| 韩建刚,李占斌.紫色土丘陵区不同土地利用类型小流域氮素流失规律初探[J].水利学报,2011,42(2): |
| 紫色土丘陵区不同土地利用类型小流域氮素流失规律初探 |
| Process characteristics of nitrogen loss by runoff in different land use watersheds in purple soil hilly region |
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| DOI： |
| 中文关键词: 紫色土 土地利用 硝态氮 铵态氮 径流 |
| 英文关键词: purple soils land use nitrate nitrogen ammonium nitrogen runoff |
| 基金项目: |
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| 中文摘要: |
| 摘要： 以紫色土丘陵区3个土地利用类型各异的小流域为研究对象，监测了20场自然降雨侵蚀下径流氮素的流失
过程，旨在为流域尺度养分流失预测模型的发展与校正提供依据。结果表明，次降雨过程中硝态氮的流失浓度随
着流量的增加而降低，峰值流量处浓度一般达到最低；此后，随着流量的减小，硝态氮的流失浓度又呈现增加趋
势。铵态氮流失过程表现为波浪形变化，径流初期其流失浓度一般较高，随着时间的延长逐渐降低并趋于稳定。
硝态氮是紫色土小流域氮素流失的主要形式，其占到径流无机氮流失的50%~97%。单一农田土地利用将导致流
域 |
| 英文摘要: |
| Abstract：Three small watersheds with different land use were employed to investigate the process characteristics of nitrogen loss during various sized natural rainfalls in purple soil hilly region. Results show that NO -3 concentrations in runoff waters were inversely proportional to the runoff rates. The NO -3 concentrations reached the lowest at their peak runoff rates；however，a gradually increasing trend occurred after the peak runoff rate for most of runoff events. While NO +4 concentrations mainly manifested as violent fluctuation，which were characterized as a high loss concentrations during early stages of runoff and decreased gradually with time. The NO 3 was the main form of N loss at watershed scale. It accounts for 50%~97% of inorganic N loss and depends on various rain. The farmland-dominated watershed would lead to high amount of nitrogen loss. In contrast，the single woodland-dominated watershed tends to increase the loss of ammonium nitrogen. The watershed with various landscape structures could decrease nitrogen loss by runoff. In addition，nitrogen loss has no scale dependence effects when watershed area varies from 1.1 to 2.0hm2 and even to 10.8hm2
. It is suggested that the NO -3 applied should be reduced in this region. When it is unavoidable，small quantity，repeated and timely applications is advocated. |
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