Returning green manure to the field increases yield and quality of chili, tomato, and cucumber

Returning green manure to the field increases yield and quality of chili, tomato, and cucumber | 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 Returning green manure to the field increases yield and quality of chili, tomato, and cucumber Yao Guo, Zhuohan Zhang, Jiayue Ma, Guoli Wang, Yijia Zhao, Emmanuel Asibi Aziiba, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9115168/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 6 You are reading this latest preprint version Abstract Aims To alleviate soil degradation and vegetable quality deterioration caused by continuous cropping, this study aimed to investigate the impacts of leguminous green manure incorporation on soil properties, plant growth, yield, and quality of chili, tomato, and cucumber under intensive cropping systems. Methods A field experiment was conducted with three treatments established: fallow control (CK), catch cropping with arrow pea, and catch cropping with hairy vetch following vegetable harvest. Results Green manure application significantly elevated soil organic matter, available nitrogen, phosphorus, and potassium contents, and enhanced soil catalase, invertase, and urease activities, alongside increased bacterial abundance. It also improved plant height, stem diameter, root morphology, root vigor, chlorophyll content, net photosynthetic rate, and stomatal conductance, thereby increasing single fruit weight and yield per unit area. For quality, green manure boosted vitamin C, soluble sugar, and soluble protein in chili, optimized the sugar-acid ratio in tomatoes, and enhanced soluble sugar and vitamin C in cucumbers. Correlation analysis indicated that yield was positively correlated with soil available nutrients and microbial quantity, while quality was closely linked to photosynthetic and plant morphological traits. Conclusions Leguminous green manure return synergistically improves vegetable yield and quality by enhancing soil fertility and plant physiological functions. Arrow pea is suitable for chili production, whereas hairy vetch benefits tomato flavor and quality improvement, offering a sustainable and effective strategy for vegetable cultivation under continuous cropping systems. Green manure Vegetables Soil quality improvement Yield quality Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Chili ( Capsicum annuum L.), tomato ( Solanum lycopersicum L.), and cucumber ( Cucumis sativus L.) are important vegetables widely cultivated around the world. chili and tomato both belong to the Solanaceae family, while cucumber belong to the Cucurbitaceae family. The three fruits are rich in vitamin C, flavonoids and various minerals, and have high nutritional and health values. Chilis contain capsaicin, while cucumbers are rich in dietary fiber and various amino acids. The expansion of production scale, improvement of intensive planting, and long-term continuous cropping have led to a series of prominent problems (Wang et al. 2024 ): decreased soil fertility, deterioration of physical and chemical properties, imbalance of micro-ecological structure (Han et al. 2024 ), and enrichment of soil-borne pathogenic bacteria (Zhou et al. 2025a ). Consequently, continuous cropping obstacles have become increasingly serious in vegetable production systems (Lyu et al. 2020 ).These factors significantly inhibit the root development and growth of chilis, tomatoes and cucumbers leading to a decline in fruit yield and quality (Zhao et al. 2025 ). This poses a serious threat to the sustainability and safe production of vegetables. Therefore, it is urgently necessary to develop scientific planting models to improve the soil micro-ecological environment, enhance land productivity, and achieve efficient and high-quality production of these economic crops. The absorption of mineral nutrients by different plants at different times are usually different. Continuous cultivation of the same plant for several years usually leads to excessive consumption of certain mineral elements, eventually resulting in soil nutrient deficiency and thus affecting the growth of plants. Diversified planting is an important method for agricultural ecosystems to enhance soil fertility. Different plant root secretions, residue retention and field management can significantly affect soil organic matter (SOM) content (Song et al. 2022b ), pH value, aggregate structure, and microbial community composition, nitrogen mineralization and cycling of phosphorus and potassium (Friberg et al. 2019 ). In wheat-corn rotation system, catch cropping of leguminous green manure such as milk vetch and hairy vetch can regulate soil pH through the secretion of organic acids by the root system. After the decomposition of the residues, it increases soil organic matter, promotes the formation of aggregates, increases soil nitrogen, and fixation of root nodules (Yao et al. 2018 ). At the same time, it provides carbon sources for the activation of phosphorus and potassium, enhances the abundance of microorganisms for nitrogen-fixation, and phosphorus-solubilization (Huang et al. 2024 ). These changes in soil properties directly affect the root formation, nutrient utilization, growth and development, and stress resistance of subsequent crops, thereby influencing yield and quality. Other studies have shown that rotation with leguminous green manures in moderately saline-alkali soil reduces soil pH and electrical conductivity (EC), increases organic matter and total nitrogen (TN), and enhances fresh yield and protein content of subsequent silage corn, confirming their positive impacts on crop productivity and quality (Zhao et al. 2024 ).Therefore, under the orientation of sustainable agriculture, scientifically screening the types of previous crops and rationally utilizing their residues to improve soil structure, increase beneficial microorganisms, and regulate nutrient availability have become the core strategies for enhancing system productivity. Studies have shown that catch cropping leguminous green manure crops can increase soil nutrient and organic matter content, and has become a core strategy for enhancing soil fertility in rotation systems of major food crops such as wheat, corn, and rice (Ramos et al. 2001 ). Ploughing and returning leguminous green manure crops to the field can significantly improve soil quality, increase the content of alkaline hydrolyzable nitrogen (AN) in the soil, replenish the organic carbon pool, promote the formation of aggregate structure, enhance soil water retention capacity, and soil porosity (Xiang et al. 2018 ). More importantly, leguminous green manure alters the microbial community structure of the plant rhizosphere, promotes the production and growth of beneficial bacteria, interferes with the growth of pathogenic bacteria, thereby stimulating plant growth, enhancing plant disease resistance, and preventing the occurrence of soil-borne diseases. It has a positive effect on increasing the yield of continuous crops (Huang et al. 2025 ). In addition, leguminous green manure can enhance the transformation ability of microorganisms, increase the utilization rate of elements such as N and P, and strengthen the nutrient supply to plant roots (Li et al. 2025b ). The above indicates that the catch cropping of leguminous green manure significantly promotes the growth, development and physiological metabolism of subsequent crops through the improvement of soil quality and the reorganization of microbial communities. At present, there is still a lack of systematic evaluation on whether re-planting green manure during the leisure period of the vegetable rotation system can effectively increase the yield and quality of the subsequent vegetables, especially in terms of the differences in the effects of different leguminous green manure combinations with specific vegetables. For this purpose, this study focused on chili (variety: XJ01), tomato (variety: Jingfan 501), and cucumber (variety: Taking Changqing No.1) as the object, and set up three treatments: no green manure planting after vegetable harvest (CK), catch cropping of arrow pea after vegetable harvest (CV), and catch cropping of hairy vetch after vegetable harvest (HV). The effects of catch cropping different leguminous green manure during the fallow period and returning it to the field on soil physical and chemical properties, biological characteristics, as well as the growth, yield and quality of vegetables were systematically compared. We explored the regulatory mechanism of green manure application on vegetable yield and quality formation to clarify the actual effect of green manure replanting during fallow periods on vegetable production. This study further aims to provide theoretical basis and technical support for green, high-yield vegetable cultivation and the improvement of cultivated soil quality. Materials and methods Test materials Varieties linear chili “XJ01”, “Jingfan 501”, and “Changqing No.1” of chili, tomato, and cucumber were used respectively. Three different pre-crop treatment methods were formed by using two types of green manure: no replanting of green manure after vegetable harvest (CK), replanted arrow pea after vegetable harvest (CV), and hairy vetch (HV). The experiment was conducted in 2024. The soil type was loam with a PH of 6.8 to 7.8 with an organic matter content of 16.3 to 28.6 g·kg -1 . Experimental design The experiment was conducted in a greenhouse in Li jiazhuang, Yu zhong County, Gansu Province. On September 20, 2023, seedlings of tomato, chili, and cucumber were raised. They were planted on ridges, with the bottom width being 1 m, surface width being 0.8 m, and the length being 6 m. The spacing between ridges was 0.25 m, and the plant and row spacing was 0.4 m × 0.6 m respectively. They were planted in double rows. The plot area was 5 m × 6 m = 30 m 2 . In this experiment, tomatoes were planted on November 5, 2023. Before planting, 400 kg·ha -1 of organic fertilizer was applied at one time. The application rates of chemical fertilizer as base fertilizer were 23.70 kg·ha -1 of N, 38.40 kg·ha -1 of P₂O₅, and 72.90 kg·ha -1 of K₂O. The tomato harvest started on March 5, 2024, and ended on April 30. Peppers were planted on December 10, 2023. Before planting, 500 kg·ha -1 of organic fertilizer was applied at one time, and the application rate of chemical fertilizer as base fertilizer was the same as that for tomatoes. The harvest period of peppers was from February 25 to April 30, 2024. Cucumbers were planted on January 20, 2024. Before planting, 500 kg·ha -1 of organic fertilizer was applied at one time, and the application rate of chemical fertilizer as base fertilizer was the same as that for tomatoes and peppers. The harvest period of cucumbers was from March 15 to April 30, 2024. These fertilizers are common commercially available diammonium phosphate (with N content of 15.5% and P 2 O 5 content of 46%), calcium nitrate (with N content of 15%), and agricultural potassium sulfate (with K 2 O content of 52%). The experiment adopted a randomized block design and set up three pre-crop treatments. Two types of green manure, namely, no replanting of green manure after vegetable harvest (CK), replanting of arrow pea after vegetable harvest (CV), and hairy vetch (HV), were selected to form three different pre-crop treatment methods. Three vegetable varieties were planted, namely chili, tomato, and cucumber. Each treatment was repeated three times, with a total of 27 plots. Under different treatments of the previous crop, all were managed in accordance with the conventional cultivation methods. The arrow pea (LAN Jian No. 2) and the Turkmen hairy vetch were sown on July 5, 2023, and were fully crushed and returned to the soil by manual return to the field in early October of the same year. The sowing rates of arrow pea and hairy vetch were 225 kg·ha -1 and 25 kg·ha -1 respectively. Both green manure sowing methods were row sowing with a row spacing of 15 cm. Nitrogen and phosphorus fertilizers were applied as base fertilizer, while green manure was irrigated at 700 m 3 ·ha -1 and 900 m 3 ·ha –1 during the seedling and bud formation stages, respectively. Ta ble 1 Treatment combination codes and specific measures for different vegetables under different planting models Vegetables Planting Patterns Treatment Combination Codes Chili No catch - cropping of green manure after harvest C-CK Catch - cropping of vicia sativa after harvest C-CV Catch - cropping of hairy vetch after harvest C-HV Tomato No catch - cropping of green manure after harvest T-CK Catch - cropping of vicia sativa after harvest T-CV Catch - cropping of hairy vetch after harvest T-HV Cucumber No catch - cropping of green manure after harvest Cu-CK Catch - cropping of vicia sativa after harvest Cu-CV Catch - cropping of hairy vetch after harvest Cu-HV Measurement indicators and methods Physical and chemical properties of soil Soil samples were taken from the plough layer of each plot before and after the vegetable planting. Rhizosphere soil samples at a depth of 5-15 cm were collected at three random points. The soil samples were mixed evenly, air-dried and ground, and passed through a 100-mesh sieve for the determination of soil physical and chemical properties. The samples were analyzed according to traditional soil agrochemical techniques: The determination of SOM adopted the potassium dichromate oxidation - external heating method; The determination of alkaline hydrolyzable nitrogen (AN) was carried out by the alkaline diffusion method. After ammonium fluoride-hydrochloric acid extraction, the available phosphorus (AP) was determined by the molybdenum-antimony colorimetric method. Determination of available potassium (AK) by atomic absorption spectrophotometry after ammonium acetate extraction. Soil pH was determined in accordance with the Chinese National Environmental Protection Standard HJ 962-2018. Firstly, the dry soil was weighed 10 grams and put into a 50 mL beaker. 25 mL of water was added (volume ratio 1:2.5) and sealed with a film. It was stirred vigorously with a magnetic stirrer for 2 minutes and left to stand for 30 minutes before the pH was measured with a pH meter. The conductivity (EC) was measured using a DSS-307 conductivity meter for the extract with a soil-to-water ratio of 1:5(w/v), and the reading was taken after calibration at a constant temperature of 25°C. Soil biological characteristics Soil samples were taken from the plough layer of each plot before and after vegetable planting. Rhizosphere soil samples at a depth of 5-15 cm were collected at three random points. The samples were mixed evenly, air-dried and ground, and sieved through a 100-mesh sieve for the determination of soil biological characteristics. The activity of catalase (CAT) was determined by potassium permanganate titration using 5 g of soil sample weighed, 40 mL of 0.3% H 2 O 2 solution was added, shaken for 20 minutes, and 5 mL of 1.5 mol·L -1 H 2 SO 4 solution added. The remaining H 2 O 2 was titrated with 0.1 mol·L -1 KMnO 4 solution, and the enzyme activity was calculated. The activity of invertase (Inv) was determined by the 3, 5-dinitrosalicylic acid colorimetric method using 5 g of soil sample weighed, 15 mL of 8% sucrose solution and 0.5 mL of toluene were added, and the mixture was cultured at 37°C for 24 hours. Subsequently, DNS reagent was added for color development, and the absorbance was measured at a wavelength of 540 nm to calculate the enzyme activity. Urease (Ure) activity was determined by the sodium phenol-sodium hypochlorite colorimetric method using 5 g of soil sample weighed, 10 mL of 10% urea solution and 0.2 mL of toluene were added, and the sample was cultured at 37°C for 24 hours. Subsequently, after color development treatment, the absorbance was measured at a wavelength of 578 nm, and the enzyme activity was calculated. Fresh soil sample was weighed 10 g added 90 mL of sterile physiological saline and shook at 25°C and 180 r·min -1 for 30 minutes to prepare a 10 -1 soil suspension. A series of diluents of 10 -2 , 10 -3 , 10 -4 , 10 -5 , 10 -6 and 10 -7 were prepared in sequence by the gradient dilution method. Three dilution gradients of 10 -5 , 10 -6 , and 10 -7 were selected and taken 0.1 mL of soil suspension from each gradient and evenly spread on the beef extract peptone medium plate with three repetitions for each gradient. The plate was inverted and incubated in a constant incubator temperature at 28°C for 48 hours. After the cultivation was completed, plates with a colony count ranging from 30 to 300 were selected for counting. The number of bacteria per gram of dry soil was calculated (the mass of dry soil was converted based on soil moisture content), and the result was expressed as CFU·g -1 dry soil. Two dilution gradients of 10 -3 and 10 -4 were selected. 