三峡库区不同土地利用方式土壤肥力变化——以汝溪河流域为例

Soil Fertility Changes in Different Land-Use Types in the Three Gorges Reservoir Region:A Case Study in Ruxihe Watershed

以三峡库区汝溪河流域为例,选取了马尾松林地、退耕柏木林地、退耕草地和耕地4种土地利用类型,通过实地采样的方法研究了各个土地利用类型的土壤肥力状况.土壤肥力指标选取了土壤含水量、粒径组成、pH值、有机质,全氮、全磷、全钾、碱解氮、有效磷和速效钾.这些指标在不同土地利用类型间均存在较明显的差异.耕地土壤有机质要显著低于另外3种土地利用类型.养分间的相关分析发现,有机质和全氮、有机质和碱解氮、pH值与全磷、pH值与有效磷、pH值与全钾、全氮与全磷、全钾与全磷、全钾与有效磷间都具有明显的相关性,养分间存在耦合作用.退耕还林还草对提高土壤肥力特别是有机质具有很好的效果.

Four land-use types have been selected to study the soil fertility changes in Ruxihe watershed. These four land-use types include： nature forest, forest convert from farmland, grassland convert from farmland and cultivated land. Soil fertility indices are：soil water content, particle composition, Ph, organ- ic matter（OM） ,total N（TN）, total P（TP）, total K（TK） ,hydrolysoble N（HN）, available P（AP） and a- vailable K（AK）. There are significant differences of these indices between different land-use types. Soil organic matter is significant lower in cultivated land than in other land-use types. Through Pearson coeffi- cient analyzing, it shows that there exists highly positive relation between OM and TN, OM and HN, pH and TP, pH and AP, pH and TK, TN and TP, TK and TP, TK and AP.