农牧业交错区禾本植被过滤带过滤效果模拟

Simulation the Filtering Effect of Grass Vegetation Filter Strip in Agro-pastoral Ecotone

为探究内蒙古岱海流域农牧业交错区禾本植被过滤带截流减沙效果对入流强度和泥沙含量的响应。在内蒙古中部农牧业交错区的巨宝庄镇试验区设置不同来水流量(0.77,0.9,1.08,1.26 L/s)和泥沙含量(0.04,0.06,0.08,0.1 g/cm^(3)),共计16个处理,研究不同来水条件下植被过滤带的截流减沙效果。基于VFSMOD模型模拟,并优化该地区植被过滤带参数。结果表明:VFSMOD模型可以较好地对冰草、羊草混播植被过滤带泥沙和径流出流量进行模拟。植被过滤带前期对径流拦蓄主要依靠入渗,入流强度增加缩短了径流出流时间,0.77 L/s入流强度水流经过过滤带后出流时间分别为0.9,1.08,1.26 L/s入流强度下出流时间的1.3,1.6,1.6倍。0.77,0.9 L/s入流强度下泥沙出流量趋于稳定,而1.08,1.26 L/s入流强度下泥沙出流量随时间推移而增加。入流泥沙含量和入流强度对出流泥沙量影响显著(p<0.05)。

In order to explore the response of interception and sediment reduction effect of grass-based vegetation filter strip to incoming water flow and sediment concentration,different incoming water flows(0.77,0.9,1.08,1.26 L/s)and sediment concentrations(0.04,0.06,0.08,0.1 g/cm^(3))were set up in a agro-pastoral ecotone in the central Inner Mongolia.The effect of river closure and sediment reduction of stem spacing in vegetation filter strip under different inflow conditions was studied.Based on VFSMOD model simulation,the relevant parameters of vegetation filter strip in this area were optimized.The results showed that VFSMOD model could well predict the sediment and runoff yield in the filter strip of agropyron cristatum and Leymus chinensis.The runoff interception of vegetation in the early stage mainly depended on soil infiltration,and the runoff outflow time was shortened with the increases of inflow intensities.The outflow time of 0.77 L/s inflow intensity was 1.3,1.6 and 1.6 times of 0.9,1.08 and 1.26 L/s.The sediment discharge under 0.77 and 0.9 L/s tended to be stable,while the 1.08 and 1.26 L/s increased with time.The inflow sediment content and inflow intensity have significant influence on the outflow sediment quantity(p<0.05).