Optimization of Tobacco-Grain Intercropping Models Based on the Entropy Weight-TOPSIS Method

Optimization of Tobacco-Grain Intercropping Models Based on the Entropy Weight-TOPSIS Method | 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 Article Optimization of Tobacco-Grain Intercropping Models Based on the Entropy Weight-TOPSIS Method Yinping Bai, Fusong Wang, Hao Li, Qiang Wu, Hongbo luo, Jun Xia, and 9 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8429844/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Alleviating continuous cropping obstacles while ensuring grain security requires sustainable farming system designs. This study evaluated the spatial configuration and crop combinations in tobacco-based systems to balance soil health and economic output. A field experiment was conducted comparing tobacco monoculture (CK) with tobacco intercropped with soybean (B1, B2) or sweet potato (S1, S2) under two spatial modes: furrow (T1) and on-ridge (T2) intercropping. An Entropy-Weight TOPSIS model was employed to synthesize soil enzymatic activity, nutrient cycling, agronomic traits, leaf quality, and economic benefits. The results showed that intercropping significantly regulated the rhizosphere environment. Compared to CK, intercropping improved soil pH and organic matter. Specifically, tobacco–soybean intercropping (T1B1) increased available nitrogen by 35.38%, while tobacco–sweet potato (T2S1) boosted available phosphorus by 17.1% and sucrase activity to 38.98 U/g. Spatially, the on-ridge mode (T2) mitigated interspecific competition more effectively than the furrow mode (T1), enhancing plant height by 10.63% and optimizing chemical coordination (e.g., improved K/Cl ratios and increased protein content). Economically, the T2S1 system maximized synergism, with high-class tobacco reaching 61.6%. The Entropy-TOPSIS evaluation confirmed that intercropping systems outperformed monoculture, with T2S1 identified as the optimal design for achieving the best trade-off between productivity, leaf quality, and soil sustainability. These findings offer a strategic framework for the spatial optimization of cash-grain intensive farming systems. Biological sciences/Ecology Earth and environmental sciences/Ecology Earth and environmental sciences/Environmental sciences Biological sciences/Plant sciences Flue-cured tobacco Intercropping patterns Spatial configuration Economic performance EW-TOPSIS model Figures Figure 1 Figure 2 Figure 3 Figure 4 1.Introduction Flue-cured tobacco ( Nicotiana tabacum L. ) is a pivotal industrial crop in China, contributing substantially to national fiscal and tax revenues. However, the current cultivation of flue-cured tobacco is characterized by severe continuous cropping, which accounts for 30% to 60% of the total planting area 1 Such intensive continuous cropping significantly compromises soil health, leading to a marked decline in both tobacco quality and yield 2 , which further threatens the overall sustainability of the agro-ecosystem. Furthermore, the competition for land resources between tobacco and other crops poses a challenge to the existing agricultural planting structure and national food security 3 . Therefore, exploring the intercropping of flue-cured tobacco with food crops to leverage interspecific complementary effects is essential for the sustainable development of the tobacco industry. This approach is of strategic significance for ensuring the supply security of specialized agricultural products and the sustainable utilization of arable land. Continuous cropping obstacles (CCOs) represent a critical bottleneck constraining the sustainable development of the tobacco industry. Prolonged continuous cropping of flue-cured tobacco exacerbates the incidence of pests and soil-borne diseases, most notably tobacco black shank (Phytophthora nicotianae), thereby compromising soil health 1 , 4 – 9 . Various mitigation strategies for CCOs have been explored, including the optimization of cultivation systems, the application of microbial inoculants, physical and chemical soil disinfection, the incorporation of straw and green manure, and the refinement of irrigation regimes 10 . Research indicates that adjusting planting patterns can effectively alleviate or even eliminate CCOs 11 . Specifically, intercropping has been shown to significantly enhance rhizosphere soil nutrient content and enzymatic activities, while increasing the diversity and richness of bacterial communities and optimizing their composition 12 – 14 . Furthermore, intercropping can effectively reduce the disease index of tobacco black shank and the population of its causal pathogens in the rhizosphere, while promoting the abundance of beneficial microbes 15 . Properly managed intercropping systems also bolster the nutritional status and physiological resistance of the primary crop 16 , 17 . Given the efficacy of intercropping in mitigating continuous cropping obstacles (CCOs), selecting appropriate intercrop species and systematically evaluating their holistic benefits have become imperative. Previous research has explored intercropping flue-cured tobacco with crops such as maize, peanut, and sweet clover (Melilotus officinalis) 18 – 20 , demonstrating their potential to improve the soil micro-ecosystem and suppress soil-borne diseases. However, current literature predominantly focuses on singular effects, lacking a multi-dimensional systematic comparison and comprehensive evaluation of different intercropping systems across soil health, crop quality, economic returns, and long-term sustainability. Furthermore, a scientific framework for quantifying the overall performance of diverse intercropping systems has yet to be established for crops like flue-cured tobacco, which possess complex value structures characterized by significant price differentials based on quality. Conventional indices, such as the Land Equivalent Ratio (LER) and Land Equivalent Coefficient (LEC), primarily focus on yield and land-use efficiency; consequently, they fail to encapsulate the integrated impacts of intercropping on soil quality, tobacco leaf chemical constituents, and ultimate economic profitability 21 , 22 . Consequently, to develop an optimized model that alleviates CCOs while simultaneously ensuring food security and economic viability, this study selected soybean (Glycine max) and sweet potato (Ipomoea batatas) as intercropping partners for flue-cured tobacco. Soybean, a legume, was chosen for its biological nitrogen fixation capacity, which facilitates soil nitrogen cycling, and its compact plant architecture and broad adaptability 23 – 27 . Sweet potato was selected as a high-yielding, resilient "staple-security crop" with significant potential for enhancing food security and system-wide economic value 28 – 30 ; both crops offer potential spatiotemporal and functional complementarity with tobacco in resource utilization. To circumvent the limitations of traditional evaluation methods and achieve an objective, multi-dimensional comparison of these intercropping systems, this study introduced the Entropy Weight-Technique for Order Preference by Similarity to Ideal Solution (EW-TOPSIS) algorithm. This approach objectively determines the weights of evaluation indicators using the entropy weight method and subsequently calculates the proximity of each treatment to the ideal solution via the TOPSIS model, thereby facilitating the ranking of complex multi-indicator systems 31 – 33 . By effectively integrating heterogeneous data, including agronomic traits, soil indicators, leaf chemical quality, and economic attributes, this method mitigates the subjectivity inherent in manual weighting 34 , providing a robust quantitative basis for screening optimal intercropping patterns. In summary, this study aims to systematically elucidate the impacts of two intercropping patterns—tobacco-soybean and tobacco-sweet potato—on soil health, tobacco growth and quality, system productivity, and economic profitability through field experiments. By employing the EW-TOPSIS model to quantitatively evaluate and compare the multi-dimensional performance of these systems, we seek to identify an optimized intercropping model that harmonizes sustainable tobacco production with food security and the sustainable utilization of arable land. These findings are intended to provide a robust scientific framework and empirical evidence for both agricultural production practices and policy formulation. 2. Materials and methods 2.1 Overview of the Experimental Site The field experiment was conducted in 2024 at the Tobacco Science and Technology Innovation Park in Zhiluo Town, Fu County, Yan’an City, Shaanxi Province, China (108.61° E, 35.74° N). This region is characterized by a warm temperate continental monsoon climate, with a mean annual temperature of 10 ℃, an average frost-free period of 165 days, and approximately 3,000 annual sunshine hours. Precipitation is primarily concentrated between June and September. The baseline physicochemical properties of the topsoil (0–20 cm layer) prior to the experiment are summarized in Table 1 . Table 1 Nutrient status of 0–20 cm soil layer Total nitrogen g/kg total phosphorous g/kg total potassium g/kg alkaline hydrolysis nitrogen mg/kg rapidly available potassium mg/kg rapidly available potassium mg/kg Organic matter g/kg pH 0.29 1.21 13.5 57.48 21.4 193.92 17.09 7.67 2.2 Experimental Design and Treatments The experiment followed an incomplete randomized split-plot design with a total of nine treatments, each replicated three times, resulting in 27 experimental plots. The treatments included four combinations of two sweet potato varieties (Qinshu 5: S1; Wanshu 10: S2) and four combinations of two soybean varieties (Zhongdou 63: B1; Sudou 051: B2) planted either on the ridge top (T2) or ridge side (T1), along with a monoculture flue-cured tobacco control (CK). Each plot covered an area of 96 m2 and consisted of 10 ridges (60 cm wide and 30 cm high). Flue-cured tobacco was planted at a fixed spacing of 1.2 m times 0.6 m. For the intercropping components, sweet potato was configured with a row spacing of 55 cm and plant spacing of 30 cm, while soybean was planted with a row spacing of 30 cm, plant spacing of 25 cm, and a sowing depth of 4–5 cm. Basal fertilizers were applied during land preparation prior to ridging, including soybean cake fertilizer at 3,750 kg ha - 1 and tobacco-specific compound fertilizer (N:P2O5:K2O = 11:16:16) at 750 kg ha - 1 . During the ridging process, additional fertilization included oil cake (N:P:K = 1:1:1) at 300 kg ha - 1 , organic fertilizer (N:P:K = 5:4:3) at 375 kg ha - 1 , phosphate fertilizer at 37 kg ha - 1 , and potassium fertilizer at 225 kg ha - 1 . No supplementary fertilizers were applied in the later growth stages. Other agronomic management practices, including pest and disease control, were performed in accordance with local conventional standards. 2.3 Measurement Indicators and Methods 2.3.1 Determination of Soil Chemical Properties Prior to the transplantation of tobacco seedlings, the baseline fertility of the 0–20 cm topsoil layer was determined. Soil samples were subsequently collected from both the tobacco ridges and intercrop ridges in each plot at four critical phenological stages: the rosette stage, vigorous growth stage, topping stage, and maturity stage. After collection, the soil samples were air-dried, ground, and passed through a sieve for further analysis. The measured soil indicators included soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzable nitrogen (AN), available phosphorus (AP), available potassium (AK), and pH. All soil physicochemical properties were determined according to the standard protocols established by Bao 35 . 2.3.2 Determination of Soil Enzyme Activities During each phenological stage of the flue-cured tobacco, soil samples were collected following the procedures described in Section 1.3.1. The collected samples were immediately placed into sterile polyethylene bags and stored in a refrigerator at 4℃ prior to analysis. The activities of four key soil enzymes—invertase (also known as sucrase), urease, catalase, and β-glucosidase—were commissioned to and determined by Anhui Yangou Technology Co., Ltd. (Hefei, China). 2.3.3 Measurement of Agronomic Traits At various phenological stages of flue-cured tobacco (rosette, vigorous growth, and topping stages), agronomic traits—comprising plant height, stem girth, internode length, and the length and width of the largest leaf—were measured. The leaf area of the largest leaf was subsequently calculated based on these dimensions. All measurement procedures were performed in accordance with the tobacco industry standard (YC/T 142—2010) 36 . 2.3.4 Determination of Tobacco Leaf Quality leaves were harvested, individually labeled by treatment group, and subjected to standardized flue-curing. Following the curing process, 150 g of representative C3F (Medium Orange 3) grade tobacco leaves were randomly sampled from each group, ground, and passed through a sieve for analysis. The chemical characterization was commissioned to Anhui Yangou Technology Co., Ltd. (Hefei, China). The determined chemical constituents included total alkaloids (nicotine), reducing sugars, total sugars, chloride (Cl-), potassium (K+), total nitrogen (TN), protein, and starch. Furthermore, key quality parameters—including the reducing sugar/total sugar ratio, nitrogen/alkaloid ratio, potassium/chloride ratio, and sugar/alkaloid ratio—were calculated to evaluate the chemical equilibrium and overall quality of the tobacco leaves. 