植被过滤带模式对内蒙农牧交错区截流减沙的影响及优选

为了提高农牧业交错带禾本植被过滤带截流减沙效果,在内蒙古中部巨宝庄试验基地设置过滤带茎间距(0.9cm、1.2cm、1.7cm)和宽度(3m、6m、9m)2个因素,包括空白对照共10个处理.研究了植被过滤带茎间距和宽度对截流减沙的响应,并运用熵权TOPSIS模型评价了不同植被过滤带模式的综合效益,筛选该地区禾本植被过滤带适宜茎间距和宽度.结果显示,在相同植被过滤带茎间距条件下,增加过滤带宽度显著降低径流与泥沙出流量,过滤带宽度为9m与6m处理比3m处理在过滤带末端平均泥沙含量分别减少了80.97%和60.66%,平均径流量分别降低了62.14%、33.59%,并分别推迟水沙出流时间7min和2min.在相同过滤带宽度下,减少植被茎间距有效提高截流减沙效果,其中过滤带茎间距为0.9cm处理比1.2cm与1.7cm处理在过滤带末端平均泥沙含量分别减少了35.4%和48.28%;平均径流量分别降低了16.5%和18.26%.茎间距与宽度对径流、泥沙拦截量影响极显著,过滤带宽度对径流影响更大,且两者交互作用对泥沙拦截量影响极显著.通过熵权TOPSIS评价得出过滤带宽度为9m,茎间距为0.9cm的禾本植被过滤带模式综合评分最高,经济与截流减沙综合效益最优,研究结果对当地植被过滤带建设有重要指导意义.

Optimization and influence of vegetative filter strip's pattern on reduction of runoff and its sediment in the Inner Mongolia farming-pastoral ecotone

In order to improve the performance of vegetative(grass)filter strips(VFS) decreasing runoff and its sediment in the farming-pastoral ecotone,the experiment was carried out at the Jubaozhuang experimental site in central Inner Mongolia, including three stem spacing (0.9cm, 1.2cm, 1.7cm) and three width (3m, 6m, 9m) of VFS treatments plus one control treatment (no VFS). The response of the reduction of runoff and its sediment on VFS's stem spacing and width were studied, the comprehensive benefits of different treatments were evaluated by the entropy TOPSIS model, and the suitable stem spacing and width of VFS were determined. The results showed that the bigger VFS's width caused to the lower runoff and its sediment discharge under the condition of same VFS's stem spacing. Compared to VFS's width of 3m, the treatments of width of 9m and 6m decreased averagely 62.14% and 33.59% runoff, respectively; 80.97% and 60.66% for sediment, additionally, outflow time was delayed by 7min and 2min. Under the condition of same VFS's width, the decrease of VFS's stem spacing can effectively decreased runoff and its sediment. When VFS's stem spacing was 0.9cm, average sediment quantity at the end of VFS was reduced by 35.4% and 48.28% compared with that of 1.2cm and 1.7cm stem spacing, respectively; 16.5% and 18.26% reduction for runoff. So, the runoff and its sediment can be significantly affected by VFS's stem spacing and width, and there was more significant effects for runoff reduction by VFS's width. Additionally, the highly significant reduction for the sediment by their interaction effects appeared. The optimal VFS pattern with stem spacing of 0.9cm and width of 9m was obtained by TOPSIS, and there was best comprehensive benefits. The results has important guiding significance in both theory and practice for VFS construction.