The role of soil organic nitrogen (e.g., amino acids) in regulating soil microbial community has not been well documented, which is much different from that of soil organic carbon. Feather-based compost (FBC) is rich in amino acids that can enhance soil life and microbial activity. Therefore, this study was designed to evaluate the possible role of amino acids in FBC in regulating soil microbial community. In pot experiment, FBC was applied to lettuce ( Lactuca sativa ) grown in an infertile subtropical soil. Soil chemical property, enzyme activity, and hydrolysable amino acids were analyzed, and microbial community was characterized with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. FBC significantly increased plant biomass, soil available nutrient contents, and enzyme activity. Thirteen kinds of amino acids were detected in soil, and FBC significantly increased the contents of 12 kinds of amino acids, with 5 absent in soils without FBC application. Both amino acids and soil chemical property were significantly correlated with microbial community and soil enzyme activity, and their contributions to the changes in microbial community and soil enzyme activity were comparable. Phenylalanine, leucine, and glutamate were the top 3 kinds of amino acids structuring microbial community. Our results suggest that FBC greatly promoted plant growth probably via the regulatory effects of amino acids on soil microbial community, which sheds light on the application of amino acid-rich compost in agricultural production.

中文翻译：

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羽毛堆肥显着调节亚热带土壤中的土壤微生物群落和莴苣生长：氨基酸的可能作用

土壤有机氮（如氨基酸）在调节土壤微生物群落中的作用尚未得到充分证明，这与土壤有机碳的作用有很大不同。羽毛堆肥 (FBC) 富含氨基酸，可增强土壤生命和微生物活动。因此，本研究旨在评估 FBC 中氨基酸在调节土壤微生物群落中的可能作用。在盆栽试验中，将 FBC 施用于生长在贫瘠亚热带土壤中的莴苣 (Lactuca sativa)。分析土壤化学性质、酶活性和可水解氨基酸，并通过聚合酶链反应-变性梯度凝胶电泳（PCR-DGGE）分析表征微生物群落。FBC 显着增加了植物生物量、土壤有效养分含量和酶活性。土壤中检测到13种氨基酸，FBC显着增加了12种氨基酸的含量，未施FBC的土壤中没有5种。氨基酸和土壤化学性质均与微生物群落和土壤酶活性显着相关，它们对微生物群落和土壤酶活性变化的贡献具有可比性。苯丙氨酸、亮氨酸和谷氨酸是构成微生物群落的前 3 种氨基酸。我们的研究结果表明，FBC 可能通过氨基酸对土壤微生物群落的调节作用极大地促进了植物生长，这为富含氨基酸的堆肥在农业生产中的应用提供了启示。5 在没有 FBC 应用的土壤中不存在。氨基酸和土壤化学性质均与微生物群落和土壤酶活性显着相关，它们对微生物群落和土壤酶活性变化的贡献具有可比性。苯丙氨酸、亮氨酸和谷氨酸是构成微生物群落的前 3 种氨基酸。我们的研究结果表明，FBC 可能通过氨基酸对土壤微生物群落的调节作用极大地促进了植物生长，这为富含氨基酸的堆肥在农业生产中的应用提供了启示。5 在没有 FBC 应用的土壤中不存在。氨基酸和土壤化学性质均与微生物群落和土壤酶活性显着相关，它们对微生物群落和土壤酶活性变化的贡献具有可比性。苯丙氨酸、亮氨酸和谷氨酸是构成微生物群落的前 3 种氨基酸。我们的研究结果表明，FBC 可能通过氨基酸对土壤微生物群落的调节作用极大地促进了植物生长，这为富含氨基酸的堆肥在农业生产中的应用提供了启示。它们对微生物群落和土壤酶活性变化的贡献具有可比性。苯丙氨酸、亮氨酸和谷氨酸是构成微生物群落的前 3 种氨基酸。我们的研究结果表明，FBC 可能通过氨基酸对土壤微生物群落的调节作用极大地促进了植物生长，这为富含氨基酸的堆肥在农业生产中的应用提供了启示。它们对微生物群落和土壤酶活性变化的贡献具有可比性。苯丙氨酸、亮氨酸和谷氨酸是构成微生物群落的前 3 种氨基酸。我们的研究结果表明，FBC 可能通过氨基酸对土壤微生物群落的调节作用极大地促进了植物生长，这为富含氨基酸的堆肥在农业生产中的应用提供了启示。