2.3.5 Economic Benefits of Tobacco Fields Cured tobacco leaves were harvested sequentially from the lower to the upper stalk positions as they reached maturity. Following the flue-curing process, the leaves were categorized into upper, middle, and lower grades according to national grading standards. Each grade was weighed to determine its proportion relative to the total yield for each treatment. Professional local tobacco graders performed the classification of the cured leaves. Economic indicators, including the hectare yield (kg·ha - 1 ) and gross output value, were calculated based on the prevailing market prices for different tobacco grades. Simultaneously, the intercropped soybean and sweet potato were harvested, and their economic value was determined according to the current local market prices. The following parameters were calculated to evaluate the economic performance of the systems: Proportion of middle-to-high grade tobacco (%): Ratio M-H = (Yield of middle and upper grade) /( leaves Total yield)·100% Net Profit (CNY): Net Profit = Gross Output Value - Total Production Costs Where production costs include expenditures on tobacco seedlings, seeds, fertilizers, and other agricultural inputs. 2.4 Data Processing and Analysis Raw data were organized and pre-processed using Microsoft Excel. Statistical analyses, including analysis of variance (ANOVA), Duncan’s multiple range test (α = 0.05), and Pearson correlation analysis, were performed using SPSS 27.0 software. Data visualization and figure generation were conducted via Origin 2024. To intuitively compare the variations across different treatments and indicators, the Hiplot platform ( https://hiplot.com.cn/ ) was utilized to perform Z-score standardization and Ward’s hierarchical clustering analysis. The specific mathematical procedures and calculation steps for the Entropy Weight-TOPSIS (EW-TOPSIS) method were adopted from previous literature 32 . In this study, the EW-TOPSIS analysis was implemented using the pymcdm library within the Python 3.13 environment. This computational approach ensured the objectivity of weight assignment and the robustness of the multi-dimensional comprehensive evaluation. 3. Results 3.1 Impact of Intercropping on the Agronomic Traits of Flue-cured Tobacco According to Fig. 2 , intercropping patterns exerted a significant influence on the plant height, stem girth, internode length, leaf number, and largest leaf traits of flue-cured tobacco. Plant Height: During the rosette and vigorous growth stages, the CK group exhibited the highest plant height. Following the topping stage, plant height stabilized, with the T2 group generally outperforming T1. Specifically, the plant height in the T2 group was 10.63% and 1.53% higher than those in the T1 and CK groups, respectively. Stem Girth: At the topping stage, intercropping with sweet potato increased stem girth by 2.7%–6.1% compared to the CK. Internode Length: In the rosette stage, the T2S1 treatment reached the maximum value (6.17 cm, a 3.7% increase over CK). While a significant decline was observed in the T1 group during the vigorous growth stage, the T2S1 treatment again showed the highest internode length (6.27 cm) by the topping stage. Number of Functional Leaves: The T1 group produced one fewer leaf than the CK during the vigorous growth stage. Largest Leaf Traits: During the vigorous growth stage, all intercropping treatments resulted in lower leaf length and width compared to the CK, with T1S1 showing the most substantial reduction of 19.88%. By the topping stage, the most pronounced inhibitory effects were observed in the T1B1 and T1B2 treatments. Overall, Sweet potato intercropping had minimal impact on, or even slightly promoted, the agronomic traits of flue-cured tobacco. In contrast, soybean intercropping—particularly in the T1B2 treatment—exerted a certain inhibitory effect on plant height, stem girth, internode length, and leaf morphological development. 3.2 Effects of Intercropping on Soil Physicochemical Properties and Enzymatic Activities Figure 3 and supplementary materials illustrate the significant regulatory effects of intercropping patterns on soil physicochemical properties and enzymatic activities. Soil pH and Organic Matter. Intercropping treatments exerted a notable buffering effect on soil pH and organic matter (SOM). In the CK group, pH values exhibited a progressive decline throughout the growth period. However, at the maturity stage, pH values in intercropping treatments were generally higher than those in the CK, with the T1S1 treatment reaching the maximum (8.18, a 0.24 increase over CK). Regarding SOM, the T2 group showed significant accumulation during the vigorous growth stage, with T2S2 and T2B1 averaging 16.08 g/kg and 16.11 g/kg, respectively; in contrast, the T1 group remained overall lower than the CK. Soil Nutrient Dynamics. Total Nutrients: Total nitrogen (TN) showed significant depletion during the growth stages. In the T1 group, TN levels recovered after the topping stage and, with the exception of T2S2, were higher than the CK at maturity. The variation in total phosphorus (TP) for the T2 group (excluding T2S2) mirrored the CK trend, while the T1 group exhibited a continuous increase following a decline from the rosette to the vigorous growth stage. Total potassium (TK) remained highest in the CK from the rosette to the topping stage. Available Nutrients: Alkali-hydrolyzable nitrogen (AN) fluctuated across phenological stages. Soybean intercropping significantly enhanced AN levels; specifically, T1B1 at the topping stage was 35.38% higher than the CK. Sweet potato intercropping was more effective in increasing available phosphorus (AP). The T2S1 treatment recorded 38.1 mg/kg and 37.97 mg/kg at the rosette and topping stages, respectively (17.1% and 20.13% higher than CK). At maturity, T2S2 reached the maximum AP (36.23 mg/kg, a 22.56% increase over CK). Notably, available potassium (AK) in all intercropping treatments remained lower than the CK, with the T2 group outperforming the T1 group. Soil Enzyme Activities. Soil enzyme activities exhibited fluctuating patterns throughout the growing season, Invertase: Activities peaked during the vigorous growth stage, with T2S1 reaching 38.98 U/g, significantly higher than the CK. Urease: Significant enhancement occurred at the topping stage (T1S2 was 21.6% higher than CK). By maturity, the urease activity in T1S2 was 1.31 times higher than that of the CK. Catalase: Reached its maximum during the vigorous growth stage, with T1B1 being 48.5% higher than the CK. β-glucosidase: T2S1 showed the highest activity at the rosette stage (47.4% higher than CK), while the T1 group performed better during the topping and maturity stages (e.g., T1S1 was 24.3% higher than CK). Overall, intercropping treatments demonstrated superior soil health indicators compared to the CK. The T2 group exhibited a distinct advantage in nutrient accumulation, whereas the T1 group was more effective in stimulating enzyme activities. These results indicate that different crop species and intercropping configurations exert divergent regulatory effects on soil nutrient cycling and biochemical potential. 3.3 Effects of Intercropping on Tobacco Leaf Quality As a specialty crop, the quality of flue-cured tobacco is of paramount importance, with price differentials between grades reaching up to ten-fold. Tobacco leaves are characterized as high-quality only when their chemical constituents fall within specific standardized ranges; detailed criteria for these indicators are provided in Reference 37 . Figure 4 and Table 2 illustrate the effects of various intercropping treatments on the chemical quality of tobacco. Different intercropping treatments exerted varying degrees of influence on the chemical composition of cured leaves: Alkaloids and Sugars. Total alkaloid contents in all treatments remained within the optimal range for high-quality tobacco, though they were generally lower than those in the CK. Regarding carbohydrates, the reducing sugar and total sugar contents in the T1 and CK groups generally exceeded the optimal thresholds, indicating inferior quality compared to the T2 group. Chlorine and Potassium. Chloride (Cl-) content across all treatments ranged from 0.20% to 0.26%, which is below the ideal range, with no significant difference observed compared to the CK. Potassium (K+) content was generally below the ideal range but remained higher than the CK across all treatments, with T1S2 showing the most substantial increase (29.36%). Nitrogen, Protein, and Starch. Total nitrogen (TN) levels were within the optimal range for all treatments but showed a decline relative to the CK, with T1S2 exhibiting the most significant reduction (13.2%). Although protein content was below the ideal range across all groups, the T2 group performed comparatively better, with T2S1 and T2S2 increasing by 4.77% and 3.41% over the CK, respectively. Starch content for all treatments fell within the ideal range (3.5%–6.0%), peaking in T1S2 at 5.12% (a 16.1% increase over CK). Quality Ratios. The total sugar/reducing sugar ratio and the sugar/alkaloid ratio were within the optimal ranges for all treatments. The K+/Cl- ratio was higher than the CK in all intercropping groups, with T1S1 reaching the maximum. Except for T1S1 and T1S2, which failed to meet the ideal criteria, the nitrogen/alkaloid ratios for all other treatments were within the optimal range, with T1B1 being the highest. Overall, the T2 group outperformed the T1 group in terms of total alkaloids, sugars, and protein content, proving more effective in enhancing the overall chemical quality of flue-cured tobacco. While the T1 group significantly increased potassium content and the K+/Cl- ratio, it was characterized by excessive sugar levels and suboptimal nitrogen/alkaloid ratios, resulting in less effective quality improvement than the T2 group. Table 2 Effects of different intercropping treatments on chemical quality of flue-cured tobacco leaves Treatment Tobacco chemical composition (%) 质量比(Mass ratio) Nicotine Reducing sugar Total sugar Chlorine Potassium Total nitrogen Protein Starch Two sugar ratio Ratio of sugar to alkali Ratio of chloride to potassium Ratio of nitrogen to alkali T1S1 2.74a 23.59a 26.81a 0.21bc 1.37ab 2.09d 5.71d 4.98ab 0.88b 9.78cd 6.52a 0.76cd T1S2 2.65c 21.91cd 25.18c 0.26a 1.41a 1.97e 5.78c 5.12a 0.87bc 8.27f 5.42de 0.74d T1B1 2.23f 23.66a 26.41ab 0.26a 1.34abc 2.13d 5.69d 3.96e 0.90ab 11.84a 5.15f 0.96a T1B2 2.39e 22.11c 25.36bc 0.25ab 1.32bcd 2.16bc 5.61e 4.11e 0.87bc 10.61b 5.28ef 0.90ab T2S1 2.55d 21.9cd 23.1de 0.23abc 1.23cde 2.07d 6.15a 4.81b 0.95a 9.06ef 5.35def 0.81bc T2S2 2.43e 20.64e 22.72e 0.20c 1.19e 2.21ab 6.07a 4.89b 0.91a 9.35def 5.95bc 0.91ab T2B1 2.39e 21.03de 24.55cd 0.20c 1.21de 2.18abc 5.89b 4.32d 0.86c 10.27bc 6.05b 0.91ab T2B2 2.68ab 20.24e 22.68e 0.21bc 1.17e 2.14cd 5.66de 4.57c 0.89ab 8.46f 5.57cd 0.80c CK 2.83a 22.91b 26.56ab 0.22abc 1.09e 2.27a 5.87b 4.41cd 0.86c 9.39de 4.95g 0.80c 3.4 Impact of Intercropping on the Economic Traits of Tobacco Fields Table 3 presents the differences in economic traits of the tobacco fields under different treatment regimes. Tobacco Grade Distribution. The proportion of high-grade tobacco generally followed the order of T2 group > T1 group. Specifically, the T2S1 treatment achieved the highest proportion at 61.6%, representing a 10.59% increase compared to the CK. Similarly, the highest proportion of middle-to-high grade tobacco was recorded in T2S1 (91.4%). Conversely, the proportions of low-grade and miscellaneous tobacco were notably higher in the T1 group than in both the CK and the T2 group. Yield and Pricing. Overall yield followed the trend of T2 group > CK > T1 group, with the T2B1 treatment reaching the peak yield, surpassing the CK by 5.42%. In terms of the average market price, the T2 group consistently outperformed the CK, with T2S2 showing the highest increase of 6.31% over the CK. In contrast, the average price in the T1 group exhibited a declining trend. Net Output Value and Profitability. Except for the B2 treatments, the net output value across all configurations followed the general trend of T2 > T1 > CK. Furthermore, intercropping with sweet potato yielded higher economic returns than intercropping with soybean. The specific ranking for net output value was as follows: T2S1 > T1S1 > T2S2 > T2B1 > T1S2 > CK > T1B2 > T2B2 > T1B1. Notably, T2S1 achieved a net output value of 63,838.5 CNY ha - 1 , providing an incremental value of 11,098.1 CNY ha - 1 over the CK. Overall, the average price of tobacco in the T2 treatments was generally higher than that in the CK, and the secondary income from intercrops in the T2 group also surpassed that of the T1 group. Among all tested patterns, the T2S (tobacco-sweet potato intercropping on the ridge side) configuration demonstrated the optimal overall economic benefit. Table 3 Economic Characteristics of Tobacco Fields under Different Intercropping Treatments Treatment Tobacco leaf Intercropped Crops Overall Economic Benefits of Tobacco Fields high-grade(%) medium-grade(%) low-grade(%) miscellaneous(%) Yield (kg/hm 2 ) Average price (yuan/kg) Yield (kg/hm 2 ) Average price (yuan/kg) Production costs (yuan/ hm 2 ) Net output value (yuan/hm 2 ) Relative value-added (yuan/hm 2 ) T1S1 56.1 31.5 8.2 4.2 2452.5 26.3 2760 3 15675 57106.5 4366.5 