公路石质边坡喷播绿化植被的降雨、灌溉水分分配特征

为提高边坡水分利用效率,通过客土喷播的方式人工模拟公路石质边坡,观测坡体表面土壤裂隙发育情况及地表径流、底层渗漏及土壤储存等水分分配过程,分析灌溉及降雨条件下的坡面水分分配特征。结果表明:坡体表面形成的土壤裂隙分布不均匀,呈现由坡顶至坡底逐渐减少的趋势,且阳坡不同坡位的裂隙总面积均大于阴坡;不同坡向坡体灌溉水分分配特征存在一定差异,阳坡0.02%的水分通过坡上植被蒸散消耗,7.00%的灌溉用水沿着坡面运动形成地表径流,10.00%的灌溉水分转化为底层渗漏量,53.00%的灌溉水分被土壤储存;阴坡植物蒸散、地表径流、底层渗漏及土壤储存水分的比例分别为0.01%,35.00%,0.25%和39.00%;随着植被覆盖度的增加,灌溉产生的地表径流减少,土壤储存水分增大;降雨强度对坡面水分分配特征具有显著影响,在小雨强条件下,约95.00%的降雨被土壤储存,底层渗漏量、地表径流分别在中雨强及大雨强条件下达到最大值;在不同雨强下,阴坡的地表径流是阳坡的1.1~3.0倍,阳坡的底层渗漏量大于阴坡且阳坡较阴坡具有更高的水分利用效率。该结果可为公路边坡植被恢复过程中水分的有效利用提供依据。

Water Distribution Characteristics of Highway Slope Greening Under Irrigation and Rainfall Conditions

To improve the water use efficiency of slope, cracks on slope, surface runoff, bottom leakage and soil storage were measured by the method of soil spraying, and the water distribution on slope was analyzed under irrigation and rainfall conditions. The results showed that the distribution of soil cracks on slope was not uniform, and the soil cracks tended to decrease from the top slope to the bottom. The total area of cracks on sunny slope was greater than that on the shady slope. Water distribution characteristics under irrigation condition varied from different slope directions. On the sunny slope, 0.02% of the water was dissipated through evapotranspiration, 7.00% of the irrigation water moved along the slope forming surface runoff, 10.00% of water turned into the bottom leakage and 53.00% of the irrigation water was stored in soil. The ratios of evapotranspiration, surface runoff, bottom leakage and soil moisture were 0.01%, 35.00%, 0.25% and 39.00% on the shady slope respectively. With the growth of vegetation coverage, the surface runoff formed by irrigation decreased and the soil water storage increased. Rainfall intensity had a significant effect on water distribution characteristics. About 95.00% of the rainfall was stored in the soil under the light rain, and the amount of bottom leakage and surface runoff reached the maximum under moderate and heavy rain conditions respectively. With various rainfall intensities, surface runoff on shady slopes was 1.1~3.0 times higher than sunny slopes. The sunny slopes had a higher water use efficiency with greater amount of bottom leakage than the shady slopes. These results could provide a scientific reference for the effective use of water in the highway slope greening.