长期不同施肥对农田土壤养分与微生物群落结构的影响

Responses of Soil Nutrients and Microbial Biomass and Community Composition to Long-term Fertilization in Cultivated Land

为了阐明长期不同施肥对土壤养分与微生物群落的影响及影响机理,以杭嘉湖平原典型稻麦轮作区长期定位施肥试验土壤为对象,采用磷脂脂肪酸(Phospholipid fatty acid,PLFA)分析方法,研究了施用化肥(NPK)、秸秆(Straw)、栏肥(Manure)、化肥与秸秆配施(S+NPK)、化肥与栏肥配施(M+NPK)5种不同施肥方式对土壤主要养分指标与微生物量及微生物群落结构的影响,试验以不施肥处理为对照。结果表明,所有施肥处理均提高了土壤有机碳,其中秸秆与化肥配施、栏肥无论是单独施用还是与化肥配施所提高的有机碳含量均达到显著水平;施用化肥、有机肥、秸秆+化肥及有机肥+化肥均可在一定程度增加土壤氮、磷、钾养分。施用秸秆和栏肥显著提高了土壤中总PLFA、细菌、真菌、放线菌等含量以及微生物群落Shannon指数(P<0.05),但施用化肥可引起土壤微生物量和多样性指数的下降。相关分析结果表明,土壤微生物PLFA含量及Shannon指数与土壤碳氮比呈显著正相关(P<0.05)。典范对应分析结果表明,土壤有机碳含量(F=2.18,P=0.027)是影响微生物群落结构的主要环境因子。可得出结论,长期秸秆还田或施用栏肥可显著提高土壤微生物量并改变其群落结构,土壤有机碳含量及碳氮比对于土壤质量和肥力的提高具有至关重要的作用。

To study the influences of long-term different fertilization on soil fertility and microbial community,a long-term fertilization experiment based on wheat-rice rotation agricultural system was conducted in Hang-Jia-Hu plain.The experiment included five fertilization treatments and a control without application of anyfertilizers.The five different fertilization treatments were inorganic fertilizer（NPK）,straw（Straw）,organicmanure（Manure）,inorganic fertilizer plus straw（S＋NPK）,and inorganic fertilizer plus organic manure（M＋NPK）.The phospholipid fatty acid technique was used to characterize the soil microbial biomass and community.Results indicated that all of fertilization treatments increased soil organic carbon,as comparedwith control.Contents of organic carbon in the soils applied with S ＋ NPK,manure,and M ＋ NPK weresignificantly higher than that of the control.Application of chemical fertilizer,manure,S＋NPK and M＋NPKincreased total N,total P and available K in the soils in a certain extent.Application of straw or organic manuresignificantly increased soil total PLFA,as well as bacterial,fungal,actinomycete PLFA and Shannon indices（P〈0.05）.Application of chemical fertilizer decreased soil microbial biomass PLFA.Pearson＇s correlationanalysis indicated that soil microbial biomass PLFA and Shannon indices were significantly correlated withsoil C/N ratio（P〈0.05）.The result of Canonical Correspondence Analysis indicated that soil organic carboncontent（F=2.18,P=0.027） had significant contribution to the variation of soil microbial communities.It can beconcluded that long-term of straw incorporation or organic manure application can benefit soil microbialbiomass and change soil microbial community.Soil organic carbon and C/N ratio can have important impact onsoil quality.