化肥配施γ-聚谷氨酸对采后棉田土壤理化性质及碳氮循环微生物群落的影响OA

In response to the issues of soil degradation and increased ecological risks in Xinjiang cotton fields caused by long-term excessive fertilizer application,in this study,regulatory effects of an environmentally friendly fertilizer synergist γ-polyglutamic acid(γ-PGA)combined with chemical fertilizer on the physicochemical properties of post-harvest cotton soil and the microbial community structure associated with nutrient cycling were investigated.Relying on a field experiment,four treatments were established:no fertilization(CK),chemic0al fertilizer alone(NK),chemical fertilizer combined with γ-PGA aqueous solution(YT),and chemical fertilizer combined with γ-PGA granules(GT).Using soil agrochemical analysis and high-throughput sequencing technology,the nutrient characteristics of post-harvest cotton soil and the composition of the microbial community related to carbon and nitrogen cycling were determined.The results showed that the YT treatment significantly optimized the post-harvest soil nutrient storage capacity.The GT treatment increased the readily oxidizable organic carbon content to 8.03 g/kg and carbon-to-nitrogen ratio(C/N ratio)to 11.57.The YT treatment achieved a total phosphorus content of 1.62 g/kg,significantly higher than that under other treatments.Regarding nitrogen forms,the GT treatment demonstrated the best performance in soil nitrogen nutrient retention and accumulation.The soil alkali-hydrolyzable nitrogen content under the GT treatment was significantly higher than that under CK and YT treatments,with a stronger effective nitrogen supply capacity,indicating that the GT treatment not only promoted the retention of ammonium nitrogen in the soil but also effectively reduced the accumulation of nitrate nitrogen prone to leaching.In terms of phosphorus nutrient accumulation and retention,the YT treatment had the highest total phosphorus content in the soil,significantly higher than that under other treatments.Its total phosphorus accumulation ability was the strongest,and the YT treament also maintained a high level of the available phosphorus content.Moreover,its microbial biomass nitrogen was the highest among all treatments,indicating that YT could effectively promote phosphorus transformation and biological retention,improve the stability and bioavailability of soil phosphorus storage.The combined application of γ-polyglutamic acid could improve soil nutrient availability and achieve comprehensive enhancement of soil quality in cotton field by regulating microbial community structure.