岩溶生态系统退化与土壤有机碳贮量  

Degradation of Karst Ecosystem and Soil Organic Carbon Storage

作　　者：李小永 田小琴 LI xiaoyong;TIAN xiaoqin(Guizhou Forestry Inventory and Planning Institute,Guiyang 550005,China;Guizhou Walnut Institute,Guiyang 550005,China)

机构地区：[1]贵州省林业调查规划院,贵州贵阳550005 [2]贵州省核桃研究所,贵州贵阳550005

出　　处：《四川林业科技》2023年第4期82-87,共6页Journal of Sichuan Forestry Science and Technology

摘　　要：岩溶生态系统退化过程(森林-灌丛-草被的变化过程)中,土壤总有机碳贮量显著下降,表明岩溶土壤由大气CO_(2)碳汇变成碳源,对大气环境产生不利影响。而植被类型也由C3植被向C4植被变化,使土壤有机碳呈现变重的趋势。土壤活动性有机碳组分中的微生物量碳也发生相应变化,在B层土壤微生物量碳显著下降,但土壤中溶解性有机碳含量并未产生显著差异,这可能是退化岩溶生态系统土壤有机碳下降的一个原因之一。因此,有效防止岩溶生态系统的退化,将显著促进岩溶生态系统在全球变化中作为大气CO_(2)汇的作用,同时,对于岩溶生态系统生物多样性的保护等方面具有重要作用。岩溶森林土壤具有较高的碳贮量,表层土壤含有高达87.12±35.10 g·kg^(-1)的有机碳,整个剖面的有机碳含量均高,而且下部土壤层次的碳含量较之其他植被类型的下部土壤层次高,岩溶生态系统的退化,并未显著影响到岩溶土壤DOC的量,但从三种植被条件下的含量大小来看,以森林植被最高,而以灌丛地最低,草地的DOC含量高于灌丛地。岩溶土壤有机碳的稳定同位素δ^(13)C值森林下为-26.15‰,变为灌丛下的-25.44‰,变化较小,表现出与植物叶的稳定碳同位素变化较为一致的现象,而变为草地系统后,土壤的稳定碳同位素δ^(13)C值则显著增重,达到-20.83‰,也同样表现出与植被的碳同位素值相同的变化。During the process of karst ecosystem degradation(forest-shrub-grass cover change process),the total organic carbon storage of soil decreased significantly,indicating that karst soil changed from atmospheric CO_(2) sink to carbon source,which had adverse effects on the atmospheric environment.The vegetation type also changed from C3 vegetation to C4 vegetation,which made soil organic carbon become heavier.The microbial biomass carbon in the active organic carbon component of soil also changed correspondingly,and the microbial biomass carbon in soil layer B decreased significantly,but the content of dissolved organic carbon in soil did not show a significant difference,which may be one of the reasons for the decline of soil organic carbon in degraded karst ecosystem.Therefore,effectively preventing the degradation of the karst ecosystem will significantly promote the role of the karst ecosystem as a sink of atmospheric CO_(2) in global change.At the same time,it will play an important role in protecting the biodiversity of the karst ecosystem.The karst forest soil had a high carbon storage,and the organic carbon content in the top soil was as high as 87.12±35.10 g·kg^(-1),and the organic carbon content in the whole profile was high,and the carbon content in the lower soil layer was higher than that in the lower soil layer of other vegetation types.The degradation of karst ecosystem had not significantly affected the DOC content in karst soil,but from the perspective of the content under the three vegetation conditions,the forest vegetation was the highest,while the shrub land was the lowest and grassland was the lowest.The stable isotope δ^(13)C value of organic carbon in karst soil changed from 26.15‰ under forest to 25.44‰ under shrub,showing a relatively consistent phenomenon with the stable carbon isotope change of plant leaves.After changing into grassland system,the stable carbon isotope δ^(13)C value of soil increased significantly,reaching -20.83‰,which also showed the same change as that of vege

关 键 词：岩溶生态系统 退化过程 土壤有机碳 

分 类 号：S153.6[农业科学—土壤学]