等高反坡阶对坡耕地产流产沙和氮磷迁移的作用研究

Study on Contour Reverse-slope Terrace Controlling Soil and Water Loss and Nitrogen and Phosphorus Transfer in the Sloping Farmland

在云南抚仙湖尖山河典型小流域,建立标准径流场并挖设等高反坡阶,采用野外田间试验定点监测的方法,以烤烟坡耕地为研究对象,从水平和垂直两个方向研究2007—2008年氮磷的迁移特征。结果表明:(1)等高反坡阶作用下,坡耕地径流控制率和土壤侵蚀控制率分别为61.90%和77.40%,雨季地表径流产生次数减少18次,次降雨下径流控制率为71.27%,土壤侵蚀控制率为84.13%,等高反坡阶对土壤侵蚀量的控制效果较好;(2)地表径流总氮、硝态氮和总磷迁移通量控制率分别为51.04%,45.77%和57.40%,径流泥沙全氮迁移通量较原状坡面减少了81.10%,碱解氮迁移通量较原状坡面减少了90.93%,全磷迁移通量较原状坡面减少了92.37%,速效磷迁移通量较原状坡面减少了88.00%;(3)坡面0—110cm内壤中流总氮浓度与土壤深度之间无显著关系,阶面0—200cm内总氮浓度与土壤深度有明显的关系,0—50cm等高反坡阶阶面总氮浓度明显增加,是原状坡面的1.03～2.19倍,壤中流总氮浓度在0—50cm土层对等高反坡阶响应较高;等高反坡阶措施增加或者削减坡耕地氮磷含量,且在各土层深度间有差异。

An experiment was conducted on a slope cropland in Jianshan River basin, a typical catchment in the area of Fuxian Lake, the contour reverse-slope terrace was built in the typical catchment area of the tobacco field. The dynamic characteristics of nitrogen/phosphorus horizontal and vertical transfer in the sloping farmland from 2007 to 2008 were monitored under the condition of natural rainfall. The results showed that： （1） under the function of the contour reverse-slope terrace, it clearly reduced about 61.9% of the surface runoff and decreased 77.4% of soil erosion rate, and the events of erosion were reduced by 18 events, in the single rainfall event, the runoff and soil erosion control rate was 71.27% and 84.13%, respectively, the latter one has better function; （2） the control rates of transfer flux of TN, NO3^- -N and TP in the runoff were 51.04%, 45.77% and 57.40%, respectively, the control rates of transfer flux in the runoff soil TN, hydrolysis N,TPandavailable P were 81.10%, 90.93%, 92.37% and 88.00%; （3） there was no difference between the TN concentration and the soil deep in the soil layer from 0 to 110 cm of sloping land, but it was different in the soil layer from 0 to 200 cm in the level terrace surface, the TN concentration increased in the soil layer from 0 to 50 cm in the level terrace surface, it was 1.03-2.19 times of sloping farmland, the total nitrogen concentration in the soil deep of 0-50 cm has a high reaction to the contour reverse-slope terrace; under the condition of different rainfall intensity and different fertilizer levels, there was difference betweennitrogen and phosphorus transfer concentrations in the different soil layers, this measure can reduce or increase the transfer concentration.