东北黑土区不同坡段等间距植物篱减流减沙特征

Characteristics of Runoff and Sediment Reduction by Equidistant Hedgerows at Different Slope Sections in Northeast Black Soil Area

植物篱作为一种有效的水土保持措施,带间距是其配置的关键参数,当前大部分植物篱布设时采用等间距设计,但不同坡段等间距植物篱的作用效果如何尚不明确。以东北黑土区不同坡段等间距植物篱为研究对象,通过含沙径流冲刷试验,模拟不同坡段等间距植物篱在坡度5°,雨强100 mm/h降雨条件下的产流产沙过程。结果表明:与裸地对照相比,各坡段植物篱能够阻延坡面径流,且随坡段的下移,滞后时间逐渐缩短;各坡段植物篱产流、产沙速率在时间尺度上表现基本一致,在上、中坡段植物篱坡面相对平稳,下坡段植物篱坡面后期呈明显波动,其变化趋势与坡面侵蚀形态密切相关,且整体均小于对照坡面;不同坡段植物篱减流效益为5.40%~10.16%、减沙效益为51.90%~75.72%,尽管有较好的减沙作用,但下坡段植物篱坡面的侵蚀模数已达到259.96 t/km^2,超过东北黑土区允许土壤流失量。可见,等间距植物篱需设计改进后,方可应用于东北黑土区。研究结果为东北黑土区植物篱设计提供重要科学依据。

Hedgerow is effective in soil and water conservation, and the distance between hedgerows is the key parameter for their allocation. At present, the equidistance is often designed in the most hedgerow arrangements, but the effect of equidistant hedgerows at different slope sections is not clear. Equidistant hedgerows at different slope sections in the northeast black soil region were selected as the object. A runoff erosion experiment with sediment was carried out to simulate the runoff sediment yield process of hedgerows with equal spacing in different slope segments under the condition of 5° slope, 100 mm/h rain intensity. The results showed that: Compared with the control of bare land, hedgerows in all slope segments could prevent slope runoff, and the lag time was shortened gradually with the downward slope segments. The runoff and sediment yield of hedgerows in different slope sections were basically consistent on time scales. The upper and middle slopes were relatively stable, and the lower slopes showed obvious fluctuation at the later stage. The changing trend was closely related to the erosion morphology in the slope, and the overall trend was smaller than that of the control. Hedgerows in the different slope sections reduced the runoff by 5.40%~ 10.16%, and reduced sediment by 51.90%~ 75.72%. Although it had a positive effect on runoff and sediment reduction, the erosion module in the lower slope reached 259.96 t/km^2, exceeding the soil loss tolerance of the northeast black soil area. It could be concluded that the equidistant hedgerow should be improved for its application in the northeast black soil area. This study could provide an important scientific basis for the hedgerow design in the northeast black soil area.