次暴雨下灌区排水河道氮素迁移转化试验研究

以江苏溧水县岔河为研究对象,比较了在降雨条件下农田排水口与近农田河道中氮素浓度的差异,分析了TN、NH4+-N和NO3--N在不同生态护坡河道中时空变化规律。结果表明,产流初期农田排水出口氮素浓度较高,此后呈下降趋势,而河道中不同形态氮素浓度大多先于径流达到峰值,TN、NH4+-N浓度均呈现随降雨径流先增大后减小的趋势,NO3--N变化趋势比较平缓。且可溶性氮是氮素流失主要形态。TN、NH4+-N和NO3--N浓度在空间上也有其变化规律,由于河道生态系统的净化功能使得河道断面浓度明显低于农田排水出口,并且经过生态整治的河道在降雨径流条件下对氮素有较好的截留作用。而不同治理模式的河段对氮素的截留效果有明显差异,采用自然生态治理模式和植生型抛石护岸的河段对氮的截留效果要优于采用浆砌石护坡的河段。

Transference and Transformation of Nitrogen in A Drainage Cannel Using Different Ecological Slope in One Rainstorm Event

This paper researched the temporal-spatial variation rule of nitrogen in Cha he stream which using different ecological slope and compared the discrepancy of concentration of nitrogen between farmland drainage and watercourse water in one rainstorm.Results show that concentration of nitrogen of farmland drainage hold a high level in the runoff initiation time,Later,they decreased.But in watercourse near farmlands,the concentration of nitrogen reach the peak value earlier than the runoff and then decreases gradually and the concentration of NO-3-N shows no appreciable change.Soluble nitrogen was the predominant nitrogen.Spatial distribution of TN、NH+4-N and NO-3-N concentration indicates that a stream with different ecological characteristics slope can efficiently intercept and remove nitrogen.The bank slope using natural type,engineering project and natural type is superior to concrete banks in reducing agricultural pollutant.