三峡库区坡改梯土壤养分状况与变化趋势

Situation and Change Trend of Soil Nutrients in Terraced Fields from Sloping Land in Three Gorges Reservoir Area

为准确掌握三峡库区坡改梯工程实施后的土壤肥力状况,以巫山县为例,采用时空代换法分析其不同年限坡改梯土壤的养分状况及其变化趋势。结果表明:研究区土壤肥力总体较低,根据全国第二次土地普查土壤养分分级标准,其全氮、速效钾、有机质和速效磷含量均值分别处于三级、三级、四级和五级标准,土壤养分的空间异质性较小。相较于坡耕地,坡改梯土壤养分随着耕种年限的增加总体呈上升趋势。坡改梯年限为2年的土壤养分各指标的均值相对于坡耕地土壤有所降低且土壤肥力差异性最大,坡改梯年限为14年的土壤养分各指标的均值呈直线上升趋势且土壤肥力差异性减小。

The situation and change trend of soil nutrients in terraced fields from sloping land with different cultivation years were analyzed by the space-time substitution method in Wushan County to grasp exactly the soil fertility situation after implementing the project of terraced field construction from sloping land in Three Gorges Reservoir Area.Results：The average content of total nitrogen,available potassium,organic matter and available phosphorus is in Grade Ⅲ,Grade Ⅲ,Grade Ⅳ and Grade Ⅴ respectively according to the classification standard of soil nutrients recommended by National Second Land general survey and the spatial heterogeneity of soil nutrient is small.The soil nutrients in terraced fields from slope cropland present the rising trend with increase of cultivation years compared with slope cropland overall.The average values of different soil nutrient indexes in terraced fields from slope cropland with two cultivation years are lower than slope cropland and there is a significant difference in soil fertility.The average values of different soil nutrient indexes in terraced fields from slope cropland with fourteen cultivation years present the linear rising trend and there is no significant difference in soil fertility.