短期宽窄行种植模式下秸秆机械化还田潮土微生物多样性特征

Characteristics of Microbial Diversity of Mechanized Straw Returning to the Field in Fluvo-Aquic Soil under Planting Patten of Short Term Wide-Narrow Row

为揭示宽窄行种植模式下秸秆还田的土壤微生物多样性特征,基于高通量测序技术,分析在小麦/玉米轮作模式下宽行和窄行0~20、20~40和40~60 cm共3个深度范围土层中微生物群落多样性的特征及与土壤理化因子的关系。宽行和窄行土样的微生物多样性(Shannon指数)都随土壤深度增加而降低。同一深度下,宽行土样的物种多样性普遍高于窄行。不同地区及不同深度土样的群落结构具有较大差异。在门水平上,两种土样中的优势菌门为变形菌门、拟杆菌门、芽单胞菌门、酸杆菌门和放线菌门。窄行变形菌门、拟杆菌门的相对丰度略高于宽行,而芽单胞菌门、酸杆菌门、放线菌门、绿弯菌门和厚壁菌门低于宽行。在属水平上,溶杆菌属、交替赤杆菌属和鞘氨醇单胞菌等为优势菌属。全氮、碱解氮、速效磷、速效钾和有机质与绿弯菌门、酸杆菌门、放线菌门和芽单胞菌门呈正相关,但与变形菌门、拟杆菌门等呈现负相关关系。宽行表层土的碳水化合物代谢功能基因拷贝数显著高于窄行表层土样。短期宽窄行种植模式下麦秸和玉米秸秆还田可增加土壤物种的多样性,为进一步优化秸秆还田方法、改良土壤生态系统奠定了坚实的基础。

To reveal characteristics of short term mechanized returning straw to the field by wide/narrow row on soil microbial diversity,changes of microbial community diversity and its relationship with soil physical and chemical factors in fluvo-aquic soils in wheat planting area and corn straw furrow at 0 ~ 20,20 ~ 40 and 40 ~ 60 cm depths under maize/wheat alternate planting mode were analyzed based on high-throughput sequencing method. Results showed that the Shannon index of soil microbial diversity decreased with increase of soil depth for both two types of soil. At the same depth,microbial diversity of corn stalk returning ditch samples was generally higher than that of wheat planting soil. The community structures of soil samples from different areas and different depths were quite different. At the phylum level,the dominant phyla in two soil samples were Proteobacteria,Bacteroidetes,Gemmatimonadetes,Acidobacteria and Acitinobacteria. The relative abundances of Proteobacteria and Bacteroides in wheat planting area were slightly higher than those of corn stalk returning ditch samples,while abundances of Gemmatimonadetes,Acidobacteria,Actinomycetes,Chloroflexi and Firmicutes were lower than those of corn stalk returning ditch samples. At the genus level,Lysobacter,Altererythrobacter and Sphingomonas were the dominant genera. Total nitrogen,alkali hydrolyzed nitrogen,available phosphorus,available potassium and organic matter were positively correlated with Chloroflexi,Acidobacteria,Acitinobacteria,Gemmatimonadetes,but negatively correlated with Proteobacteria and Bacteroidetes. The copy numbers of carbohydrate metabolism functional genes in topsoil of corn stalk returning ditch were significantly higher than those of wheat planting top soil. Straw returning increased microbial diversity of soil,which laid a solid foundation to further optimize straw returning method and to improve soil ecosystem.