草带措施对坡耕地产流产沙和氮磷迁移的控制作用

植被在坡面的位置对坡面保持水土的作用是不同的。动态监测澄江抚仙湖一级支流尖山河小流域坡耕地降雨-径流过程及水土流失量,研究草带措施对云南红壤坡耕地产流产沙和氮磷迁移的削减作用。结果表明:草带调控处理下雨季降雨量、总产流次数、径流深和土壤侵蚀量较原状坡面明显减少,次降雨下,宽草带的径流控制率和土壤侵蚀控制率分别为79.19%和64.55%,窄草带的径流控制率和土壤侵蚀控制率分别为85.15%和73.77%,坡耕地土壤侵蚀量变异系数>径流深变异系数>降雨量变异系数,原状坡面变异系数间增幅差异为31.42%,宽草带调控措施作用下变异系数间增幅差异为20.37%,窄草带调控措施作用下变异系数间增幅差异为19.11%,窄草带对坡耕地径流和泥沙的调控能力更强;宽草带和窄草带2种草带作用下,径流氮磷迁移浓度差异不显著,较原状坡面相比,草带措施明显控制氮磷迁移通量,径流总氮迁移通量控制率分别为81.23%和81.68%,铵态氮迁移通量控制率为78.25%和59.50%,总磷迁移通量控制率为71.36%和82.03%;径流泥沙速效养分含量明显增加,较原状坡面相比,草带措施能明显控制径流泥沙氮磷迁移通量,且径流泥沙氮磷迁移控制率较径流氮磷迁移控制率高,径流泥沙全氮迁移通量控制率为98.43%和94.30%,碱解氮迁移通量控制率为98.43%和93.10%,全磷迁移通量控制率为96.43%和89.77%,速效磷迁移通量控制率为90.34%和57.43%。

Functions of Grass Strip Treasures Controlling Runoff and Sediment Yields,Nitrogen and Phosphorus Transfer in the Sloping Farmland

Vegetation at different slope positions has different roles in soil and water conservation.A dynamic monitoring on the rainfall-runoff process and soil and water erosion of the sloping farmland in the watershed of Jianshan river,which is the first tributary of Fuxian lake,Chengjiang,aimed to study the effects of grass strip treasures reducing the runoff and sediment and nitrogen and phosphorus transfer in red soil sloping farmland of Yunnan.The results showed that: Grass strip treasures reduced precipitation,runoff frequency,runoff and sediment yield more significantly than that in the undisturbed sloping farmland,in the single rain event,the runoff control rate and soil erosion control rate of wide grass strip was 79.19% and 64.55%,the runoff control rate and soil erosion control rate of narrow grass strip was 85.15% and 73.77%,the variation coefficients of the test parameters for undisturbed sloping farmland and grass strips were in the order of sediment yield >runoff >rainfall,the growth rate of the variation coefficients in the wide grass strip and narrow grass strip was 20.37% and 19.11%,respectively,the latter one had a remarkable effect on controlling runoff and sediment yield in the sloping farmland;there was no significant difference on nitrogen and phosphorus concentration in the runoff between the two grass strip treasures,compare with the undisturbed sloping farmland,the grass strips could clearly reduce the nutrient flux,the control rate of transfer flux of runoff TN,NH+4-N and TP in the wide grass strip and narrow grass strip was 81.23% and 81.68%,78.25% and 59.50%,71.36% and 82.03%;the available nutrients content in the runoff soil was increased under the condition of grass strips,and the grass strip had higher nutrients control rate than the runoff nutrients control rate,the control rate of transfer flux in the runoff soil TN,hydrolysis N,TP and available P in the wide grass strip and narrow grass strip was 98.43% and 94.30%,98.43% and 93.10%,96.43% and 89.77%,90.34% and 57.43%.