0.1 mL of soil suspension was taken from each gradient and evenly spread on Marding's medium plates. Three repetitions were set for each gradient and the plates were inverted and incubated in a constant incubator temperature at 28°C for 72 hours. After the cultivation was completed, plates with a colony count ranging from 10 to 100 were selected for counting. The number of fungi per gram of dry soil was calculated (the mass of dry soil was converted based on soil moisture content), and the result was expressed as CFU·g -1 dry soil. Plant growth and development Parameters Three representative plants were randomly selected from each community to measure their growth and development. The plant height was measured with a ruler. The measurement range was the vertical height from the ground to the growth point of the plant, with the unit being cm. The stem diameter was measured with a vernier caliper with an accuracy of 0.01mm, and the measurement position was the diameter 2 cm above the base of the stem. After washing the root systems of the plants, they were scanned and analyzed using the WinRHIZO LA-S root scanner. The measured parameters included root length, root surface area, and root volume. Root vitality was reduced by the 2,3, 5-triphenyltetrazolium chloride reduction method (TTC reduction method). Fresh plant roots were weighed 0.5g and soaked in 0.4% TTC-phosphate buffer solution (pH 7.5), kept under 37°C in the dark for 2 hours, to extract the reaction products with toluene. The absorbance was measured at a wavelength of 485 nm, and the root activity calculated. Photosynthetic physiological characteristics The functional leaves were determined using the portable photosynthesis meter LI-6400XT. The light intensity was set to 1200 μmol·m -2 ·s -1 , CO 2 concentration to 400 μmol·mol -1 , and temperature to 25±1°C. On a sunny day, from 10:00 to 14:00 in the morning. Net photosynthetic rate was recorded (P n , μmol·m -2 ·s -1 ), stomatal conductance (G s , mol·m -2 ·s -1 ), transpiration rate (T r , mmol·m -2 ·s -1 ), intercellular CO 2 concentration (C i , μmol·mol -1 ). The relative content of chlorophyll was determined by the SPAD value in the middle of fully unfolded leaves using the SPAD-502 chlorophyll meter, with each leaf repeated 5 times. The measurement was repeated three times for each treatment. Output and quality Parameters Chili fruits were harvested in batches during the maturity period, and the number of effective fruits per plant and the fresh weight of each fruit were counted. For tomato, 7 clusters of fruits were uniformly retained from the marked plants, harvested in batches, and the number of fruits per plant and the fresh weight of each fruit were recorded. For cucumber, mature commercial melons are harvested in batches during the growth period, and the number of fruits per plant and the weight of each fruit were counted, with the unit being g, and then converted to the yield per unit area, with the unit being kg·ha -1 . The longitudinal diameter of representative fruits of chili and cucumber, which is the length from the top to the shoulder of the fruit, and the transverse diameter, which is the maximum diameter at the equator of the fruit, were measured using a digital vernier caliper with an accuracy of 0.01mm. The results were expressed in cm. The hardness of the equatorial part of each treatment of no less than 20 representative tomato fruits was measured using the GY-4 fruit hardness tester, and the results were expressed as N·cm -2 . For quality analysis, mixed samples collected from the equatorial region of the fruit were immediately frozen in liquid nitrogen and stored at -80°C, and then various indicators were determined separately. The content of soluble protein was measured by the Coomassie brilliant blue G-250 method at a wavelength of 595 nm and quantified by the bovine serum albumin standard curve. The results were expressed as mg·g -1 FW. The content of soluble sugar was measured by the anthrone-sulfuric acid colorimetric method at a wavelength of 620 nm and quantified by the glucose standard curve and the results expressed as mg·g -1 FW. The content of vitamin C was determined by the 2, 6-dichlorophenol titration method, and the results expressed as mg·100g -1 FW. The total flavonoid content was measured by the aluminum nitrate colorimetric method at a wavelength of 510 nm and quantified by the rutin standard curve and the results expressed as mg·g -1 FW. The content of organic acids was determined by the sodium hydroxide titration method in accordance with the national standard GB/T 12456-2021 for the determination of total acids in food, and the result was expressed as a percentage. Data analysis The data were collated using Microsoft Excel 2021, plotted using Origin 2024, and the significance test was conducted using SPSS 27.0. Results and analysis The influence of catch cropping of leguminous green manure on vegetable yield Influence on the weight of individual fruits The catch cropping of leguminous green manure after vegetable harvest significantly affected the single fruit weight (P < 0.05). Compared with no green manure (C-CK) after chili harvest, the single fruit weight increased by 36.07% in the treatment of catch cropping arrow pea (C-CV) after chili harvest; The single fruit weight increased by 19.67% compared with that of C-CK in the treatment of catch cropping hairy vetch (C-HV) after chili harvest. After cucumber harvest, catch cropping arrow pea (Cu-CV) treatment increased the single fruit weight by 1.57% compared with cucumber harvest without catch cropping green manure (Cu-CK) treatment. After cucumber harvest, the single fruit weight increased by 1.00% compared with the Cu-CK treatment after catch cropping hairy vetch (Cu-HV). Single fruit weight of tomato also showed a similar positive trend. The results showed that the catch cropping arrow pea after vegetable harvest was most significant in increasing the single fruit weight of vegetables. Impact on total output The effect of catch cropping leguminous green manure after vegetable harvest on the total yield was significant (P < 0.05). Compared with the C-CK treatment, the total output increased by 19.42% under the C-CV treatment. C-HV increased by 16.17% compared with C-CK treatment. Compared with the T-CK treatment, the total output increased by 6.11% under the T-CV treatment. T-HV increased by 5.93% compared with T-CK treatment. The total output of Cu-CV treatment increased by 8.44% compared with that of Cu-CK treatment. Cu-HV increased by 5.00% compared with Cu-CK treatment. To sum up, the treatment of returning leguminous green manure to the field significantly increased vegetable yields, and the effect of catch cropping arrow pea on increasing yields was better than that of hairy vetch. The influence of catch cropping leguminous green manure on vegetable quality Re-planting leguminous green manure after vegetable harvest can improve the quality of vegetables compared with not re-planting green manure after vegetable harvest. The soluble protein content increased by 12.15% compared with the treatment of no re-planting green manure (C-CK) after chili harvest and the treatment of re-planting arrow pea (C-CV) after chili harvest. The content of soluble sugar increased by 30.33%. The content of vitamin C increased by 113.99%. The total flavonoid content increased by 12.06%. After the harvest of chili peppers，the contents of soluble protein, soluble sugar and vitamin C were increased by 6.07%, 8.20% and 29.28% respectively compared with those of C-CK under the treatment of catch cropping hairy vetch (C-HV). Overall, the treatment of catch cropping arrow pea after chili harvest was more effective in increasing vitamin C and soluble protein. Catch cropping of leguminous green manure after tomato harvest also has a positive impact on flavor and nutritional quality. After tomato harvest, catch cropping arrow pea (T-CV) increased the soluble sugar content by 15.37% compared with non-catch cropping of green manure after tomato harvest (T-CK). The content of vitamin C increased by 19.33%. The content of organic acids decreased by 3.20%. After tomato harvest, the contents of soluble sugar and vitamin C increased by 16.25% and 10.42% respectively compared with those of T-CK under the treatment of catch cropping hairy vetch (T-HV). The content of organic acids decreased by 3.35%. After tomato harvest, the catch cropping arrow pea treatment is more conducive to the accumulation of vitamin C, while the catch cropping hairy vetch treatment after tomato harvest performed better in promoting the accumulation of soluble sugar and reducing organic acids, which helped to optimize the sugar-acid ratio and improved flavor. In terms of cucumber, the catch cropping of leguminous green manure also brought about positive changes in nutritional parameters. The soluble protein content increased by 7.96% when cucumbers were treated with catch cropping arrow pea (Cu-CV) after harvest, compared with cucumbers without catch cropping of green manure (Cu-CK). The content of soluble sugar increased by 63.05%. Vitamin C content increased by 7.71%. After cucumber harvest, the contents of soluble protein, soluble sugar, and vitamin C increased by 7.00%, 67.00%, and 6.00% respectively compared with Cu-CK under the treatment of catch cropping hairy vetch (Cu-HV). After the harvest of cucumber, the catch cropping arrow pea had more advantages in terms of protein and vitamin C, while the catch cropping hairy vetch after the harvest of cucumbers had a more obvious effect on the increase of soluble sugar and is more conducive to improving the flavor of cucumbers. The influence of catch cropping of leguminous green manure on the growth status of vegetables Effects on plant morphology The re-planting of leguminous green manure after the harvest of chili significantly improved the morphogenesis of the plants. Compared with the treatment without replanting green manure (C-CK) after chili harvest, the treatment with replanting arrow pea (C-CV) after chili harvest significantly increased chili plant height by 29.55% and stem thickness by 30.80%. After the harvest of chili peppers the plant height and stem diameter under the treatment of catch cropping hairy vetch (C-HV) increased by 26.31% and 28.23% respectively compared with C-CK. After tomato harvest, the plant height and stem thickness under the treatment of catch cropping arrow pea (T-CV) increased by 21.97% and 17.12% respectively compared with the treatment without catch cropping green manure after tomato harvest (T-CK). After tomato harvest, plant height and stem thickness increased by 18.58% and 16.22% respectively under the treatment with catch cropping hairy vetch (T-HV) compared with the treatment with T-CK. In cucumber cultivation, both catch cropping green manure treatments also promoted plant growth. Compared with the treatment of no catch cropping green manure after cucumber harvest (Cu-CK), the treatment of catch cropping arrow pea after cucumber harvest (Cu-CV) significantly increased cucumber plant height by 2.66% and stem thickness by 6.19%. When cucumber harvested, plant height and stem thickness increased by 3.00% and 4.00% respectively compared with Cu-CK under the treatment of catch cropping hairy vetch (Cu-HV). Comprehensive comparison showed that the catch cropping of the two leguminous green manure can effectively promote the upright growth of vegetable plants and the thickening of stems, which is conducive to the construction of a better canopy structure. Among them, the catch cropping of arrow pea after vegetable harvest was particularly effective in promoting the thickening of chili stems and the height growth of tomato plants, indicating that its ability to optimize plant morphology was slightly better than that of hairy vetch. Effects on photosynthetic characteristics After the harvest of vegetables, the catch cropping of leguminous green manure improved the light energy utilization rate of chilis, tomatoes and cucumbers by enhancing photosynthetic parameters. Compared with the C-CK treatment, under the C-CV treatment, its net photosynthetic rate (P n ) increased by 59.79%, stomatal conductance (G s ) by 28.33%, and chlorophyll content (SPAD) by 14.06%. Under C-HV treatment, P n , G s and SPAD increased by 51.30%, 25.80% and 10.07% respectively compared with C-CK. In terms of tomato, the P n under T-CV treatment increased by 9.39% compared with T-CK. G s increased by 8.57% compared with T-CK. The P n and G s under T-HV treatment increased by 8.14% and 6.06% respectively compared with T-CK. In terms of cucumber, the P n under Cu-CV treatment was 33.53% higher than that of Cu-CK. G s was 38.44% higher than that of Cu-CK, and SPAD was 17.70% higher than that of Cu-CK. The P n , G s and SPAD under Cu-HV treatment increased by 42.00%, 33.00%, and 15.00% respectively compared with Cu-CK. When comparing the two green manure catch cropping treatments, the catch cropping of arrow pea after vegetable harvest had a better effect in increasing the stomatal conductance and chlorophyll content of chili, while the promotion of the net photosynthetic rate of cucumber was greater. Effects on root development The catch cropping of leguminous green manure after the harvest of chili significantly enhanced the development capacity of chili roots. Under C-CV treatment, compared with C-CK, the root length of chili increased by 17.83%, surface area by 23.71%, volume by 36.09%, and vitality by 24.41%. The root length, root surface area, root volume, and root vitality treated by C-HV increased by 15.11%, 18.50%, 20.55%, and 19.23% respectively compared with those treated by C-CK. In cucumber cultivation, under Cu-CV treatment, compared with Cu-CK, total root length increased by 14.62%, root surface area by 9.44%, root volume by 11.56%, root vitality by 12.27%, and the average root diameter by 3.68%. The root length, root surface area, root volume, and root vitality under Cu-HV treatment increased by 10.00%, 10.00%, 16.00%, and 14.00% respectively compared with those of Cu-CK. Comprehensive comparison showed that both leguminous green manures catch cropping can effectively optimize the root structure and physiological activity of vegetables. Among them, the catch cropping arrow pea after vegetable harvest has a better effect on promoting the root volume and root vitality of chili peppers and the growth of cucumber root length, while the catch cropping hairy vetch after vegetable harvest has a slightly more prominent effect on increasing the root volume of cucumber. The regulatory effect of catch cropping leguminous green manure on vegetable Soil quality Improvement of soil quality The catch cropping of arrow pea and hairy vetch after chili harvest significantly increased the nutrient content of chili soil. Compared with the treatment of no re-planting of green manure after chili harvest (C-CK), the two re-planting treatments of green manure after chili harvest both showed significant improvement on soil organic matter, alkaline hydrolyzable nitrogen, available phosphorus, and available potassium before and after planting. Compared with the treatment of no re-planting green manure (C-CK) after chili harvest, the treatment of re-planting arrow pea (C-CV) after chili harvest increased soil organic matter content by 12.60% before planting and by 25.85% after planting. After the harvest of chili peppers under the treatment of catch cropping hairy vetch (C-HV), the organic matter content before and after transplanting increased by 17.26% and 24.22% respectively compared with C-CK. The alkaline hydrolyzed nitrogen content increased significantly under C-CV treatment by 44.97% and 57.82% respectively before and after planting compared with C-CK and showed good effects under C-HV treatment. The alkaline hydrolyzed nitrogen content before and after planting was 35.81% and 44.54% higher than that of C-CK. In terms of available phosphorus, the C-CV treatment increased by 20.24% before planting compared with C-CK, and by 20.49% after planting compared with C-CK. Under C-HV treatment, the available phosphorus content before and after planting increased by 19.81% and 25.16% respectively compared with C-CK. Available potassium content was 87.54% higher than that of C-CK before transplanting under C-CV treatment and 58.52% higher than that of C-CK after transplanting. Under C-HV treatment, they increased by 86.93% and 66.69% respectively. A comprehensive comparison showed that both leguminous green manures can effectively improve soil nutrient status. Among them, the treatment of catch cropping arrow pea after chili harvest showed better performance in improving alkaline hydrolyzable nitrogen, especially maintaining a high nitrogen supply capacity after transplanting. The increase in available phosphorus and available potassium after transplanting was slightly higher than that of after transplanting with arrow pea after chili harvest, indicating that it has a good nutrient release potential in the later growth stage. The improvement of these soil nutrients provides a good soil foundation for vegetable growth and may be one of the important mechanisms by which green manure treatment promoted plant growth and yield formation. The catch cropping of leguminous green manure after tomato harvest has a significant effect on soil nutrient status. Compared with the treatment of no re-planting of green manure after tomato harvest (T-CK), the two re-planting treatments of green manure after tomato harvest showed significant improvement on soil organic matter, alkaline hydrolyzable nitrogen, available phosphorus, and available potassium both before and after planting. Compared with T-CK treatment, the post-harvest tomato catch cropping arrow pea (T-CV) increased soil organic matter content by 24.40% before planting and 42.31% after planting. Under the treatment of catch cropping hairy vetch (T-HV) after tomato harvest, the organic matter content before and after transplanting increased by 26.32% and 50.20% respectively compared with T-CK. The alkaline hydrolyzable nitrogen content increased significantly under the T-CV treatment by 53.97% and 50.91% respectively before and after planting compared with the T-CK treatment. Good effects were also shown under T-HV treatment. The alkaline hydrolyzable nitrogen content before and after planting increased by 53.53% and 47.18% respectively compared with T-CK treatment. In terms of available phosphorus, the T-CV treatment increased the content before planting by 20.94% compared with the T-CK treatment, and after planting by 11.49% compared with the T-CK treatment. The available phosphorus content before and after transplanting under T-HV treatment increased by 21.55% and 22.83% respectively compared with that under T-CK treatment. Available potassium content under T-CV treatment was 16.61% higher than that under T-CK treatment before transplanting and 8.76% higher than that under T-CK treatment after transplanting. Under T-HV treatment, they increased by 12.54% and 5.18% respectively. Comprehensive comparison showed that both leguminous green manures can effectively improve soil nutrient levels. Among them, the treatment of catch cropping arrow pea after tomato harvest performed better in improving alkaline hydrolyzable nitrogen and available potassium, showing a stronger nitrogen supply capacity. The increase in available phosphorus after transplanting was greater than that after transplanting by the catch cropping hairy vetch treatment after tomato harvest than by the catch cropping arrow pea treatment, indicating that it has a more persistent potential for phosphorus release. The improvement of these soil nutrients provides a good foundation for the growth of vegetables. Tab le 2 Effects of leguminous green manure crops on soil quality of chili, tomato, and cucumber Pre - planting Treatment Organic Matter (g·kg⁻¹) Alkaline Hydrolyzable Nitrogen (mg·kg⁻¹) Available Phosphorus (mg·kg⁻¹) Available Potassium (mg·kg⁻¹) Pre-planting Post-planting Pre-planting Post-planting Pre-planting Post-planting Pre-planting Post-planting C-CK 16.1±0.3b 12.2±1.1b 177.2±9.7b 152.1±4.4c 99.8±2.2b 81.3±6.9b 142.6±15.5b 134.2±16.1b C-CV 18.2±1.5a 15.4±0.7a 256.9±8.8a 240.1±5.2a 120.0±6.0a 98.0±3.8a 267.4±17.8a 212.7±10.5a C-HV 18.9±0.8a 15.2±1.0a 240.7±5.1a 219.9±1.5b 119.6±11.0a 101.8±11.5a 266.5±19.5a 223.7±17.5a T-CK 20.9±1.8b 16.5±1.2b 161.0±4.2b 156.9±4.2b 109.0±6.0b 93.1±2.7c 124.4±10.6a 120.3±7.1a T-CV 26.0±1.6a 23.4±1.0a 247.9±13.2a 236.8±14.8a 131.9±7.6a 103.8±1.7b 145.1±7.3a 130.8±4.9a T-HV 26.4±2.1a 24.7±0.8a 247.2±18.9a 231.0±7.6a 132.5±2.7a 114.4±2.0a 140.0±19.3a 126.5±13.6a Cu-CK 29.1±0.5b 25.9±0.7b 192.4±2.9b 186.7±11.7b 127.3±6.3b 