摘要
【目的】通过研究秸秆还田下氮肥运筹对夏玉米不同生育期土壤酶活性和细菌群落结构的影响,揭示土壤细菌群落对不同施肥措施的响应规律,为调节土壤养分,提高作物产量,改善土壤生物功能提供科学依据。【方法】基于河南农业科学院原阳试验基地5年连续定位试验,选取不施肥(CK)、单施化肥(氮肥基追比1∶1,N)和秸秆全量还田下氮肥基追比1∶1(SN1)、1∶1.5(SN2)和1∶2(SN3)共5个处理,于2016年夏玉米抽丝期和收获期采集0-20 cm土壤样品,采用常规方法测定土壤基础理化性质,采用荧光微型板酶检测技术测定土壤酶活性,采用Illumina Miseq高通量测序方法测定土壤细菌群落结构。【结果】秸秆还田下氮肥基追比对玉米产量及氮肥利用率产生明显影响,相比于N处理,SN1处理显著增产9.98%;SN1和SN2处理氮肥利用率分别提高9.83、5.10个百分点。在夏玉米抽丝期和收获期,相比于N处理,秸秆还田下各氮肥运筹处理不同程度地提高了土壤pH、有机碳、全氮和速效钾含量,其中均以SN1处理增幅最为明显。在玉米抽丝期,除土壤磷酸酶外,SN1处理土壤酶活性均为最高;SN1处理对收获期土壤β-葡萄糖苷酶、纤维二糖甘酶、β-木糖苷酶、α-葡萄糖苷酶和酚氧化酶活性的促进最明显。细菌群落除抽丝期SN1与CK处理Shanno指数显著高于N处理而Simpson指数显著低于N处理外,其余处理间差异不显著。各施肥处理下门水平和纲水平的主要优势种群均为变形菌门、放线菌门和α-变形菌纲和放线菌纲。线性判别效应分析(LEfSe)显示,不同生育期比较,抽丝期最大LDA(linear discriminant analysis)值为酸杆菌纲,收获期为芽单胞菌纲;而同一生育期各处理间比较,抽丝期各处理最大LDA值均为变形菌门的α-变形菌纲,收获期均为γ-变形菌纲。典范对应分析表明,抽丝期土壤pH(P=0.002)、有机质含量(P=0.004)和收获期土壤pH(P=0.03)、硝态氮(P=0.036)、速效钾(P=0.044)含量对细菌群落结构产生显著影响。【结论】土壤pH、有机碳、硝态氮和速效钾含量是影响细菌群落结构变化的主要因素。秸秆还田条件下,氮肥运筹显著影响土壤酶活性和细菌群落结构,氮肥基追比为1∶1时可显著提升土壤养分含量和酶活性,提高δ-变形菌纲、绿弯菌纲和TK10(未分类)相对丰度,从而更有效地促进秸秆分解和转化,发挥有机质调节土壤养分释放、减少养分损失的作用,最终提高玉米产量和氮肥利用率。
【Objectives】Wheat straw directly returning to field before summer maize sowing is common practice in winter wheat–summer maize rotation system in North China Plain.Suitable nitrogen managements on maize in the system were studied from enzymatic activity and bacterial communities,aiming to deeper understanding on the mechanism in increasing yield and fertilizer efficiency.【Methods】A field experiment was conducted consecutively for five years in Henan Academy of Agricultural Sciences.The treatments included zero fertilization(CK),mineral N application(the ratio of basal∶topdressing nitrogen was 1∶1,N),and whole wheat straw returned into field with mineral N separately applied in ratio of basal to topdressing of 1∶1(SN1),1∶1.5(SN2)and 1∶2(SN3).Soil samples were collected from topsoil(0–20 cm)at silking stage and harvesting stage of maize in 2016.The soil basic physicochemical properties were determined by conventional method,enzyme activities by fluorescence microplate enzyme assays,and soil bacterial community structures by PCR and Illumina Miseq high-throughput sequencing platform.【Results】The three straw incorporation with N management treatments improved maize yield and nitrogen use efficiency.Compared with N treatment,SN1 treatment increased the yield by 9.98%.The nitrogen use efficiency of SN1 and SN2 treatments was 9.83 and5.10 percentage points higher than that of N treatment,respectively.Compared with N treatment,the highest increase in soil total-N,NO3–-N,NH4+-N,available P and available K contents at silking stage and harvesting stages were all in SN1;all the enzyme activities,except phosphatase at silking stage,were significantly enhanced in SN1 treatment;the diversity of bacterial community was significantly increased in SN1 at the silking stage.The dominant populations in the phylum and class levels were Proteobacteria,Actinomycetes andα-Proteobacteria,Actinomycetes,respectively.LEfSe analysis showed that the maximum LDA(linear discriminant analysis)value of individual SN treatments wasα-Proteobacteria andγ-Proteobacteria at silking stage and harvesting stage,respectively;while that was Pcidobacteria at silking stage and Blastomonas at harvesting stage.Canonical correspondence analysis(CCA)showed that soil pH(P=0.002),organic matter content(P=0.004)at silking stage and soil pH(P=0.03),nitrate N(P=0.036),available K(P=0.044)at the harvesting stage significantly affected bacterial community structure.【Conclusions】Soil pH,organic carbon,nitrate nitrogen and available potassium contents are the main factors influencing the bacterial community structure.Under straw incorporation,the ratio of basal application to topdressing of nitrogen fertilizer significantly effects the soil enzymatic activities,the diversities and richness of bacterial community and the bacterial community structure.When the ratio of basal∶topdressing N is 1∶1,the activities of most soil nutrients and enzymes,the relative abundance ofα-Proteobacteria,Chloroflexi and TK10(unclassified)will be increased significantly,which implies the fast decomposition of returned straws and the effective nutrition regulation by the formed organic matters,thereby the increase of maize yield and nitrogen use efficiency.
作者
张鑫
周卫
艾超
黄绍敏
梁国庆
ZHANG Xin;ZHOU Wei;AI Chao;HUANG Shao-min;LIANG Guo-qing(Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences/Key Laboratory of Plant Nutrition and Fertilizer,Ministry of Agriculture and Rural Affairs,Beijing 100081,China;Institute of Plant Nutrient and Environmental Resources,Henan Academy of Agricultural Sciences,Zhengzhou 450002,China)
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2020年第2期295-306,共12页
Journal of Plant Nutrition and Fertilizers
基金
国家重点研发计划课题(2016YFD0200109)
国家自然科学基金项目(31772392)。
关键词
秸秆还田
小麦–玉米轮作体系
氮肥运筹
高通量测序
土壤酶活性
细菌群落
straw incorporation
wheat–maize rotation system
nitrogen management
high throughput sequencing
soil enzyme activity
bacterial community