T1S2 55.6 29.7 8.1 6.6 2437.5 26.1 1387.5 5 15675 54882 2142 T1B1 53.4 29.2 10.3 7.9 2407.5 25.8 337.5 12 15600 50563.5 -2176.5 T1B2 53.9 28.4 11.3 6.4 2422.5 25.6 427.5 12 15600 51546 −1 194 T2S1 61.6 29.8 5.2 3.4 2634 28.6 10440 3 17700 63838.5 11098.1 T2S2 59.4 30.5 5.8 4.3 2602 28.7 4762.5 5 17700 55932 3191.9 T2B1 59.2 28.1 7.9 4.8 2656.5 28.5 1770 12 16800 54910.5 2170.2 T2B2 57.8 29.8 9.6 2.8 2611.5 27.9 1635 12 16800 51391.5 −1 349.7 CK 55.7 30.4 8.7 5.2 2520 27 0 0 15300 52740 0 3.5 Entropy Weight-TOPSIS Analysis of Different Treatments To account for the soil acidification trend, the pH decline value (calculated as the pH at the rosette stage minus the pH at the maturity stage) was employed as a cost-type (negative) indicator. After converting all cost-type and interval-type indicators into benefit-type (positive) indicators through normalization, an Entropy Weight-TOPSIS analysis was performed. The entropy weighting results (Table 4 ) revealed that leaf chloride (Cl-) content carried the highest weight at 18.67%. The evaluation framework was primarily driven by tobacco chemical quality indicators, which collectively accounted for over 78% of the total weight. Among the soil-related parameters, the pH decline value was the most influential, representing 9.64% of the weight. Overall, the top 10 indicators contributed to more than 90% of the total weighting distribution. The final EW-TOPSIS analysis (Table 5 ) determined the closeness coefficients (Ci), yielding the following preferential ranking: T2S1 > T2S2 > T2B2 > T1B2 > T2B1 > T1S2 > T1B1 > CK > T1S1. This hierarchy indicates that: Intercropping systems generally outperformed the monoculture control (CK). Ridge-top intercropping (T2) exhibited superior comprehensive benefits compared to ridge-side intercropping (T1). Within the ridge-top (T2) treatments, sweet potato intercropping was more effective than soybean (S > B). Within the ridge-side (T1) treatments, soybean (particularly the B2 variety) showed higher potential than sweet potato, with a sub-ranking of B2 > S2 > B1 > S1. Table 4 Index weights determined by the entropy weight method Indicator Weights Indicator Weights Chloride (leaf) 18.67% Potassium (leaf) 9.26% Total sugar (leaf) 15.44% Nitrogen/alkaloid ratio (leaf) 6.49% Reducing sugar (leaf) 13.32% Proportion of miscellaneous (leaf) 2.06% Protein (leaf) 15.06% Proportion of low-grade (leaf) 1.29% Soil pH alleviation (Soil) 9.64% Soil catalase activity at the maturity stage (soil) 1.03% Note: Only indicators with weights greater than 1% are listed Table 5 Ranking results based on the entropy weight–TOPSIS method Treatment Positive Ideal Solution Distance S+ Negative Ideal Solution Distance S- Closeness Coefficient Ci Ranking T2S1 0.081 0.162 0.675 1 T2S2 0.111 0.161 0.605 2 T2B2 0.138 0.142 0.549 3 T1B2 0.132 0.126 0.541 4 T2B1 0.126 0.121 0.525 5 T1S2 0.116 0.142 0.524 6 T1B1 0.150 0.130 0.502 7 CK 0.161 0.086 0.397 8 T1S1 0.173 0.083 0.334 9 4. Discussion 4.1 Effects of Intercropping on Soil Properties This study demonstrates that intercropping exerts a distinct regulatory effect on soil available nutrients, whereas its impact on total nutrient stocks remains statistically insignificant. Compared with tobacco monoculture, intercropping configurations facilitate a more balanced ratio of available nutrients, thereby promoting synchronized nutrient uptake by flue-cured tobacco 38 . Our results indicate that while total nitrogen (TN), total phosphorus (TP), and total potassium (TK) levels in intercropping treatments did not deviate significantly from the CK across growth stages, the available nutrient fractions were markedly modulated. These findings align with previous reports suggesting that tobacco-based intercropping primarily influences rapid-acting nutrient pools rather than recalcitrant total nutrient stocks 39 . Similarly, research on tobacco-soybean intercropping found no significant differences in TN compared to monoculture 13 , a result consistent with our observations. However, our findings partially diverge from those of Wu 40 , who reported that while Salvia miltiorrhiza and Dianthus chinensis intercropping showed no significant differences in TN and TP, soybean and selenium-enriched sweet potato treatments resulted in significantly lower nutrient levels than the control. This discrepancy may be attributed to differences in sampling chronologies and specific crop cultivars. In the present study, significant differences were observed at specific sampling intervals, and even under identical intercropping patterns, different cultivars exhibited divergent effects on soil properties. Furthermore, this study highlights the significant regulatory role of intercropping in soil enzymatic activities. Specifically, intercropping significantly enhanced soil urease activity (p < 0.05), confirming that this planting model can bolster urease levels, thereby accelerating the mineralization and decomposition of organic matter, optimizing energy transformation efficiency, and ultimately enhancing soil fertility 41 . Regarding soil organic matter (SOM), a declining trend was observed in intercropping systems relative to the CK. Throughout the growing season, the ridge-side intercropping treatments (T1) showed a noticeable reduction in SOM, whereas the ridge-top treatments (T2) remained comparable to the CK. This phenomenon may be explained by the "priming effect": the increased crop density in ridge-side intercropping likely enriched root exudates and rhizospheric microbial populations, which in turn accelerated the microbial mineralization of SOM. Hu et al. 42 reported that intercropping walnut with legumes significantly increased SOM, whereas walnut–Isatis indigotica intercropping led to a decrease. Such variability highlights the complex interactions between root exudates, residue decomposition rates, and microbial community shifts, underscoring the inherent complexity of SOM dynamics in field ecosystems, which warrants further long-term verification. 4.2 Differences Among Various Intercropping Treatments The results of this study indicate that intercropping systems generally offer superior benefits over monoculture. Among the tested configurations, ridge-top intercropping (T2) outperformed ridge-side intercropping (T1). Regarding crop combinations, the tobacco-sweet potato system exhibited particularly outstanding performance, surpassing the tobacco-soybean system. The relative inferiority of ridge-side intercropping can be attributed to increased planting density per unit area and the closer proximity of the intercrop to the tobacco plants. This spatial proximity encroaches upon the growth space of tobacco, leading to intense competition for light and other essential resources. Specifically, at the rosette stage, the taller soybean canopy tended to shade tobacco leaves, resulting in a reduction in both the functional leaf number and plant height compared to the CK. Furthermore, the high planting density on the same ridge restricted the expansion of middle leaves (waist leaves), thereby limiting the maximum leaf dimensions (length and width). Beyond above-ground competition, the intertwining of tobacco and intercrop root systems triggers complex rhizospheric interactions. Root exudates can alter soil nutrient concentrations and their bioavailability. For instance, in maize/faba bean intercropping systems, faba bean roots secrete substantial amounts of acid phosphatase and organic acids (e.g., citric and malic acids), which acidify the rhizosphere and mobilize sparingly soluble phosphorus 43 , thereby enhancing phosphorus nutrition and yield in maize. The advantage of sweet potato over soybean in this study stems from its prostrate growth habit. As a creeping herbaceous plant, sweet potato stems spread across the ridges and furrows, while its adventitious roots at the nodes expand the nutrient uptake range. This architecture allows for more efficient spatiotemporal resource utilization and promotes better ventilation and light penetration, minimizing direct competition with tobacco. Interestingly, while the preference on the ridge-top (T2) followed the order S1 > S2 > B2 > B1, a different pattern emerged on the ridge-side (T1), where soybean performed relatively better than sweet potato (B2 > S2 > B1 > S1). This shift underscores the complexity of root-root interactions under different spatial constraints, the mechanisms of which require further investigation. Consequently, the optimization of intercropping configurations remains a critical factor in agricultural practice. Previous research has shown that row-ratio configurations significantly influence the productivity of wheat-pea systems 44 , and increased row ratios in tobacco-peanut intercropping can effectively lower the disease index of tobacco black shank 19 . Our findings further confirm that ridge-top intercropping is superior to ridge-side intercropping for tobacco, with sweet potato being the preferred partner. Future research should continue to explore idealized spatial arrangements for diverse crop combinations to maximize system synergy. 5. Conclusions This study demonstrates that intercropping patterns significantly optimize the soil micro-ecology of tobacco fields. Both soybean and sweet potato intercropping effectively improved soil pH, organic matter content, and enzymatic activities. Specifically, soybean intercropping primarily drove the accumulation of alkali-hydrolyzable nitrogen (AN), whereas sweet potato intercropping significantly promoted the mobilization of available phosphorus (AP). Notably, although ridge-side intercropping (T1) exhibited higher activity in stimulating certain soil enzymes, its overall contribution to above-ground growth was constrained by intense interspecific competition. Ridge-top intercropping (T2) was identified as the superior spatial configuration strategy. Compared to the ridge-side (T1) pattern, which induced growth inhibition due to resource competition, the T2 pattern significantly promoted tobacco growth by enhancing the spatial complementarity of light and thermal resources. Furthermore, the T2 configuration optimized the coordination of chemical constituents in tobacco leaves, effectively reducing total alkaloids and sugar contents while increasing potassium and protein levels, thereby aligning with high-quality tobacco standards. Based on multi-objective decision-making, comprehensive economic performance, and EW-TOPSIS evaluation, ridge-top intercropping consistently outperformed ridge-side intercropping, and sweet potato proved to be a more suitable partner than soybean. In particular, the "Tobacco–Qinshu No. 5" ridge-top intercropping pattern (T2S1) maximized both the proportion of high-grade leaves (61.6%) and the net output value. This configuration achieved the optimal balance between agronomic development, soil health, and economic output, representing a highly effective model for the sustainable intensification of tobacco production. Declarations Competing interests: The authors declare no competing interests. Funding: This study is financially supported by the Science and Technology Project of Shaanxi Provincial Company of China Tobacco Corporation (KJ-2023-04), and the Science and Technology Project of Sichuan Provincial Company of China Tobacco Corporation (SCYC202305, SCYC202106). Author Contribution Fusong Wang: Writing – original draft, Formal analysis, Investigation, Data curation. Hao Li: Writing – original draft, Formal analysis, Investigation, Data curation. Qiang Wu: Investigation, Data curation, Validation. Hongbo Luo: Investigation, Data curation. Jun Xia: Investigation, Data curation. Biao Wang: Investigation. Jiawei Song: Investigation. Wenqing Lu: Investigation. Dahang Liao: Investigation. Yi Wang: Investigation. Hongjia Yang: Resources, Investigation. Yang Gang: Resources, Investigation. Junkang Guo: Methodology, Investigation. Jiangbo Hai: Writing – review & editing, Supervision, Conceptualization. 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Influence of Row Ratio Configuration on the Productivity and Resource Utilization Efficiency of Wheat - (Pea Intercropping System D; Northwest Agriculture and Forestry University, 2025). Additional Declarations No competing interests reported. Supplementary Files Supplementalfiles.docx floatimage5.png Fig. A.1 Effects of intercropping on soil nutrients and pH. The figure displays the variations in eight soil indicators measured at the Rosette stage, Vigorous growth stage, Topping stage, and Maturity stage: (a) Soil pH; (b) Organic matter content (g/kg); (c) Total nitrogen content (g/kg); (d) Total potassium content (g/kg); (e) Total phosphorus content (g/kg); (f) Alkali-hydrolyzable nitrogen content (mg/kg); (g) Available phosphorus content (mg/kg); (h) Available potassium content (mg/kg). floatimage6.png Fig. A.2 Effects of intercropping on soil enzyme activities. The figure illustrates the fluctuations of four key soil enzymes across the Rosette, Vigorous growth, Topping, and Maturity stages: (a) Urease activity (U/kg); (b) β-glucosidase activity (U/kg); (c) Catalase activity (U/kg); (d) Invertase activity (U/kg). Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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-8429844","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":582604864,"identity":"528304ec-bffd-460d-a0dc-8035e63a470b","order_by":0,"name":"Yinping 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design. a, T2B; b, T2S; c, T1B; d, T1S. For ridge-top intercropping (T2), soybean and sweet potato were planted in four rows and two rows per ridge, respectively. For ridge-side intercropping (T1), both crops were planted in a single row.