Ecological stoichiometry is an important indicator presenting multiple elements balance in agro-ecosystems. However, information on microbial communities and nutrient stoichiometry in soil aggregate fractions under different croplands (rice, maize, and soybean fields) remains limited. Thus, this study investigated water-stable aggregate structure and their internal nutrient stoichiometry under different croplands and ascertain their interaction mechanism with microbial communities. The results showed that no significant difference on the carbon-to-nitrogen ratio (C:N) in soil aggregate fractions was observed, while the carbon-to-phosphorus ratio (C:P) and the nitrogen-to-phosphorus ratio (N:P) were ranked as rice field > maize field > soybean field, and were higher in mega-aggregates (ME, > 1 mm). General fatty acid methyl ester (FAME), Gram-positive bacteria (G+), and Gram-negative bacteria (G−) were predominant microbial communities in all croplands and tented to condense into coarse-aggregates. Redundancy analysis (RDA) demonstrated that N:P ratio was primary environmental controls on the distribution of soil microorganisms. In the Sanjiang Plain, N was the nutrient element limiting agro-ecosystem productivity, and rice cultivation is expected to improve the N-limited nutrient status.

中文翻译：

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不同耕地的骨料相关微生物群落和养分化学计量

生态化学计量学是表明农业生态系统中多种元素平衡的重要指标。但是，有关不同耕地（水稻，玉米和大豆田）下土壤团聚体中微生物群落和营养化学计量的信息仍然有限。因此，本研究调查了不同农田下水稳定的团聚体结构及其内部养分化学计量关系，并确定了它们与微生物群落的相互作用机制。结果表明，土壤团聚体中碳氮比（C：N）没有显着差异，而碳磷比（C：P）和氮磷比（N ：P）被列为稻田>玉米田>大豆田，并且在大型聚集体中（ME，> 1 mm）更高。普通脂肪酸甲酯（FAME），革兰氏阳性细菌（G +）和革兰氏阴性细菌（G-）是所有农田中的主要微生物群落，其帐篷被凝结成粗聚集体。冗余分析（RDA）表明，N：P比是控制土壤微生物分布的主要环境控制。在三江平原，氮是限制农业生态系统生产力的养分元素，水稻种植有望改善氮限制的养分状况。