不同地形条件下样点密度对土壤养分空间变异的影响

Effect of spatial variability with soil nutrient and the sample point density under different terrain

以湖南省安仁县的豪山乡(山地地形)和渡口乡(丘陵区)为研究对象,根据传统统计学和地统计学的相关原理,运用变异函数分析法和空间插值估计法,研究耕地土壤养分碱解氮含量、有效磷含量、速效钾含量、有机质含量的空间变异及其分布特征,研究不同地形条件样点密度对插值精度的影响。结果表明:土壤养分变异系数为16.56%～97.9%,属于中等变异;山地地区碱解氮含量、速效钾含量、有机质含量的基底效应值<25%,丘陵区有机质含量、碱解氮含量的基底效应值为38.15%～74.45%,2种地形有效磷含量的基底效应值为88.44%～100%;根据研究区土壤养分的空间变异情况,建议山地区采样密度为0.16个/hm2,丘陵区采样密度为0.10个/hm2。

Based on traditional principles and methods of statistics and geostatistics, variogram analysis and estimation of spatial interpolation were employed to study the nutrients nitrogen content, the spatial variability of available phosphorus content, available potassium, organic matter content and its distribution characteristics on statistical samples taken from the mountainous terrain in Haoshan township and the hilly terrain in Dukou township in Anren county, Hunan province. The article had also studied the influnce on interpolation precisions for four groups of samples with different topographic conditions and sampling densities, and the results showed that the soil nutrient coefficient of variation ranges between 16.56% and 97.9%, which fell under the medium variation category. The substrate effect of the Alkaline hydrolysis of nitrogen, available potassium and organic matter was lower than 25% in mountainous area, while that of Organic matters and alkaline nitrogen matter fell within a range of 38.15%-74.45% in hilly area. On the other hand, the substrate effects of available phosphorus in both regions were in range of 88.44% -100%. According to the study on the spatial variability of soil nutrient, it was concluded that the sampling density should be 0.16/hm^2 in mountain terrain, and 0.10/hm^2 in hilly terrain, respectively.