子午岭不同土地利用方式对土壤性质的影响

通过野外调查和室内分析相结合的方法,研究子午岭次生林区不同土地利用方式下的土壤性质状况,分析土地利用状况与土壤质量之间的关系,结果表明:不同土地利用方式表层土壤有机质、全氮、全磷、pH值、脲酶、蔗糖酶和碱性磷酸酶含量或活性差异显著,农地主要土壤养分含量和酶活性较低,林地则较高。除pH值外,不同利用方式下土壤养分和酶活性均随土层深度的增加而逐渐减小。除土壤pH值外,不同利用方式下土壤有机质、全氮、全磷、铵态氮、脲酶、蔗糖酶、碱性磷酸酶和过氧化氢酶之间呈显著或极显著正相关性。以林地为对照的土壤退化指数表明农用地和撂荒翻耕地土壤质量退化显著,其表层(0～20cm)土壤退化指数分别为44.86%和43.10%;撂荒未翻耕地深层(20～130cm)土壤质量则有所提高。

Effects of Land Use on Soil Properties in Ziwuling Region

Land use exerts great influence on soil properties,including soil physical,chemical and biological properties,which in turn impact soil quality.In this paper,field investigation and laboratory analysis were conducted to reveal the relationship between land use conditions and changes of soil quality,which will provide valuable evidence for land management and eco-environment rebuilding.We studied major soil chemical properties and soil enzymatic activities under four land use conditions,i.e.forest land,farmland,ploughed abandoned land and unploughed abandoned land,in Ziwuling secondary forest area,and analyzed the relationship between land use and soil chemical and biological properties based on soil quality.The results showed that significant difference existed among soil organic matter,total nitrogen,total phosphorous contents,pH values,and activities of soil urease,invertase and alkaline-phosphatase in surface soils at different land use conditions.The major lower soil nutrients and enzymatic activities were observed in farmland,while the higher nutrients and enzymatic activities were observed in forest land.The major soil properties,exceptx pH values,were reduced with the increase of soil depth in soil profiles.The statistical analysis showed that significant or marked significant correlationship existed among soil organic matter,total nitrogen,total phosphorus,ammonia nitrogen,urease,invertase,alkaline-phosphatase and catalase.Soil degraded index(SQI),which was calculated based on forest area,indicated that soil quality has been greatly degraded in farmland and ploughed abandoned land.The soil degraded index in surface layer(0-20cm)were 44.86% and 43.10%,respectively.However,soil quality has been improved in deep layer soil(20-130cm)in unploughed abandoned land.