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8429844/v1/59432f54a23b53f0cfad05c3.jpeg"},{"id":101530061,"identity":"d67d3159-8c49-48f6-9fab-f676313dd0e9","added_by":"auto","created_at":"2026-01-30 19:43:36","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":660747,"visible":true,"origin":"","legend":"\u003cp\u003eEffects of intercropping on the agronomic traits of flue-cured tobacco. Heatmaps of clustering at (a) the rosette stage, (b) the vigorous growth stage, and (c) the topping stage; (d) line charts of various indicators. PH, plant height; SG, stem girth; IL, internode length; MLL, maximum leaf length; MLW, maximum leaf width; NEL, number of effective leaves.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8429844/v1/a0ebb530f8151a84adb4cb0d.png"},{"id":101530063,"identity":"2424b2d6-232e-4c82-ab70-9008cf374398","added_by":"auto","created_at":"2026-01-30 19:43:36","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":441711,"visible":true,"origin":"","legend":"\u003cp\u003eCluster heatmap of soil physicochemical properties and enzyme activities. Phenological Stages: a, rosette stage; b, vigorous growth stage; c, topping stage; d, maturity stage. Soil Indicators: SOM, soil organic matter; TN, total nitrogen; TP, total phosphorus; TK, total potassium; AN, alkali-hydrolyzable nitrogen; AP, available phosphorus; AK, available potassium; pH, soil acidity/alkalinity. Soil Enzyme Activities: SC, sucrase (invertase); UE, urease; CAT, catalase; BG, β-glucosidase.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8429844/v1/c41a84ed8e0eab8be310c233.jpeg"},{"id":101752419,"identity":"4fb8b788-3f73-4e65-b366-7489e1759ee6","added_by":"auto","created_at":"2026-02-03 10:27:23","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":118346,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8429844/v1/9aea64e58e2982a119f954e6.jpeg"},{"id":103507370,"identity":"07ee42b6-16ad-4632-9d9c-90fb90bd9af1","added_by":"auto","created_at":"2026-02-26 13:41:09","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3303973,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8429844/v1/cfe685c6-b688-465f-86a9-c2405bae30f8.pdf"},{"id":101530067,"identity":"3b3608b3-8fc7-4d40-a352-88a3c60ef4ad","added_by":"auto","created_at":"2026-01-30 19:43:36","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":1091981,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementalfiles.docx","url":"https://assets-eu.researchsquare.com/files/rs-8429844/v1/affa7c18c5b39aac438021ff.docx"},{"id":101530065,"identity":"ed4c0e83-c4b3-4126-9666-c1240b40ceaa","added_by":"auto","created_at":"2026-01-30 19:43:36","extension":"png","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":720255,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFig. A.1 \u003c/strong\u003eEffects of intercropping on soil nutrients and pH. The figure displays the variations in eight soil indicators measured at the Rosette stage, Vigorous growth stage, Topping stage, and Maturity stage: (a) Soil pH; (b) Organic matter content (g/kg); (c) Total nitrogen content (g/kg); (d) Total potassium content (g/kg); (e) Total phosphorus content (g/kg); (f) Alkali-hydrolyzable nitrogen content (mg/kg); (g) Available phosphorus content (mg/kg); (h) Available potassium content (mg/kg).\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8429844/v1/f646ee19e5946a1086ad10f8.png"},{"id":101530066,"identity":"1b81a8be-4c05-46b3-bd2d-4cc7c9588661","added_by":"auto","created_at":"2026-01-30 19:43:36","extension":"png","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":354572,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFig. A.2 \u003c/strong\u003eEffects of intercropping on soil enzyme activities. The figure illustrates the fluctuations of four key soil enzymes across the Rosette, Vigorous growth, Topping, and Maturity stages: (a) Urease activity (U/kg); (b) β-glucosidase activity (U/kg); (c) Catalase activity (U/kg); (d) Invertase activity (U/kg).\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8429844/v1/09fab6c4b4b994c46c7609ac.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Optimization of Tobacco-Grain Intercropping Models Based on the Entropy Weight-TOPSIS Method","fulltext":[{"header":"1.Introduction","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eFlue-cured tobacco (\u003cem\u003eNicotiana tabacum L.\u003c/em\u003e) is a pivotal industrial crop in China, contributing substantially to national fiscal and tax revenues. However, the current cultivation of flue-cured tobacco is characterized by severe continuous cropping, which accounts for 30% to 60% of the total planting area\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e Such intensive continuous cropping significantly compromises soil health, leading to a marked decline in both tobacco quality and yield\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e, which further threatens the overall sustainability of the agro-ecosystem. Furthermore, the competition for land resources between tobacco and other crops poses a challenge to the existing agricultural planting structure and national food security\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Therefore, exploring the intercropping of flue-cured tobacco with food crops to leverage interspecific complementary effects is essential for the sustainable development of the tobacco industry. This approach is of strategic significance for ensuring the supply security of specialized agricultural products and the sustainable utilization of arable land.\u003c/p\u003e \u003cp\u003eContinuous cropping obstacles (CCOs) represent a critical bottleneck constraining the sustainable development of the tobacco industry. Prolonged continuous cropping of flue-cured tobacco exacerbates the incidence of pests and soil-borne diseases, most notably tobacco black shank (Phytophthora nicotianae), thereby compromising soil health\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan additionalcitationids=\"CR5 CR6 CR7 CR8\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Various mitigation strategies for CCOs have been explored, including the optimization of cultivation systems, the application of microbial inoculants, physical and chemical soil disinfection, the incorporation of straw and green manure, and the refinement of irrigation regimes\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. Research indicates that adjusting planting patterns can effectively alleviate or even eliminate CCOs\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. Specifically, intercropping has been shown to significantly enhance rhizosphere soil nutrient content and enzymatic activities, while increasing the diversity and richness of bacterial communities and optimizing their composition\u003csup\u003e\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. Furthermore, intercropping can effectively reduce the disease index of tobacco black shank and the population of its causal pathogens in the rhizosphere, while promoting the abundance of beneficial microbes\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. Properly managed intercropping systems also bolster the nutritional status and physiological resistance of the primary crop\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eGiven the efficacy of intercropping in mitigating continuous cropping obstacles (CCOs), selecting appropriate intercrop species and systematically evaluating their holistic benefits have become imperative. Previous research has explored intercropping flue-cured tobacco with crops such as maize, peanut, and sweet clover (Melilotus officinalis)\u003csup\u003e\u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e, demonstrating their potential to improve the soil micro-ecosystem and suppress soil-borne diseases. However, current literature predominantly focuses on singular effects, lacking a multi-dimensional systematic comparison and comprehensive evaluation of different intercropping systems across soil health, crop quality, economic returns, and long-term sustainability. Furthermore, a scientific framework for quantifying the overall performance of diverse intercropping systems has yet to be established for crops like flue-cured tobacco, which possess complex value structures characterized by significant price differentials based on quality. Conventional indices, such as the Land Equivalent Ratio (LER) and Land Equivalent Coefficient (LEC), primarily focus on yield and land-use efficiency; consequently, they fail to encapsulate the integrated impacts of intercropping on soil quality, tobacco leaf chemical constituents, and ultimate economic profitability\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eConsequently, to develop an optimized model that alleviates CCOs while simultaneously ensuring food security and economic viability, this study selected soybean (Glycine max) and sweet potato (Ipomoea batatas) as intercropping partners for flue-cured tobacco. Soybean, a legume, was chosen for its biological nitrogen fixation capacity, which facilitates soil nitrogen cycling, and its compact plant architecture and broad adaptability\u003csup\u003e\u003cspan additionalcitationids=\"CR24 CR25 CR26\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. Sweet potato was selected as a high-yielding, resilient \"staple-security crop\" with significant potential for enhancing food security and system-wide economic value\u003csup\u003e\u003cspan additionalcitationids=\"CR29\" citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e; both crops offer potential spatiotemporal and functional complementarity with tobacco in resource utilization. To circumvent the limitations of traditional evaluation methods and achieve an objective, multi-dimensional comparison of these intercropping systems, this study introduced the Entropy Weight-Technique for Order Preference by Similarity to Ideal Solution (EW-TOPSIS) algorithm. This approach objectively determines the weights of evaluation indicators using the entropy weight method and subsequently calculates the proximity of each treatment to the ideal solution via the TOPSIS model, thereby facilitating the ranking of complex multi-indicator systems\u003csup\u003e\u003cspan additionalcitationids=\"CR32\" citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. By effectively integrating heterogeneous data, including agronomic traits, soil indicators, leaf chemical quality, and economic attributes, this method mitigates the subjectivity inherent in manual weighting\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e, providing a robust quantitative basis for screening optimal intercropping patterns.\u003c/p\u003e \u003cp\u003eIn summary, this study aims to systematically elucidate the impacts of two intercropping patterns\u0026mdash;tobacco-soybean and tobacco-sweet potato\u0026mdash;on soil health, tobacco growth and quality, system productivity, and economic profitability through field experiments. By employing the EW-TOPSIS model to quantitatively evaluate and compare the multi-dimensional performance of these systems, we seek to identify an optimized intercropping model that harmonizes sustainable tobacco production with food security and the sustainable utilization of arable land. These findings are intended to provide a robust scientific framework and empirical evidence for both agricultural production practices and policy formulation.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Overview of the Experimental Site\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe field experiment was conducted in 2024 at the Tobacco Science and Technology Innovation Park in Zhiluo Town, Fu County, Yan\u0026rsquo;an City, Shaanxi Province, China (108.61\u0026deg; E, 35.74\u0026deg; N). This region is characterized by a warm temperate continental monsoon climate, with a mean annual temperature of 10 ℃, an average frost-free period of 165 days, and approximately 3,000 annual sunshine hours. Precipitation is primarily concentrated between June and September. The baseline physicochemical properties of the topsoil (0\u0026ndash;20 cm layer) prior to the experiment are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eNutrient status of 0\u0026ndash;20 cm soil layer\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal nitrogen\u003c/p\u003e \u003cp\u003eg/kg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003etotal phosphorous\u003c/p\u003e \u003cp\u003eg/kg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003etotal potassium\u003c/p\u003e \u003cp\u003eg/kg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ealkaline hydrolysis nitrogen\u003c/p\u003e \u003cp\u003emg/kg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003erapidly available potassium\u003c/p\u003e \u003cp\u003emg/kg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003erapidly available potassium\u003c/p\u003e \u003cp\u003emg/kg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eOrganic matter\u003c/p\u003e \u003cp\u003eg/kg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003epH\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e57.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e21.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e193.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e17.