中文摘要：

通过径流小区试验，研究了4种施肥条件下紫色土坡耕地氮素淋失特征。结果表明，单施氮肥、氮磷配施和氮磷钾配施等施肥处理渗漏液中硝态氮含量在10．17-21．88mg·L^-1之间，渗漏液硝态氮占总氮含量的比例在85．5％-90．8％之间。各施肥处理渗漏液硝态氮含量呈前期较低，迅速上升，而后逐渐降低的季节变化趋势。玉米生长季各处理硝态氮淋失总量顺序为：单施氮肥〉氮磷配施〉氮磷钾配施〉无肥处理，单施氮肥处理硝态氮淋失总量最高（44．31kg·hm^-1），氮磷配施和氮磷钾配施处理硝态氮淋失量分别较单施氮肥降低47．6％和54．2％。氮磷钾合理配施方式有助于显著减少紫色土坡耕地硝态氮淋失。

英文摘要：

Nitrogen leaching is an important route of nitrogen loss, whose mechanism in fiat cropland has been documented. However, it is unclear how nitrogen leaching takes place in sloping cropland. Field runoff plot experiments were performed to monitor nitrogen leaching in sloping cropland of purple soil. Results showed that NO3-N contents of the leakage in three fertilization treatments, i.e. N（ N ）, N with P（NP）, N with P and K（ NPK ）, ranged from 10.17 to 21.88 mg·L^-1, which accounted for 85.8%-90.8% of total nitrogen in the leakage. NO3^- -N leaching exhibited obvious seasonal patterns with a rapid increase in the beginning and a gentle decrease in the end of the maize growth stage. The estimated total amount of NO3^- -N leaching in the maize growth season in difference treatments followed an order of： N〉NP〉NPK〉CK. The total leaching of NO3^- -N for the treatment N was 44.31 kg·hm^-2, whereas that for the treatment NP and NPK decreased by 47.62% and 54.23%, respectively. Therefore, nitrogen losses by leaching could be reduced through rational fertilizations in cropland of the hillslope. The estimated total amount of NO3^- -N absorbed by crops in different treatments followed an order of： NPK〉NP〉N〉CK. The total N absorbed by crop for the treatment NPK was 93.02 kg·hm^-2, while that for the treatment N and NP decreased by 23.8% and 10.6%, respectively. The difference of crops absorbing N ability could be the main reason of the effect of fertilization on nitrogen leaching in sloping cropland of purple soil.