坡度对坡面土壤矿质氮素水蚀流失负荷的影响  

Soil Mineral Nitrogen Loss in Surface Runoff and Sediment as Affected by Slope Gradient on Loess Slope

作　　者：张亚丽[1] 李怀恩[1] 张兴昌[2] 肖波[2] 

机构地区：[1]西安理工大学西北水资源与环境生态教育部重点实验室,陕西西安710048 [2]中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100

出　　处：《水土保持通报》2007年第2期14-17,共4页Bulletin of Soil and Water Conservation

基　　金：国家自然科学基金(90610030);陕西省教育厅省级重点实验室重点科研计划项目(05JS35);黄土高原土壤侵蚀与旱地农业国家重点实验室基金课(10501-142);西安理工大学优秀博士论文基金(106-210623)

摘　　要：坡度是影响坡面水土流失和土壤养分流失过程的重要因素。室内模拟降雨试验表明,当坡长一定时,不仅土壤侵蚀量存在一个“侵蚀临界坡度”,土壤矿质氮流失量随坡度变化也存在一个“养分流失临界坡度”。试验测定这2个临界坡度均在15°～20°之间。土壤矿质氮地表流失以随地表径流流失为主,约占总流失量的99%。坡面矿质氮总流失量的96%为硝态氮,硝态氮对径流中矿质氮总量的贡献率明显高于在侵蚀泥沙中的贡献率。采取一定的截流措施是控制坡面矿质氮流失的关键。Slope gradient has many The results from artificial rainfall impacts on soil erosion by water and experiments are as folbws. Only mineral nitrogen loss in an erosion process. in a certain range of slope gradient, the amounts of soil erosion and mineral nitrogen loss aggrandized with the increase in slope gradient. Exceeding the range, however, the amounts of the losses decreased. With the same slope length, the critical slope gradients for soil erosion and mineral nitrogen loss were validated between 15° and 20°. Soil mineral nitrogen loss showed two trends. First, soil mineral nitrogen loss by runoff was much more than.that by sediment, being about 99% of the total loss amount. Second, soil nitrate loss in erosion process was the main trend, being about 96% of the total amount of mineral nitrogen loss. The percent of nitrate lost in surface runoff was much more than that in sediment. Further measures to reduce runoff flow are suggested to control soil mineral nitrogen loss by surface runoff.

关 键 词：坡度 矿质氮素 水土流失 临界坡度 

分 类 号：S175.1[农业科学—农业基础科学]