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7.67\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Experimental Design and Treatments\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe experiment followed an incomplete randomized split-plot design with a total of nine treatments, each replicated three times, resulting in 27 experimental plots. The treatments included four combinations of two sweet potato varieties (Qinshu 5: S1; Wanshu 10: S2) and four combinations of two soybean varieties (Zhongdou 63: B1; Sudou 051: B2) planted either on the ridge top (T2) or ridge side (T1), along with a monoculture flue-cured tobacco control (CK). Each plot covered an area of 96 m2 and consisted of 10 ridges (60 cm wide and 30 cm high).\u003c/p\u003e \u003cp\u003eFlue-cured tobacco was planted at a fixed spacing of 1.2 m times 0.6 m. For the intercropping components, sweet potato was configured with a row spacing of 55 cm and plant spacing of 30 cm, while soybean was planted with a row spacing of 30 cm, plant spacing of 25 cm, and a sowing depth of 4\u0026ndash;5 cm.\u003c/p\u003e \u003cp\u003eBasal fertilizers were applied during land preparation prior to ridging, including soybean cake fertilizer at 3,750 kg ha\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e and tobacco-specific compound fertilizer (N:P2O5:K2O\u0026thinsp;=\u0026thinsp;11:16:16) at 750 kg ha\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. During the ridging process, additional fertilization included oil cake (N:P:K\u0026thinsp;=\u0026thinsp;1:1:1) at 300 kg ha\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e, organic fertilizer (N:P:K\u0026thinsp;=\u0026thinsp;5:4:3) at 375 kg ha\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e, phosphate fertilizer at 37 kg ha\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e, and potassium fertilizer at 225 kg ha\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. No supplementary fertilizers were applied in the later growth stages. Other agronomic management practices, including pest and disease control, were performed in accordance with local conventional standards.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Measurement Indicators and Methods\u003c/h2\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.3.1 Determination of Soil Chemical Properties\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003ePrior to the transplantation of tobacco seedlings, the baseline fertility of the 0\u0026ndash;20 cm topsoil layer was determined. Soil samples were subsequently collected from both the tobacco ridges and intercrop ridges in each plot at four critical phenological stages: the rosette stage, vigorous growth stage, topping stage, and maturity stage. After collection, the soil samples were air-dried, ground, and passed through a sieve for further analysis. The measured soil indicators included soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzable nitrogen (AN), available phosphorus (AP), available potassium (AK), and pH. All soil physicochemical properties were determined according to the standard protocols established by Bao\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.3.2 Determination of Soil Enzyme Activities\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eDuring each phenological stage of the flue-cured tobacco, soil samples were collected following the procedures described in Section 1.3.1. The collected samples were immediately placed into sterile polyethylene bags and stored in a refrigerator at 4℃ prior to analysis. The activities of four key soil enzymes\u0026mdash;invertase (also known as sucrase), urease, catalase, and β-glucosidase\u0026mdash;were commissioned to and determined by Anhui Yangou Technology Co., Ltd. (Hefei, China).\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.3.3 Measurement of Agronomic Traits\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eAt various phenological stages of flue-cured tobacco (rosette, vigorous growth, and topping stages), agronomic traits\u0026mdash;comprising plant height, stem girth, internode length, and the length and width of the largest leaf\u0026mdash;were measured. The leaf area of the largest leaf was subsequently calculated based on these dimensions. All measurement procedures were performed in accordance with the tobacco industry standard (YC/T 142\u0026mdash;2010)\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.3.4 Determination of Tobacco Leaf Quality\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eleaves were harvested, individually labeled by treatment group, and subjected to standardized flue-curing. Following the curing process, 150 g of representative C3F (Medium Orange 3) grade tobacco leaves were randomly sampled from each group, ground, and passed through a sieve for analysis. The chemical characterization was commissioned to Anhui Yangou Technology Co., Ltd. (Hefei, China). The determined chemical constituents included total alkaloids (nicotine), reducing sugars, total sugars, chloride (Cl-), potassium (K+), total nitrogen (TN), protein, and starch. Furthermore, key quality parameters\u0026mdash;including the reducing sugar/total sugar ratio, nitrogen/alkaloid ratio, potassium/chloride ratio, and sugar/alkaloid ratio\u0026mdash;were calculated to evaluate the chemical equilibrium and overall quality of the tobacco leaves.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.3.5 Economic Benefits of Tobacco Fields\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eCured tobacco leaves were harvested sequentially from the lower to the upper stalk positions as they reached maturity. Following the flue-curing process, the leaves were categorized into upper, middle, and lower grades according to national grading standards. Each grade was weighed to determine its proportion relative to the total yield for each treatment.\u003c/p\u003e \u003cp\u003eProfessional local tobacco graders performed the classification of the cured leaves. Economic indicators, including the hectare yield (kg\u0026middot;ha\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e) and gross output value, were calculated based on the prevailing market prices for different tobacco grades. Simultaneously, the intercropped soybean and sweet potato were harvested, and their economic value was determined according to the current local market prices. The following parameters were calculated to evaluate the economic performance of the systems:\u003c/p\u003e \u003cp\u003eProportion of middle-to-high grade tobacco (%):\u003c/p\u003e \u003cp\u003eRatio M-H = (Yield of middle and upper grade) /( leaves Total yield)\u0026middot;100%\u003c/p\u003e \u003cp\u003eNet Profit (CNY):\u003c/p\u003e \u003cp\u003eNet Profit\u0026thinsp;=\u0026thinsp;Gross Output Value - Total Production Costs\u003c/p\u003e \u003cp\u003eWhere production costs include expenditures on tobacco seedlings, seeds, fertilizers, and other agricultural inputs.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Data Processing and Analysis\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eRaw data were organized and pre-processed using Microsoft Excel. Statistical analyses, including analysis of variance (ANOVA), Duncan\u0026rsquo;s multiple range test (α\u0026thinsp;=\u0026thinsp;0.05), and Pearson correlation analysis, were performed using SPSS 27.0 software. Data visualization and figure generation were conducted via Origin 2024.\u003c/p\u003e \u003cp\u003eTo intuitively compare the variations across different treatments and indicators, the Hiplot platform (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://hiplot.com.cn/\u003c/span\u003e\u003cspan address=\"https://hiplot.com.cn/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e) was utilized to perform Z-score standardization and Ward\u0026rsquo;s hierarchical clustering analysis. The specific mathematical procedures and calculation steps for the Entropy Weight-TOPSIS (EW-TOPSIS) method were adopted from previous literature\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. In this study, the EW-TOPSIS analysis was implemented using the pymcdm library within the Python 3.13 environment. This computational approach ensured the objectivity of weight assignment and the robustness of the multi-dimensional comprehensive evaluation.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Impact of Intercropping on the Agronomic Traits of Flue-cured Tobacco\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eAccording to Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, intercropping patterns exerted a significant influence on the plant height, stem girth, internode length, leaf number, and largest leaf traits of flue-cured tobacco.\u003c/p\u003e \u003cp\u003ePlant Height: During the rosette and vigorous growth stages, the CK group exhibited the highest plant height. Following the topping stage, plant height stabilized, with the T2 group generally outperforming T1. Specifically, the plant height in the T2 group was 10.63% and 1.53% higher than those in the T1 and CK groups, respectively. Stem Girth: At the topping stage, intercropping with sweet potato increased stem girth by 2.7%\u0026ndash;6.1% compared to the CK. Internode Length: In the rosette stage, the T2S1 treatment reached the maximum value (6.17 cm, a 3.7% increase over CK). While a significant decline was observed in the T1 group during the vigorous growth stage, the T2S1 treatment again showed the highest internode length (6.27 cm) by the topping stage. Number of Functional Leaves: The T1 group produced one fewer leaf than the CK during the vigorous growth stage. Largest Leaf Traits: During the vigorous growth stage, all intercropping treatments resulted in lower leaf length and width compared to the CK, with T1S1 showing the most substantial reduction of 19.88%. By the topping stage, the most pronounced inhibitory effects were observed in the T1B1 and T1B2 treatments.\u003c/p\u003e \u003cp\u003eOverall, Sweet potato intercropping had minimal impact on, or even slightly promoted, the agronomic traits of flue-cured tobacco. In contrast, soybean intercropping\u0026mdash;particularly in the T1B2 treatment\u0026mdash;exerted a certain inhibitory effect on plant height, stem girth, internode length, and leaf morphological development.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Effects of Intercropping on Soil Physicochemical Properties and Enzymatic Activities\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and supplementary materials illustrate the significant regulatory effects of intercropping patterns on soil physicochemical properties and enzymatic activities.\u003c/p\u003e \u003cp\u003eSoil pH and Organic Matter. Intercropping treatments exerted a notable buffering effect on soil pH and organic matter (SOM). In the CK group, pH values exhibited a progressive decline throughout the growth period. However, at the maturity stage, pH values in intercropping treatments were generally higher than those in the CK, with the T1S1 treatment reaching the maximum (8.18, a 0.24 increase over CK). Regarding SOM, the T2 group showed significant accumulation during the vigorous growth stage, with T2S2 and T2B1 averaging 16.08 g/kg and 16.11 g/kg, respectively; in contrast, the T1 group remained overall lower than the CK.\u003c/p\u003e \u003cp\u003eSoil Nutrient Dynamics. Total Nutrients: Total nitrogen (TN) showed significant depletion during the growth stages. In the T1 group, TN levels recovered after the topping stage and, with the exception of T2S2, were higher than the CK at maturity. The variation in total phosphorus (TP) for the T2 group (excluding T2S2) mirrored the CK trend, while the T1 group exhibited a continuous increase following a decline from the rosette to the vigorous growth stage. Total potassium (TK) remained highest in the CK from the rosette to the topping stage. Available Nutrients: Alkali-hydrolyzable nitrogen (AN) fluctuated across phenological stages. Soybean intercropping significantly enhanced AN levels; specifically, T1B1 at the topping stage was 35.38% higher than the CK. Sweet potato intercropping was more effective in increasing available phosphorus (AP). The T2S1 treatment recorded 38.1 mg/kg and 37.97 mg/kg at the rosette and topping stages, respectively (17.1% and 20.13% higher than CK). At maturity, T2S2 reached the maximum AP (36.23 mg/kg, a 22.56% increase over CK). Notably, available potassium (AK) in all intercropping treatments remained lower than the CK, with the T2 group outperforming the T1 group.\u003c/p\u003e \u003cp\u003eSoil Enzyme Activities. Soil enzyme activities exhibited fluctuating patterns throughout the growing season, Invertase: Activities peaked during the vigorous growth stage, with T2S1 reaching 38.98 U/g, significantly higher than the CK. Urease: Significant enhancement occurred at the topping stage (T1S2 was 21.6% higher than CK). By maturity, the urease activity in T1S2 was 1.31 times higher than that of the CK. Catalase: Reached its maximum during the vigorous growth stage, with T1B1 being 48.5% higher than the CK. β-glucosidase: T2S1 showed the highest activity at the rosette stage (47.4% higher than CK), while the T1 group performed better during the topping and maturity stages (e.g., T1S1 was 24.3% higher than CK).\u003c/p\u003e \u003cp\u003eOverall, intercropping treatments demonstrated superior soil health indicators compared to the CK. The T2 group exhibited a distinct advantage in nutrient accumulation, whereas the T1 group was more effective in stimulating enzyme activities. These results indicate that different crop species and intercropping configurations exert divergent regulatory effects on soil nutrient cycling and biochemical potential.