青海省湟水河流域退耕还林地土壤可蚀性研究

以青海湟水河流域2000—2009年退耕还林地为研究对象,基于野外定点观测和室内实验分析,测定土壤理化性质,采用EPIC模型中的算法求算土壤可蚀性K值,研究不同退耕还林年限和不同植被类型土壤可蚀性的变化情况。结果表明:1)随着退耕年限的增加,土壤孔隙度逐渐增大;砂粒含量略微增加;粉粒含量略有减少;黏粒含量则基本不变;有机质在退耕7年内逐渐减少,之后又开始增加;土壤可蚀性有降低的趋势,退耕9年后对土壤可蚀性有较明显的改善。2)相同退耕年限,退耕植被类型改善土壤可蚀性能力为乔木混交林>乔灌混交林>乔木林>灌木林,且退耕年限越长变幅越大,差别越明显。

Study on Soil Erosiveness in the Area of Returning Farmland to Forest in Huangshui River Watershed of Qinghai Province

With the area of returning farmland to forest in Huangshui River watershed of Qinghai province in the years from 2000 to 2009 as a study object,research work was conducted on changes of soil erosiveness in different years of vegetation restoration and different vegetation types.Soil physical and chemical properties were measured by field investigation and experiment and soil erodibility(K-factor) was calculated by EPIC model.The conclusions showed that with the increase of returning farmland to forest years,soil porosity would become smaller gradually,the sand content was increased little,the silt content had a little decrease and the clay content was almost invariant.Soil organic matter gradually decreased in the previous seven years of returning farmland to forest,and then increased.There was some tendency indicating that soil erodibility would become smaller,particularly after nine years of returning farmland to forest.In the same year,the ability of improvement of soil erodibility was as follows: tree mixed forest>tree and shrub mixed forest>tree forest>shrub forest,and with the year increase the difference became bigger.