【摘要】 以武功县为例,应用地统计学和GIS相结合的方法,对土壤有机质、速效磷、速效钾、碱解氮等土壤养分空间变异特征进行研究,并对不同采样密度下有机质的空间插值结果进行分析比较,用均方根误差和相关系数检验不同密度下的插值精度,以确定县域有机质合理采样数。研究结果表明:各土壤养分均存在中等强度空间变异,土壤养分变异系数的顺序是速效磷>速效钾>有机质>碱解氮。各土壤养分均存在正的基底效应,其中,有机质和速效钾的空间变异性受人为因素影响较小,控制其空间变异性的主要因素与成土母质、土壤类型、气候条件等有关。而碱解氮和速效磷的空间变异性受人为因素影响较大,控制其空间变异性的主要因素与耕作方式及农业生产中施肥等有关。随着采样点密度的增加,克里格插值精度提高,适当减少样点数可以满足插值分析的需要,充分考虑土壤养分空间变异评价的精度分析,确定县域土壤有机质合理采样数应控制在2213个以上,即最大以17.8 hm2为一个采样单元。更多还原

【Abstract】 Spatial variations of soil organic matter, available nitrogen, phosphorus and potassium were discussed based on geostatistics combined with GIS technology in Wugong County. Spatial interpolation results from different sampling densities of organic matter were analyzed and compared by testing interpolation accuracy under different densities with the Root Mean Square Error(RMSE) and correlation coefficient(r) in order to determine a reasonable number of samples in the county. The results showed that there existed moderate spatial variability in the soil nutrient. The order of coefficient of variation of soil nutrient was available phosphorus>available potassium>organic matter> available nitrogen. The soil nutrients, with positive base effect, showed moderate spatial variation and moderate spatial autocorrelation. Among them, the spatial variability of organic matter and potassium was little affected by human factors, but related with the soil parent material, soil type, climate conditions, respectively. Nevertheless, the spatial variability of available nitrogen and phosphorus was much influenced by human factors, and related with the tillage and fertilizer agricultural practices. With the increase of sampling density, kriging interpolation accuracy was improved. It was possible to reduce the number of samples to satisfy the need of the research regarding spatial variability of soil nutrients. Taking spatial prediction accuracy into consideration, more than 2213 samples should be the suitable number to evaluate the spatial variability of soil organic matter on county scale, and the maximum sampling unit was 17.8 hm2.更多还原