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Effects of Intercropping on Tobacco Leaf Quality\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eAs a specialty crop, the quality of flue-cured tobacco is of paramount importance, with price differentials between grades reaching up to ten-fold. Tobacco leaves are characterized as high-quality only when their chemical constituents fall within specific standardized ranges; detailed criteria for these indicators are provided in Reference\u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e and Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e illustrate the effects of various intercropping treatments on the chemical quality of tobacco.\u003c/p\u003e \u003cp\u003eDifferent intercropping treatments exerted varying degrees of influence on the chemical composition of cured leaves:\u003c/p\u003e \u003cp\u003eAlkaloids and Sugars. Total alkaloid contents in all treatments remained within the optimal range for high-quality tobacco, though they were generally lower than those in the CK. Regarding carbohydrates, the reducing sugar and total sugar contents in the T1 and CK groups generally exceeded the optimal thresholds, indicating inferior quality compared to the T2 group. Chlorine and Potassium. Chloride (Cl-) content across all treatments ranged from 0.20% to 0.26%, which is below the ideal range, with no significant difference observed compared to the CK. Potassium (K+) content was generally below the ideal range but remained higher than the CK across all treatments, with T1S2 showing the most substantial increase (29.36%). Nitrogen, Protein, and Starch. Total nitrogen (TN) levels were within the optimal range for all treatments but showed a decline relative to the CK, with T1S2 exhibiting the most significant reduction (13.2%). Although protein content was below the ideal range across all groups, the T2 group performed comparatively better, with T2S1 and T2S2 increasing by 4.77% and 3.41% over the CK, respectively. Starch content for all treatments fell within the ideal range (3.5%\u0026ndash;6.0%), peaking in T1S2 at 5.12% (a 16.1% increase over CK). Quality Ratios. The total sugar/reducing sugar ratio and the sugar/alkaloid ratio were within the optimal ranges for all treatments. The K+/Cl- ratio was higher than the CK in all intercropping groups, with T1S1 reaching the maximum. Except for T1S1 and T1S2, which failed to meet the ideal criteria, the nitrogen/alkaloid ratios for all other treatments were within the optimal range, with T1B1 being the highest.\u003c/p\u003e \u003cp\u003eOverall, the T2 group outperformed the T1 group in terms of total alkaloids, sugars, and protein content, proving more effective in enhancing the overall chemical quality of flue-cured tobacco. While the T1 group significantly increased potassium content and the K+/Cl- ratio, it was characterized by excessive sugar levels and suboptimal nitrogen/alkaloid ratios, resulting in less effective quality improvement than the T2 group.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEffects of different intercropping treatments on chemical quality of flue-cured tobacco leaves\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"15\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c15\" colnum=\"15\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTreatment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"7\" nameend=\"c8\" namest=\"c2\"\u003e \u003cp\u003eTobacco chemical composition (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c15\" namest=\"c11\"\u003e \u003cp\u003e质量比(Mass ratio)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNicotine\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eReducing\u003c/p\u003e \u003cp\u003esugar\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003cp\u003esugar\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eChlorine\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePotassium\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003cp\u003enitrogen\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003eProtein\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003eStarch\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c12\"\u003e \u003cp\u003eTwo\u003c/p\u003e \u003cp\u003esugar ratio\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c13\"\u003e \u003cp\u003eRatio of\u003c/p\u003e \u003cp\u003esugar to\u003c/p\u003e \u003cp\u003ealkali\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c14\"\u003e \u003cp\u003eRatio of\u003c/p\u003e \u003cp\u003echloride to\u003c/p\u003e \u003cp\u003epotassium\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c15\"\u003e \u003cp\u003eRatio of\u003c/p\u003e \u003cp\u003enitrogen\u003c/p\u003e \u003cp\u003eto alkali\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.74a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23.59a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26.81a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.21bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.37ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.09d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e5.71d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e4.98ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.88b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e9.78cd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e6.52a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e0.76cd\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.65c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21.91cd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25.18c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.26a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.41a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.97e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e5.78c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e5.12a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.87bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e8.27f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e5.42de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e0.74d\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1B1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.23f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23.66a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26.41ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.26a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.34abc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.13d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e5.69d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e3.96e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.90ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e11.84a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e5.15f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e0.96a\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1B2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.39e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.11c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25.36bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.25ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.32bcd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.16bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e5.61e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e4.11e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.87bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e10.61b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e5.28ef\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e0.90ab\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.55d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21.9cd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23.1de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.23abc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.23cde\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.07d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e6.15a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e4.81b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.95a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e9.06ef\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e5.35def\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e0.81bc\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.43e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20.64e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22.72e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.20c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.19e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.21ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e6.07a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e4.89b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.91a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e9.35def\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e5.95bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e0.91ab\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2B1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.39e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21.03de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24.55cd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.20c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.21de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.18abc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e5.89b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e4.32d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.86c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e10.27bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e6.05b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e0.91ab\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2B2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.68ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20.24e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22.68e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.21bc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.17e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.14cd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e5.66de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e4.57c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.89ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e8.46f\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e5.57cd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e0.80c\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCK\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.83a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.91b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26.56ab\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.22abc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.09e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.27a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e5.87b\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e4.41cd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e0.86c\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e9.39de\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e \u003cp\u003e4.95g\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e \u003cp\u003e0.80c\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Impact of Intercropping on the Economic Traits of Tobacco Fields\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e presents the differences in economic traits of the tobacco fields under different treatment regimes.\u003c/p\u003e \u003cp\u003eTobacco Grade Distribution. The proportion of high-grade tobacco generally followed the order of T2 group\u0026thinsp;\u0026gt;\u0026thinsp;T1 group. Specifically, the T2S1 treatment achieved the highest proportion at 61.6%, representing a 10.59% increase compared to the CK. Similarly, the highest proportion of middle-to-high grade tobacco was recorded in T2S1 (91.4%). Conversely, the proportions of low-grade and miscellaneous tobacco were notably higher in the T1 group than in both the CK and the T2 group.\u003c/p\u003e \u003cp\u003eYield and Pricing. Overall yield followed the trend of T2 group\u0026thinsp;\u0026gt;\u0026thinsp;CK\u0026thinsp;\u0026gt;\u0026thinsp;T1 group, with the T2B1 treatment reaching the peak yield, surpassing the CK by 5.42%. In terms of the average market price, the T2 group consistently outperformed the CK, with T2S2 showing the highest increase of 6.31% over the CK. In contrast, the average price in the T1 group exhibited a declining trend.\u003c/p\u003e \u003cp\u003eNet Output Value and Profitability. Except for the B2 treatments, the net output value across all configurations followed the general trend of T2\u0026thinsp;\u0026gt;\u0026thinsp;T1\u0026thinsp;\u0026gt;\u0026thinsp;CK. Furthermore, intercropping with sweet potato yielded higher economic returns than intercropping with soybean. The specific ranking for net output value was as follows: T2S1\u0026thinsp;\u0026gt;\u0026thinsp;T1S1\u0026thinsp;\u0026gt;\u0026thinsp;T2S2\u0026thinsp;\u0026gt;\u0026thinsp;T2B1\u0026thinsp;\u0026gt;\u0026thinsp;T1S2\u0026thinsp;\u0026gt;\u0026thinsp;CK\u0026thinsp;\u0026gt;\u0026thinsp;T1B2\u0026thinsp;\u0026gt;\u0026thinsp;T2B2\u0026thinsp;\u0026gt;\u0026thinsp;T1B1. Notably, T2S1 achieved a net output value of 63,838.5 CNY ha\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e, providing an incremental value of 11,098.1 CNY ha\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e over the CK.