黄土坡面不同土地利用方式对土壤有机碳流失的影响

Effects of Different Land Use Patterns on Soil Organic Carbon Loss on the Loess Slope

坡面土地利用方式与产流、产沙及土壤有机碳的流失具有密切关系。对延安燕沟流域的坡耕地、草地、刈割草地、灌木地、刈割灌木以及刺槐林地径流小区的径流、泥沙及有机碳流失量进行了分析。结果表明:在不同土地利用方式下,产流、产沙量与植被覆盖度呈负相关关系;随径流流失的可溶性有机碳量表现为:坡耕地>刈割草地>草地>刈割灌木地>灌木地>刺槐林地小区,随泥沙流失的有机碳量表现为:坡耕地>草地>灌木>刺槐林地。随泥沙流失的土壤有机碳占总流失量的主要部分,而随径流流失的有机碳只占很少的比例。因此,增加黄土坡面植被覆盖度是控制产流、产沙量和有机碳流失的重要途径。

Slope land use pattern has a close relationship with generation of runoff and sediment as well as soil organic carbon loss.A study on the runoff,sediment and organic carbon loss was conducted in 6 runoff plots on a slope in Yangou watershed.The plots were used as bare land,harvested grassland,grassland,harvested shrub land,shrub land and Robinia pseudoacacia L.woodland respectively.The results showed that the yields of runoff and sediment were negatively correlated with the vegetation coverage under different land use patterns;the losses of soluble organic carbon along with the runoff loss followed the order of bare landharvested grasslandgrasslandharvested shrub landshrub landRobinia pseudoacacia L.woodland;the losses of soil organic carbon along with the sediment followed the order as that bare landgrasslandshrub landRobinia pseudoacacia L.woodland.It is also can be seen that most of lost soil organic carbon from the total loss coupled with the transfer of the sediment,whereas only a small part of organic carbon in the soluble form lost along with runoff.Therefore,it is suggested that the key way to control runoff,sediment yield and soil organic carbon loss is to increase the vegetation coverage on the loess slope.