农田排水策略对氮素流失影响试验研究

通过测筒试验模拟了排水间隔时间、强度和地下水位对农田地下排水中氮素流失的影响规律。结果表明,相同模拟条件下,排水间隔时间的延长可减少排水量和降低总氮流失率,以间隔3～5d减少最为明显;间隔3、5和7d排水总氮流失量分别较间隔1d减少了45.5%、81.1%和100%;排水强度的降低可以减少氮素的流失,出流中氨氮质量浓度递减并趋于稳定,硝态氮质量浓度先上升后减少,相对于2mm/d的排水强度,4、6和8mm/d排水强度下总氮流失量分别增加了126.8%、264.8%和401%。地下水位的升高可明显减少总排水量和总氮流失量,40cm和60cm地下控制水位比80cm水位排水总氮量分别减少63.2%和40.9%。

Effects of Farmland Drainage Strategy on Nitrogen Loss

Effects of the interval time,intensity and groundwater level of drainage on nitrogen loss in farmland subsurface drainage were simulated.The results showed that the extension of drainage interval time would reduce drainage outflow and TN loss in the same simulated conditions,and the interval time of 3～5 ddecreased the most obviously.Compared to the interval time of 1d,TN losses of the interval time of drainage 3d,5d,and 7 dreduced by 45.5%,81.1% and 100% respectively.The reduction of drainage intensity could reduce the loss of nitrogen.The NH4+-N concentration of outflow decreased and trended to be stable finally,and the concentration of NO3--N increased first and then decreased.TN loss of drainage intensity of 4mm/d,6mm/d and 8mm/d increased by 126.8%,264.8% and 401%respectively compared to drainage intensity of 2mm/d.The rise of groundwater level could significantly reduce the outflow and TN loss.TN loss under ground water level of 40cm and 60cm decreased by 63.2% and 40.9%respectively compared to ground water level of 80cm.