147.9±7.6c 129.4±5.8a 122.6±2.5b Cu-CV 43.4±2.0a 37.0±1.5a 261.5±14.9a 264.2±8.5a 176.8±7.8a 176.0±5.0a 150.1±55.3a 183.5±3.7a Cu-HV 44.7±2.1a 36.1±0.4a 260.2±17.7a 261.2±7.1a 166.5±8.9a 159.3±3.6b 169.7±1.4a 176.8±4.5a The data are presented as means ± SDs (n=3). Different lowercase letters indicate significant differences among green manure treatments within the same vegetable (p<0.05, Duncan’s multiple range test). Corresponding one-way ANOVA results are provided in Table 2 The catch cropping of leguminous green manure had a significant effect on the soil nutrient level of cucumber. Compared with the treatment of no re-planting of green manure (Cu-CK) after cucumber harvest, the two re-planting treatments of green manure after cucumber harvest showed significant effects on soil organic matter, alkaline hydrolyzable nitrogen, available phosphorus, and available potassium both before and after planting. Compared with the Cu-CK treatment, the post-harvest cucumber catch cropping arrow pea (Cu-CV) increased the content of soil organic matter by 48.97% before planting and 42.99% after planting. After cucumber harvest, the organic matter content before and after transplanting increased by 53.21% and 39.03% respectively compared with Cu-CK under the treatment of catch cropping hairy vetch (Cu-HV). The alkaline hydrolyzable nitrogen content increased significantly under the Cu-CV treatment by 35.90% and 41.49% respectively before and after planting compared with the Cu-CK treatment. Good effects were also shown under the treatment of Cu-HV. The alkaline hydrolyzed nitrogen content before and after planting increased by 35.25% and 40.37% respectively compared with the treatment of Cu-CK. In terms of available phosphorus, the Cu-CV treatment increased the content before planting by 38.86% compared with the Cu-CK treatment, and after planting by 19.03% compared with the Cu-CK treatment. Available phosphorus content before and after planting under Cu-HV treatment was 31.00% and 8.00% higher than that of Cu-CK treatment, respectively. Available potassium content was 15.94% higher than that of Cu-CK before transplanting under Cu-CV treatment and 49.65% higher after transplanting than that of Cu-CK treatment. Under Cu-HV treatment, they increased by 31.00% and 44.00% respectively. Comprehensive comparison showed that both leguminous green manures can effectively improve soil nutrient levels. Among them, the treatment of catch cropping arrow pea after cucumber harvest showed better performance in improving alkaline hydrolyzable nitrogen and available potassium, demonstrating a stronger nitrogen supply capacity. The catch cropping of leguminous green manure significantly enhanced soil nutrients, providing a favorable environment for vegetable growth. Effects on soil enzyme activity The catch cropping of leguminous green manure after vegetable harvest has a significant enhancing effect on the enzyme activity in the rhizosphere soil. In the rhizoidal soil of chili, C-CV treatment increased the activities of catalase, invertase, and urease before planting by 32.42%, 23.21%, and 13.85% respectively compared with C-CK treatment, and increased them by 25.55%, 27.51%, and 12.13% respectively after planting. C-HV treatment also significantly enhanced the activities of these three enzymes. Compared with C-CK, the increase before colonization were 40.92%, 17.05%, and 17.35% respectively, and the increase after colonization were 50.16%, 15.94%, and 16.07% respectively. For tomato soil, T-CV treatment increased the activities of catalase, invertase and urease by 13.97%, 27.49%, and 20.65% respectively before planting compared with T-CK treatment, and by 28.70%, 46.73%, and 25.69% respectively after planting. Compared with the T-CK treatment, the corresponding parameters of the T-HV treatment increased by 9.29%, 28.84%, and 12.87% before colonization, and by 41.57%, 50.28%, and 18.09% after colonization. In cucumber soil, compared with the Cu-CK treatment, the Cu-CV treatment significantly increased the urease activity, with an increase of 93.39% before and 57.25% after planting. The invertase activity increased by 27.66% and 31.20% respectively in the two periods. The increase in catalase activity was relatively small, being 6.67% before transplanting and 7.66% after transplanting, respectively. The Cu-HV treatment also showed a similar trend, among which the increase in urease activity was the most prominent, being 79.00% before and 52.00% after transplanting, respectively. Comprehensive comparison showed that both leguminous green manures can effectively activate the soil enzyme system. Among them, the hairy vetch showed better performance in enhancing the catalase activity of chili peppers, while the arrow pea has a more significant effect in promoting the urease activity of cucumber. Tab le 3 Effects of leguminous green manure crops on soil enzyme activities of chili, tomato, and cucumber Pre - planting Treatment Peroxidase (μmol·d -1 ·g -1 ) Invertase (mg·d -1 ·g -1 ) Urease (ug·d -1 ·g -1 ) Pre - planting Post - planting Pre - planting Post - planting Pre - planting Post - planting C-CK 25.5±0.9b 21.4±1.0c 20.5±0.9b 17.6±0.8c 222.1±9.0b 204.7±6.5b C-CV 33.8±1.8a 26.9±1.6b 25.3±1.0a 22.4±1.0a 252.9±8.1a 229.5±3.4a C-HV 35.9±1.1a 32.1±2.4a 24.0±2.5a 20.4±0.6b 260.6±16.0a 237.6±5.4a T-CK 52.7±1.4b 32.6±2.7c 24.7±3.7b 17.8±1.3b 236.0±9.9c 203.6±6.6b T-CV 60.1±1.2a 42.0±1.7b 31.5±2.8a 26.2±2.3a 284.7±8.0a 255.9±9.0a T-HV 57.6±1.2a 46.2±0.9a 31.9±3.5a 26.8±2.2a 266.4±9.1b 240.4±14.7a Cu-CK 47.0±0.2c 29.6±0.6b 30.4±0.7b 15.6±1.1b 125.1±3.7c 102.5±2.1b Cu-CV 50.1±0.3a 31.9±0.6a 38.8±1.1a 20.5±0.9a 241.9±6.5a 161.1±2.3a Cu-HV 49.3±0.5b 32.4±1.1a 39.4±0.7a 19.4±0.4a 224.3±11.1a 156.1±10.1a The data are presented as means ± SDs (n=3). Different lowercase letters indicate significant differences among green manure treatments within the same vegetable (p<0.05, Duncan’s multiple range test). Corresponding one-way ANOVA results are provided in Table 3 Impact on the quantity of soil microorganisms In the rhizosphere soil of chili peppers, compared with the C-CK treatment, the C-CV treatment increased the quantity of bacteria after planting by 60.96%. The quantity of fungi increased by 56.54%. C-HV treatment also showed a similar trend, with the quantity of bacteria and fungi increasing by 60.11% and 61.36% respectively compared to C-CK treatment. The two are similar in bacterial promoting effect, while the hairy vetch is slightly better than the arrow pea in increasing the quantity of fungi. The influence on the rhizosphere microorganisms of tomato was more significant. Compared with T-CK treatment, T-CV treatment increased the quantity of bacteria by 46.50%. The quantity of fungi increased by 90.62%. Bacterial and fungal quantities under T-HV treatment increased by 35.40% and 82.96% respectively compared with those under T-CK treatment. In tomato cultivation, arrow pea was significant in promoting fungal proliferation. In the rhizosphere soil of cucumber, the increase in the quantity of microorganisms were relatively moderate. Compared with the Cu-CK treatment, the Cu-CV treatment increased the bacterial count by 3.61% before colonization and by 3.79% after colonization. The Cu-HV treatment also showed a similar trend. The increase in the number of bacteria before and after colonization was 3.00% compared with the Cu-CK treatment. Correlation analysis Correlation between yield and the physicochemical properties and biological characteristics of soil The yield of chili peppers was positively correlated with all soil parameters. Among them, the correlation with alkaline hydrolyzable nitrogen was the strongest (r=0.841), followed by available potassium (r=0.798), and organic matter (r=0.794). The quantity of soil microorganisms was closely related to the yield. The correlation coefficients between the quantity of bacteria and fungi and the yield reach 0.758 and 0.792 respectively. Among soil enzyme activities, urease has the highest correlation with yield (r=0.671), indicating that nitrogen conversion efficiency has a significant impact on the improvement of chili yield. Tomato yield has the strongest correlation with soil available phosphorus content (r=0.857), and also showed a significant positive correlation with urease activity (r=0.775) and bacterial count (r=0.760). It is worth noting that tomato yield was negatively correlated with the quantity of fungi (r=-0.487), which may be related to the specific microbial community structure in the tomato root zone. The correlation between cucumber yield and various soil parameters is relatively weak, but it still maintains a significant positive correlation with organic matter (r=0.752) and bacterial quantity (r=0.760), indicating that soil basic fertility and microbial activity support the stability of cucumber yield. Comprehensive analysis shows that the return of leguminous green manure to the field simultaneously enhances the availability of soil nutrients, especially alkaline hydrolyzable nitrogen and available phosphorus. Return of leguminous green manure to the field enhanced the activities of the enzyme system, especially urease and invertase; promoted the proliferation of microorganisms, mainly bacteria and formed the soil biological basis for the increased in yield. Correlation between quality parameters and physiological morphology parameters of the aboveground parts The quality of chili peppers is closely related to photosynthetic physiological parameters. The content of soluble sugar had the highest correlation with the transpiration rate (T r ) (r=0.870), and also showed a significant positive correlation with stomatal conductance (G s ) (r=0.750). The content of vitamin C was highly correlated with the SPAD value (r=0.813) and the transpiration rate (r=0.879). Notably, the intercellular CO₂ concentration (C i ) was negatively correlated with most quality parameters., which might reflect the indirect influence of stomatal regulation on the distribution of carbon assimilation products. Analysis of tomato quality revealed that soluble sugar was significantly correlated with net photosynthetic rate (P n ) and SPAD value (r>0.849), while vitamin C was highly correlated with SPAD value (r=0.949), further verifying the core role of photosynthetic capacity in the formation of fruit nutritional quality. The quality of cucumbers showed a similar pattern. The content of soluble sugar was significantly correlated with plant height (r=0.900) and transpiration rate (r=0.844). The content of vitamin C was also highly correlated with plant height (r=0.894) and transpiration rate (r=0.821). The content of organic acids was negatively correlated with most above-ground indicators, especially having the strongest negative phase correlation with stomatal conductance (G s ) (r=-0.890), indicating that enhanced photosynthesis helps to reduce fruit acidity and optimize the sugar-acid ratio. Discussion The synergistic promoting effect of multi-cropping leguminous green manure on vegetable yield and single fruit weight The results of this study demonstrated that, compared with no catch cropping of green manure after vegetable harvest, planting legume green manure as a catch crop significantly increased the single‑fruit weight and yield per unit area of chili, tomato, and cucumber. Specifically, the total yield of chili increased by 19.42% after catch cropping with common vetch (Vicia sativa) and by 16.17% after hairy vetch (Vicia villosa). Tomato and cucumber also exhibited consistent yield‑enhancing trends under the corresponding green manure treatments, which aligns with previous findings in cereal‑based cropping systems (Wei et al. 2025 ). The yield‑improving effects of legume green manure are closely associated with comprehensive improvements in soil physicochemical properties and biological activity. Specifically, green manure crops, through rhizobial nitrogen fixation, significantly increase soil alkali‑hydrolyzable nitrogen content, thereby providing sustained nitrogen supply for subsequent vegetable crops and creating a favorable soil nutrient environment (Li et al. 2025c ). Meanwhile, catch cropping with green manure significantly enhanced the activities of soil catalase, sucrase, and urease, promoting nutrient transformation and supply capacity and effectively improving soil fertility (Mi et al. 2024 ), thus optimizing nutrient uptake efficiency of vegetable roots. In addition, green manure treatments promoted an increase in soil bacterial and fungal populations, improved the rhizosphere micro‑ecological environment, and enhanced the stability and nutrient‑cycling capacity of the soil system (Chen et al. 2022 ; Nie et al. 2025 ), providing favorable rhizosphere conditions for vegetable growth. From the perspective of plant physiology, green manure treatments significantly improved plant height, stem diameter, root morphological indices, and root activity (He et al. 2025 ), while increasing net photosynthetic rate, stomatal conductance, and chlorophyll content, thereby enhancing light‑use efficiency and laying a physiological foundation for yield improvement. It is noteworthy that the significant increase in single‑fruit weight further confirms the positive role of green manure in promoting the translocation and accumulation of photosynthetic products into fruits, particularly evident in larger‑fruited crops such as cucumber. This suggests that catch cropping with green manure helps optimize carbon allocation and sink strength expression during fruit development (Li et al. 2025a ). In summary, catch cropping with legume green manure systematically improved soil quality, enhanced nutrient supply, optimized microbial community structure and plant physiological functions, ultimately leading to a significant increase in vegetable yield. Against the context of rational reduction in chemical fertilizer application, green manure, as an efficient and environmentally friendly bio‑fertilizer, holds significant potential for widespread adoption. Response mechanism of chili nutritional quality to catch cropping with legume green manure The results of this study indicated that catch cropping with legume green manure can significantly enhance the nutritional quality of chili fruits, with the most pronounced effects observed under the common vetch treatment. Specifically, vitamin C content increased by 113.99% and soluble sugar content by 30.33%, demonstrating that legume green manure positively regulates the accumulation of secondary metabolites and nutrients in chili fruits. This quality improvement is closely associated with the comprehensive amelioration of soil physicochemical properties, enzyme activities, and plant physiological functions by green manure. From a physiological perspective, catch cropping with green manure significantly improved the photosynthetic performance and root activity of chili. This promoted the translocation of photosynthetic assimilates to the fruits and optimized the carbon-nitrogen metabolic balance, thereby providing the material basis for the synthesis of vitamin C, soluble sugars, and proteins (Zhou et al. 2025b ). Regarding the soil environment, the gradual decomposition of legume green manure continuously released mineral nutrients, effectively ensuring a balanced nutrient supply during the fruit development stage and directly contributing to the synthesis of proteins and vitamins (Makino et al. 2022 ; Zhang et al. 2025 ). Concurrently, the green manure treatment enhanced the activities of key soil enzymes, accelerated the transformation and cycling of soil nutrients, and intensified the biological activity within the rhizosphere microenvironment (Yang et al. 2023 ), indirectly supporting fruit quality formation. It is noteworthy that the significant increase in single-fruit weight of chili was accompanied by a synergistic enhancement of key nutritional parameters such as vitamin C, with no observed dilution effect. This suggests that the green manure treatment not only promoted fruit expansion but also concurrently strengthened the bio-enrichment capacity for nutrients during this process (Liu et al. 2022 ). This highlights the integrated agronomic value of green manure in coordinating both the yield and quality of vegetable crops. Flavor quality formation pathway: optimization of tomato sugar-acid ratio and regulation by green manure The balance of the sugar-acid ratio was central to tomato flavor quality. In this study, the hairy vetch catch crop treatment increased the soluble sugar content of tomato by 16.25% while decreasing the organic acid content by 3.35%, thereby significantly optimizing the sugar-acid ratio and improving fruit flavor. This enhancement in flavor quality was closely linked to the integrated regulation of plant physiological traits and the rhizosphere microenvironment by the green manure. From the perspective of photosynthetic performance, the green manure treatment significantly increased the net photosynthetic rate and stomatal conductance of tomato leaves. This promoted the accumulation of photosynthetic products and their translocation to the fruits, providing an ample material foundation for sugar synthesis (Ozturk and Ozer 2019 ). Regarding soil nutrients, the decomposition process of the legume green manure continuously releases mineral elements such as nitrogen (Song et al. 2022a ). This sustained and balanced nutrient supply regulated the activities of key enzymes involved in organic acid metabolism, such as malic enzyme and citrate synthase, during fruit development, thereby influencing the metabolic flux of malic and citric acids (Song et al. 2023 ). Furthermore, catch cropping with green manure significantly altered the rhizosphere microbial community structure. These changes in the microbial community indirectly regulated key nodes in the sugar-acid metabolic pathways by modulating plant endogenous hormone levels or carbon allocation patterns (Wang et al. 2021 ). Analyzing fruit development dynamics, the single-fruit weight of tomato showed steady growth under the green manure treatment, with no observed decline in sugar content due to fruit enlargement. This indicated that the green manure treatment possesses a distinct advantage in coordinating fruit sink strength with the accumulation of flavor compounds, achieving a synergistic improvement in both yield and flavor. These findings provide a new theoretical basis for the targeted regulation of tomato flavor quality. Green manure-driven mechanisms underlying the accumulation of sugars and vitamin C in cucumber Within the cucumber cultivation system, catch cropping with legume green manure notably enhanced the fruit's soluble sugar and vitamin C contents. Specifically, the hairy vetch treatment increased soluble sugar by 67.00%, while the common vetch