中文摘要：

选取中国西北部石羊河流域的武威地区典型土壤为研究对象，通过Cl-， NO-3质量浓度分布组合特征，揭示了干旱区平沙地、板结地和荒农地3种类型土壤剖面硝酸盐的来源与空间分布特征，探究了Cl-与NO-3质量浓度的相关关系。结果表明：土壤中Cl-与NO-3都主要分布于表土层，在深土层二者质量浓度都有不同程度的降低；随着土壤深度的增加，均呈活塞式分布，这种分布特征对于平沙地土壤表现得尤为明显。 Cl-与NO-3在土壤中的分布具有极大的相关性，二者质量浓度的变化趋势保持高度一致，相对较高的NO-3/Cl-原子比值反映了干旱区土壤中硝酸盐的富集度较高。干旱区土壤中的NO-3主要来自大气沉降（尤其是降水带入），干旱的气候和贫瘠的土地使得农耕地土壤中的NO-3主要来自农田肥料和污水灌溉，其次是生活污物、人畜排泄物以及硝化作用。

英文摘要：

By adopting the method of combining artificial sampling and experimental analysis, we select a typical soil from the Wuwei region of the Shiyang River Basin in Northwest China as the research object, determined the concentration of Cl- and NO-3 , revealed the spatial distribution characteristics of nitrates in three types of the soil profile, i.e. sand, hardened earth and farm land in arid areas, explored the correlation between the concentration of Cl- and NO-3 , and analyzed the main source of nitrate at the same time. The results showed that Cl- and NO-3 were mainly distributed in the top soil in this three soil profiles and, in the deep soil layer, both the content of Cl- and NO-3 were reduced at the varying degrees. With the increase of soil depth, the contents were distributed in piston type, and this distribution characteristic was especially obvious in the sandy soil. The distribution of Cl- and NO-3 in the soil had a great relevance, the changing tendency of these concentrations were highly consistent, and the NO-3/Cl- atomic ratio was relatively high, indicating that the abundance of nitrate was higher in the soil in arid areas. In the arid soil, NO-3 were mainly from the atmospheric precipitation （especially the entrance of precipitation）;in the farmland soil, NO-3 were mainly from the farmland fertilizers and the sewage irrigation, and secondly from life sewage, human or animal waste and the nitrification too.