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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。
Taking the conversion of cropland to forest in Qiongshui River Basin of Qinghai from 2000 to 2009 as the research object, the physical and chemical properties of soil were determined based on the field fixed point observation and indoor experiment analysis. The soil erodibility K value was calculated by EPIC model. Changes of forest erodibility and soil age under different vegetation types. The results showed that: 1) with the increase of returning farmland age, the porosity of soil increased gradually; the content of sand increased slightly; the content of powder decreased slightly; the content of clay remained unchanged; the content of organic matter decreased gradually within 7 years after returning farmland, Increase; soil erodibility has a tendency to reduce, nine years after the withdrawal of soil erodibility has been significantly improved. 2) The same returning farmland, the ability of returning degraded cultivated land to improve soil erodibility is mixed forest> mixed forest> arbor forest> shrub forest.