模拟降雨条件下坡地氮流失特征研究

通过人工模拟降雨研究了5种雨强对紫色土坡地氮径流损失的影响.结果发现,(1)随着雨强的增大,地表径流占总径流量的比例上升.(2)径流中氮的流失是随着雨强的增加而逐渐降低的.其中铵氮和硝态氮作为可溶性氮,它们的流失浓度随着时间的变化有一定的规律性,主要表现为径流前期浓度较高,随着降雨时间的延长,浓度趋于稳定或减小,后期则又有所上升.(3)地表径流量对硝态氮的流失量起决定性作用,而浓度对壤中流流失量起主导作用.小雨强下紫色土坡地径流硝态氮流失以壤中流为主,随着雨强的增大,地表径流流失量的贡献率越发明显.

Characteristics of Nitrogen Loss on Slope Under Simulated Rainfall

Nitrogen loss on the slope with purple soil is studied by simulated rainfall of 5 rainfall intensities. The following conclusions can be drawn: (1) Proportion of surface runoff is increased wi h rainfall intensity increasing. (2) Nitrogen loss is reduced gradually with the rainfall intensity increasing. Ammonium nitrogen and nitric nitrogen are the soluble nitrogen. Their density is high in the initial time, tends to be stable or decrease with rainfall continuing, and increases in the later period. (3) Surface runoff plays a key role in nitric nitrogen loss and nitric nitrogen density plays a leading role in interflow loss. Soil nitric nit rogen loss is dominated at small rainfall intensity, but surface nitric nitrogen loss is increased with increased rainfall intensity.