\u003c/p\u003e \u003cp\u003eOverall, the average price of tobacco in the T2 treatments was generally higher than that in the CK, and the secondary income from intercrops in the T2 group also surpassed that of the T1 group. Among all tested patterns, the T2S (tobacco-sweet potato intercropping on the ridge side) configuration demonstrated the optimal overall economic benefit.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEconomic Characteristics of Tobacco Fields under Different Intercropping Treatments\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"14\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTreatment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"6\" nameend=\"c7\" namest=\"c2\"\u003e \u003cp\u003eTobacco leaf\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c10\" namest=\"c8\"\u003e \u003cp\u003eIntercropped Crops\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c13\" namest=\"c11\"\u003e \u003cp\u003eOverall Economic Benefits of Tobacco Fields\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"1\" nameend=\"c14\" namest=\"c14\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ehigh-grade(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003emedium-grade(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003elow-grade(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003emiscellaneous(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eYield\u003c/p\u003e \u003cp\u003e(kg/hm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003eAverage price\u003c/p\u003e \u003cp\u003e(yuan/kg)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eYield\u003c/p\u003e \u003cp\u003e(kg/hm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eAverage price\u003c/p\u003e \u003cp\u003e(yuan/kg)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003eProduction costs\u003c/p\u003e \u003cp\u003e(yuan/ hm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c12\"\u003e \u003cp\u003eNet output value (yuan/hm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003eRelative value-added\u003c/p\u003e \u003cp\u003e(yuan/hm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e56.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e31.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2452.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e26.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2760\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e15675\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e57106.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003e4366.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e55.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2437.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e26.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1387.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e15675\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e54882\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003e2142\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1B1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2407.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e25.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e337.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e15600\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e50563.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003e-2176.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1B2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2422.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e25.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e427.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e15600\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e51546\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003e\u003csup\u003e\u0026minus;1\u003c/sup\u003e194\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e61.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2634\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e28.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e10440\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e17700\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e63838.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003e11098.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e59.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2602\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e28.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e4762.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e17700\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e55932\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003e3191.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2B1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e59.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2656.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e28.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1770\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e16800\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e54910.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003e2170.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2B2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e57.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2611.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e27.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1635\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e16800\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e51391.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003e\u003csup\u003e\u0026minus;1\u003c/sup\u003e349.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCK\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e55.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2520\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e15300\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e52740\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c14\" namest=\"c13\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Entropy Weight-TOPSIS Analysis of Different Treatments\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eTo account for the soil acidification trend, the pH decline value (calculated as the pH at the rosette stage minus the pH at the maturity stage) was employed as a cost-type (negative) indicator. After converting all cost-type and interval-type indicators into benefit-type (positive) indicators through normalization, an Entropy Weight-TOPSIS analysis was performed.\u003c/p\u003e \u003cp\u003eThe entropy weighting results (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e) revealed that leaf chloride (Cl-) content carried the highest weight at 18.67%. The evaluation framework was primarily driven by tobacco chemical quality indicators, which collectively accounted for over 78% of the total weight. Among the soil-related parameters, the pH decline value was the most influential, representing 9.64% of the weight. Overall, the top 10 indicators contributed to more than 90% of the total weighting distribution.\u003c/p\u003e \u003cp\u003eThe final EW-TOPSIS analysis (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e) determined the closeness coefficients (Ci), yielding the following preferential ranking: T2S1\u0026thinsp;\u0026gt;\u0026thinsp;T2S2\u0026thinsp;\u0026gt;\u0026thinsp;T2B2\u0026thinsp;\u0026gt;\u0026thinsp;T1B2\u0026thinsp;\u0026gt;\u0026thinsp;T2B1\u0026thinsp;\u0026gt;\u0026thinsp;T1S2\u0026thinsp;\u0026gt;\u0026thinsp;T1B1\u0026thinsp;\u0026gt;\u0026thinsp;CK\u0026thinsp;\u0026gt;\u0026thinsp;T1S1. This hierarchy indicates that: Intercropping systems generally outperformed the monoculture control (CK). Ridge-top intercropping (T2) exhibited superior comprehensive benefits compared to ridge-side intercropping (T1). Within the ridge-top (T2) treatments, sweet potato intercropping was more effective than soybean (S\u0026thinsp;\u0026gt;\u0026thinsp;B). Within the ridge-side (T1) treatments, soybean (particularly the B2 variety) showed higher potential than sweet potato, with a sub-ranking of B2\u0026thinsp;\u0026gt;\u0026thinsp;S2\u0026thinsp;\u0026gt;\u0026thinsp;B1\u0026thinsp;\u0026gt;\u0026thinsp;S1.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eIndex weights determined by the entropy weight method\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIndicator\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWeights\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eIndicator\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eWeights\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChloride (leaf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18.67%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePotassium (leaf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.26%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal sugar (leaf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.44%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNitrogen/alkaloid ratio (leaf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.49%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReducing sugar (leaf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.32%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eProportion of miscellaneous (leaf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.06%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProtein (leaf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.06%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eProportion of low-grade (leaf)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.29%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSoil pH alleviation (Soil)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.64%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSoil catalase activity at the maturity stage (soil)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.03%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eNote: Only indicators with weights greater than 1% are listed\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRanking results based on the entropy weight\u0026ndash;TOPSIS method\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePositive Ideal Solution Distance\u003c/p\u003e \u003cp\u003e\u003cem\u003eS+\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNegative Ideal Solution Distance\u003c/p\u003e \u003cp\u003e\u003cem\u003eS-\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCloseness Coefficient\u003c/p\u003e \u003cp\u003e\u003cem\u003eCi\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRanking\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.081\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.162\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.675\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.111\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.161\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.605\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2B2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.138\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.142\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.549\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1B2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.132\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.126\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.541\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT2B1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.126\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.121\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.525\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.116\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.142\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.524\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1B1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.150\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.130\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.502\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCK\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.161\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.086\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.397\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eT1S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.173\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.083\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.334\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Effects of Intercropping on Soil Properties\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThis study demonstrates that intercropping exerts a distinct regulatory effect on soil available nutrients, whereas its impact on total nutrient stocks remains statistically insignificant. Compared with tobacco monoculture, intercropping configurations facilitate a more balanced ratio of available nutrients, thereby promoting synchronized nutrient uptake by flue-cured tobacco\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e. Our results indicate that while total nitrogen (TN), total phosphorus (TP), and total potassium (TK) levels in intercropping treatments did not deviate significantly from the CK across growth stages, the available nutrient fractions were markedly modulated. These findings align with previous reports suggesting that tobacco-based intercropping primarily influences rapid-acting nutrient pools rather than recalcitrant total nutrient stocks\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. Similarly, research on tobacco-soybean intercropping found no significant differences in TN compared to monoculture\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e, a result consistent with our observations. However, our findings partially diverge from those of Wu\u003csup\u003e40\u003c/sup\u003e, who reported that while Salvia miltiorrhiza and Dianthus chinensis intercropping showed no significant differences in TN and TP, soybean and selenium-enriched sweet potato treatments resulted in significantly lower nutrient levels than the control. This discrepancy may be attributed to differences in sampling chronologies and specific crop cultivars. In the present study, significant differences were observed at specific sampling intervals, and even under identical intercropping patterns, different cultivars exhibited divergent effects on soil properties.