%0 Journal Article
%T Comparison of Nitrogen Loss via Surface Runoff from Two Agricultural Catchments in Semi-arid North China<br>华北半干旱区2个农业流域地表氮素流失特征的对比研究
%A LU Hai-ming
%A YIN Cheng-qing
%A WANG Xia-hui
%A ZOU Ying
%A <br>陆海明
%A 尹澄清
%A 王夏晖
%A 邹鹰
%J 环境科学
%D 2008
%I 
%X Nitrogen loss characteristics via surface runoff from two typical agricultural catchments into Yuqiao Reservoir-the important drinking water source area for Tianjin city in semi-arid North China were investigated through two-year in-situ monitoring and indoor chemical analysis. The results showed that annual nitrogen export mainly concentrated in the rainy period between June to September. About 41% of the annual water output and 52% of the annual total nitrogen output took place in two rainfall events with rainfall> 60 mm in Taohuasi catchment (T catchment), while the distribution of water and nitrogen export among various rainfalls in Caogezhuang catchment (C catchment) was smooth. The rainfall thresholds for the appearance of water and nitrogen export from the outlet of T catchment and C catchment were 20 mm and 10 mm. The mean annual runoff coefficients of C and T catchments were 0.013 2 and 0.001 6, respectively. The mean annual total nitrogen exports from C catchment and T catchment were 1.048 kg·(hm2·a)-1 and 0.158 kg·(hm2·a)-1 respectively. The difference of micro-topography, landscape pattern and hydrological pathway between two catchments could explain the nitrogen export gap. Micro-topographical features created by long-term anthropological disturbance decrease the runoff generation ability. The distance between nitrogen source area and the outlet in T catchment was around 1 500 m, while such distance in C catchment was just around 200 m. The short distance added the nitrogen export risk via surface runoff. Road-type hydrological pathway in C catchment could transfer nitrogen into the receiving water via surface runoff directly, while nitrogen could be detained within the pathway by many sink structures such as small stones, vegetated buffer strip and dry ponds in T catchment.
%K North China
%K agricultural catchment
%K nitrogen
%K surface runoff
%K transfer
%K landscape pattern
%K hydrological pathway<br>华北
%K 农业流域
%K 氮
%K 地表径流
%K 迁移
%K 景观格局
%K 迁移廊道
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=3FF3ABA7486768130C3FF830376F43B398E0C97F0FF2DD53&cid=A7CA601309F5FED03C078BCE383971DC&jid=64CD0AA99DD39F69401C615B85F123EF&aid=8243BA085622EE07F4D1B3D74BEEEDD6&yid=67289AFF6305E306&vid=771469D9D58C34FF&iid=F3090AE9B60B7ED1&sid=1859BB4E70D588F0&eid=6A318E74358630E6&journal_id=0250-3301&journal_name=环境科学&referenced_num=2&reference_num=19