中文摘要：

为探索土地利用方式变化对土壤理化性状的影响,以青藏高原青海省海北州原生矮嵩草（Kobresia humil）草甸、原生灌丛草甸、退化矮嵩草草甸、退化灌丛草草甸、人工草地、农田地为研究对象,对各利用方式下土壤的基本理化性状进行研究。结果表明：退化导致0～10cm土层土壤容重增大,而对下层土壤容重没有明显影响,2种退化草地0～10cm土层的土壤容重均大于10～20cm土层,其中退化灌丛草甸与原生灌丛草甸之间差异显著（P〈0.05）,人工种植也导致表层土壤容重有升高的趋势,人工种草和开垦均导致0～20cm土层土壤容重的变异消失。草地退化和开垦均导致土壤有机碳和全氮含量降低,草地退化还导致土壤全磷含量降低,但开垦为农田后对土壤全磷的影响不大;草地退化和开垦也导致土壤有机碳、全氮、全磷含量沿土壤深度的变异消失。草地退化后表层土壤的有机碳、全氮和全磷含量明显降低,而退化对10～20cm土层的有机碳含量影响不大。草地退化、开垦和农用均导致土壤表层速效氮的损失,草地开垦和农用的损失尤为剧烈;不同利用方式对土壤速效磷的影响较为复杂,未表现出一致的规律性。

英文摘要：

Five grassland use patterns： enclosed native Kobresia humilis meadow,native shrub meadow,degraded Kobresia humilis meadow,degraded shrub meadow,artificial grassland and farmland,were selected to study the effects of land use patterns on soil basic properties in the Northern of Tibetan Plateau,Qinghai province.Results showed that grassland degradation mainly led the soil bulk density of 0~10 cm layer to increase significantly,and had no significant influence on lower depth soil bulk capacity.Soil bulk density of 0~10 cm layer was higher than that of 10~20 cm layer in two degraded land use patterns.There was significant difference between degraded shrub meadow and native shrub meadow.Both planting and reclamation did not lead to the variation of soil bulk density in 0~20 cm soil depth.Grassland degradation and reclamation led soil organic carbon and total nitrogen content to decrease.Grassland degradation also decreased soil total phosphorus content,but reclamation had little influence on soil total phosphorus content.Grassland degradation and reclamation led the variation of soil organic carbon,total nitrogen and total phosphorus content to disappear with soil depth increasing.Degradation was making grassland into farmland.Grassland degradation led the soil organic carbon,total nitrogen and total phosphorus of surface soil to lose severely,but had little effect on that of 10~20 cm soil.Grassland degradation,reclamation-and farm,especially grassland reclamation and agricultural utilization led to decline the soil available nitrogen of surface soil.The effects of land use patterns on soil available phosphorus was more complicated,and with no consistent regularity