湘西北天然林转换对土壤活性有机碳与酶活性的影响  

Effects of Native Forest Conversion on Soil Labile Organic Carbon and Enzyme Activity in Northwestern Hunan Province

作　　者：肖华翠 李雪[1] 盛浩[1] 张丽娜[1] 罗飞雪 周萍[2] Xiao Huacui;Li Xue;Sheng Hao;Zhang Lina;Luo Feixue;Zhou Ping(College of Resources,Hunan Agricultural University,Changsha,Hunan 410128,China;Key Laboratory of Agro-ecological Processes in Subtropical Region,Institute of Subtropical Agriculture,Chinese Academy of Sciences,Changsha,Hunan 410125,China)

机构地区：[1]湖南农业大学资源学院,湖南长沙410128 [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,湖南长沙410125

出　　处：《水土保持通报》2023年第5期411-418,共8页Bulletin of Soil and Water Conservation

基　　金：国家自然科学基金项目“亚热带丘陵区典型农林用地底土有机碳稳定机理研究”(41571234);2023年湖南农业大学研究生科研创新项目“热点区土壤微生物多样性及功能对土地利用变化的响应”(2023XC115);湖南省重点研发计划项目(2023NK2026)。

摘　　要：[目的]了解土壤活性有机碳(SOC)组分和酶活性对天然林转换的响应,为预测区域土壤健康演变和环境变迁提供科学依据。[方法]选取本底一致,利用历史清晰的天然常绿阔叶林以及由此转变而来的针叶人工林、果园、坡耕地和水田,应用物理、化学和生物化学分析技术,研究表土活性有机碳组分和酶活性对天然林转换的响应规律与差异。[结果]天然林改为果园、坡耕地和水田后显著降低土壤有机碳、活性有机碳含量和酶活性,降幅分别为42%~67%,47%~88%和36%~89%。其中,以易氧化有机碳、微生物生物量碳含量和蔗糖酶活性的敏感性相对高于SOC敏感性,敏感地指示土壤有机碳库及活性的降低,易氧化有机碳更适宜推广应用。天然林改为人工林,土壤活性有机碳、酶活性的敏感性一般低于天然林改为果园、坡耕地,相对有利于土壤中活性有机碳库的保存。活性有机碳占总有机碳的比例由天然林改为人工林后显著降低,敏感地指示土壤碳库质量的下降。[结论]天然林转换不仅导致土壤活性有机碳数量大幅减少,有机碳库的质量下降,与之相关的酶活性也降低;土壤有机碳的活性和酶活性的降低,指示天然林转换后土壤生物健康/质量的退化。[Objective]The response of soil labile organic carbon components and enzyme activities to natural forest conversion was analyzed in order to provide a scientific basis for predicting regional soil health evolution and environmental change.[Methods]A native evergreen broad-leaved forest and a converted conifer plantation,an orchard,a sloping tillage area,and a paddy with similar geographical background and clear land use history were studied.The responses of labile organic carbon fractions and enzyme activities in topsoil to native forest conversion were investigated using various physical,chemical,and biochemical techniques.[Results]The native forest conversion to an orchard,a sloping tillage area,and a paddy significantly reduced the soil organic carbon content,labile carbon fraction contents,and enzyme activities by 42%—67%,47%—88%,and 36%—89%,respectively.Notably,the readily oxidizable organic carbon,microbial biomass carbon,and invertase activity experienced the greatest reduction compared with the native forest conversion,sensitively indicating the reduction in soil organic carbon content and its lability.Readily oxidizable organic carbon was,therefore,considered to be a practical index.Reductions in soil labile organic carbon fractions and enzyme activities were lower for the conversion of native forest conversion to plantation than for the native forest conversion to orchard and sloping tillage area,showing the preservation capacity of soil labile carbon in the plantation.The ratio of labile organic carbon to total organic carbon in soil was significantly reduced after the native forest conversion to plantation,sensitively reflecting the reduction in soil carbon quality.[Conclusion]Native forest conversion led to substantial reductions in labile organic carbon quantity,carbon quality,and related enzyme activities in soil,suggesting a degradation of soil biological health and a decline in soil quality.

关 键 词：天然林转换 活性有机碳组分 酶活性 土壤健康 湘西北 

分 类 号：S718.55[农业科学—林学] S153