潮土长期不同施氮水平对秸秆降解及其细菌群落结构的影响  

Influences of Long-term Different N Application Rates on Straw Decomposition and Bacterial Community Structure in a Fluvo-aquic Soil

作　　者：李敬王 陈林[1,2] 马东豪[1,2] 张丛志[1,2] 张佳宝[1,2,3] LI Jingwang;CHEN Lin;MA Donghao;ZHANG Congzhi;ZHANG Jiabao(State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;Fengqiu Agro-Ecological National Experimental Station,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所),南京210008 [2]中国科学院封丘农业生态实验站(中国科学院南京土壤研究所),南京210008 [3]中国科学院大学,北京100049

出　　处：《土壤学报》2022年第5期1359-1368,共10页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41807017);中国科学院战略性先导科技专项子课题(XDA24020104)资助。

摘　　要：农田过量施氮所引发的问题已经引起广泛关注,但长期施氮后土壤无机氮水平状况及其对秸秆降解的作用尚不清楚。以中国科学院封丘农业生态实验站长期试验(2005—2018年)的潮土为研究对象,选择5个施氮水平(0(N0)、150(N1)、190(N2)、230(N3)和270(N4)kg·hm^(–2)·a^(–1))土壤,开展短期(50 d)的秸秆降解-土壤培育实验。培育期间监测秸秆碳的矿化、土壤无机氮(硝态氮和铵态氮)、可溶性有机碳、微生物生物量碳的动态变化,利用高通量测序测定细菌群落结构。结果表明,长期施氮后,土壤无机氮含量和秸秆碳的矿化率随施氮水平的升高而增加。不同长期施氮水平的土壤细菌群落结构呈现显著差异。网络分析揭示:秸秆降解过程中细菌群落内部物种间的共现模式随长期施氮水平发生改变,具体体现为长期高施氮水平下细菌群落彼此间的负相关得到了加强;同时,变形菌主导地位减弱、酸杆菌主导地位增强。综上,土壤无机氮含量随着长期施氮水平的升高而增加,进而引起土壤细菌群落结构发生了改变,使得在秸秆降解过程中起到的作用不同,表现为秸秆降解随着施氮水平的增加而增加。本研究探究了长期不同施氮水平下土壤中无机氮的水平状况、秸秆降解状况以及秸秆降解过程中土壤细菌的生物特性,以期为秸秆还田和科学施氮提供一定的数据支撑和思路启示。【Objective】The problems caused by excessive nitrogen(N)application in agriculture has been of growing concern,but the soil mineral N level and its effect on straw decomposition after long-term N application remain unclear.【Method】We used a fluvo-aquic soil treated for 14 years(2005-2018)with N at the rates of 0(N0),150(N1),190(N2),230(N3)and 270(N4)kg·hm^(-2)·a^(–1),and conducted a 50-day laboratory incubation experiment with and without straw addition.Soil CO_(2) emission was determined during the incubation,soil mineral N(nitrate and ammonium nitrogen),dissolved organic carbon(DOC),microbial biomass carbon(MBC)were measure before and after the incubation,and the bacterial community structure was determined using amplicon sequencing of the 16S rRNA genes.【Result】Results show that soil mineral N content and straw decomposition efficiency increased with increasing N application rates and the bacterial community composition was significantly(P<0.05)influenced by N application rates.The network analysis revealed that the co-occurrence pattern among species within the bacterial community during straw decomposition changed with the N application level,and the negative association among bacterial communities was strengthened under a high N application level.At the same time,the dominant position of Proteobacteria was weakened and that of Acidobacteria was enhanced.【Conclusion】The soil inorganic nitrogen content increased with the increase of long-term nitrogen application level,resulting in changing in soil bacterial community structure.Thus soil bacterial community structure of different long-term nitrogen application played different roles in the process of straw degradation,which was manifested as the increase of straw degradation with the increase of nitrogen application level.The relationship among soil mineral N content,bacterial community structure and species changed with the difference of long-term N application level.The results of this study provide guidelines for the use of straws to ame

关 键 词：长期施氮 土壤无机氮残留 秸秆降解 细菌 

分 类 号：S154.1[农业科学—土壤学]