Poly‐γ‐glutamic acid enhanced the yield and photosynthesis of soybeans by adjusting soil aggregates and water distribution

Abstract

BackgroundThe Poly‐γ‐glutamic acid (γ‐PGA) is extensively employed in agricultural practices to enhance soil water retention; however, the underlying mechanism by which γ‐PGA improves soil structure and soybean productivity in arid regions remains poorly understood. A micro‐scale field experiment was conducted in the arid region of northwest China, employing five levels [0 (CK), 10 (P1), 20 (P2), 40 (P3), and 80 kg ha−1 (P4)] of γ‐PGA to investigate its impacts on soybean yield, photosynthesis, and water use efficiency, as well as soil aggregates and water distribution.ResultsResults demonstrated the γ‐PGA application significantly improved soybean yield, photosynthesis, and chlorophyll content. The γ‐PGA application resulted in a decrease in soil aggregate content with a diameter of <0.053 mm and an increase in soil aggregates stability. The γ‐PGA application has significantly increased soil water content, particularly in the uppermost layer of soil (0–30 cm), while effectively reducing water consumption and improving water use efficiency in soybean. Overall, the P3 treatment exhibited the most pronounced enhancement in soybean yield, photosynthesis, water use efficiency, as well as soil aggregates and water distribution. In addition, the correlation matrix heatmap revealed a strong correlation between improvement of soybean yield or photosynthesis at various γ‐PGA application levels and the enhancement of soil stability or soil water content.ConclusionThe multivariate regression analysis revealed that an optimal application level of 46 kg ha−1 γ‐PGA could effectively enhance both yield and water use efficiency of soybean in the arid region of northwest China.This article is protected by copyright. All rights reserved.