等高反坡阶对昆明市松华坝水源区坡耕地氮、磷流失的影响

Effects of Contour Reverse-slope Terrace on Nitrogen and Phosphorus Loss in Sloping Farmland in the Water Resource Area of Songhua Dam in Kunming City

选取昆明市松华坝水源区典型小流域——迤者小流域为试验区,通过布设标准径流小区,在2009—2015年对坡耕地产流产沙及氮、磷流失情况进行长期的野外观测研究,从年际尺度上来探讨等高反坡阶对于坡耕地产流产沙及氮、磷等养分流失的影响。结果表明:等高反坡阶对于径流和泥沙的削减效果均较为明显,年平均减流率为50.64%,年平均减沙率74.99%,减沙率显著大于减流率;等高反坡阶对于径流和泥沙中氮、磷均有较为明显的削减效果,平均每年可以削减68.75%的氮流失和82.16%的磷流失,其中对径流中总氮和泥沙中全氮年削减率分别达到59.51%和76.43%,对径流中总磷和泥沙中全磷年削减率分别达到64.22%和83.73%。

To study the influence of contour reverse-slope terrace on runoff and sediment production,nitrogen and phosphorus loss in sloping farmland,the loss of runoff,sediment,nitrogen and phosphorus of sloping farmland were monitored from 2009 to 2015 through conducting the standard runoff plots in a typical Yizhe small watershed in Water Source Area of Songhua Dam in Kunming City.The results showed that the reduction effect of contour reverse-slope terrace on runoff and sediment was significant,the annual average reduction rate of runoff was 50.64% and the annual average reduction rate of sediment was 74.99%,the latter was significantly greater than the former.The reduction effect of contour reverse-slope terrace on nitrogen,phosphorus in runoff and sediment was significant,it reduced 68.75%of nitrogen loss and 82.16%of phosphorus loss every year,the annual reduction rates of total nitrogen in runoff and in sediment were 59.51% and 76.43%respectively,and the values for total phosphorus were 64.22% and 83.73%,respectively.