treatment demonstrated superior performance in boosting vitamin C levels. This indicated functional specificity among different green manure species in regulating cucumber nutritional quality. This quality improvement stems from the synergistic regulation of plant physiological traits and the soil environment by green manure. Regarding photosynthetic performance, the green manure treatment significantly increased the net photosynthetic rate and stomatal conductance of cucumber leaves, promoting carbohydrate synthesis within the foliage (Merlo Mendes et al. 2022 ) and thereby providing ample material for sugar accumulation in the fruits. In terms of root development, catch cropping with green manure effectively optimized cucumber root architecture and physiological activity (He et al. 2025 ), enhancing the plant's capacity for water and mineral nutrient uptake, which supports nutritional balance in the developing fruits. From a soil nutrient perspective, the green manure treatment significantly increased the contents of available phosphorus and potassium. The effective supply of these key nutrients likely directly participates in the biochemical pathways of sugar metabolism and vitamin C synthesis, regulating the activities of key enzymes such as fructokinase and GDP-galactose phosphorylase (Bhalla and Garg 2021 ). Considering the relationship between single-fruit weight and quality, cucumber fruit size increased steadily under green manure treatments, accompanied by simultaneous rise in sugar content and vitamin C levels. This indicated that the green manure treatment effectively coordinated to the synergistic improvement of both quality and yield while promoting fruit development, providing a viable technical pathway for the green and high-quality production of cucumber. Conclusion This study systematically assessed the effects of legume green manure catch cropping on chili, tomato and cucumber. Results showed that incorporating common vetch or hairy vetch after harvest significantly improved soil organic matter content, nutrient availability, enzyme activities and microbial populations. This practice also enhanced plant growth including height, stem diameter and root development, as well as photosynthetic performance, contributing to higher single fruit weight and total yield. Improvements in vegetable quality included increased vitamin C, soluble sugars and protein in chili, optimized sugar acid ratio in tomato, and elevated soluble sugar and vitamin C in cucumber. Legume green manure catch cropping synergistically boosts vegetable yield, quality and soil health, offering a reliable theoretical basis for green and high yield vegetable cultivation. Declarations Acknowledgments We are very grateful for the Research Program Sponsored by the Scientific Research Innovation Capability Support Project for Young Faculty (SRICSPYF-BS2025119), the National Natural Science Foundation of China (32372238 and 32460547), the financial support of the Science and Technology Program in Gansu Province (24JRRA124 and 25JRRA347), the Lanzhou Youth Science and Technology Talent Innovation Project of Gansu Province (2024–QN–128), the Young Doctor Support Project of Gansu Province (2024QB–008), the Young Teachers Research Ability Enhancement Project in Northwest Normal University of China (NWNU-LKQN2024-16 and NWNU–LKQN2023–09), and the Gansu-Tianjin Cooperation Project of the Science and Technology Department of Gansu Province (24CXNA077). Author contributions Yao Guo: Conceptualization, Data curation, Formal analysis, Project administration, and Writing–original draft. Zhuohan Zhang: Data curation and Methodology, and Writing–original draft. 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Front Plant Sci 14:1186376. https://doi.org/10.3389/fpls.2023.1186376 Yao Z, Zhang D, Yao P, et al (2018) Optimizing the synthetic nitrogen rate to balance residual nitrate and crop yield in a leguminous green-manured wheat cropping system. Sci Total Environ 631–632:1234–1242. https://doi.org/10.1016/j.scitotenv.2018.03.115 Zhang H, Chen L, Wang Y, et al (2025) Straw and green manure return can improve soil fertility and rice yield in long-term cultivation paddy fields with high initial organic matter content. Plants (basel Switz) 14:1967. https://doi.org/10.3390/plants14131967 Zhao N, Bai L, Han D, et al (2024) Combined Application of Leguminous Green Manure and Straw Determined Grain Yield and Nutrient Use Efficiency in Wheat-Maize-Sunflower Rotations System in Northwest China. Plants (Basel) 13:1358. https://doi.org/10.3390/plants13101358 Zhao Q, Cao X, Zhang L, et al (2025) Analysis of the differences in rhizosphere microbial communities and pathogen adaptability in chili root rot disease between continuous cropping and rotation cropping systems. Microorganisms 13:1806. https://doi.org/10.3390/microorganisms13081806 Zhou F, Xu L, Liu X, et al (2025a) Preceding Crop Straw Return Methods Influence the Disease Severity of Wheat Crown Rot. Phytopathology 115:783–793. https://doi.org/10.1094/PHYTO-12-24-0386-R Zhou G, Li G, Liang H, et al (2025b) Green manure coupled with straw returning increases soil organic carbon via decreased priming effect and enhanced microbial carbon pump. Global Change Biol 31:e70232. https://doi.org/10.1111/gcb.70232 Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Major revisions 10 May, 2026 Reviewers agreed at journal 15 Apr, 2026 Reviewers invited by journal 15 Apr, 2026 Editor invited by journal 14 Apr, 2026 Editor assigned by journal 13 Apr, 2026 First submitted to journal 09 Apr, 2026 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9115168","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":623548107,"identity":"e20e72ff-e7bc-4252-b977-0214587bf2aa","order_by":0,"name":"Yao Guo","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Yao","middleName":"","lastName":"Guo","suffix":""},{"id":623548108,"identity":"1cc85b8e-4287-48c4-a4ca-e4c132e854c4","order_by":1,"name":"Zhuohan Zhang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4ElEQVRIiWNgGAWjYBACNvbmg49/VNjI8QMZDxIqaghr4eM5lmzMcCbNWLLnWLLBgzPHCGuRk8hRk2ZsO5xocCPHTPJhCzMRDuM5wyBd2HY4weBGWlpFYgMbA397dwIBv/QeMJ5xLj1P8szjYzcSd8gwSJw5u4GALecSEnjKrIv5jqel3Ug8w8ZgIJFLQItEjsEBHjbmxIYDOWYFiW3MRGkxbOZpc06ccCLHjIE4LcBAZpwBDWSJhDPHeAj6Rb69+fiPD9Co/PijokaOv70XvxYMwEOa8lEwCkbBKBgFWAEA+vVQp+p9MlEAAAAASUVORK5CYII=","orcid":"","institution":"Northwest Normal University","correspondingAuthor":true,"prefix":"","firstName":"Zhuohan","middleName":"","lastName":"Zhang","suffix":""},{"id":623548109,"identity":"fe06be8f-bbf4-49ff-acab-128d6e3234a9","order_by":2,"name":"Jiayue Ma","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Jiayue","middleName":"","lastName":"Ma","suffix":""},{"id":623548110,"identity":"f907954c-5dbc-47e3-aecf-2dd2291d6484","order_by":3,"name":"Guoli 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13:19:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9115168/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9115168/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107631405,"identity":"1f8729b7-7973-42ed-8acf-1aba0c4b937d","added_by":"auto","created_at":"2026-04-23 11:48:49","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":140828,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(A) \u003c/strong\u003eThe effect of catch cropping leguminous green manure on the single fruit weight of chili and cucumber\u003cstrong\u003e (B) \u003c/strong\u003eThe effect of catch cropping leguminous green manure on the total vegetable output\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-9115168/v1/303e3a3f3ca2cd0ff58a56fb.png"},{"id":107707312,"identity":"58dc0ed6-97cb-4388-bedc-e35aa879cd60","added_by":"auto","created_at":"2026-04-24 09:20:03","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":95474,"visible":true,"origin":"","legend":"\u003cp\u003eEffects of catch cropping leguminous green manure on vegetable quality\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-9115168/v1/6376e35aab940fd732f81866.png"},{"id":107631407,"identity":"e0c22a7b-de42-4b9e-b93d-6abd519bb2fd","added_by":"auto","created_at":"2026-04-23 11:48:49","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":150968,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(A) \u003c/strong\u003eThe effect of returning leguminous green manure to the field on the net photosynthetic rate of vegetables \u003cstrong\u003e(B) \u003c/strong\u003eThe effects of leguminous green manure crops on the number of soil microorganisms before and after the planting of chili, tomato, and cucumber.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-9115168/v1/453ed08c82bd652014ebcebc.png"},{"id":107631408,"identity":"b0e26f95-7bef-4e9c-a0ee-b882123bb29e","added_by":"auto","created_at":"2026-04-23 11:48:49","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":424330,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation analysis of the impacts of returning leguminous green manure to the field on the yield and quality of vegetables. \u003cstrong\u003e(A)\u003c/strong\u003e Correlation analysis of the effects of leguminous green manure incorporation on pepper yield and quality, \u003cstrong\u003e(B)\u003c/strong\u003e Correlation analysis of the effects of leguminous green manure incorporation on tomato yield and quality, \u003cstrong\u003e(C)\u003c/strong\u003e Correlation analysis of the effects of leguminous green manure incorporation on cucumber yield and quality\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-9115168/v1/8ed5c654dd0077cb4b1b9860.png"},{"id":107709197,"identity":"fe1a4944-5dfd-4c85-ac88-2d1f2667ef86","added_by":"auto","created_at":"2026-04-24 09:34:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1073872,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9115168/v1/828b862b-43cd-401c-a3b0-11a0332aa043.pdf"}],"financialInterests":"","formattedTitle":"Returning green manure to the field increases yield and quality of chili, tomato, and cucumber","fulltext":[{"header":"Introduction","content":"\u003cp\u003eChili (\u003cem\u003eCapsicum annuum\u003c/em\u003e L.), tomato (\u003cem\u003eSolanum lycopersicum\u003c/em\u003e L.), and cucumber (\u003cem\u003eCucumis sativus\u003c/em\u003e L.) are important vegetables widely cultivated around the world. chili and tomato both belong to the Solanaceae family, while cucumber belong to the Cucurbitaceae family. The three fruits are rich in vitamin C, flavonoids and various minerals, and have high nutritional and health values. Chilis contain capsaicin, while cucumbers are rich in dietary fiber and various amino acids. The expansion of production scale, improvement of intensive planting, and long-term continuous cropping have led to a series of prominent problems (Wang et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2024\u003c/span\u003e): decreased soil fertility, deterioration of physical and chemical properties, imbalance of micro-ecological structure (Han et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), and enrichment of soil-borne pathogenic bacteria (Zhou et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2025a\u003c/span\u003e). Consequently, continuous cropping obstacles have become increasingly serious in vegetable production systems (Lyu et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).These factors significantly inhibit the root development and growth of chilis, tomatoes and cucumbers leading to a decline in fruit yield and quality (Zhao et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). This poses a serious threat to the sustainability and safe production of vegetables. Therefore, it is urgently necessary to develop scientific planting models to improve the soil micro-ecological environment, enhance land productivity, and achieve efficient and high-quality production of these economic crops.\u003c/p\u003e \u003cp\u003eThe absorption of mineral nutrients by different plants at different times are usually different. Continuous cultivation of the same plant for several years usually leads to excessive consumption of certain mineral elements, eventually resulting in soil nutrient deficiency and thus affecting the growth of plants. Diversified planting is an important method for agricultural ecosystems to enhance soil fertility. Different plant root secretions, residue retention and field management can significantly affect soil organic matter (SOM) content (Song et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2022b\u003c/span\u003e), pH value, aggregate structure, and microbial community composition, nitrogen mineralization and cycling of phosphorus and potassium (Friberg et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). In wheat-corn rotation system, catch cropping of leguminous green manure such as milk vetch and hairy vetch can regulate soil pH through the secretion of organic acids by the root system. After the decomposition of the residues, it increases soil organic matter, promotes the formation of aggregates, increases soil nitrogen, and fixation of root nodules (Yao et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). At the same time, it provides carbon sources for the activation of phosphorus and potassium, enhances the abundance of microorganisms for nitrogen-fixation, and phosphorus-solubilization (Huang et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). These changes in soil properties directly affect the root formation, nutrient utilization, growth and development, and stress resistance of subsequent crops, thereby influencing yield and quality. Other studies have shown that rotation with leguminous green manures in moderately saline-alkali soil reduces soil pH and electrical conductivity (EC), increases organic matter and total nitrogen (TN), and enhances fresh yield and protein content of subsequent silage corn, confirming their positive impacts on crop productivity and quality (Zhao et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).Therefore, under the orientation of sustainable agriculture, scientifically screening the types of previous crops and rationally utilizing their residues to improve soil structure, increase beneficial microorganisms, and regulate nutrient availability have become the core strategies for enhancing system productivity.\u003c/p\u003e \u003cp\u003eStudies have shown that catch cropping leguminous green manure crops can increase soil nutrient and organic matter content, and has become a core strategy for enhancing soil fertility in rotation systems of major food crops such as wheat, corn, and rice (Ramos et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). Ploughing and returning leguminous green manure crops to the field can significantly improve soil quality, increase the content of alkaline hydrolyzable nitrogen (AN) in the soil, replenish the organic carbon pool, promote the formation of aggregate structure, enhance soil water retention capacity, and soil porosity (Xiang et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). More importantly, leguminous green manure alters the microbial community structure of the plant rhizosphere, promotes the production and growth of beneficial bacteria, interferes with the growth of pathogenic bacteria, thereby stimulating plant growth, enhancing plant disease resistance, and preventing the occurrence of soil-borne diseases. It has a positive effect on increasing the yield of continuous crops (Huang et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). In addition, leguminous green manure can enhance the transformation ability of microorganisms, increase the utilization rate of elements such as N and P, and strengthen the nutrient supply to plant roots (Li et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2025b\u003c/span\u003e). The above indicates that the catch cropping of leguminous green manure significantly promotes the growth, development and physiological metabolism of subsequent crops through the improvement of soil quality and the reorganization of microbial communities.\u003c/p\u003e \u003cp\u003eAt present, there is still a lack of systematic evaluation on whether re-planting green manure during the leisure period of the vegetable rotation system can effectively increase the yield and quality of the subsequent vegetables, especially in terms of the differences in the effects of different leguminous green manure combinations with specific vegetables. For this purpose, this study focused on chili (variety: XJ01), tomato (variety: Jingfan 501), and cucumber (variety: Taking Changqing No.1) as the object, and set up three treatments: no green manure planting after vegetable harvest (CK), catch cropping of arrow pea after vegetable harvest (CV), and catch cropping of hairy vetch after vegetable harvest (HV). The effects of catch cropping different leguminous green manure during the fallow period and returning it to the field on soil physical and chemical properties, biological characteristics, as well as the growth, yield and quality of vegetables were systematically compared. We explored the regulatory mechanism of green manure application on vegetable yield and quality formation to clarify the actual effect of green manure replanting during fallow periods on vegetable production. This study further aims to provide theoretical basis and technical support for green, high-yield vegetable cultivation and the improvement of cultivated soil quality.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003eTest materials\u003c/p\u003e\n\u003cp\u003eVarieties linear chili \u0026ldquo;XJ01\u0026rdquo;, \u0026ldquo;Jingfan 501\u0026rdquo;, and \u0026ldquo;Changqing No.1\u0026rdquo; of chili, tomato, and cucumber were used respectively. Three different pre-crop treatment methods were formed by using two types of green manure: no replanting of green manure after vegetable harvest (CK), replanted arrow pea after vegetable harvest (CV), and hairy vetch (HV). The experiment was conducted in 2024. The soil type was loam with a PH of 6.8 to 7.8 with an organic matter content of 16.3 to 28.6 g\u0026middot;kg\u003csup\u003e-1\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eExperimental design\u003c/p\u003e\n\u003cp\u003eThe experiment was conducted in a greenhouse in Li jiazhuang, Yu zhong County, Gansu Province. On September 20, 2023, seedlings of tomato, chili, and cucumber were raised. They were planted on ridges, with the bottom width being 1 m, surface width being 0.8 m, and the length being 6 m. The spacing between ridges was 0.25 m, and the plant and row spacing was 0.4 m \u0026times; 0.6 m respectively. They were planted in double rows. The plot area was 5 m \u0026times; 6 m = 30 m\u003csup\u003e2\u003c/sup\u003e. In this experiment, tomatoes were planted on November 5, 2023. Before planting, 400 kg\u0026middot;ha\u003csup\u003e-1\u003c/sup\u003e of organic fertilizer was applied at one time. The application rates of chemical fertilizer as base fertilizer were 23.70 kg\u0026middot;ha\u003csup\u003e-1\u003c/sup\u003e of N, 38.40 kg\u0026middot;ha\u003csup\u003e-1\u003c/sup\u003e of P₂O₅, and 72.90 kg\u0026middot;ha\u003csup\u003e-1\u003c/sup\u003e of K₂O. The tomato harvest started on March 5, 2024, and ended on April 30. Peppers were planted on December 10, 2023. Before planting, 500 kg\u0026middot;ha\u003csup\u003e-1\u003c/sup\u003e of organic fertilizer was applied at one time, and the application rate of chemical fertilizer as base fertilizer was the same as that for tomatoes. The harvest period of peppers was from February 25 to April 30, 2024. Cucumbers were planted on January 20, 2024. Before planting, 500 kg\u0026middot;ha\u003csup\u003e-1\u003c/sup\u003e of organic fertilizer was applied at one time, and the application rate of chemical fertilizer as base fertilizer was the same as that for tomatoes and peppers. The harvest period of cucumbers was from March 15 to April 30, 2024. These fertilizers are common commercially available diammonium phosphate (with N content of 15.5% and P\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e content of 46%), calcium nitrate (with N content of 15%), and agricultural potassium sulfate (with K\u003csub\u003e2\u003c/sub\u003eO content of 52%).