免耕对土壤团聚体特征以及有机碳储量的影响  

Effect of no-tillage on soil aggregate and organic carbon storage

作　　者：姜学兵[1,2] 李运生[1] 欧阳竹[1] 侯瑞星[1,2] 李发东[1] 

机构地区：[1]中国科学院地理科学与资源研究所中国科学院生态系统网络观测与模拟重点实验室中国科学院禹城综合试验站,北京100101 [2]中国科学院研究生院,北京100049

出　　处：《中国生态农业学报》2012年第3期270-278,共9页Chinese Journal of Eco-Agriculture

基　　金：国家科技支撑计划项目(2009BADA3B05-7);中国科学院知识创新工程重要方向项目(KSCX2-EW-B-1);中国科学院战略性先导科技专项"应对气候变化的碳收支认证及相关问题"(XDA05050502)资助

摘　　要：以实施7年的中国科学院禹城综合试验站冬小麦夏玉米轮作免耕长期定位试验场为对象,研究免耕条件下土壤水稳性团聚体和有机碳储量的变化,为进一步评价免耕措施对黄淮海平原土壤结构和质量的影响提供科学依据。设置免耕（NT）、免耕秸秆不还田（NTRR）、常规耕作（CT）3种处理,分析土壤表层（0-20 cm）及深层（20-60 cm）水稳性团聚体分布特征、土壤有机碳以及团聚体有机碳的变化和相互关系。研究结果表明：由于减少了对土壤的破坏以及增加了秸秆还田和有机肥的施用,与常规耕作相比,NT和NTRR可提高表层土壤有机碳含量和储量、水稳性团聚体平均重量直径（MWD）和几何平均直径（GMD）,以及大团聚体有机碳的含量和储量。其中,秸秆覆盖比施用有机肥对表层土壤有机碳储量和0.25-2 mm团聚体有机碳储量的提高具有更显著的作用。与表层不同,深层土壤有机碳和大团聚体有机碳的含量和储量表现为NT〈NTRR〈CT,说明与CT相比,NT和NTRR不利于深层土壤有机碳的积累,与秸秆覆盖相比,施用有机肥对深层有机碳的积累更有利。从整个剖面（0-60 cm）来看,NT和NTRR处理土壤总有机碳储量低于CT。各处理土壤总有机碳与0.25-2 mm水稳性团聚体有机碳关系最为密切,说明该粒级团聚体有机碳能够指示土壤总有机碳的变化。No-tillage（NT） is an increasingly agronomic practice in China.Tillage practices deeply affect soil quality and organic carbon（SOC） accumulation.The effect of NT,as a form of conservation tillage,on soil organic carbon storage had remained highly contentious.To shed further view on the effect of NT on soil structure and quality in the Huang-Huai-Hai Plain（HP）,a long-term no-tillage experimental site for the main crop rotation-winter wheat（Triticum aestivum L.） and summer maize（Zea Mays L.）-was investigated.The experimental site belongs to the Yucheng Comprehensive Experimental Station（YCES） of Chinese Academy of Sciences（CAS） and has been used in studying the changes in soil aggregates and organic carbon storage under different tillage systems for 7 years now.NT,no-tillage with removed residue and organic fertilization（NTRR） and conventional tillage（CT） treatments were set up in the study.The impact of the three tillage systems on total soil organic carbon content and storage,water-stable aggregate stability,water-stable aggregate SOC content and storage,and relationship between total SOC content and water-stable aggregate SOC content were analyzed.Compared with CT,SOC content and storage,and water-stable aggregate mean weight diameter（MWD） and geometric mean diameter（GMD） along with macro-aggregate organic carbon content and storage in the 0-20 cm soil layer significantly increased in NT and NTRR treatments.This was possibly due to reduced soil disturbances and residue mulch and organic fertilizer applications.No tillage plots with residue mulch stored more SOC and macro-aggregate organic carbon than those with applied organic fertilizer.For the treatments,the order of the content of SOC and macro-aggregate organic carbon in the 20-60 cm soil depth was NT NTRR CT.In comparison with NT and NTRR,CT limited deep-soil organic carbon accumulation.Compared with straw mulch,the application of organic fertilizer enhanced deep-soil organic carbon accumulation under no tillage.On

关 键 词：免耕 秸秆覆盖 施有机肥 土壤有机碳 水稳性团聚体 有机碳储量 

分 类 号：S316[农业科学—作物栽培与耕作技术]