于桥水库流域地表水中水溶性氮季节变化特征

Seasonal change of solvable nitrogen in surface water of Yuqiao reservoir basin

通过对于桥水库流域1999~2000年枯水期(6月)、丰水期(8月)和平水期(10月)地表水体采样分析,研究了地表水中水溶性氮浓度(硝态氮+氨氮)的季节动态变化特征,可以分为以下6种变化模式.I平水期>丰水期>枯水期;II丰水期>平水期>枯水期;III平水期>枯水期>丰水期;IV丰水期>枯水期>平水期;V枯水期>平水期>丰水期;VI枯水期>丰水期>平水期.干旱年份,不同控制小区地表水中水溶性氮浓度的季节变化比较简单,主要表现出I、II、III 3种变化特征;而平水年份地表水中水溶性氮浓度的季节变化比较复杂,包括I、II、III、IV、V、VI 6种变化模式.这种变化特征主要与控制小区地形、土地利用、地表径流和水系特征有关.

The seasonal change characteristics of solvable nitrogen (nitrate and ammonia nitrogen) concentration in the surface water of Yuqiao reservoir basin, were studied by water sample analysis in low-flow period (June), high-flow period (August) and mean-flow period (October) from 1999 to 2000; and it could be divided into following change models: ①mean-flow period > high-flow period > low-flow period; ②high-flow period > mean flow period > low flow period; ③mean-flow period > low-flow period > high-flow period; ④high-flow period > low-flow period > mean-flow period; ⑤low-flow period > mean-flow period > high-flow period; ⑥low-flow period > high-flow period > mean-flow period. It was found that seasonal change of solvable nitrogen concentration was relatively simple in the surface water regarding different controlled areas in the dry year, expressing mainly the change characteristics of ①, ② and ③ as mentioned above; while it was relatively complex during mean-flow year, including ①~⑥ six models. These change characteristics were related mainly to the topography, land use, surface run-off and drainage characteristics of the controlled areas.