机构地区:[1]西北农林科技大学资源环境学院/农业部西北植物营养与农业环境重点实验室,陕西杨凌712100 [2]西北农林科技大学水利与建筑工程学院,陕西杨凌712100 [3]西北农林科技大学水土保持研究所,陕西杨凌712100 [4]西北农林科技大学中国旱区节水农业研究院,陕西杨凌712100
出 处:《植物营养与肥料学报》2020年第2期307-315,共9页Journal of Plant Nutrition and Fertilizers
基 金:国家高技术研究发展计划(2013AA102904);陕西省科技统筹创新工程计划项目(2016KTZDNY03-06);陕西省自然科学基础研究计划项目(2018JM4007);高等学校学科创新引智计划资助(B12007)。
摘 要:【目的】研究不同施肥处理下土壤细菌群落的特征,为建立促进土壤生态系统稳定和健康的养分管理制度提供依据。【方法】陕西省杨凌示范区"国家黄土肥力与肥料效益监测基地"的28年长期定位试验始于1990年秋,种植制度为冬小麦–夏休闲,无灌溉。本研究选取定位试验中不施肥(CK)、施用氮磷钾肥(N、P2O5、K2O分别为135、108、67.5 kg/hm^2,NPK)和有机无机肥配施(70%N来自牛粪,MNPK)3个处理。于2018年6月小麦收获后采集0-20 cm耕层土样,测定养分含量、含水量、微生物量碳含量、微生物量氮含量及目标土壤微生物。以1%琼脂糖凝胶电泳法检测土壤中DNA,根据97%相似度对序列进行OTU聚类、α多样性分析(包括Shannon、ACE和Chao1等指数),使用CANOCO 4.5软件对土壤细菌门水平群落结构、细菌相对丰度等与土壤理化性质进行冗余分析。【结果】与CK相比,NPK和MNPK处理显著提高了土壤有机碳、全氮、微生物量碳、微生物量氮、硝态氮和铵态氮含量,显著降低了土壤pH值。不同处理细菌基因拷贝数为每克干土6.69×10^9~16.46×10^9,与CK相比,NPK和MNPK处理细菌数量分别提高了77%和146%。MNPK处理的土壤细菌Shannon多样性指数显著高于CK和NPK处理,而Simpson指数显著低于CK和NPK处理,NPK与CK处理间两个指数无显著差异。3个处理的细菌丰富度指数(Chao1指数和ACE指数)和均匀度指数均没有显著差异。在门水平上,共获得35个细菌类群,其中,放线菌门(Actinobacteria)、变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)和绿弯菌门(Chloroflexi)为主要优势菌门(相对丰度>10%),占到全部菌门的80.1%~81.7%。与CK相比,MNPK处理显著降低了放线菌门(F=5.845,P<0.05)的相对丰度,增加了拟杆菌门(F=4.461,P<0.05)的相对丰度,3个处理间其他菌门均无显著差异。冗余分析结果显示,CK与NPK、MNPK处理的土壤细菌群落结构具有明显差异,且MNPK处理对土【Objectives】The fertility change in nutrient contents and microbial structure of farmland after longterm fertilization was studied in this paper,which would provide theoretical base for reasonable fertilization practice to maintain a stable and healthy soil ecosystem.【Methods】The investigated farmland was from a 28-years’long-term fertilization experiment in the"National Monitoring Base of Soil Fertility and Fertilizer Efficiency on Loess Soil"in Yangling Demonstration Zone,Shaanxi Province,where the cropping system was winter wheat-summer fallow and without irrigation.The soil samples were collected from three of the experiment treatments,namely,no fertilization control(CK),pure chemical fertilizer(NPK,N–P2O5–K O=135–108–67.5 kg/hm^2)and chemical fertilizer and manure combination(MNPK,70%of N from cattle manure).After harvest of wheat,soil samples of 0–20 cm in depth were collected.The soil nutrient contents,water content,microbial biomass C and N contents were determined.The DNA of genome in soil samples were extracted and detected by 1%agarose gel electrophoresis,and sequenced afterwards.The Shannon,ACE and Chao1 indices were calculated.【Results】Compared with CK,the NPK and MNPK significantly increased soil organic carbon,total nitrogen,microbial biomass carbon,microbial biomass nitrogen,nitrate nitrogen and ammonium nitrogen,while significantly reduced soil pH.The copy number of bacterial genes were 6.69×10^9–16.46×10^9 per gram of dry soil for the three treatments,and those in NPK and MNPK treatments were 77%and 146%significantly higher than that in CK.The Shannon diversity index of soil bacteria of MNPK was significantly higher,while Simpson index were significantly lower than those of CK and NPK treatments,and there was no significant difference between NPK and CK.The bacterial richness index(Chao 1 index and ACE index)and the uniformity index were not significantly different among the 3 treatments.A total of 35 groups of bacteria were obtained at the level of phylum,in which Ac
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