\u003c/p\u003e\n\u003cp\u003eThe experiment adopted a randomized block design and set up three pre-crop treatments. Two types of green manure, namely, no replanting of green manure after vegetable harvest (CK), replanting of arrow pea after vegetable harvest (CV), and hairy vetch (HV), were selected to form three different pre-crop treatment methods. Three vegetable varieties were planted, namely chili, tomato, and cucumber. Each treatment was repeated three times, with a total of 27 plots. Under different treatments of the previous crop, all were managed in accordance with the conventional cultivation methods. The arrow pea (LAN Jian No. 2) and the Turkmen hairy vetch were sown on July 5, 2023, and were fully crushed and returned to the soil by manual return to the field in early October of the same year. The sowing rates of arrow pea and hairy vetch were 225 kg\u0026middot;ha\u003csup\u003e-1\u003c/sup\u003e and 25 kg\u0026middot;ha\u003csup\u003e-1\u003c/sup\u003e respectively. Both green manure sowing methods were row sowing with a row spacing of 15 cm. Nitrogen and phosphorus fertilizers were applied as base fertilizer, while green manure was irrigated at 700 m\u003csup\u003e3\u003c/sup\u003e\u0026middot;ha\u003csup\u003e-1\u003c/sup\u003e and 900 m\u003csup\u003e3\u003c/sup\u003e\u0026middot;ha\u003csup\u003e\u0026ndash;1\u003c/sup\u003e during the seedling and bud formation stages, respectively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTa\u003c/strong\u003e\u003cstrong\u003eble\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e1\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eTreatment combination codes and specific measures for different vegetables under different planting models\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" align=\"\" width=\"589\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003eVegetables\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 295px;\"\u003e\n \u003cp\u003ePlanting Patterns\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 200px;\"\u003e\n \u003cp\u003eTreatment Combination Codes\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 94px;\"\u003e\n \u003cp\u003eChili\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 295px;\"\u003e\n \u003cp\u003eNo catch - cropping of green manure after harvest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 200px;\"\u003e\n \u003cp\u003eC-CK\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 295px;\"\u003e\n \u003cp\u003eCatch - cropping of vicia sativa after harvest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 200px;\"\u003e\n \u003cp\u003eC-CV\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 295px;\"\u003e\n \u003cp\u003eCatch - cropping of hairy vetch after harvest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 200px;\"\u003e\n \u003cp\u003eC-HV\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 94px;\"\u003e\n \u003cp\u003eTomato\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 295px;\"\u003e\n \u003cp\u003eNo catch - cropping of green manure after harvest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 200px;\"\u003e\n \u003cp\u003eT-CK\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 295px;\"\u003e\n \u003cp\u003eCatch - cropping of vicia sativa after harvest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 200px;\"\u003e\n \u003cp\u003eT-CV\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 295px;\"\u003e\n \u003cp\u003eCatch - cropping of hairy vetch after harvest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 200px;\"\u003e\n \u003cp\u003eT-HV\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 94px;\"\u003e\n \u003cp\u003eCucumber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 295px;\"\u003e\n \u003cp\u003eNo catch - cropping of green manure after harvest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 200px;\"\u003e\n \u003cp\u003eCu-CK\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 295px;\"\u003e\n \u003cp\u003eCatch - cropping of vicia sativa after harvest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 200px;\"\u003e\n \u003cp\u003eCu-CV\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 295px;\"\u003e\n \u003cp\u003eCatch - cropping of hairy vetch after harvest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 200px;\"\u003e\n \u003cp\u003eCu-HV\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eMeasurement indicators and methods\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePhysical and chemical properties of soil\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eSoil samples were taken from the plough layer of each plot before and after the vegetable planting. Rhizosphere soil samples at a depth of 5-15 cm were collected at three random points. The soil samples were mixed evenly, air-dried and ground, and passed through a 100-mesh sieve for the determination of soil physical and chemical properties. The samples were analyzed according to traditional soil agrochemical techniques: The determination of SOM adopted the potassium dichromate oxidation - external heating method; The determination of alkaline hydrolyzable nitrogen (AN) was carried out by the alkaline diffusion method. After ammonium fluoride-hydrochloric acid extraction, the available phosphorus (AP) was determined by the molybdenum-antimony colorimetric method. Determination of available potassium (AK) by atomic absorption spectrophotometry after ammonium acetate extraction. Soil pH was determined in accordance with the Chinese National Environmental Protection Standard HJ 962-2018. Firstly, the dry soil was weighed 10 grams and put into a 50 mL beaker. 25 mL of water was added (volume ratio 1:2.5) and sealed with a film. It was stirred vigorously with a magnetic stirrer for 2 minutes and left to stand for 30 minutes before the pH was measured with a pH meter. The conductivity (EC) was measured using a DSS-307 conductivity meter for the extract with a soil-to-water ratio of 1:5(w/v), and the reading was taken after calibration at a constant temperature of 25\u0026deg;C.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eSoil biological characteristics\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eSoil samples were taken from the plough layer of each plot before and after vegetable planting. Rhizosphere soil samples at a depth of 5-15 cm were collected at three random points. The samples were mixed evenly, air-dried and ground, and sieved through a 100-mesh sieve for the determination of soil biological characteristics. The activity of catalase (CAT) was determined by potassium permanganate titration using 5 g of soil sample weighed, 40 mL of 0.3% H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e solution was added, shaken for 20 minutes, and 5 mL of 1.5 mol\u0026middot;L\u003csup\u003e-1\u003c/sup\u003e H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e solution added. The remaining H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e was titrated with 0.1 mol\u0026middot;L\u003csup\u003e-1\u003c/sup\u003e KMnO\u003csub\u003e4\u003c/sub\u003e solution, and the enzyme activity was calculated. The activity of invertase (Inv) was determined by the 3, 5-dinitrosalicylic acid colorimetric method using 5 g of soil sample weighed, 15 mL of 8% sucrose solution and 0.5 mL of toluene were added, and the mixture was cultured at 37\u0026deg;C for 24 hours. Subsequently, DNS reagent was added for color development, and the absorbance was measured at a wavelength of 540 nm to calculate the enzyme activity. Urease (Ure) activity was determined by the sodium phenol-sodium hypochlorite colorimetric method using 5 g of soil sample weighed, 10 mL of 10% urea solution and 0.2 mL of toluene were added, and the sample was cultured at 37\u0026deg;C for 24 hours. Subsequently, after color development treatment, the absorbance was measured at a wavelength of 578 nm, and the enzyme activity was calculated.\u003c/p\u003e\n\u003cp\u003eFresh soil sample was weighed 10 g added 90 mL of sterile physiological saline and shook at 25\u0026deg;C and 180 r\u0026middot;min\u003csup\u003e-1\u003c/sup\u003e for 30 minutes to prepare a 10\u003csup\u003e-1\u003c/sup\u003e soil suspension. A series of diluents of 10\u003csup\u003e-2\u003c/sup\u003e, 10\u003csup\u003e-3\u003c/sup\u003e, 10\u003csup\u003e-4\u003c/sup\u003e, 10\u003csup\u003e-5\u003c/sup\u003e, 10\u003csup\u003e-6\u003c/sup\u003e and 10\u003csup\u003e-7\u003c/sup\u003e were prepared in sequence by the gradient dilution method. Three dilution gradients of 10\u003csup\u003e-5\u003c/sup\u003e, 10\u003csup\u003e-6\u003c/sup\u003e, and 10\u003csup\u003e-7\u003c/sup\u003e were selected and taken 0.1 mL of soil suspension from each gradient and evenly spread on the beef extract peptone medium plate with three repetitions for each gradient. The plate was inverted and incubated in a constant incubator temperature at 28\u0026deg;C for 48 hours. After the cultivation was completed, plates with a colony count ranging from 30 to 300 were selected for counting. The number of bacteria per gram of dry soil was calculated (the mass of dry soil was converted based on soil moisture content), and the result was expressed as CFU\u0026middot;g\u003csup\u003e-1\u003c/sup\u003e dry soil. Two dilution gradients of 10\u003csup\u003e-3\u003c/sup\u003e and 10\u003csup\u003e-4\u003c/sup\u003e were selected. 0.1 mL of soil suspension was taken from each gradient and evenly spread on Marding\u0026apos;s medium plates. Three repetitions were set for each gradient and the plates were inverted and incubated in a constant incubator temperature at 28\u0026deg;C for 72 hours. After the cultivation was completed, plates with a colony count ranging from 10 to 100 were selected for counting. The number of fungi per gram of dry soil was calculated (the mass of dry soil was converted based on soil moisture content), and the result was expressed as CFU\u0026middot;g\u003csup\u003e-1\u003c/sup\u003e dry soil.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePlant growth and development Parameters\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThree representative plants were randomly selected from each community to measure their growth and development. The plant height was measured with a ruler. The measurement range was the vertical height from the ground to the growth point of the plant, with the unit being cm. The stem diameter was measured with a vernier caliper with an accuracy of 0.01mm, and the measurement position was the diameter 2 cm above the base of the stem. After washing the root systems of the plants, they were scanned and analyzed using the WinRHIZO LA-S root scanner. The measured parameters included root length, root surface area, and root volume. Root vitality was reduced by the 2,3, 5-triphenyltetrazolium chloride reduction method (TTC reduction method). Fresh plant roots were weighed 0.5g and soaked in 0.4% TTC-phosphate buffer solution (pH 7.5), kept under 37\u0026deg;C in the dark for 2 hours, to extract the reaction products with toluene. The absorbance was measured at a wavelength of 485 nm, and the root activity calculated.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePhotosynthetic physiological characteristics\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe functional leaves were determined using the portable photosynthesis meter LI-6400XT. The light intensity was set to 1200 \u0026mu;mol\u0026middot;m\u003csup\u003e-2\u003c/sup\u003e\u0026middot;s\u003csup\u003e-1\u003c/sup\u003e, CO\u003csub\u003e2\u003c/sub\u003e concentration to 400 \u0026mu;mol\u0026middot;mol\u003csup\u003e-1\u003c/sup\u003e, and temperature to 25\u0026plusmn;1\u0026deg;C. On a sunny day, from 10:00 to 14:00 in the morning. Net photosynthetic rate was recorded (P\u003csub\u003en\u003c/sub\u003e,\u0026nbsp;\u0026mu;mol\u0026middot;m\u003csup\u003e-2\u003c/sup\u003e\u0026middot;s\u003csup\u003e-1\u003c/sup\u003e), stomatal conductance (G\u003csub\u003es\u003c/sub\u003e,\u0026nbsp;mol\u0026middot;m\u003csup\u003e-2\u003c/sup\u003e\u0026middot;s\u003csup\u003e-1\u003c/sup\u003e), transpiration rate (T\u003csub\u003er\u003c/sub\u003e,\u0026nbsp;mmol\u0026middot;m\u003csup\u003e-2\u003c/sup\u003e\u0026middot;s\u003csup\u003e-1\u003c/sup\u003e), intercellular CO\u003csub\u003e2\u003c/sub\u003e concentration (C\u003csub\u003ei\u003c/sub\u003e,\u0026nbsp;\u0026mu;mol\u0026middot;mol\u003csup\u003e-1\u003c/sup\u003e). The relative content of chlorophyll was determined by the SPAD value in the middle of fully unfolded leaves using the SPAD-502 chlorophyll meter, with each leaf repeated 5 times. The measurement was repeated three times for each treatment.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eOutput and quality Parameters\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eChili fruits were harvested in batches during the maturity period, and the number of effective fruits per plant and the fresh weight of each fruit were counted. For tomato, 7 clusters of fruits were uniformly retained from the marked plants, harvested in batches, and the number of fruits per plant and the fresh weight of each fruit were recorded. For cucumber, mature commercial melons are harvested in batches during the growth period, and the number of fruits per plant and the weight of each fruit were counted, with the unit being g, and then converted to the yield per unit area, with the unit being kg\u0026middot;ha\u003csup\u003e-1\u003c/sup\u003e. The longitudinal diameter of representative fruits of chili and cucumber, which is the length from the top to the shoulder of the fruit, and the transverse diameter, which is the maximum diameter at the equator of the fruit, were measured using a digital vernier caliper with an accuracy of 0.01mm. The results were expressed in cm. The hardness of the equatorial part of each treatment of no less than 20 representative tomato fruits was measured using the GY-4 fruit hardness tester, and the results were expressed as N\u0026middot;cm\u003csup\u003e-2\u003c/sup\u003e. For quality analysis, mixed samples collected from the equatorial region of the fruit were immediately frozen in liquid nitrogen and stored at -80\u0026deg;C, and then various indicators were determined separately. The content of soluble protein was measured by the Coomassie brilliant blue G-250 method at a wavelength of 595 nm and quantified by the bovine serum albumin standard curve. The results were expressed as mg\u0026middot;g\u003csup\u003e-1\u003c/sup\u003e FW. The content of soluble sugar was measured by the anthrone-sulfuric acid colorimetric method at a wavelength of 620 nm and quantified by the glucose standard curve and the results expressed as mg\u0026middot;g\u003csup\u003e-1\u003c/sup\u003e FW. The content of vitamin C was determined by the 2, 6-dichlorophenol titration method, and the results expressed as mg\u0026middot;100g\u003csup\u003e-1\u003c/sup\u003e FW. The total flavonoid content was measured by the aluminum nitrate colorimetric method at a wavelength of 510 nm and quantified by the rutin standard curve and the results expressed as mg\u0026middot;g\u003csup\u003e-1\u003c/sup\u003e FW. The content of organic acids was determined by the sodium hydroxide titration method in accordance with the national standard GB/T 12456-2021 for the determination of total acids in food, and the result was expressed as a percentage.\u003c/p\u003e\n\u003cp\u003eData analysis\u003c/p\u003e\n\u003cp\u003eThe data were collated using Microsoft Excel 2021, plotted using Origin 2024, and the significance test was conducted using SPSS 27.0.\u003c/p\u003e"},{"header":"Results and analysis","content":"\u003cp\u003eThe influence of catch cropping of leguminous green manure on vegetable yield\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eInfluence on the weight of individual fruits\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe catch cropping of leguminous green manure after vegetable harvest significantly affected the single fruit weight (P \u0026lt; 0.05). Compared with no green manure (C-CK) after chili harvest, the single fruit weight increased by 36.07% in the treatment of catch cropping arrow pea (C-CV) after chili harvest; The single fruit weight increased by 19.67% compared with that of C-CK in the treatment of catch cropping hairy vetch (C-HV) after chili harvest. After cucumber harvest, catch cropping arrow pea (Cu-CV) treatment increased the single fruit weight by 1.57% compared with cucumber harvest without catch cropping green manure (Cu-CK) treatment. After cucumber harvest, the single fruit weight increased by 1.00% compared with the Cu-CK treatment after catch cropping hairy vetch (Cu-HV). Single fruit weight of tomato also showed a similar positive trend. The results showed that the catch cropping arrow pea after vegetable harvest was most significant in increasing the single fruit weight of vegetables.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eImpact on total output\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe effect of catch cropping leguminous green manure after vegetable harvest on the total yield was significant (P \u0026lt; 0.05). Compared with the C-CK treatment, the total output increased by 19.42% under the C-CV treatment. C-HV increased by 16.17% compared with C-CK treatment. Compared with the T-CK treatment, the total output increased by 6.11% under the T-CV treatment. T-HV increased by 5.93% compared with T-CK treatment. The total output of Cu-CV treatment increased by 8.44% compared with that of Cu-CK treatment. Cu-HV increased by 5.00% compared with Cu-CK treatment. To sum up, the treatment of returning leguminous green manure to the field significantly increased vegetable yields, and the effect of catch cropping arrow pea on increasing yields was better than that of hairy vetch.