典型黑土区陡坡植草水土流失防治效果研究

目的]研究陡坡生物防治与影响因素的变化关系,为侵蚀沟治理、水土保持植被措施配置等决策提供科学依据。方法]设置2个坡度,7种草本植被配置模式,于2018年6—9月开展了自然小区水土流失监测。结果] 1∶1.5和1∶1.2坡比边坡草本建植当年分别较裸地平均减流27%和26%,减沙52%和21%,坡度由34°增加到40°,地表径流虽未增加,但土壤侵蚀量明显增加;影响产流产沙的降雨因子主要有雨量,I_(30),E,EI_(30),坡度变陡,相关性增强;建植草无芒雀麦和紫花苜蓿混播减流减沙效果最好,紫花苜蓿、无芒雀麦、早熟禾3种草种混播减流效果优于单播;1∶1.2坡比边坡随着植被盖度的增加减沙效果逐渐增强,且在植被盖度大于50%时减沙效果接近1∶1.5坡比边坡。结论]在无芒雀麦和紫花苜蓿混播草本配置下,1∶1.2坡比削坡在侵蚀沟治理时可采用,能减少20%的削坡占地面积。

Effects of Artificial Grass on Soil Erosion Control on Steep Slope in Typical Mollisols Area

Objective] The relationship between biological measures and their influence factors on soil erosion on steep slopes were studied, in order to provide theoretical basis for gully control and vegetation measure allocation of soil and water conservation.Methods] Two slope gradients and seven herb vegetation models were set up by small plots, and runoffs and soil losses of the plots were monitored from June to September in 2018.Results] Compared to bare plot, the average runoff at 1:1.5 and 1:1.2 ratio slope with herb vegetation was declined by 27% and 26%, and the average soil loss reduced by 52% and 21%, respectively. As the slope steepness increased from 34° to 40°, runoff didn''t show significant increase, but the amount of soil loss increased markedly. The dominant rainfall factors influencing runoff and sediment were precipitation, I₃₀, E and EI₃₀. The correlations among runoff, sediment and rainfall increased with the increase of slope steepness. The mixture of Bromus inermis and Medicago sativa L had the best effect on reducing runoff and sediment. The soil erosion control effect of mixed sowing of Bromus inermis, Medicago sativa L and Poa annua L was better than that of single sowing. With the increase of vegetation coverage, the sediment reduction effect of 1:1.2 slope was gradually enhanced, and when the vegetation coverage was more than 50%, the effect of sediment reduction was close to 1:1.5 slope.Conclusion] Under the mixed herb configuration of Bromus inermis and Medicago sativa L. the 1:1.2 ratio slope could be used for gully erosion control, which could save 20% of the gully slope cutting area.