中文摘要：

以三种取样间距（100m、50m、25m）进行网格取样，对土壤有机质、全量氮磷进行空间变异性分析。结果表明：土壤有机质与全氮含量处于较低水平，全磷含量处于中等水平。全氮的变异系数随不同间距变化幅度较小，有机质与全磷的变异系数随着取样间距增加而减小．取样间距对合理取样数目具有一定的影响，合理取样数目分别为：有机质（24）、全氮（34）、全磷（10）．土壤全量养分的空间变异性主要受结构因素影响，随机因素影响较弱，但不同取样间距对全量养分空间变异规律影响不明显；对于全量养分100m的取样间距就可以满足干旱区农田土壤样品的精度要求。

英文摘要：

The spatial variability of total amount of N ,P and organic matter in arable soil was studied at three sampling distances, i. e. 100 meter,50 meter and 25 meter. The results indicated that the contents of total N and soil organic matter were low, and total the P content was medium. The coefficient of variation of total N changed in relatively small extent at dfferent sampling distance, but that of organic matter and total P was reduced with increasing sampling distance. The reasonable sampling numbers for soil organic matter, total N and total P were 24,34 and 10 respectively. The soil depth profile structure was the leading factor to influence the spatial variability of soil total nutrients, while the effect of random factor was weak. The influence of sampling distance on the spatial variability of soil total nutrients was not evident. The sampling distance of 100 meters could be appropriate to study the total nutrients of cultivated soil in arid areas precisely.