\u003c/p\u003e\n\u003cp\u003eThe influence of catch cropping leguminous green manure on vegetable quality\u003c/p\u003e\n\u003cp\u003eRe-planting leguminous green manure after vegetable harvest can improve the quality of vegetables compared with not re-planting green manure after vegetable harvest. The soluble protein content increased by 12.15% compared with the treatment of no re-planting green manure (C-CK) after chili harvest and the treatment of re-planting arrow pea (C-CV) after chili harvest. The content of soluble sugar increased by 30.33%. The content of vitamin C increased by 113.99%. The total flavonoid content increased by 12.06%. After the harvest of chili peppers，the contents of soluble protein, soluble sugar and vitamin C were increased by 6.07%, 8.20% and 29.28% respectively compared with those of C-CK under the treatment of catch cropping hairy vetch (C-HV). Overall, the treatment of catch cropping arrow pea after chili harvest was more effective in increasing vitamin C and soluble protein.\u003c/p\u003e\n\u003cp\u003eCatch cropping of leguminous green manure after tomato harvest also has a positive impact on flavor and nutritional quality. After tomato harvest, catch cropping arrow pea (T-CV) increased the soluble sugar content by 15.37% compared with non-catch cropping of green manure after tomato harvest (T-CK). The content of vitamin C increased by 19.33%. The content of organic acids decreased by 3.20%. After tomato harvest, the contents of soluble sugar and vitamin C increased by 16.25% and 10.42% respectively compared with those of T-CK under the treatment of catch cropping hairy vetch (T-HV). The content of organic acids decreased by 3.35%. After tomato harvest, the catch cropping arrow pea treatment is more conducive to the accumulation of vitamin C, while the catch cropping hairy vetch treatment after tomato harvest performed better in promoting the accumulation of soluble sugar and reducing organic acids, which helped to optimize the sugar-acid ratio and improved flavor.\u003c/p\u003e\n\u003cp\u003eIn terms of cucumber, the catch cropping of leguminous green manure also brought about positive changes in nutritional parameters. The soluble protein content increased by 7.96% when cucumbers were treated with catch cropping arrow pea (Cu-CV) after harvest, compared with cucumbers without catch cropping of green manure (Cu-CK). The content of soluble sugar increased by 63.05%. Vitamin C content increased by 7.71%. After cucumber harvest, the contents of soluble protein, soluble sugar, and vitamin C increased by 7.00%, 67.00%, and 6.00% respectively compared with Cu-CK under the treatment of catch cropping hairy vetch (Cu-HV). After the harvest of cucumber, the catch cropping arrow pea had more advantages in terms of protein and vitamin C, while the catch cropping hairy vetch after the harvest of cucumbers had a more obvious effect on the increase of soluble sugar and is more conducive to improving the flavor of cucumbers.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe influence of catch cropping of leguminous green manure on the growth status of vegetables\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eEffects on plant morphology\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe re-planting of leguminous green manure after the harvest of chili significantly improved the morphogenesis of the plants. Compared with the treatment without replanting green manure (C-CK) after chili harvest, the treatment with replanting arrow pea (C-CV) after chili harvest significantly increased chili plant height by 29.55% and stem thickness by 30.80%. After the harvest of chili peppers the plant height and stem diameter under the treatment of catch cropping hairy vetch (C-HV) increased by 26.31% and 28.23% respectively compared with C-CK. After tomato harvest, the plant height and stem thickness under the treatment of catch cropping arrow pea (T-CV) increased by 21.97% and 17.12% respectively compared with the treatment without catch cropping green manure after tomato harvest (T-CK). After tomato harvest, plant height and stem thickness increased by 18.58% and 16.22% respectively under the treatment with catch cropping hairy vetch (T-HV) compared with the treatment with T-CK. In cucumber cultivation, both catch cropping green manure treatments also promoted plant growth. Compared with the treatment of no catch cropping green manure after cucumber harvest (Cu-CK), the treatment of catch cropping arrow pea after cucumber harvest (Cu-CV) significantly increased cucumber plant height by 2.66% and stem thickness by 6.19%. When cucumber harvested, plant height and stem thickness increased by 3.00% and 4.00% respectively compared with Cu-CK under the treatment of catch cropping hairy vetch (Cu-HV). Comprehensive comparison showed that the catch cropping of the two leguminous green manure can effectively promote the upright growth of vegetable plants and the thickening of stems, which is conducive to the construction of a better canopy structure. Among them, the catch cropping of arrow pea after vegetable harvest was particularly effective in promoting the thickening of chili stems and the height growth of tomato plants, indicating that its ability to optimize plant morphology was slightly better than that of hairy vetch.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eEffects on photosynthetic characteristics\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAfter the harvest of vegetables, the catch cropping of leguminous green manure improved the light energy utilization rate of chilis, tomatoes and cucumbers by enhancing photosynthetic parameters. Compared with the C-CK treatment, under the C-CV treatment, its net photosynthetic rate (P\u003csub\u003en\u003c/sub\u003e) increased by 59.79%, stomatal conductance (G\u003csub\u003es\u003c/sub\u003e) by 28.33%, and chlorophyll content (SPAD) by 14.06%. Under C-HV treatment, P\u003csub\u003en\u003c/sub\u003e, G\u003csub\u003es\u003c/sub\u003e and SPAD increased by 51.30%, 25.80% and 10.07% respectively compared with C-CK. In terms of tomato, the P\u003csub\u003en\u003c/sub\u003e under T-CV treatment increased by 9.39% compared with T-CK. G\u003csub\u003es\u003c/sub\u003e increased by 8.57% compared with T-CK. The P\u003csub\u003en\u003c/sub\u003e and G\u003csub\u003es\u003c/sub\u003e under T-HV treatment increased by 8.14% and 6.06% respectively compared with T-CK. In terms of cucumber, the P\u003csub\u003en\u003c/sub\u003e under Cu-CV treatment was 33.53% higher than that of Cu-CK. G\u003csub\u003es\u003c/sub\u003e was 38.44% higher than that of Cu-CK, and SPAD was 17.70% higher than that of Cu-CK. The P\u003csub\u003en\u003c/sub\u003e, G\u003csub\u003es\u003c/sub\u003e and SPAD under Cu-HV treatment increased by 42.00%, 33.00%, and 15.00% respectively compared with Cu-CK. When comparing the two green manure catch cropping treatments, the catch cropping of arrow pea after vegetable harvest had a better effect in increasing the stomatal conductance and chlorophyll content of chili, while the promotion of the net photosynthetic rate of cucumber was greater.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eEffects on root development\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe catch cropping of leguminous green manure after the harvest of chili significantly enhanced the development capacity of chili roots. Under C-CV treatment, compared with C-CK, the root length of chili increased by 17.83%, surface area by 23.71%, volume by 36.09%, and vitality by 24.41%. The root length, root surface area, root volume, and root vitality treated by C-HV increased by 15.11%, 18.50%, 20.55%, and 19.23% respectively compared with those treated by C-CK. In cucumber cultivation, under Cu-CV treatment, compared with Cu-CK, total root length increased by 14.62%, root surface area by 9.44%, root volume by 11.56%, root vitality by 12.27%, and the average root diameter by 3.68%. The root length, root surface area, root volume, and root vitality under Cu-HV treatment increased by 10.00%, 10.00%, 16.00%, and 14.00% respectively compared with those of Cu-CK. Comprehensive comparison showed that both leguminous green manures catch cropping can effectively optimize the root structure and physiological activity of vegetables. Among them, the catch cropping arrow pea after vegetable harvest has a better effect on promoting the root volume and root vitality of chili peppers and the growth of cucumber root length, while the catch cropping hairy vetch after vegetable harvest has a slightly more prominent effect on increasing the root volume of cucumber.\u003c/p\u003e\n\u003cp\u003eThe regulatory effect of catch cropping leguminous green manure on vegetable Soil quality\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eImprovement of soil quality\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe catch cropping of arrow pea and hairy vetch after chili harvest significantly increased the nutrient content of chili soil. Compared with the treatment of no re-planting of green manure after chili harvest (C-CK), the two re-planting treatments of green manure after chili harvest both showed significant improvement on soil organic matter, alkaline hydrolyzable nitrogen, available phosphorus, and available potassium before and after planting. Compared with the treatment of no re-planting green manure (C-CK) after chili harvest, the treatment of re-planting arrow pea (C-CV) after chili harvest increased soil organic matter content by 12.60% before planting and by 25.85% after planting. After the harvest of chili peppers under the treatment of catch cropping hairy vetch (C-HV), the organic matter content before and after transplanting increased by 17.26% and 24.22% respectively compared with C-CK. The alkaline hydrolyzed nitrogen content increased significantly under C-CV treatment by 44.97% and 57.82% respectively before and after planting compared with C-CK and showed good effects under C-HV treatment. The alkaline hydrolyzed nitrogen content before and after planting was 35.81% and 44.54% higher than that of C-CK. In terms of available phosphorus, the C-CV treatment increased by 20.24% before planting compared with C-CK, and by 20.49% after planting compared with C-CK. Under C-HV treatment, the available phosphorus content before and after planting increased by 19.81% and 25.16% respectively compared with C-CK. Available potassium content was 87.54% higher than that of C-CK before transplanting under C-CV treatment and 58.52% higher than that of C-CK after transplanting. Under C-HV treatment, they increased by 86.93% and 66.69% respectively. A comprehensive comparison showed that both leguminous green manures can effectively improve soil nutrient status. Among them, the treatment of catch cropping arrow pea after chili harvest showed better performance in improving alkaline hydrolyzable nitrogen, especially maintaining a high nitrogen supply capacity after transplanting. The increase in available phosphorus and available potassium after transplanting was slightly higher than that of after transplanting with arrow pea after chili harvest, indicating that it has a good nutrient release potential in the later growth stage. The improvement of these soil nutrients provides a good soil foundation for vegetable growth and may be one of the important mechanisms by which green manure treatment promoted plant growth and yield formation.\u003c/p\u003e\n\u003cp\u003eThe catch cropping of leguminous green manure after tomato harvest has a significant effect on soil nutrient status. Compared with the treatment of no re-planting of green manure after tomato harvest (T-CK), the two re-planting treatments of green manure after tomato harvest showed significant improvement on soil organic matter, alkaline hydrolyzable nitrogen, available phosphorus, and available potassium both before and after planting. Compared with T-CK treatment, the post-harvest tomato catch cropping arrow pea (T-CV) increased soil organic matter content by 24.40% before planting and 42.31% after planting. Under the treatment of catch cropping hairy vetch (T-HV) after tomato harvest, the organic matter content before and after transplanting increased by 26.32% and 50.20% respectively compared with T-CK. The alkaline hydrolyzable nitrogen content increased significantly under the T-CV treatment by 53.97% and 50.91% respectively before and after planting compared with the T-CK treatment. Good effects were also shown under T-HV treatment. The alkaline hydrolyzable nitrogen content before and after planting increased by 53.53% and 47.18% respectively compared with T-CK treatment. In terms of available phosphorus, the T-CV treatment increased the content before planting by 20.94% compared with the T-CK treatment, and after planting by 11.49% compared with the T-CK treatment. The available phosphorus content before and after transplanting under T-HV treatment increased by 21.55% and 22.83% respectively compared with that under T-CK treatment. Available potassium content under T-CV treatment was 16.61% higher than that under T-CK treatment before transplanting and 8.76% higher than that under T-CK treatment after transplanting. Under T-HV treatment, they increased by 12.54% and 5.18% respectively. Comprehensive comparison showed that both leguminous green manures can effectively improve soil nutrient levels. Among them, the treatment of catch cropping arrow pea after tomato harvest performed better in improving alkaline hydrolyzable nitrogen and available potassium, showing a stronger nitrogen supply capacity. The increase in available phosphorus after transplanting was greater than that after transplanting by the catch cropping hairy vetch treatment after tomato harvest than by the catch cropping arrow pea treatment, indicating that it has a more persistent potential for phosphorus release. The improvement of these soil nutrients provides a good foundation for the growth of vegetables.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTab\u003c/strong\u003e\u003cstrong\u003ele\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eEffects of leguminous green manure crops on soil quality of chili, tomato, and cucumber\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"\" width=\"685\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 87px;\"\u003e\n \u003cp\u003ePre - planting Treatment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 150px;\"\u003e\n \u003cp\u003eOrganic Matter\u003c/p\u003e\n \u003cp\u003e(g\u0026middot;kg⁻\u0026sup1;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 150px;\"\u003e\n \u003cp\u003eAlkaline Hydrolyzable Nitrogen (mg\u0026middot;kg⁻\u0026sup1;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 150px;\"\u003e\n \u003cp\u003eAvailable Phosphorus\u003c/p\u003e\n \u003cp\u003e(mg\u0026middot;kg⁻\u0026sup1;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 150px;\"\u003e\n \u003cp\u003eAvailable Potassium\u003c/p\u003e\n \u003cp\u003e(mg\u0026middot;kg⁻\u0026sup1;)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003ePre-planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003ePost-planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003ePre-planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003ePost-planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003ePre-planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003ePost-planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003ePre-planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 75px;\"\u003e\n \u003cp\u003ePost-planting\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003eC-CK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e16.1\u0026plusmn;0.3b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e12.2\u0026plusmn;1.1b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e177.2\u0026plusmn;9.7b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e152.1\u0026plusmn;4.4c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e99.8\u0026plusmn;2.2b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e81.3\u0026plusmn;6.9b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e142.6\u0026plusmn;15.5b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e134.2\u0026plusmn;16.1b\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003eC-CV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e18.2\u0026plusmn;1.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e15.4\u0026plusmn;0.7a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e256.9\u0026plusmn;8.8a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e240.1\u0026plusmn;5.2a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e120.0\u0026plusmn;6.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e98.0\u0026plusmn;3.8a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e267.4\u0026plusmn;17.8a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e212.7\u0026plusmn;10.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003eC-HV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e18.9\u0026plusmn;0.8a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e15.2\u0026plusmn;1.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e240.7\u0026plusmn;5.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e219.9\u0026plusmn;1.5b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e119.6\u0026plusmn;11.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e101.8\u0026plusmn;11.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e266.5\u0026plusmn;19.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e223.7\u0026plusmn;17.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003eT-CK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e20.9\u0026plusmn;1.8b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e16.5\u0026plusmn;1.2b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e161.0\u0026plusmn;4.2b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e156.9\u0026plusmn;4.2b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e109.0\u0026plusmn;6.0b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e93.1\u0026plusmn;2.7c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e124.4\u0026plusmn;10.6a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e120.3\u0026plusmn;7.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003eT-CV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e26.0\u0026plusmn;1.6a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e23.4\u0026plusmn;1.