Fertilization practices affect biological nitrogen fixation by modulating diazotrophic communities in an acidic soil in southern China  

作　　者：Long GUO Chao WANG Manman ZHENG Wenxing LI Zejiang CAI Boren WANG Juan CHEN Ren Fang SHEN 

机构地区：[1]State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008(China) [2]University of Chinese Academy of Sciences,Beijing 100049(China) [3]Qiyang Red Soil Experimental Station,Chinese Academy of Agricultural Sciences,Qiyang 426182(China) [4]Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education,Hohai University,Nanjing 210098(China)

出　　处：《Pedosphere》2023年第2期301-311,共11页土壤圈（英文版）

基　　金：supported by the National Key Plan for Research and Development of China(No.2022YFD1900602);the National Natural Science Foundation of China(Nos.42020104004,52022028,51779077,and 41501328)。

摘　　要：Biological nitrogen(N)fixation(BNF)driven by diazotrophs is an important pathway for N input in agricultural ecosystems.However,free-living BNF and its associated diazotrophic communities under different fertilization practices in acidic soils are poorly studied.Here,we conducted a long-term(29 years)fertilization experiment to explore how fertilization affected free-living BNF via changing biotic and abiotic variables.The fertilization treatments included an unfertilized control(CK),chemical N,phosphorus(P),and potassium(K)fertilizers(NPK),NPK plus lime(NPKL),NPK plus straw(NPKS),NPK plus straw and lime(NPKSL),and NPK plus manure(NPKM).Compared with CK(1.51 nmol C_(2)H_(2)g^(-1)d^(-1)),BNF rate was significantly(P<0.05)higher in NPKM(1.99 nmol C_(2)H_(2)g^(-1)d^(-1))but lower in NPK(0.55 nmol C_(2)H_(2)g^(-1)d^(-1)),NPKL(0.61 nmol C_(2)H_(2)g^(-1)d^(-1)),and NPKS(0.69nmol C_(2)H_(2)g^(-1)d^(-1)).Similarly,chemical fertilization treatments without manure reduced the gene abundance(0.71×10^(8)-1.18×10^(8)copies g^(-1))andα-diversity(Shannon index,1.11-2.43)of diazotrophic communities,whereas the treatment with manure had a positive effect on diazotrophic abundance(3.23×10^(8)copies g^(-1))and Shannon index(3.36).Non-parametric multivariate analysis of variance(PERMANOVA)suggested that manure application(R^(2)=0.212,P=0.001)had a stronger influence on diazotrophic community composition than the addition of lime(R^(2)=0.115,P=0.019)or straw(R^(2)=0.064,P=0.161).Random forest modeling revealed that BNF rates can be significantly(P<0.05)explained by soil pH(9.9%),diazotrophic community attributes(composition,8.5%;Chao 1 index,8.1%;abundance,6.0%;Shannon index,5.7%),and soil total carbon(5.1%).Partial least squares path modeling(PLS-PM)suggested that the diazotrophic community attributes and soil properties mainly provided direct and indirect contributions to the variations in BNF rates,respectively.The dominant genera,Pelomonas,Azospirillum,and Dechloromonas,were positively associated with BNF rates,with their mem

关 键 词：chemical fertilizer community composition free-living N fixation long-term fertilization practices manure application soil pH 

分 类 号：S154.3[农业科学—土壤学]