摘要
秸秆还田和适宜的种植密度有利于改良土壤理化性质,优化微生物群落结构.本研究采用Illumina MiSeq高通量测序技术,在宁夏引黄灌区玉米农田开展连续 5a 设置裂区试验,探讨不同秸秆还田模式(H1:秸秆粉碎深翻还田、H0:秸秆不还田)和种植密度(D1:67500 株·hm-2、D2:82500 株·hm-2、D3:97500 株·hm-2)下玉米成熟期根际土壤真菌多样性、群落结构的变化及其驱动因素.结果表明:(1)秸秆还田模式和种植密度两因素交互效应极显著提高了土壤真菌群落Chao1 指数、ACE指数及香农指数(P<0.01),以H1D2 处理下最高.(2)农田玉米根际土壤真菌群落主要由子囊菌门(63.50%～81.82%)、担子菌门(4.83%～18.03%)和被孢霉门(3.18%～9.61%)等 14 个门及 509 个属的真菌组成,真菌群落组成分析表明,秸秆还田模式各密度处理间群落结构不同,优势菌门和优势菌属相对丰度差异较大.(3)秸秆还田模式和种植密度两因素交互效应极显著降低土壤 pH 值,提高了有机质、碱解氮及速效磷含量(P<0.01),以 H1D2 处理下最高.Pearson相关分析表明,土壤pH值、有机质、全氮、全磷、碱解氮、速效磷、速效钾含量与真菌α多样性呈显著或极显著的相关性;土壤pH值与枝孢菌属(Cladosporium)相对丰度呈显著负相关(P<0.05),有机质、全磷、碱解氮、速效钾含量与枝孢菌属(Cladosporium)相对丰度呈显著正相关(P<0.05),有机质含量与毛壳菌属(Chaetomium)相对丰度呈显著负相关(P<0.05).RDA分析表明全氮、有机质、速效钾和pH值是驱动秸秆还田模式下各密度处理中玉米根际土壤真菌群落变异的主要环境因子.本研究中,秸秆还田结合种植密度 82500 株·hm-2 处理,对提高农田土壤肥力和改善根际土壤真菌多样性最有利.
Abstract
Straw return and appropriate planting density are beneficial for improving soil physicochemical properties and optimizing microbial community structure.This study investigated the effect of different straw-returning modes(H1:straw crushing deep plowing back to the field,H0:straw was not returned to the field)and different planting densities(D1:67500plants·ha-1,D2:82500plants·ha-1,D3:97500plants·ha-1)on the diversity and community structure of rhizosphere fungi at maize maturity using Illumina MiSeq high-throughput sequencing technology.The study was established as a split-plot experiment and conducted on maize farmland of the Yinhuang Irrigation area in Ningxia for five consecutive years.Results showed that:(1)the interaction effect of straw return mode and planting density was highly significant for the Chao1 index,ACE index,and Shannon index of soil fungal communities(P<0.01),with the indexes being highest under the H1D2 treatment.(2)Soil fungal community in the inter-root area of maize in the farmland was mainly composed of fungi from 509 genera in 14 phyla,such as Ascomycota(63.50%-81.82%),Basidiomycota(4.83%-18.03%),and Mortierellomycota(3.18%-9.61%),etc.The structure of the fungal community differed among different density and straw return mode combinations,and the relative abundance of the dominant phyla and genera varied greatly.(3)The interaction of straw return mode and planting density significantly influenced the soil pH,organic matter,alkaline dissolved nitrogen,and quick-acting phosphorus content(P<0.01),with H1D2 treatment being the optimal treatment combination.Pearson's correlation analysis showed that there were significant or highly significant correlations among soil pH,organic matter,total nitrogen,total phosphorus,alkaline dissolved nitrogen,quick-acting phosphorus,quick-acting potassium content,and the α-diversity of the fungi.Soil pH was significantly and negatively correlated with the relative abundance of Cladosporium(P<0.05).Organic matter,total phosphorus,alkaline-dissolved nitrogen.And quick-acting potassium content were significantly and positively correlated with the relative abundance of Cladosporium(P<0.05).Organic matter content was significantly and negatively correlated with the relative abundance of Chaetomium(P<0.05).RDA analyzes showed that total nitrogen,organic matter,fast-acting potassium,and pH were the main environmental factors that drive the variation of soil fungal communities in maize rhizosphere at different densities under different straw return patterns.In this study,straw return combined with a planting density of 82500 plants·ha-1 was optimum for increasing farmland soil fertility and improving inter-root soil fungal diversity.
基金项目
宁夏高质量发展与生态保护科技创新示范项目(NGSB-2021-3-02)
宁夏区重点研发项目(2019BBF02003)
宁夏区重点研发项目(2018BBF02018)
宁夏自然科学基金(2021AAC03072)
维普
万方数据