中文摘要：

通过对宁夏南部山区阳洼流域不同土地类型下土壤养分分布特征进行研究，结果表明：流域土壤养分整体上表现为草地〉农地〉梯田〉林地〉沟道．流域各类型下土壤养分随土层深度增加，有逐渐下降的趋势．在a=0．05下，不同土层间土壤速效磷、速效钾、全磷存在显著差异．在不同土地类型下土壤全磷受母质影响，变异系数仅为21．41％，在土壤中以稳定态存在，而流域有效磷的变异系数可达178．56％，土壤有效磷含量的空间分布较为复杂，易受随机因素影响．草地利用类型下土壤有机质、碱解氮的变异系数为35．24％，29．04％，远高于林地利用类型．pH值与速效磷、全氮、有机质和碱解氮都有极显著的相关关系，有机质和碱解氮、全氮相关性较高，相关系数（R）分别为0．914^＊＊,0．839^＊＊，而全磷与有效磷之间没有表现出明显相关关系．

英文摘要：

The characteristic of soil nutrient distribution of Yangwa watershed under different land patterns on the loess plateau in the south Ningxia were researched. The result showed that the changing tendency of soil nutrient were described as follows： pasture~farming land （gentle slope,steep slope）~terrace~ woodland~channel path. Soil nutrient were gradually decreased with soil depth. There were significant differences of available phosphorus, available potassium and total phosphorus between different soil depths when a was approaching to 0.05 level. The total phosphorus was mainly effected by soil parent material. Variance coefficient was only 21. 41~/00. So the changes of total phosphorus were relatively stabilized in watershed. The spatial distribution of the available phosphorus in the watershed was rather complexes, which was easily effected by occasional factors. The variance coefficient was 178. 56%. The variance coefficients of organic matter and available nitrogen were 35. 24% and 29. 04% under native pasture, which were over sparseness woodland. There as a significant correlation among pH and available phosphorus, total nitrogen, organic matter, available nitrogen. The correlation coefficients were 0. 914^＊＊ and 0. 839^＊＊ between organic matter and available and total nitrogen. There was no correlation between the total phosphorus and the available phosphorus.