典型喀斯特山区耕地土壤养分空间变异特征:以贵州省长顺县为例

摘要

The spatial variation pattern and distribution characteristics of arable soil nutrients were analyzed by using the geostatistics and GIS combination method in Changshun County,Guizhou to provide the theoretical basis for soil scientific nutrient management,decision fertilization and industrial structure adjustment in karst mountainous area.Result:The variation coefficient of various soil nutrient indexes is 10％-100％ (at intermediate variation level)and various variables present the normal distribution.Soil pH,organic matter,available phosphorus and rapidly available potassium all have the trend effect but total nitrogen has no the trend effect.Semivariogram analysis shows that rapidly available potassium,pH, organic matter fit the exponential model and their determination coefficients are 0.919,0.701and 0.518 respectively.Total nitrogen and available phosphorus fit the linear model and F test of their determination coefficients is at very significant level.The pH has strong spatial auto-correlation, organic matter and rapidly available potassium have medium spatial auto-correlation but available phosphorus and total nitrogen have weak spatial auto-correlation.The variation of various soil nutrients in S-N direction is more than in E-W direction, which indicates the strong anisotropy.The arable area of weak alkaline soil and strong acidic soil is maximum and minimum respectively.The content of organic matter and total nitrogen is higher and their distribution pattern is the same.The available phosphorus content in most soils is at the intermediate level and the soils are mainly distributed in Northern and Southern of Changshun County.The rapidly available potassium content of soils is at first level and the soils are distributed in Western and Northeastern of Changshun County mainly.%为喀斯特山区耕地进行科学养分管理、决策施肥及产业结构方向调整提供理论依据, 以典型喀斯特山区贵州省长顺县耕地为分析对象, 综合运用地统计学和GIS相结合的方法, 分析其耕地土壤养分空间变异规律和分布特征.结果表明, 各土壤养分指标变异系数在10％～100％, 属中等变异, 各变量呈正态分布;土壤pH、有机质、有效磷和速效钾具有趋势效应, 全氮无趋势效应.速效钾、pH、有机质用指数模型拟合好, 决定系数分别为0.919、0.701和0.518;全氮和有效磷用线性模型拟合好, 决定系数F检验均达极显著水平;pH具有强烈的空间自相关, 有机质和速效钾具有中等空间自相关, 有效磷和全氮具有弱空间自相关;各土壤养分在S-N方向上变异大于E-W方向, 具有强烈各向异性.长顺县耕地土壤pH为弱碱的耕地面积最大, 强酸耕地面积最小;有机质和全氮含量普遍较高且分布规律较一致;有效磷含量中等水平占多数, 主要分布在长顺县北部和南部;土壤速效钾上等水平主要分布在长顺县的西部和东北部.