Changes in bacterial community of soil induced by long-term straw returning

ABSTRACT: Straw returning is an effective way to improve soil quality. Whether the bacterial community development has been changed by long-term straw returning in non-calcareous soil is not clear. In this study, the following five treatments were administered: soil without fertilizer (CK); wheat and corn straw returning (WC); wheat straw returning with 276 kg N ha−1 yr−1 (WN); manure, 60,000 kg ha−1 pig manure compost (M) and wheat and corn straw returning with 276 kg N ha−1 yr−1 (WCN). The high-throughput 16S rRNA sequencing technology was used to evaluate the bacterial communities. The results showed that the community was composed mostly of two dominant groups (Proteobacteria and Acidobacteria). Bacterial diversity increased after the application of straw and manure. Principal component analyses revealed that the soil bacterial community differed significantly between treatments. The WCN treatment showed relatively higher total soil N, available P, available K, and organic carbon and invertase, urease, cellulase activities and yield than the WC treatment. Our results suggested that application of N fertilizer to straw returning soil had significantly higher soil fertility and enzyme activity than straw returning alone, which resulted in a different bacterial community composition, Stenotrophomonas, Pseudoxanthomonas, and Acinetobacter which were the dominant genera in the WC treatment while Candidatus, Koribacter and Granulicella were the dominant genera in the WCN treatment. To summarize, wheat and maize straw returning with N fertilizer would be the optimum proposal for improving soil quality and yield in the future in non-calcareous fluro-acquic-wheat and maize cultivated soils in the North China Plain in China.

摘要：秸秆还田是提升土壤质量的有效途径。目前尚不明确长期秸秆还田是否会改变非石灰性土壤中的细菌群落组成与动态。本研究设置5组处理：不施肥对照组（CK）、小麦-玉米秸秆还田组（WC）、施276 kg N·ha⁻¹·yr⁻¹氮肥配施小麦秸秆还田组（WN）、施60000 kg·ha⁻¹猪粪堆肥组（M）以及施276 kg N·ha⁻¹·yr⁻¹氮肥配施小麦-玉米秸秆还田组（WCN）。采用高通量16S rRNA测序技术对土壤细菌群落进行分析。结果表明，土壤细菌群落主要由两个优势菌门组成：变形菌门（Proteobacteria）和酸杆菌门（Acidobacteria）。施用秸秆与猪粪堆肥后，土壤细菌多样性显著提升。主成分分析（PCA）结果显示，不同处理组的土壤细菌群落结构存在显著差异。与WC组相比，WCN组的土壤全氮、有效磷、速效钾、有机碳含量以及蔗糖酶、脲酶、纤维素酶活性和作物产量均显著更高。研究结果表明，秸秆还田配施氮肥较单纯秸秆还田可显著提升土壤肥力与酶活性，进而重塑细菌群落组成：WC组的优势菌属为寡养单胞菌属（Stenotrophomonas）、假黄单胞菌属（Pseudoxanthomonas）和不动杆菌属（Acinetobacter），而WCN组的优势菌属为候选菌属（Candidatus）、科里杆菌属（Koribacter）和颗粒杆菌属（Granulicella）。综上所述，在中国华北平原的非石灰性潮土小麦-玉米轮作耕地中，配施氮肥的小麦-玉米秸秆还田模式是未来提升土壤质量与作物产量的最优方案。