State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, China.
J Sci Food Agric. 2023 Nov;103(14):7284-7292. doi: 10.1002/jsfa.12814. Epub 2023 Jul 11.
Poly-γ-glutamic acid (γ-PGA) can promote crop growth and improve soil properties efficiently. However, the optimal application rate of γ-PGA in legume/non-legume intercropping systems is still unclear. A potted experiment was conducted to investigate the effects of five γ-PGA rates (0%, 0.1%, 0.2%, 0.3%, and 0.4%, represented by CK, P1, P2, P3, and P4, respectively) on biological nitrogen (N) fixation (BNF), water-N productivity, and nitrate distribution in a cotton/soybean intercropping system.
The results showed that the growth indicators (plant height, stem diameter, leaf area index, root dry weight, root length) of cotton and soybean increased first and then decreased with increasing γ-PGA rates, and all growth indicators of cotton and soybean showed peaks in P3 and P2 treatments. The stable N isotope method indicated that γ-PGA promoted the BNF capacity of soybean and soil. In particular, the percentage of N derived from the atmosphere (Ndfa) in soybean reached 61.94% in the P2 treatment. Poly-γ-glutamic acid improved the water-N productivity, and the total N partial factor productivity (NPFP) and water productivity (WP) in P3 treatment increased by 23.80% and 43.86% compared with the CK treatment. The γ-PGA mitigation of potential nitrate residue also decreased first and then increased with increasing γ-PGA rates.
Multivariate regression analysis showed that 0.22% of the optimal γ-PGA application rate could obtain a higher yield and water-N productivity in cotton/soybean intercropping system simultaneously. © 2023 Society of Chemical Industry.
聚γ-谷氨酸（γ-PGA）能有效促进作物生长，改善土壤性质。然而，γ-PGA 在豆科/非豆科间作系统中的最佳应用率尚不清楚。通过盆栽试验研究了 5 种 γ-PGA 用量（0%、0.1%、0.2%、0.3%和 0.4%，分别用 CK、P1、P2、P3 和 P4 表示）对棉花/大豆间作系统生物固氮（BNF）、水氮生产力和硝酸盐分布的影响。
结果表明，棉花和大豆的生长指标（株高、茎粗、叶面积指数、根干重、根长）随 γ-PGA 用量的增加先增加后减少，棉花和大豆的所有生长指标在 P3 和 P2 处理中达到峰值。稳定氮同位素法表明，γ-PGA 促进了大豆和土壤的 BNF 能力。特别是，P2 处理中大豆的大气氮来源百分比（Ndfa）达到 61.94%。γ-PGA 提高了水氮生产力，P3 处理的总 N 偏生产力（NPFP）和水生产力（WP）比 CK 处理分别提高了 23.80%和 43.86%。γ-PGA 对潜在硝酸盐残留的缓解作用也随 γ-PGA 用量的增加先减少后增加。
多元回归分析表明，在棉花/大豆间作系统中，γ-PGA 的最佳应用率为 0.22%时，可同时获得较高的产量和水氮生产力。© 2023 化学工业协会。