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e247.9\u0026plusmn;13.2a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e236.8\u0026plusmn;14.8a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e131.9\u0026plusmn;7.6a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e103.8\u0026plusmn;1.7b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e145.1\u0026plusmn;7.3a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e130.8\u0026plusmn;4.9a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003eT-HV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e26.4\u0026plusmn;2.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e24.7\u0026plusmn;0.8a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e247.2\u0026plusmn;18.9a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e231.0\u0026plusmn;7.6a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e132.5\u0026plusmn;2.7a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e114.4\u0026plusmn;2.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e140.0\u0026plusmn;19.3a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e126.5\u0026plusmn;13.6a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003eCu-CK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e29.1\u0026plusmn;0.5b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e25.9\u0026plusmn;0.7b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e192.4\u0026plusmn;2.9b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e186.7\u0026plusmn;11.7b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e127.3\u0026plusmn;6.3b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e147.9\u0026plusmn;7.6c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e129.4\u0026plusmn;5.8a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e122.6\u0026plusmn;2.5b\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003eCu-CV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e43.4\u0026plusmn;2.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e37.0\u0026plusmn;1.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e261.5\u0026plusmn;14.9a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e264.2\u0026plusmn;8.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e176.8\u0026plusmn;7.8a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e176.0\u0026plusmn;5.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e150.1\u0026plusmn;55.3a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e183.5\u0026plusmn;3.7a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003eCu-HV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e44.7\u0026plusmn;2.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e36.1\u0026plusmn;0.4a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e260.2\u0026plusmn;17.7a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e261.2\u0026plusmn;7.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e166.5\u0026plusmn;8.9a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e159.3\u0026plusmn;3.6b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e169.7\u0026plusmn;1.4a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 75px;\"\u003e\n \u003cp\u003e176.8\u0026plusmn;4.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eThe data are presented as means\u0026nbsp;\u0026plusmn;\u0026nbsp;SDs (n=3). Different lowercase letters indicate significant differences among green manure treatments within the same vegetable (p\u0026lt;0.05, Duncan\u0026rsquo;s multiple range test). Corresponding one-way ANOVA results are provided in Table\u0026nbsp;2\u003c/p\u003e\n\u003cp\u003eThe catch cropping of leguminous green manure had a significant effect on the soil nutrient level of cucumber. Compared with the treatment of no re-planting of green manure (Cu-CK) after cucumber harvest, the two re-planting treatments of green manure after cucumber harvest showed significant effects on soil organic matter, alkaline hydrolyzable nitrogen, available phosphorus, and available potassium both before and after planting. Compared with the Cu-CK treatment, the post-harvest cucumber catch cropping arrow pea (Cu-CV) increased the content of soil organic matter by 48.97% before planting and 42.99% after planting. After cucumber harvest, the organic matter content before and after transplanting increased by 53.21% and 39.03% respectively compared with Cu-CK under the treatment of catch cropping hairy vetch (Cu-HV). The alkaline hydrolyzable nitrogen content increased significantly under the Cu-CV treatment by 35.90% and 41.49% respectively before and after planting compared with the Cu-CK treatment. Good effects were also shown under the treatment of Cu-HV. The alkaline hydrolyzed nitrogen content before and after planting increased by 35.25% and 40.37% respectively compared with the treatment of Cu-CK. In terms of available phosphorus, the Cu-CV treatment increased the content before planting by 38.86% compared with the Cu-CK treatment, and after planting by 19.03% compared with the Cu-CK treatment. Available phosphorus content before and after planting under Cu-HV treatment was 31.00% and 8.00% higher than that of Cu-CK treatment, respectively. Available potassium content was 15.94% higher than that of Cu-CK before transplanting under Cu-CV treatment and 49.65% higher after transplanting than that of Cu-CK treatment. Under Cu-HV treatment, they increased by 31.00% and 44.00% respectively. Comprehensive comparison showed that both leguminous green manures can effectively improve soil nutrient levels. Among them, the treatment of catch cropping arrow pea after cucumber harvest showed better performance in improving alkaline hydrolyzable nitrogen and available potassium, demonstrating a stronger nitrogen supply capacity. The catch cropping of leguminous green manure significantly enhanced soil nutrients, providing a favorable environment for vegetable growth.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eEffects on soil enzyme activity\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe catch cropping of leguminous green manure after vegetable harvest has a significant enhancing effect on the enzyme activity in the rhizosphere soil. In the rhizoidal soil of chili, C-CV treatment increased the activities of catalase, invertase, and urease before planting by 32.42%, 23.21%, and 13.85% respectively compared with C-CK treatment, and increased them by 25.55%, 27.51%, and 12.13% respectively after planting. C-HV treatment also significantly enhanced the activities of these three enzymes. Compared with C-CK, the increase before colonization were 40.92%, 17.05%, and 17.35% respectively, and the increase after colonization were 50.16%, 15.94%, and 16.07% respectively. For tomato soil, T-CV treatment increased the activities of catalase, invertase and urease by 13.97%, 27.49%, and 20.65% respectively before planting compared with T-CK treatment, and by 28.70%, 46.73%, and 25.69% respectively after planting. Compared with the T-CK treatment, the corresponding parameters of the T-HV treatment increased by 9.29%, 28.84%, and 12.87% before colonization, and by 41.57%, 50.28%, and 18.09% after colonization. In cucumber soil, compared with the Cu-CK treatment, the Cu-CV treatment significantly increased the urease activity, with an increase of 93.39% before and 57.25% after planting. The invertase activity increased by 27.66% and 31.20% respectively in the two periods. The increase in catalase activity was relatively small, being 6.67% before transplanting and 7.66% after transplanting, respectively. The Cu-HV treatment also showed a similar trend, among which the increase in urease activity was the most prominent, being 79.00% before and 52.00% after transplanting, respectively. Comprehensive comparison showed that both leguminous green manures can effectively activate the soil enzyme system. Among them, the hairy vetch showed better performance in enhancing the catalase activity of chili peppers, while the arrow pea has a more significant effect in promoting the urease activity of cucumber.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTab\u003c/strong\u003e\u003cstrong\u003ele\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e3\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eEffects of leguminous green manure crops on soil enzyme activities of chili, tomato, and cucumber\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"\" width=\"603\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 103px;\"\u003e\n \u003cp\u003ePre - planting Treatment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 167px;\"\u003e\n \u003cp\u003ePeroxidase (\u0026mu;mol\u0026middot;d\u003csup\u003e-1\u003c/sup\u003e\u0026middot;g\u003csup\u003e-1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 167px;\"\u003e\n \u003cp\u003eInvertase (mg\u0026middot;d\u003csup\u003e-1\u003c/sup\u003e\u0026middot;g\u003csup\u003e-1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 167px;\"\u003e\n \u003cp\u003eUrease (ug\u0026middot;d\u003csup\u003e-1\u003c/sup\u003e\u0026middot;g\u003csup\u003e-1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003ePre - planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003ePost - planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003ePre - planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003ePost - planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003ePre - planting\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003ePost - planting\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003eC-CK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e25.5\u0026plusmn;0.9b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e21.4\u0026plusmn;1.0c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e20.5\u0026plusmn;0.9b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e17.6\u0026plusmn;0.8c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e222.1\u0026plusmn;9.0b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e204.7\u0026plusmn;6.5b\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003eC-CV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e33.8\u0026plusmn;1.8a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e26.9\u0026plusmn;1.6b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e25.3\u0026plusmn;1.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e22.4\u0026plusmn;1.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e252.9\u0026plusmn;8.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e229.5\u0026plusmn;3.4a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003eC-HV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e35.9\u0026plusmn;1.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e32.1\u0026plusmn;2.4a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e24.0\u0026plusmn;2.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e20.4\u0026plusmn;0.6b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e260.6\u0026plusmn;16.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e237.6\u0026plusmn;5.4a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003eT-CK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e52.7\u0026plusmn;1.4b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e32.6\u0026plusmn;2.7c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e24.7\u0026plusmn;3.7b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e17.8\u0026plusmn;1.3b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e236.0\u0026plusmn;9.9c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e203.6\u0026plusmn;6.6b\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003eT-CV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e60.1\u0026plusmn;1.2a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e42.0\u0026plusmn;1.7b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e31.5\u0026plusmn;2.8a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e26.2\u0026plusmn;2.3a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e284.7\u0026plusmn;8.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e255.9\u0026plusmn;9.0a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003eT-HV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e57.6\u0026plusmn;1.2a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e46.2\u0026plusmn;0.9a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e31.9\u0026plusmn;3.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e26.8\u0026plusmn;2.2a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e266.4\u0026plusmn;9.1b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e240.4\u0026plusmn;14.7a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003eCu-CK\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e47.0\u0026plusmn;0.2c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e29.6\u0026plusmn;0.6b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e30.4\u0026plusmn;0.7b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e15.6\u0026plusmn;1.1b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e125.1\u0026plusmn;3.7c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e102.5\u0026plusmn;2.1b\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003eCu-CV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e50.1\u0026plusmn;0.3a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e31.9\u0026plusmn;0.6a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e38.8\u0026plusmn;1.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e20.5\u0026plusmn;0.9a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e241.9\u0026plusmn;6.5a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e161.1\u0026plusmn;2.3a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003eCu-HV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e49.3\u0026plusmn;0.5b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e32.4\u0026plusmn;1.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e39.4\u0026plusmn;0.7a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e19.4\u0026plusmn;0.4a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e224.3\u0026plusmn;11.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 83px;\"\u003e\n \u003cp\u003e156.1\u0026plusmn;10.1a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eThe data are presented as means\u0026nbsp;\u0026plusmn;\u0026nbsp;SDs (n=3). Different lowercase letters indicate significant differences among green manure treatments within the same vegetable (p\u0026lt;0.05, Duncan\u0026rsquo;s multiple range test). Corresponding one-way ANOVA results are provided in Table\u0026nbsp;3\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eImpact on the quantity of soil microorganisms\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIn the rhizosphere soil of chili peppers, compared with the C-CK treatment, the C-CV treatment increased the quantity of bacteria after planting by 60.96%. The quantity of fungi increased by 56.54%. C-HV treatment also showed a similar trend, with the quantity of bacteria and fungi increasing by 60.11% and 61.36% respectively compared to C-CK treatment. The two are similar in bacterial promoting effect, while the hairy vetch is slightly better than the arrow pea in increasing the quantity of fungi. The influence on the rhizosphere microorganisms of tomato was more significant. Compared with T-CK treatment, T-CV treatment increased the quantity of bacteria by 46.50%. The quantity of fungi increased by 90.62%. Bacterial and fungal quantities under T-HV treatment increased by 35.40% and 82.96% respectively compared with those under T-CK treatment. In tomato cultivation, arrow pea was significant in promoting fungal proliferation. In the rhizosphere soil of cucumber, the increase in the quantity of microorganisms were relatively moderate. Compared with the Cu-CK treatment, the Cu-CV treatment increased the bacterial count by 3.61% before colonization and by 3.79% after colonization. The Cu-HV treatment also showed a similar trend. The increase in the number of bacteria before and after colonization was 3.00% compared with the Cu-CK treatment.\u003c/p\u003e\n\u003cp\u003eCorrelation analysis\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eCorrelation between yield and the physicochemical properties and biological characteristics of soil\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe yield of chili peppers was positively correlated with all soil parameters. Among them, the correlation with alkaline hydrolyzable nitrogen was the strongest (r=0.841), followed by available potassium (r=0.798), and organic matter (r=0.794). The quantity of soil microorganisms was closely related to the yield. The correlation coefficients between the quantity of bacteria and fungi and the yield reach 0.758 and 0.792 respectively. Among soil enzyme activities, urease has the highest correlation with yield (r=0.671), indicating that nitrogen conversion efficiency has a significant impact on the improvement of chili yield. Tomato yield has the strongest correlation with soil available phosphorus content (r=0.857), and also showed a significant positive correlation with urease activity (r=0.775) and bacterial count (r=0.760). It is worth noting that tomato yield was negatively correlated with the quantity of fungi (r=-0.487), which may be related to the specific microbial community structure in the tomato root zone. The correlation between cucumber yield and various soil parameters is relatively weak, but it still maintains a significant positive correlation with organic matter (r=0.752) and bacterial quantity (r=0.760), indicating that soil basic fertility and microbial activity support the stability of cucumber yield. Comprehensive analysis shows that the return of leguminous green manure to the field simultaneously enhances the availability of soil nutrients, especially alkaline hydrolyzable nitrogen and available phosphorus. Return of leguminous green manure to the field enhanced the activities of the enzyme system, especially urease and invertase; promoted the proliferation of microorganisms, mainly bacteria and formed the soil biological basis for the increased in yield.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eCorrelation between quality parameters and physiological morphology parameters of the aboveground parts\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr clear=\"ALL\"\u003eThe quality of chili peppers is closely related to photosynthetic physiological parameters. The content of soluble sugar had the highest correlation with the transpiration rate (T\u003csub\u003er\u003c/sub\u003e) (r=0.870), and also showed a significant positive correlation with stomatal conductance (G\u003csub\u003es\u003c/sub\u003e) (r=0.750). The content of vitamin C was highly correlated with the SPAD value (r=0.813) and the transpiration rate (r=0.879). Notably, the intercellular CO₂ concentration (C\u003csub\u003ei\u003c/sub\u003e) was negatively correlated with most quality parameters., which might reflect the indirect influence of stomatal regulation on the distribution of carbon assimilation products. Analysis of tomato quality revealed that soluble sugar was significantly correlated with net photosynthetic rate (P\u003csub\u003en\u003c/sub\u003e) and SPAD value (r\u0026gt;0.849), while vitamin C was highly correlated with SPAD value (r=0.949), further verifying the core role of photosynthetic capacity in the formation of fruit nutritional quality. The quality of cucumbers showed a similar pattern. The content of soluble sugar was significantly correlated with plant height (r=0.900) and transpiration rate (r=0.844). The content of vitamin C was also highly correlated with plant height (r=0.894) and transpiration rate (r=0.821). The content of organic acids was negatively correlated with most above-ground indicators, especially having the strongest negative phase correlation with stomatal conductance (G\u003csub\u003es\u003c/sub\u003e) (r=-0.890), indicating that enhanced photosynthesis helps to reduce fruit acidity and optimize the sugar-acid ratio.