Effect of faba bean-garlic intercropping on low-molecular-weight organic acids, yield components, and profitability under different spatial arrangements

Abstract A two-year field experiment was conducted to quantify the influence of spatial configuration on soil organic acids, agronomic traits, competitive indices, and economic returns in faba bean-garlic intercropping. Intercropping patterns, particularly the faba bean-garlic side-by-side arrangement (1SF:1SG), remarkably increased rhizosphere levels of ascorbic, salicylic, citric, oxalic, and total organic acids. Notably, the alternating ridge arrangement (2RF:2RG) maximized the stem and whole-plant dry weight of faba bean, whereas the 1SF:1SG pattern produced the heaviest fresh and dry bulb weights of garlic in both seasons. The highest yields were obtained from sole cropping, with 4275.20 kg ha−1 for faba bean and 16.07 t ha−1 for garlic, while the 2RF:2RG pattern was the top-performing intercrop, yielding 4004.06 kg ha−1 and 10.98 t ha−1, respectively. This pattern also optimized the land equivalent ratio and relative crowding coefficient. Garlic was the dominant competitor, exhibiting significantly greater competition ratio and aggressivity than faba bean (p < 0.05). Economically, the 2RF:2RG was the most profitable, achieving the maximum net returns of $3260.3 and $3980.7 ha−1 in the first and second seasons, respectively. Multivariate analyses, including Pearson’s correlation, PCA, radar plot, hierarchical clustering, confirmed that the 2RF:2RG produced a distinctly favorable profile for yield and competitive traits, thereby enhancing overall profitability.