improves soil structure and water and nitrogen status to promote sunflower (Helianthus annuus L.) growth in an arid saline area. Agric Water Manage 283:108320\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDahiya IS, Singh M, Richter J, Singh M (1984) Leaching of soluble salt during infiltration and redistribution. Irrig Sci 5(1):15\u0026ndash;24\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDai J, Cui Z, Zhang Y, Zhan L, Nie J, Cui J, Zhang D, Xu S, Sun L, Chen B, Dong H (2024) Enhancing stand establishment and yield formation of cotton with multiple drip irrigation during emergence in saline fields of Southern Xinjiang. Field Crops Res 315:109482\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDiacono M, Montemurro F (2015) Effectiveness of organic wastes as amendments and amendments in salt-affected soils. Agriculture 5(2):221\u0026ndash;230\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDu L, Zheng Z, Li T, Zhang X (2019) Effects of irrigation frequency on transportation and accumulation regularity of greenhouse soil salt during different growth stages of pepper. Sci Hort 256:108568\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDu Y, Liu X, Zhang L, Zhou W (2023) Drip irrigation in agricultural saline-alkali land controls soil salinity and improves crop yield: Evidence from a global meta-analysis. Sci Total Environ 880:163226\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFeng X, Pu J, Liu H, Wang D, Liu Y, Qiao S, Lei T, Liu R (2023) Effect of fertigation frequency on soil nitrogen distribution and tomato yield under alternate partial root-zone drip irrigation. J Integr Agric 22(3):897\u0026ndash;907\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFood and Agriculture Organization of the United Nations (2024) Global Status of Salt-Affected Soils. FAO\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGoenadi DH (2021) Fulvic acid\u0026ndash;a small but powerful natural substance for agricultural and medical applications. Menara Perkebunan 89(1):73\u0026ndash;90\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eG\u0026uuml;m\u0026uuml;ş İ, Şeker C (2015) Influence of humic acid applications on soil physicochemical properties. Solid Earth 7:2481\u0026ndash;2500\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHe P, Li J, Yu S, Ma T, Ding J, Zhang F, Chen K, Guo S, Peng S (2023) Soil moisture regulation under mulched drip irrigation influences the soil salt distribution and growth of cotton in Southern Xinjiang. China Plants 12(4):791\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHu Y, Zhan P, Thomas BW, Zhao J, Zhang X, Yan H, Zhang Z, Chen S, Shi X, Zhang Y (2022) Organic carbon and nitrogen accumulation in orchard soil with organic fertilization and cover crop management: A global meta-analysis. Sci Total Environ 852:158402\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHuang L, Liu Y, Ferreira JF, Wang M, Na J, Huang J, Liang Z (2022) Long-term combined effects of tillage and rice cultivation with phosphogypsum or farmyard manure on the concentration of salts, minerals, and heavy metals of saline-sodic paddy fields in Northeast China. Soil Tillage Res 215:105222\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJin Y, Zhang X, Yuan Y, Lan Y, Cheng K, Yang F (2023) Synthesis of artificial humic acid-urea complex improves nitrogen utilization. J Environ Manage 344:118377\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKourgialas NN, Dokou Z (2021) Water management and salinity adaptation approaches of Avocado trees: A review for hot-summer Mediterranean climate. Agric Water Manage 252:106923\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLei S, Jia X, Zhao C, Shao M (2025) A review of saline-alkali soil improvements in China: Efforts and their impacts on soil properties. Agric Water Manage 317:109617\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLeogrande R, Vitti C (2019) Use of organic amendments to reclaim saline and sodic soils: a review. Arid Land Res Manage 33(1):1\u0026ndash;21\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLi J, Zhang J, Rao M (2004) Wetting patterns and nitrogen distributions as affected by fertigation strategies from a surface point source. Agric Water Manage 67(2):89\u0026ndash;104\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLi N, Shi X, Zhang H, Shi F, Zhang H, Liang Q, Hao X, Luo H, Wang J (2024) Optimizing irrigation strategies to improve the soil microenvironment and enhance cotton water productivity under deep drip irrigation. Agric Water Manage 305:109095\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLi T, Wang S, Liu S, Zhang X, Dong H, Dai S, Chai L, Li H, Lv Y, Li T, Gao Q, Ma X (2025) Trade-offs of organic amendment input on soil quality and crop productivity in saline-alkali land globally: A meta-analysis. Eur J Agron 164:127471\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu H, Wang J, Li J (2025) The impact of drip irrigation methods and nitrogen application rates on soil salinity and nitrogen distribution, and fruit quality in arid regions of Northwest China. Agric Water Manage 319:109810\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu M, Yang J, Li X, Liu G, Yu M, Wang J (2013) Distribution and dynamics of soil water and salt under different drip irrigation regimes in northwest China. Irrig Sci 