紫色丘陵区坡耕地生物埂土壤抗冲性研究

本文以紫色丘陵区坡耕地4种典型生物埂为研究对象，采用原状土冲刷水槽法系统分析各种生物埂的土壤抗冲性。结果表明:（1）各种生物埂径流含沙量随着冲刷时间的继续出现“先急剧减小后平稳减小直至稳定”的变化趋势。在冲刷0~3 min，各生物埂土壤的径流含沙量均较大，随后径流含沙量平稳变化并趋于稳定。（2）生物埂抗冲刷过程可划分为快速冲刷阶段（0~3 min）、慢速冲刷阶段（3~20 min）和平稳冲刷阶段（20~28 min）3个阶段。生物埂土壤抗冲性随着冲刷时间的增长而不断增强，两者之间可用幂函数表示，其R²值在0.848 7~0.989 9。（3）各种生物埂土壤抗冲性随着坡度的增大而降低，两者关系达到极显著水平（R²=0.790 7，N=12，p < 0.001），可用幂函数表示。研究结果可为紫色丘陵区坡耕地生物埂措施合理布置及其稳定性评价提供科学依据。

Study on the Soil Anti-scouribility of Bio-embankment on Slope Farmland in the Purple Hilly Area

Taking 4 types of bio-embankment on slope farmland in Purple Hilly area as the research sites, we thoroughly studied the soil anti-scouribility of bio-embankments with the method of undisturbed-soil trough scouring. The results showed that:(1) the runoff sediment concentrations for all bio-embankments presented the trend in which they first decreased rapidly and then decreased stably until stable state. The runoff sediment concentrations for bio-embankments were greater in 0~3 min of scouring time, and then varied smoothly and stabilized; (2) soil scouring process for bio-embankments could be divided into rapid erosion (0~3 min), slow erosion (3~20 min) and steady erosion (20~28 min). The soil anti-scouribility of bio-embankments enhanced with the increase of scouring time and followed the power function of scouring time, their determination coefficients(R²) varied from 0.848 7 to 0.989 9; (3) the soil anti-scouribility of bio-embankments reduced with the increase of the slope gradients, meanwhile, there was a mighty prominent positive correlation (R²=0.687 7,N=21,p < 0.001) between them and could be described by a power equation. The research results could provide scientific basis for arrangement of the bio-embankment measures and the stability evaluation of bio-embankments on slope farmland in the Purple Hilly area.