为了研究黑土区坡耕地土壤养分硝态氮径流及壤中流迁移规律,开展了野外原位监测试验,揭示了玉米根系及犁底层影响下径流及壤中流驱动硝态氮迁移特征。结果 表明:降雨特征对黑土区坡耕地地表径流影响显著,径流过程表现出多变的历程特点。不同降雨特征条件下,地表径流硝态氮迁移呈现相同的上升、下降及平缓3个阶段,约4 min上升段达到峰值开始下降,12 min以后趋于平缓。黑土区坡耕地不同降雨特征条件下壤中流增长及消退变化历程一致,快速增长阶段历时约6 min,累积出流量9.0 ml/m,快速消退阶段历时约14 min,累积出流量21.2 ml/m,中间稳定阶段壤中流径流强度为6 ml/(min·m)。壤中流稳定阶段硝态氮迁移强度约为0.09 mg/(min·m),上升及消退阶段累积迁移量平均为0.20,0.25 mg/m。上升、消退段壤中流流量(硝态氮)之和加壤中流历时与壤中流(硝态氮)峰值强度乘积,可得到壤中流(硝态氮)出流总量,两次计算与实测壤中流流量(硝态氮)误差为0.7,2.4%(1.2,11.8%),精度较高,说明计算方法可行。上升、消退段壤中流流量(硝态氮)之和加壤中流历时与壤中流(硝态氮)峰值强度乘积,可得到壤中流(硝态氮)出流总量,两次计算与实测壤中流流量(硝态氮)误差为0.7,2.4%(1.2,11.8%),精度较高,说明计算方法可行。
In order to study migration of soil nitrate nitrogen in runoff and interflow in sloping farmland in black soil area, field in-situ monitoring experiments were carried out to reveal the characteristics of nitrate nitrogen migration driven by runoff and interflow under the influence of maize root system and plough pan. The results show that the rainfall characteristics have a significant effect on the surface runoff of sloping farmland in black soil area, and the runoff process shows a variable course; under different rainfall conditions, the nitrate nitrogen migration in surface runoff presented the same three stages of rise, fall and gentleness; the rise stage reached its peak after about 4 minutes and began to decline, and it tended to be gentle after 12 minutes; under different rainfall characteristics of sloping farmland in the black soil area, the growth and regression processes of interflow were the same; the rapid growth stage lasted about 6 minutes, with the cumulative flow rate of 9.0 ml/m, and the rapid regression stage lasted about 14 minutes, with the cumulative flow rate of 21.2 ml/m; in the intermediate stable stage, the runoff intensity of interflow was 6 ml/(min·m), the nitrate migration intensity was about 0.09 mg/(min·m)in the stable stage of soil flow, and the average cumulative migration was 0.20 mg/m and 0.25 mg/m in the rising and subsiding stages; the total interflow(nitrate)was equal to the sum of the flows in the rise and fall sections plus the product of interflow duration and the peak of interflow(nitrate). The errors between the two calculated and the measured interflow(nitrate)were 0.7, 2.4%(1.2, 11.8%), with high accuracy, indicating that the calculation method was feasible.