\u003c/p\u003e \u003cp\u003eFurthermore, this study highlights the significant regulatory role of intercropping in soil enzymatic activities. Specifically, intercropping significantly enhanced soil urease activity (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), confirming that this planting model can bolster urease levels, thereby accelerating the mineralization and decomposition of organic matter, optimizing energy transformation efficiency, and ultimately enhancing soil fertility\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eRegarding soil organic matter (SOM), a declining trend was observed in intercropping systems relative to the CK. Throughout the growing season, the ridge-side intercropping treatments (T1) showed a noticeable reduction in SOM, whereas the ridge-top treatments (T2) remained comparable to the CK. This phenomenon may be explained by the \"priming effect\": the increased crop density in ridge-side intercropping likely enriched root exudates and rhizospheric microbial populations, which in turn accelerated the microbial mineralization of SOM. Hu et al.\u003csup\u003e42\u003c/sup\u003e reported that intercropping walnut with legumes significantly increased SOM, whereas walnut\u0026ndash;Isatis indigotica intercropping led to a decrease. Such variability highlights the complex interactions between root exudates, residue decomposition rates, and microbial community shifts, underscoring the inherent complexity of SOM dynamics in field ecosystems, which warrants further long-term verification.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e4.2 Differences Among Various Intercropping Treatments\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe results of this study indicate that intercropping systems generally offer superior benefits over monoculture. Among the tested configurations, ridge-top intercropping (T2) outperformed ridge-side intercropping (T1). Regarding crop combinations, the tobacco-sweet potato system exhibited particularly outstanding performance, surpassing the tobacco-soybean system.\u003c/p\u003e \u003cp\u003eThe relative inferiority of ridge-side intercropping can be attributed to increased planting density per unit area and the closer proximity of the intercrop to the tobacco plants. This spatial proximity encroaches upon the growth space of tobacco, leading to intense competition for light and other essential resources. Specifically, at the rosette stage, the taller soybean canopy tended to shade tobacco leaves, resulting in a reduction in both the functional leaf number and plant height compared to the CK. Furthermore, the high planting density on the same ridge restricted the expansion of middle leaves (waist leaves), thereby limiting the maximum leaf dimensions (length and width).\u003c/p\u003e \u003cp\u003eBeyond above-ground competition, the intertwining of tobacco and intercrop root systems triggers complex rhizospheric interactions. Root exudates can alter soil nutrient concentrations and their bioavailability. For instance, in maize/faba bean intercropping systems, faba bean roots secrete substantial amounts of acid phosphatase and organic acids (e.g., citric and malic acids), which acidify the rhizosphere and mobilize sparingly soluble phosphorus \u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e, thereby enhancing phosphorus nutrition and yield in maize.\u003c/p\u003e \u003cp\u003eThe advantage of sweet potato over soybean in this study stems from its prostrate growth habit. As a creeping herbaceous plant, sweet potato stems spread across the ridges and furrows, while its adventitious roots at the nodes expand the nutrient uptake range. This architecture allows for more efficient spatiotemporal resource utilization and promotes better ventilation and light penetration, minimizing direct competition with tobacco.\u003c/p\u003e \u003cp\u003eInterestingly, while the preference on the ridge-top (T2) followed the order S1\u0026thinsp;\u0026gt;\u0026thinsp;S2\u0026thinsp;\u0026gt;\u0026thinsp;B2\u0026thinsp;\u0026gt;\u0026thinsp;B1, a different pattern emerged on the ridge-side (T1), where soybean performed relatively better than sweet potato (B2\u0026thinsp;\u0026gt;\u0026thinsp;S2\u0026thinsp;\u0026gt;\u0026thinsp;B1\u0026thinsp;\u0026gt;\u0026thinsp;S1). This shift underscores the complexity of root-root interactions under different spatial constraints, the mechanisms of which require further investigation. Consequently, the optimization of intercropping configurations remains a critical factor in agricultural practice. Previous research has shown that row-ratio configurations significantly influence the productivity of wheat-pea systems\u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e, and increased row ratios in tobacco-peanut intercropping can effectively lower the disease index of tobacco black shank\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Our findings further confirm that ridge-top intercropping is superior to ridge-side intercropping for tobacco, with sweet potato being the preferred partner. Future research should continue to explore idealized spatial arrangements for diverse crop combinations to maximize system synergy.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThis study demonstrates that intercropping patterns significantly optimize the soil micro-ecology of tobacco fields. Both soybean and sweet potato intercropping effectively improved soil pH, organic matter content, and enzymatic activities. Specifically, soybean intercropping primarily drove the accumulation of alkali-hydrolyzable nitrogen (AN), whereas sweet potato intercropping significantly promoted the mobilization of available phosphorus (AP). Notably, although ridge-side intercropping (T1) exhibited higher activity in stimulating certain soil enzymes, its overall contribution to above-ground growth was constrained by intense interspecific competition.\u003c/p\u003e \u003cp\u003eRidge-top intercropping (T2) was identified as the superior spatial configuration strategy. Compared to the ridge-side (T1) pattern, which induced growth inhibition due to resource competition, the T2 pattern significantly promoted tobacco growth by enhancing the spatial complementarity of light and thermal resources. Furthermore, the T2 configuration optimized the coordination of chemical constituents in tobacco leaves, effectively reducing total alkaloids and sugar contents while increasing potassium and protein levels, thereby aligning with high-quality tobacco standards.\u003c/p\u003e \u003cp\u003eBased on multi-objective decision-making, comprehensive economic performance, and EW-TOPSIS evaluation, ridge-top intercropping consistently outperformed ridge-side intercropping, and sweet potato proved to be a more suitable partner than soybean. In particular, the \"Tobacco\u0026ndash;Qinshu No. 5\" ridge-top intercropping pattern (T2S1) maximized both the proportion of high-grade leaves (61.6%) and the net output value. This configuration achieved the optimal balance between agronomic development, soil health, and economic output, representing a highly effective model for the sustainable intensification of tobacco production.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eCompeting interests:\u003c/h2\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003ch2\u003eFunding:\u003c/h2\u003e\n\u003cp\u003eThis study is financially supported by the Science and Technology Project of Shaanxi Provincial Company of China Tobacco Corporation (KJ-2023-04), and the Science and Technology Project of Sichuan Provincial Company of China Tobacco Corporation (SCYC202305, SCYC202106).\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eFusong Wang: Writing \u0026ndash; original draft, Formal analysis, Investigation, Data curation. Hao Li: Writing \u0026ndash; original draft, Formal analysis, Investigation, Data curation. Qiang Wu: Investigation, Data curation, Validation. Hongbo Luo: Investigation, Data curation. Jun Xia: Investigation, Data curation. Biao Wang: Investigation. Jiawei Song: Investigation. Wenqing Lu: Investigation. Dahang Liao: Investigation. Yi Wang: Investigation. Hongjia Yang: Resources, Investigation. Yang Gang: Resources, Investigation. Junkang Guo: Methodology, Investigation. Jiangbo Hai: Writing \u0026ndash; review \u0026amp; editing, Supervision, Conceptualization. Yinping Bai: Writing \u0026ndash; review \u0026amp; editing, Supervision, Project administration, Funding acquisition, Conceptualization, All authors reviewed the paper.\u003c/p\u003e\n\u003ch2\u003eData Availability\u003c/h2\u003e\n\u003cp\u003eThe original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding authors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eShi, P. et al. Symptoms,Mechanism and Controlling Measures of Tobacco Continuous Cropping ObstaclesJ. \u003cem\u003eJ. Anhui Agricultural Sci.\u003c/em\u003e \u003cb\u003e39\u003c/b\u003e (01), 120\u0026ndash;122 (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang, J. et al. Advance in Continuous Cropping Problems of TobaccoJ. \u003cem\u003eChin. Tob. 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(2007).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHe, T. \u003cem\u003eInfluence of Row Ratio Configuration on the Productivity and Resource Utilization Efficiency of Wheat -\u003c/em\u003e (Pea Intercropping System D; Northwest Agriculture and Forestry University, 2025).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Flue-cured tobacco, Intercropping patterns, Spatial configuration, Economic performance, EW-TOPSIS model","lastPublishedDoi":"10.21203/rs.3.rs-8429844/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8429844/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eAlleviating continuous cropping obstacles while ensuring grain security requires sustainable farming system designs. This study evaluated the spatial configuration and crop combinations in tobacco-based systems to balance soil health and economic output. A field experiment was conducted comparing tobacco monoculture (CK) with tobacco intercropped with soybean (B1, B2) or sweet potato (S1, S2) under two spatial modes: furrow (T1) and on-ridge (T2) intercropping. An Entropy-Weight TOPSIS model was employed to synthesize soil enzymatic activity, nutrient cycling, agronomic traits, leaf quality, and economic benefits. The results showed that intercropping significantly regulated the rhizosphere environment. Compared to CK, intercropping improved soil pH and organic matter. Specifically, tobacco\u0026ndash;soybean intercropping (T1B1) increased available nitrogen by 35.38%, while tobacco\u0026ndash;sweet potato (T2S1) boosted available phosphorus by 17.1% and sucrase activity to 38.98 U/g. Spatially, the on-ridge mode (T2) mitigated interspecific competition more effectively than the furrow mode (T1), enhancing plant height by 10.63% and optimizing chemical coordination (e.g., improved K/Cl ratios and increased protein content). Economically, the T2S1 system maximized synergism, with high-class tobacco reaching 61.6%. The Entropy-TOPSIS evaluation confirmed that intercropping systems outperformed monoculture, with T2S1 identified as the optimal design for achieving the best trade-off between productivity, leaf quality, and soil sustainability. These findings offer a strategic framework for the spatial optimization of cash-grain intensive farming systems.\u003c/p\u003e","manuscriptTitle":"Optimization of Tobacco-Grain Intercropping Models Based on the Entropy Weight-TOPSIS Method","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-30 19:43:31","doi":"10.21203/rs.3.rs-8429844/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9a4555dc-5f4f-433e-aa3d-6828538f15db","owner":[],"postedDate":"January 30th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":61986583,"name":"Biological sciences/Ecology"},{"id":61986584,"name":"Earth and environmental sciences/Ecology"},{"id":61986585,"name":"Earth and environmental sciences/Environmental sciences"},{"id":61986586,"name":"Biological sciences/Plant sciences"}],"tags":[],"updatedAt":"2026-02-25T09:28:15+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-30 19:43:31","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8429844","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8429844","identity":"rs-8429844","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}