不同采样密度下土壤特性的空间变异特征及其推估精度研究

SPATIAL VARIABILITY OF SOIL PROPERTIES AT DIFFERENT SAMPLING INTENSITIES AND ACCURACY OF THEIR ESTIMATION

对3种采样密度下的土壤特性进行了空间变异结构研究,并在此基础上对土壤特性的推估精度进行了比较。土壤空间变异结构在不同采样密度下的变化随土壤的特性而定,土壤pH、NH4+-N、P及S的变异分别符合不同的半方差模型,土壤OM、Ca及Mg则均符合同一模型;采样密度与模型的拟合度、变异的有效变程及空间相关性均没有必然联系。对模型拟合度均达显著水平的土壤特性进行推估,土壤OM及S的推估精度随采样密度的提高而增加,但土壤NH4+-N及Ca没有表现出同样的规律。

s Spatial variability of soil properties was studied, and comparison in estimation accuracy was conducted between three different sampling intensities. The structure of soil spatial variation change with sampling intensities and soil properties. Variation of soil pH, NH4+-N, P and S was best fitted with their corresponding semi-variation model, respectively, whereas that of soil OM, Ca and Mg could be simulated by the same one model. Sampling intensities did not have anything certain with the fitting degree of models, effective range and spatial dependence of variation. Soil properties with significant model-fitting degree were estimated, with results showing that the accuracy of estimation with soil OM and S increased with sampling intensity, however, it was not the case with soil NH4+-N and Ca.