荒漠化草原植被斑块分布对地表径流、侵蚀及养分流失的影响  

Effects of Vegetation Patchy Distribution on Runoff,Erosion and Nutrients Loss in Desertified Steppe Area

作　　者：李小军[1] 汪君 高永平[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所沙坡头沙漠试验研究站,甘肃兰州730000 [2]桂林林业学校,广西桂林541004

出　　处：《中国沙漠》2011年第5期1112-1118,共7页Journal of Desert Research

基　　金：国家自然科学基金项目(40701002);中国科学院"西部之光"人才培养计划"西部博士资助项目"联合资助

摘　　要：地表径流是干旱区水、养分和土壤物质迁移和再分配的主要途径之一,它在很大程度上受植被格局的影响。研究了腾格里沙漠东南缘生物土壤结皮斑块和灌丛斑块镶嵌分布的植被格局对地表径流、侵蚀及其驱动下的资源再分配的影响。结果表明,植被斑块对地表径流和侵蚀产物起着拦截作用,能显著减少资源的流失。生物土壤结皮斑块和植被斑块之间存在资源(径流、侵蚀产物及养分等)再分配的源-汇关系。模拟降雨条件下,含有灌丛斑块和生物土壤结皮斑块的样方出现表面积水和径流需要的时间均显著大于只含生物土壤结皮斑块的样方;含两类斑块的样方出现径流需要的降雨量显著大于只含生物土壤结皮斑块的样方。在模拟降水和自然降水条件下,生物土壤结皮斑块产生的径流、侵蚀产物、有机质、氮及溶解养分中均大量被位于下坡向的灌丛斑块截获;灌丛斑块土壤水分入渗深度显著大于结皮斑块。灌丛斑块对生物土壤结皮斑块产生的地表径流、侵蚀产物及其携带的资源的捕获能显著减少资源流失,有效地防止荒漠化的进一步发生发展。Runoff is the dominant pathway of water,nutrients and soil materials transfer and redistribution in arid land,which is strongly affected by vegetation pattern.The influences of the mosaic distribution of biological soil crust patches and spot-structured shrub patches in desertified steppe area in southeast fringe of Tengger desert on runoff,soil erosion,sedimentation and related resources redistribution were investigated.The results show that vegetation patches could obstruct the runoff and sediment,which inevitably leads to the reduction of resources losses.There is a source-sink relationship for resource（water,sediments and nutrients） redistribution between the biological soil crust patch and shrub patch.Under the simulated rainfall condition,the time of ponding and runoff commencement in the plots consisting of both crust and shrub patches is significantly longer than those in the plot consisting of only crust patches;the volume of rainfall for runoff commencement of the former was remarkably greater than that of the latter.In simulated and natural rainfall events,the shrub patches effectively obstructed and captured the runoff and carried sediments,organic matter and nitrogen,etc,which are generated from the biological soil crust patch.The water penetration depth in shrub patches was significantly greater than that in crust patches.The resource capture of shrub patches effectively decreases resource leakage,which is beneficial to desertification prevention.

关 键 词：地表径流 资源再分配 斑块植被 源-汇关系 荒漠化草原 腾格里沙漠 

分 类 号：P334.2[天文地球—水文科学]