添加秸秆对长期不同碳氮管理土壤各粒级团聚体激发效应的影响  

Priming effect of straw addition on different particle-size fractions of soil aggregates under long-term carbon and nitrogen managements

作　　者：曹彬彬 李雨诺 朱熠辉 师江澜 田霄鸿 CAO Binbin;LI Yunuo;ZHU Yihui;SHI Jianglan;TIAN Xiaohong(College of Natural Resources and Environment,Northwest A&F University/Key Laboratory of Plant Nutrition and the Agro-environment in Northwest China,Ministry of Agriculture,Yangling,Shaanxi 712100,China)

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

出　　处：《西北农林科技大学学报（自然科学版）》2021年第5期56-64,73,共10页Journal of Northwest A&F University(Natural Science Edition)

基　　金：国家重点研发计划项目(2016YFD0200308);陕西省重点研发计划项目(2019ZDLNY01-05-01);“十二五”国家科技支撑计划项目(2012BAD14B11)。

摘　　要：【目的】分析添加秸秆对长期不同碳氮管理土壤团聚体尺度激发效应的影响,为揭示秸秆还田对土壤有机碳(SOC)固持能力的内在影响机理提供理论依据。【方法】以2002年开始的长期定位试验中碳氮管理水平不同的2种供试土壤(S_(0)N_(0).秸秆不还田+不施氮肥;S_(1)N_(1).高量秸秆还田+高量氮肥(240 kg/hm^(2)))为材料,采用室内恒温培养试验,利用干筛法得到3种粒级的团聚体(粗大团聚体、细大团聚体和微团聚体),分别在添加玉米秸秆和不添加玉米秸秆的条件下于25℃黑暗培养70 d,测定各粒级团聚体的CO_(2)释放量、表观激发效应(PE)及有机碳(SOC)、可溶性有机碳(DOC)和微生物量碳(MBC)含量。【结果】未添加秸秆时,S_(0)N_(0)和S_(1)N_(1)土壤微团聚体的CO_(2)累积释放量均高于大团聚体(粗大团聚体和细大团聚体);添加等量秸秆后,2种土壤各粒级团聚体的CO_(2)累积释放量均有提高;在S_(0)N_(0)土壤中,粗大团聚体与微团聚体产生的表观PE无显著差异,但均显著小于细大团聚体;而在S_(1)N_(1)土壤中,不同粒级团聚体表观PE由大到小依次为细大团聚体>粗大团聚体>微团聚体。与未添加秸秆相比,添加秸秆后2种土壤各粒级团聚体SOC含量均显著增加,且2种土壤中各粒级团聚体SOC含量表现为微团聚体>大团聚体。无论添加秸秆与否,在S_(1)N_(1)土壤中,大团聚体的DOC含量均显著高于微团聚体;而在S_(0)N_(0)土壤中,3个粒级团聚体的DOC含量无显著差异。在S_(1)N_(1)土壤中,未添加秸秆时,各粒级团聚体的MBC含量无显著差异;添加秸秆后,微团聚体的MBC含量显著高于大团聚体。在S_(0)N_(0)土壤中,未添加秸秆时,大团聚体的MBC含量显著小于微团聚体;而添加秸秆后,粗大团聚体的MBC含量显著小于微团聚体和细大团聚体。【结论】作物秸秆的投入会因产生激发效应,进而改变土壤各粒级团聚体中原SOC的矿化情况;不�【Objective】To provide basis for understanding effect mechanisms of straw return on soil organic carbon(SOC)sequestration,the priming effect(PE)of straw addition on soil aggregates under long-term and different carbon and nitrogen managements were analyzed.【Method】This study used incubation experiment with soils from two long-term experiment testing sites under continuous managements with different crop residues and nitrogen(S_(0)N_(0)soil:no straw return+un-fertilization;S_(1)N_(1)soil:high straw return+high nitrogen fertilizer:240 kg/hm^(2)).Two soil samples were separated into three aggregate size classes(large macro-aggregates,small macro-aggregates and micro-aggregates)and were incubated with or without maize straw for 70 days under 25℃.CO_(2)emission,apparent priming effect(PE),SOC,dissolved organic carbon(DOC)and microbial biomass carbon(MBC)of each aggregate size class were measured.【Result】Cumulative CO_(2)emission in micro-aggregates in S_(0)N_(0)and S_(1)N_(1)soil without straw addition was higher than in macro-aggregates(both large and small macro-aggregates).The same amount of straw addition can increase cumulative CO_(2)emissions of all size classes in both soils.There was no significant diffe-rence in apparent PE between large macro-aggregate and micro-aggregate in S_(0)N_(0)soil after straw addition,but both were significantly smaller than those in small macro-aggregate.In S_(1)N_(1)soil,the apparent PE between aggregate size classes were in the decrease order of small macro-aggregates>large macro-aggre-gates>micro-aggregates.Meanwhile,straw addition significantly increased contents of SOC between size classes in both soils.Content of SOC was higher in the micro-aggregates than macro-aggregates,which was opposite to apparent PE.DOC in macro-aggregates was significantly higher than in micro-aggregates in S_(1)N_(1)soil regardless straw addition.However,there was no significant difference in DOC among size classes in S_(0)N_(0)soil.In S_(1)N_(1)soil,MBC in micro-aggregates was significa

关 键 词：土壤团聚体 表观激发效应 土壤有机碳 秸秆还田 

分 类 号：S151.92[农业科学—土壤学]