31:675\u0026ndash;688\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu X, Yang J, Tao J, Yao R (2022) Integrated application of inorganic fertilizer with fulvic acid for improving soil nutrient supply and nutrient use efficiency of winter wheat in a salt-affected soil. Appl Soil Ecol 170:104255\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMankotia S (2024) Impact of humic acid on various properties of soil and crop productivity-A review. J Agric Ecol 18:1\u0026ndash;6\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMao X, Yang Y, Guan P, Geng L, Ma L, Di H, Liu W, Li B (2022) Remediation of organic amendments on soil salinization: Focusing on the relationship between soil salts and microbial communities. Ecotoxicol Environ Saf 239:113616\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMeshkat M, Warner RC, Workman SR (2000) Evaporation reduction potential in an undisturbed soil irrigated with surface drip and sand tube irrigation. Trans ASAE 43(1):79\u0026ndash;86\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMinhas PS, Ramos TB, Ben-Gal A, Pereira LS (2020) Coping with salinity in irrigated agriculture: Crop evapotranspiration and water management issues. Agric Water Manage 227:105832\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNie Z, Zhang L, Zhang T, Guo L, Zhou J, An F, Ma H, Wang Z, Yang F (2025) Effects of lignite humic acid and lignite humic acid-based combined amendment on soil quality in saline-sodic farmlands in the west liaohe plain, china. Chin Geogra Sci 35(2):401\u0026ndash;414\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRodrigues M\u0026Acirc;, Ladeira LC, Arrobas M (2018) Azotobacter-enriched organic manures to increase nitrogen fixation and crop productivity. Eur J Agron 93:88\u0026ndash;94\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSavarese C, Drosos M, Spaccini R, Cozzolino V, Piccolo A (2021) Molecular characterization of soil organic matter and its extractable humic fraction from long-term field experiments under different cropping systems. Geoderma 383:114700\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSharmasarkar FC, Sharmasarkar S, Miller SD, Vance GF, Zhang R (2001) Assessment of drip and flood irrigation on water and fertilizer use efficiencies for sugarbeets. Agric Water Manage 46(3):241\u0026ndash;251\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSun J, Yang R, Zhu J, Pan Y, Yang M, Zhang Z (2019) Can the increase of irrigation frequency improve the rate of water and salt migration in biochar-amended saline soil? J Soils Sediments 19(12):4021\u0026ndash;4030\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSytar O, Brestic M, Zivcak M, Olsovska K, Kovar M, Shao H, He X (2017) Applying hyperspectral imaging to explore natural plant diversity towards improving salt stress tolerance. Sci Total Environ 578:90\u0026ndash;99\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTang K, Qin M, Han B, Shao D, Xu Z, Sun H, Wu Y (2024) Identifying the influencing factors of soil nitrous acid emissions using random forest model. Atmos Environ 339:120875\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eThomas CL, Acquah GE, Whitmore AP, McGrath SP, Haefele SM (2019) The effect of different organic fertilizers on yield and soil and crop nutrient concentrations. Agronomy 9(12):776\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang X, Li Y, Wang H, Wang Y, Biswas A, Chau HW, Liang J, Zhang F, Bai Y, Wu S, Chen J, Liu H, Yang G, Pulatov A (2022) Targeted biochar application alters physical, chemical, hydrological and thermal properties of salt-affected soils under cotton-sugarbeet intercropping. CATENA 216:106414\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang Y, Gao M, Chen H, Chen Y, Wang L, Wang R (2023) Organic amendments promote saline-alkali soil desalinization and enhance maize growth. Front Plant Sci 14:1177209\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWei Q, Xu J, Liu Y, Wang D, Chen S, Qian W, He M, Chen P, Zhou X, Qi Z (2024) Nitrogen losses from soil as affected by water and amendment management under drip irrigation: Development, hotspots and future perspectives. Agric Water Manage 296:108791\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eXiao C, Ji Q, Zhang F, Li Y, Fan J, Hou X, Yan F, Liu X, Gong K (2023) Effects of various soil water potential thresholds for drip irrigation on soil salinity, seed cotton yield and water productivity of cotton in northwest China. Agric Water Manage 279:108172\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eXiao C, Zhang F, Li Y, Fan J, Xu X, Liu X (2024) Optimal drip irrigation leaching amount and times enhance seed cotton yield and its stability by improving soil chemical environment and source-sink relationship. Field Crops Res 317:109531\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYao Z, Yan G, Wang R, Zheng X, Liu C, Butterbach-Bahl K (2019) Drip irrigation or reduced N-amendment rate can mitigate the high annual N\u003csub\u003e2\u003c/sub\u003eO\u0026thinsp;+\u0026thinsp;NO fluxes from Chinese intensive greenhouse vegetable systems. Atmos Environ 212:183\u0026ndash;193\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYin R, Gu X, Cheng Z, Li W, Wang Y, Zhao T, Cai W, Du Y, Cai H (2024) Optimizing nitrogen application patterns and amounts to improve maize yield and water-nitrogen use