栗钙土农田土壤养分空间变异特性及采样方法研究

以西宁市二十里铺村的农田为研究区域,采用5 m×5 m网格法,选取84个观测点取样,进行室内分析,测定土壤有机质、水解氮、速效磷、速效钾的含量,分析土壤养分的空间变异规律。研究表明,土壤有机质、水解氮、速效钾的空间变异性不太明显,速效磷的空间变异性明显;有机质、水解氮和速效钾的空间变异主要是由结构性因素引起的,速效磷的空间变异是由随机因素引起的。有机质的变异函数理论模型为指数模型,水解氮、速效磷、速效钾变异函数理论模型为球形模型。栗钙土农田采样的密度范围在1~11 m之间,将能够满足精确农业生产对这4种土壤养分的分析要求。

Studies on spatial variability of soil nutrients and sampling methods in a field of chestnut soil

Eighty-four sampling plots of 5 m×5 m were collected from a field in Er-shi-li-pu Village of Xining City,Qinghai Province,China.Soil organic matter,available N,available P,and available K were measured,and the patterns of spatial variations of soil nutrients were analyzed.The results indicated that the spatial variability of organic matter,available N,and available K was not obvious while the spatial variability of available P was obvious.The spatial variability of organic matter,available N,and available K was mainly caused by structural factors and that of available P was primarily caused by random factors.The semi-variogram of organic matter was well described by exponential model while that of available N,available P,and available K was described by spherical model.In order to analyze the soil nutrients accurately in fields of chestnut soil,the appropriate sampling density was between 1 to 11 m.