中文摘要：

包气带是连接大气层和含水层的关键地带,研究土壤中硝酸盐的迁移累积规律对防止地下水硝态氮污染至关重要。选取我国西北干旱区敦煌盆地典型土壤为研究对象,测定各土壤剖面中的Cl^-和NO-3浓度,探究硝酸盐的迁移规律和影响因素。结果表明：Cl^-和NO3^-主要集中在0～40cm近地表层土壤中,其硝酸盐的累积量占总累积量的80%以上,NO3^-在1m的土壤剖面中呈S型迁移规律,适宜的含水率、疏松的土质和较高的植被覆盖度均有利于NO-3的垂向迁移;NO3^-和Cl^-在沙漠中呈活塞式迁移规律,二者显著正相关并与含水率负相关,短暂的降雨和强烈的蒸发使硝酸盐在地表大量富集,深层土壤的含量高表明了硝酸盐的淋吸效应,较高的NO3^-/Cl^-说明硝酸盐在干旱时富集度高。

英文摘要：

Vadose zone is the key to connecting with the atmosphere and the aquifer; transfer and accumulation law of nitrate in soil is essential to prevent nitrate pollution in groundwater. We selected typical soils of Dunhuang in northwest China for the study object,measured the concentrations of Cl^-and NO3^-in each soil profile,and explored the migration of nitrate and factors. The results showed that： Cl^-and NO3^-mainly exist in 0-40 cm soil near the surface,the cumulative amount of its nitrate is accounting for above 80% of the total cumulative amount in soil,NO3^-has the S- shaped migration in the soil profile. Suitable moisture,loose soil and high vegetation coverage are conducive to vertical migration of NO3^-. NO3^-and Cl^-have the piston migration in the desert,both have significant positive correlation and negative correlation with the water content. Short rains and strong evaporation lot nitrate enriched in the surface. The high contents in deep soil show the suction effect of nitrate leaching. The high NO3^-/ Cl^-descript that nitrate is highly enriched during droughts.