efficiencies in the Loess Plateau of China: A meta-analysis. Field Crops Res 318:109599\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang G, Shen D, Ming B, Xie R, Jin X, Liu C, Hou P, Xue J, Chen J, Zhang W, Liu W, Wang K, Li S (2019) Using irrigation intervals to optimize water-use efficiency and maize yield in Xinjiang, northwest China. Crop J 7(3):322\u0026ndash;334\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang L, Zeng S, Ma J, Liang F, Wang G (2014) The effect of irrigation frequency on soil water and salt distribution and yield of rice under subsurface drip irrigation. Northwest Agricultural J 23(03):74\u0026ndash;79\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang Y, Liu H, Gong P, He X, Wang J, Wang Z, Zhang J (2022) Irrigation method and volume for korla fragrant pear: Impact on soil water and salinity, yield, and fruit quality. Agronomy. 12 (8), 1980\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhao W, Wang S, Tang L, Xiao J, Chen G (2025) Combined application of humic acid and attapulgite improves physical structure and nutrients in coastal saline-alkali soils. Land Degrad Dev 36:4415\u0026ndash;4424\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang Z, Yang P, Zheng W, Liu Y, Guo M, Yang F (2019) Effects of drip irrigation frequency on emitter clogging using saline water for processing tomato production. Irrig Sci 68(3):464\u0026ndash;475\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZoghdan MG, Abo El-Enien MMS (2019) Irrigation regime and soil conditioners impact on characteristics of sandy soil and Washington Navel orange trees. J Soil Sci Agricultural Eng 10(4):233\u0026ndash;243\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"organic amendment, soil salinity, fertigation, soil environment, random forest analysis","lastPublishedDoi":"10.21203/rs.3.rs-8199859/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8199859/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSoil salinization restricts the sustainable development of agriculture, organic amendments can ameliorate the saline\u0026ndash;alkali soil environment, and appropriate irrigation interval reduced the root zone soil salinity by leaching salt into deeper soil. While, it remains unclear how the application of soluble amendments under drip irrigation affects the soil environment, which is crucial for understanding their role in the yield and quality formation of deep-rooted crops such as fruit trees. A two-year experiment was conducted in a Korla fragrant pear orchard to investigate the effects of irrigation interval, fulvic acid (FA) application rate, and application timing on soil environment indices, i.e., soil water content (SWC), soil salinity, soil nitrate nitrogen content, and thus fruit yield and quality of drip irrigated fragrant pear. The treatments included three irrigation intervals: 10 (P1), 15 (P2) and 20 days (P3), three FA application rates: 0 (H0), 200 (H1) and 400 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (H2), and two FA application timings: once (T1), three times (T2). In addition, insoluble organic amendment (CK) was used as a control treatment. Compared with the P1 and P3 treatments, the P2 treatment increased the SWC in the root zone by 5.6% and 9.4% and decreased the soil salinity by 8.6% and 13.7%, respectively. FA application increased the SWC and nitrate nitrogen content by 5.7\u0026ndash;14.7% and 8.3\u0026ndash;35.1%, respectively, and reduced the soil salinity by 7.6\u0026ndash;23.5%. With the same organic carbon content, the SWC and nitrate nitrogen content of H2 treatment were 8.5% and 9.2% greater than that of the CK treatment, respectively, and soil salinity was 6.9% lower. Compared with single application, split application of FA resulted in a significant 17.5% increase in soil nitrate nitrogen content. In addition, the overall fruit quality was determined through principal component analysis (PCA) of various fruit quality parameters. The yield and overall quality of fragrant pear initially increased and then decreased with increasing drip irrigation interval, but increased with increasing application rate and number of FA applications. Random forest analysis revealed that the interaction of irrigation interval and FA application rate had significant effects on soil salinity, and the FA application rate was the dominant factor. In summary, the recommended irrigation interval, application rate and number of FA applications were 15 days, 400 kg ha\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, and three, respectively, for saline-affected fragrant pear orchards in arid region.\u003c/p\u003e","manuscriptTitle":"Drip irrigated with fulvic acid improves soil environment and enhances fruit yield and quality of fragrant pear planted in saline-alkali land","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-03 11:13:58","doi":"10.21203/rs.3.rs-8199859/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c19a5d5e-50e2-453e-bf38-c567def7e561","owner":[],"postedDate":"December 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-13T16:09:40+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-03 11:13:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8199859","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8199859","identity":"rs-8199859","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}