喀斯特地区翻耕和玉米种植对土壤团聚体、氮素及微生物量的影响  

Effects of Tillage and Maize Planting on Soil Aggregates,Nitrogen and Microbial Biomass Carbon in Karst Area

作　　者：陈武荣 叶莹莹[2] 陆珊 梁思琳 陆锦华 毛兵 肖霜霜 CHEN Wurong;YE Yingying;LU Shan;LIANG Silin;LU Jinhua;MAO Bing;XIAO Shuangshuang(Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation,Nanning Normal University,Nanning 530000,China;Key Laboratory of Subtropical Agriculture Ecology, Institute of Subtropical Agriculture,Chinese Academy of Sciences, Changsha 410125,China;College of Environment and Life Sciences, Nanning Normal University, Nanning 530000, China)

机构地区：[1]南宁师范大学广西地表过程与智能模拟重点实验室,南宁530000 [2]中国科学院亚热带农业生态研究所,亚热带农业生态过程重点实验室,长沙410125 [3]南宁师范大学环境与生命科学学院,南宁530000

出　　处：《亚热带资源与环境学报》2021年第2期25-31,共7页Journal of Subtropical Resources and Environment

基　　金：广西自然科学基金项目(2018GXNSFBA281157);广西地表过程与智能模拟重点实验室(南宁师范大学)系统基金(GTEU-KLOP-X1716、NNNU-KLOP-X2004);大学生创新创业训练计划项目(201810603087、201910603298)。

摘　　要：喀斯特地区农业活动在短期内可能会导致土壤团聚体破碎、微生物量降低,进而引起土壤氮快速丢失。然而翻耕和玉米种植如何影响这一过程仍不清晰。本研究基于当地常见作物玉米地的不同翻耕模式(NT-免耕不种玉米;NTM-免耕种玉米;CT-传统耕作不种玉米;CTM-传统耕作种玉米)的原位控制试验,分析一年后土壤团聚体组成、氮素及微生物量等变化规律。结果发现:双因素方差分析表明,翻耕措施显著影响土壤团聚体分布、总氮丢失量(△TN)、硝态氮(NO_(3)^(-)-N)、可溶性有机氮(DON)和微生物量生物量碳(MBC)含量,玉米种植仅对土壤NO3--N和DON有显著作用。翻耕主要破碎5~8 mm粒级大团聚体,显著提高土壤△TN,降低土壤MBC含量。土壤NO_(3)^(-)-N是喀斯特地区可溶解性氮素的主要形态,其次是DON,铵态氮(NH_(4)^(+)-N)含量最低。土壤NO_(3)^(-)-N在翻耕或玉米种植下均显著减少,DON仅在翻耕和玉米双重作用下显著降低。Pearson相关性分析表明总氮的丢失主要来自土壤团聚体5~8 mm粒级的破碎。在喀斯特脆弱生态系统中,减少耕作干扰或开展保护性耕作是减少土壤物理结构破坏,维持氮库,实现其可持续性利用的有效措施。Agricultural activities in the karst area may cause soil aggregates to break down and reduce microbial biomass,which in turn will cause rapid loss of soil nitrogen.However,it is still unclear how tillage and maize cultivation affect the process.This study is based on the in-situ control experiment of different treatments:no-tillage without maize(NT),no-tillage with maize(NTM),conventional tillage without maize(CT)and conventional tillage with maize(CTM).Soil aggregate distribution,nitrogen,and microbial biomass were measured after one year.Two-way analysis of variance showed that tillage measures significantly affected soil aggregate distribution,total nitrogen loss(△TN),nitrate nitrogen(NO_(3)^(-)-N),dissolved organic nitrogen(DON)and microbial biomass carbon(MBC)content.Maize planting only had a significant effect on soil NO_(3)^(-)-N and DON.Tillage mainly disintegrated large soil aggregates(5~8 mm),significantly increased△TN and reduced MBC.Soil NO_(3)^(-)-N is the main form of dissolved nitrogen in karst area,followed by DON,and ammonium nitrogen(NH_(4)^(+)-N)content is the lowest.Soil NO3--N was significantly decreased by plowing or corn planting,while DON was only significantly reduced under the dual effects of plowing and corn.Pearson correlation analysis revealed that the loss of soil total nitrogen mainly resulted from the fragmentation of soil 5~8 mm aggregate.In fragile karst ecosystems,reducing tillage disturbances or using conservation tillage is the effective measure to reduce the destruction of soil physical structure,maintain soil nitrogen storage,and realize its sustainable use.

关 键 词：喀斯特 翻耕扰动 玉米种植 团聚体 氮素 

分 类 号：X82[环境科学与工程—环境工程]