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe synergistic promoting effect of multi-cropping leguminous green manure on vegetable yield and single fruit weight\u003c/p\u003e \u003cp\u003eThe results of this study demonstrated that, compared with no catch cropping of green manure after vegetable harvest, planting legume green manure as a catch crop significantly increased the single‑fruit weight and yield per unit area of chili, tomato, and cucumber. Specifically, the total yield of chili increased by 19.42% after catch cropping with common vetch (Vicia sativa) and by 16.17% after hairy vetch (Vicia villosa). Tomato and cucumber also exhibited consistent yield‑enhancing trends under the corresponding green manure treatments, which aligns with previous findings in cereal‑based cropping systems (Wei et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). The yield‑improving effects of legume green manure are closely associated with comprehensive improvements in soil physicochemical properties and biological activity. Specifically, green manure crops, through rhizobial nitrogen fixation, significantly increase soil alkali‑hydrolyzable nitrogen content, thereby providing sustained nitrogen supply for subsequent vegetable crops and creating a favorable soil nutrient environment (Li et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2025c\u003c/span\u003e). Meanwhile, catch cropping with green manure significantly enhanced the activities of soil catalase, sucrase, and urease, promoting nutrient transformation and supply capacity and effectively improving soil fertility (Mi et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), thus optimizing nutrient uptake efficiency of vegetable roots. In addition, green manure treatments promoted an increase in soil bacterial and fungal populations, improved the rhizosphere micro‑ecological environment, and enhanced the stability and nutrient‑cycling capacity of the soil system (Chen et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Nie et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2025\u003c/span\u003e), providing favorable rhizosphere conditions for vegetable growth. From the perspective of plant physiology, green manure treatments significantly improved plant height, stem diameter, root morphological indices, and root activity (He et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2025\u003c/span\u003e), while increasing net photosynthetic rate, stomatal conductance, and chlorophyll content, thereby enhancing light‑use efficiency and laying a physiological foundation for yield improvement. It is noteworthy that the significant increase in single‑fruit weight further confirms the positive role of green manure in promoting the translocation and accumulation of photosynthetic products into fruits, particularly evident in larger‑fruited crops such as cucumber. This suggests that catch cropping with green manure helps optimize carbon allocation and sink strength expression during fruit development (Li et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2025a\u003c/span\u003e). In summary, catch cropping with legume green manure systematically improved soil quality, enhanced nutrient supply, optimized microbial community structure and plant physiological functions, ultimately leading to a significant increase in vegetable yield. Against the context of rational reduction in chemical fertilizer application, green manure, as an efficient and environmentally friendly bio‑fertilizer, holds significant potential for widespread adoption.\u003c/p\u003e \u003cp\u003eResponse mechanism of chili nutritional quality to catch cropping with legume green manure\u003c/p\u003e \u003cp\u003eThe results of this study indicated that catch cropping with legume green manure can significantly enhance the nutritional quality of chili fruits, with the most pronounced effects observed under the common vetch treatment. Specifically, vitamin C content increased by 113.99% and soluble sugar content by 30.33%, demonstrating that legume green manure positively regulates the accumulation of secondary metabolites and nutrients in chili fruits. This quality improvement is closely associated with the comprehensive amelioration of soil physicochemical properties, enzyme activities, and plant physiological functions by green manure.\u003c/p\u003e \u003cp\u003eFrom a physiological perspective, catch cropping with green manure significantly improved the photosynthetic performance and root activity of chili. This promoted the translocation of photosynthetic assimilates to the fruits and optimized the carbon-nitrogen metabolic balance, thereby providing the material basis for the synthesis of vitamin C, soluble sugars, and proteins (Zhou et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2025b\u003c/span\u003e). Regarding the soil environment, the gradual decomposition of legume green manure continuously released mineral nutrients, effectively ensuring a balanced nutrient supply during the fruit development stage and directly contributing to the synthesis of proteins and vitamins (Makino et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Zhang et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). Concurrently, the green manure treatment enhanced the activities of key soil enzymes, accelerated the transformation and cycling of soil nutrients, and intensified the biological activity within the rhizosphere microenvironment (Yang et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), indirectly supporting fruit quality formation.\u003c/p\u003e \u003cp\u003eIt is noteworthy that the significant increase in single-fruit weight of chili was accompanied by a synergistic enhancement of key nutritional parameters such as vitamin C, with no observed dilution effect. This suggests that the green manure treatment not only promoted fruit expansion but also concurrently strengthened the bio-enrichment capacity for nutrients during this process (Liu et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). This highlights the integrated agronomic value of green manure in coordinating both the yield and quality of vegetable crops.\u003c/p\u003e \u003cp\u003eFlavor quality formation pathway: optimization of tomato sugar-acid ratio and regulation by green manure\u003c/p\u003e \u003cp\u003eThe balance of the sugar-acid ratio was central to tomato flavor quality. In this study, the hairy vetch catch crop treatment increased the soluble sugar content of tomato by 16.25% while decreasing the organic acid content by 3.35%, thereby significantly optimizing the sugar-acid ratio and improving fruit flavor. This enhancement in flavor quality was closely linked to the integrated regulation of plant physiological traits and the rhizosphere microenvironment by the green manure.\u003c/p\u003e \u003cp\u003eFrom the perspective of photosynthetic performance, the green manure treatment significantly increased the net photosynthetic rate and stomatal conductance of tomato leaves. This promoted the accumulation of photosynthetic products and their translocation to the fruits, providing an ample material foundation for sugar synthesis (Ozturk and Ozer \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Regarding soil nutrients, the decomposition process of the legume green manure continuously releases mineral elements such as nitrogen (Song et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2022a\u003c/span\u003e). This sustained and balanced nutrient supply regulated the activities of key enzymes involved in organic acid metabolism, such as malic enzyme and citrate synthase, during fruit development, thereby influencing the metabolic flux of malic and citric acids (Song et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Furthermore, catch cropping with green manure significantly altered the rhizosphere microbial community structure. These changes in the microbial community indirectly regulated key nodes in the sugar-acid metabolic pathways by modulating plant endogenous hormone levels or carbon allocation patterns (Wang et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAnalyzing fruit development dynamics, the single-fruit weight of tomato showed steady growth under the green manure treatment, with no observed decline in sugar content due to fruit enlargement. This indicated that the green manure treatment possesses a distinct advantage in coordinating fruit sink strength with the accumulation of flavor compounds, achieving a synergistic improvement in both yield and flavor. These findings provide a new theoretical basis for the targeted regulation of tomato flavor quality.\u003c/p\u003e \u003cp\u003eGreen manure-driven mechanisms underlying the accumulation of sugars and vitamin C in cucumber\u003c/p\u003e \u003cp\u003eWithin the cucumber cultivation system, catch cropping with legume green manure notably enhanced the fruit's soluble sugar and vitamin C contents. Specifically, the hairy vetch treatment increased soluble sugar by 67.00%, while the common vetch treatment demonstrated superior performance in boosting vitamin C levels. This indicated functional specificity among different green manure species in regulating cucumber nutritional quality. This quality improvement stems from the synergistic regulation of plant physiological traits and the soil environment by green manure.\u003c/p\u003e \u003cp\u003eRegarding photosynthetic performance, the green manure treatment significantly increased the net photosynthetic rate and stomatal conductance of cucumber leaves, promoting carbohydrate synthesis within the foliage (Merlo Mendes et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) and thereby providing ample material for sugar accumulation in the fruits. In terms of root development, catch cropping with green manure effectively optimized cucumber root architecture and physiological activity (He et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2025\u003c/span\u003e), enhancing the plant's capacity for water and mineral nutrient uptake, which supports nutritional balance in the developing fruits. From a soil nutrient perspective, the green manure treatment significantly increased the contents of available phosphorus and potassium. The effective supply of these key nutrients likely directly participates in the biochemical pathways of sugar metabolism and vitamin C synthesis, regulating the activities of key enzymes such as fructokinase and GDP-galactose phosphorylase (Bhalla and Garg \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eConsidering the relationship between single-fruit weight and quality, cucumber fruit size increased steadily under green manure treatments, accompanied by simultaneous rise in sugar content and vitamin C levels. This indicated that the green manure treatment effectively coordinated to the synergistic improvement of both quality and yield while promoting fruit development, providing a viable technical pathway for the green and high-quality production of cucumber.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study systematically assessed the effects of legume green manure catch cropping on chili, tomato and cucumber. Results showed that incorporating common vetch or hairy vetch after harvest significantly improved soil organic matter content, nutrient availability, enzyme activities and microbial populations. This practice also enhanced plant growth including height, stem diameter and root development, as well as photosynthetic performance, contributing to higher single fruit weight and total yield. Improvements in vegetable quality included increased vitamin C, soluble sugars and protein in chili, optimized sugar acid ratio in tomato, and elevated soluble sugar and vitamin C in cucumber. Legume green manure catch cropping synergistically boosts vegetable yield, quality and soil health, offering a reliable theoretical basis for green and high yield vegetable cultivation.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eWe are very grateful for the Research Program Sponsored by the Scientific Research Innovation Capability Support Project for Young Faculty (SRICSPYF-BS2025119), the National Natural Science Foundation of China (32372238 and 32460547), the financial support of the Science and Technology Program in Gansu Province (24JRRA124 and 25JRRA347), the Lanzhou Youth Science and Technology Talent Innovation Project of Gansu Province (2024\u0026ndash;QN\u0026ndash;128), the Young Doctor Support Project of Gansu Province (2024QB\u0026ndash;008), the Young Teachers Research Ability Enhancement Project in Northwest Normal University of China (NWNU-LKQN2024-16 and NWNU\u0026ndash;LKQN2023\u0026ndash;09),\u0026nbsp;and the Gansu-Tianjin Cooperation Project of the Science and Technology Department of Gansu Province (24CXNA077).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eYao Guo: Conceptualization, Data curation, Formal analysis, Project administration, and Writing\u0026ndash;original draft. Zhuohan Zhang: Data curation and Methodology, and Writing\u0026ndash;original draft. Jiayue Ma: Data curation and Methodology. Guoli Wang: Data curation, Methodology, and Validation. Yijia Zhao: Data curation, Methodology, and Validation. Aziiba Emmanuel Asibi: Methodology. Wen Yin: Formal analysis, Project administration, and review \u0026amp; editing.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eData will be made available on request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interest\u003c/strong\u003e\u003cstrong\u003es\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBhalla S, Garg N (2021) Arbuscular mycorrhizae and silicon alleviate arsenic toxicity by enhancing soil nutrient availability, starch degradation and productivity in cajanus cajan (L.) millsp. 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Global Change Biol 31:e70232. https://doi.org/10.1111/gcb.70232\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"plant-and-soil","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"plso","sideBox":"Learn more about [Plant and Soil](https://www.springer.com/journal/11104)","snPcode":"11104","submissionUrl":"https://submission.nature.com/new-submission/11104/3","title":"Plant and Soil","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Green manure, Vegetables Soil, quality improvement, Yield quality","lastPublishedDoi":"10.21203/rs.3.rs-9115168/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9115168/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eAims\u003c/h2\u003e \u003cp\u003eTo alleviate soil degradation and vegetable quality deterioration caused by continuous cropping, this study aimed to investigate the impacts of leguminous green manure incorporation on soil properties, plant growth, yield, and quality of chili, tomato, and cucumber under intensive cropping systems.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA field experiment was conducted with three treatments established: fallow control (CK), catch cropping with arrow pea, and catch cropping with hairy vetch following vegetable harvest.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eGreen manure application significantly elevated soil organic matter, available nitrogen, phosphorus, and potassium contents, and enhanced soil catalase, invertase, and urease activities, alongside increased bacterial abundance. It also improved plant height, stem diameter, root morphology, root vigor, chlorophyll content, net photosynthetic rate, and stomatal conductance, thereby increasing single fruit weight and yield per unit area. For quality, green manure boosted vitamin C, soluble sugar, and soluble protein in chili, optimized the sugar-acid ratio in tomatoes, and enhanced soluble sugar and vitamin C in cucumbers. Correlation analysis indicated that yield was positively correlated with soil available nutrients and microbial quantity, while quality was closely linked to photosynthetic and plant morphological traits.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eLeguminous green manure return synergistically improves vegetable yield and quality by enhancing soil fertility and plant physiological functions. Arrow pea is suitable for chili production, whereas hairy vetch benefits tomato flavor and quality improvement, offering a sustainable and effective strategy for vegetable cultivation under continuous cropping systems.\u003c/p\u003e","manuscriptTitle":"Returning green manure to the field increases yield and quality of chili, tomato, and cucumber","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-23 11:48:45","doi":"10.21203/rs.3.rs-9115168/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revisions","date":"2026-05-10T08:28:30+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2026-04-15T12:20:16+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-15T09:43:38+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Plant and Soil","date":"2026-04-14T08:37:04+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-14T03:17:52+00:00","index":"","fulltext":""},{"type":"submitted","content":"Plant and Soil","date":"2026-04-09T08:03:32+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"plant-and-soil","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"plso","sideBox":"Learn more about [Plant and Soil](https://www.springer.com/journal/11104)","snPcode":"11104","submissionUrl":"https://submission.nature.com/new-submission/11104/3","title":"Plant and Soil","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"bcd17d72-3103-4c3f-b299-aae1b424675b","owner":[],"postedDate":"April 23rd, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Major revisions","date":"2026-05-10T08:28:30+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-05-10T12:28:49+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-23 11:48:45","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9115168","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9115168","identity":"rs-9115168","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}