坡面尺度土地利用空间配置的产沙效应——以陕北黄土丘陵沟壑区为例

Effects of Land Use Configuration on Soil Erosion at Slope Scale——A Case Study in the Hilly-gullied Loess Region,Northern Shaanxi

为了研究黄土丘陵沟壑区缓坡地土地利用与水土流失的作用机理,选取中科院安塞水土保持综合试验站9个缓坡试验小区为研究对象,分析了2009—2011年不同土地利用配置方式(谷子地、柳枝稷地、撂荒地、2/3谷子-1/3柳枝稷地、2/3谷子-1/3撂荒地)的侵蚀产沙特征及其与降雨、植被覆盖度的关系以及减沙效益。结果表明:缓坡不同土地利用配置方式的次降雨产沙量大小为谷子地>2/3谷子-1/3柳枝稷地>2/3谷子-1/3撂荒地>柳枝稷地>撂荒地,与短历时高强度降雨关系密切;7月可能是泥沙量产生的敏感时期;短历时高强度暴雨往往是年产沙量变化的主要原因;与谷子地相比,柳枝稷地、撂荒地、2/3谷子-1/3柳枝稷地、2/3谷子-1/3撂荒地均表现出不同程度的减沙效应,减沙效应大小为:撂荒地>柳枝稷地>2/3谷子-1/3撂荒地>2/3谷子-1/3柳枝稷地;植被覆盖度的提高能有效地减少产沙量。研究结果可以为缓坡土地利用对水土流失的影响评价提供一定的参考依据。

To study the mechanism of land use and soil erosion at gentle slope in the hilly-gullied loess region,based on the experiment plot research（from 2009 to 2011） in Ansai Integrated Experimental Station of the Chinese Academy of Sciences,effects of soil erosion under different land use pattern at gentle slope were discussed.Five kinds of land use configuration types were designed,including Setaria italica（F）,Panicum virgatum（S）,Abandoned land（A）,two-thirds Setaria italica and one-third Panicum virgatum（FS）,two-thirds Setaria italica and one-third Abandoned land（FA）.The research results indicated that,for the five land use types,sediment amounts under individual rainfall events were in the order of F 〉 FS 〉 FA 〉 S 〉 A,and sediment amounts were significantly associated with rainfall depth and rainfall intensity.In the whole observation period,July might be the sensitive time of producing sediments.One or two erosive storms were the main reason for the change of annual sediment amount.Compared with Setaria italica（F）,the other four land use configuration types（S,A,FS,FA） had positive effects of sediment reduction,and effects of sediment reduction were in the order of A 〉 S 〉 FA 〉 FS.High vegetation coverage had a positive effect on reducing sediment amount for the five land use types（F,S,A,FS,FA）.The results would provide reference for the effect evaluation of land use on soil and water losses at gentle slope.