Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, No. 50, Zhongling Street, Xuanwu District, Nanjing, Jiangsu 210014, People's Republic of China.
Future Industries Institute, University of South Australia, Building X, X1-17, Mawson Lakes Campus, Mawson Lakes, South Australia 5095, Australia.
FEMS Microbiol Ecol. 2020 May 1;96(5). doi: 10.1093/femsec/fiaa046.
Straw return is widely applied to increase soil fertility and soil organic carbon storage. However, its effect on N2O emissions from paddy soil and the associated microbial mechanisms are still unclear. In this study, wheat straw was amended to two paddy soils (2% w/w) from Taizhou (TZ) and Yixing (YX), China, which were flooded and incubated for 30 d. Real-time PCR and Illumina sequencing were used to characterize changes in denitrifying functional gene abundance and denitrifying bacterial communities. Compared to unamended controls, straw addition significantly decreased accumulated N2O emissions in both TZ (5071 to 96 mg kg-1) and YX (1501 to 112 mg kg-1). This was mainly due to reduced N2O production with decreased abundance of major genera of nirK and nirS-bacterial communities and reduced nirK and nirS gene abundances. Further analyses showed that nirK-, nirS- and nosZ-bacterial community composition shifted mainly along the easily oxidizable carbon (EOC) arrows following straw amendment among four different soil organic carbon fractions, suggesting that increased EOC was the main driver of alerted denitrifying bacterial community composition. This study revealed straw return suppressed N2O emission via altering denitrifying bacterial community compositions and highlighted the importance of EOC in controlling denitrifying bacterial communities.
秸秆还田广泛应用于提高土壤肥力和土壤有机碳储量。然而，其对稻田 N2O 排放的影响及其相关微生物机制仍不清楚。本研究采用中国泰州（TZ）和宜兴（YX）的两种稻田土（2% w/w）进行淹水培养 30 天，添加小麦秸秆。实时 PCR 和 Illumina 测序用于表征反硝化功能基因丰度和反硝化细菌群落的变化。与未添加对照相比，秸秆添加显著降低了 TZ（5071 至 96 mg kg-1）和 YX（1501 至 112 mg kg-1）中累积 N2O 的排放。这主要是由于nirK 和 nirS 细菌群落的主要属的丰度降低，以及 nirK 和 nirS 基因丰度降低，导致 N2O 生成减少。进一步分析表明，秸秆添加后，nirK-、nirS-和 nosZ-细菌群落组成主要沿着易氧化碳（EOC）箭头发生变化，这表明增加的 EOC 是反硝化细菌群落组成发生变化的主要驱动因素。本研究表明，秸秆还田通过改变反硝化细菌群落组成抑制了 N2O 的排放，并强调了 EOC 在控制反硝化细菌群落中的重要性。
