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黄土高原不同降雨强度下生物土壤结皮对坡面流水动力参数的影响
Effects of Biological Soil Crust on Dynamic Parameters of Slope Flow Under Different Rainfall Intensities in the Loess Plateau
【摘要】 [目的]明确不同降雨强度下生物土壤结皮对坡面流水动力参数的影响,进一步评估生物结皮的水土保持功能。[方法]以黄土高原典型藻结皮和苔藓结皮为研究对象,系统研究了60,90,120,150,200 mm/h雨强下生物土壤结皮对坡面流水动力参数的影响。[结果](1)所有雨强下藻结皮和苔藓结皮坡面流流型均为层流,除200 mm/h雨强下苔藓结皮坡面流为急流外,所有雨强下藻结皮和苔藓结皮流态均为急流;(2)藻结皮在90,120,150,200 mm/h雨强下流速、径流量和径流系数分别是60 mm/h雨强的1.76~3.9,4.89~9.26,3.91~4.13倍,苔藓结皮则为1.34~2.56,5.86~13.81,2.46~4.26倍,流速和径流量均随雨强呈线性函数增加(R~2≥0.85,p<0.01),径流系数呈幂函数增加(R~2≥0.49,p<0.05);(3) 60,90,120,150,200 mm/h雨强下藻结皮阻力系数和曼宁糙率系数变化范围分别为0.15~0.74,0.01~0.03,苔藓结皮则为0.82~3.02,0.03~0.06,阻力系数和曼宁系数均随雨强成指数函数降低(R~2≥0.47,p<0.05);(4)降雨强度与生物结皮种类均与坡面水动力参数显著相关。所有雨强下,藻结皮坡面流速显著高于苔藓结皮(11.77%~118.31%),而径流量、阻力系数和曼宁系数则低于苔藓结皮(1.41%~37.55%,53.32%~90.42%和38.08%~73.00%)。[结论]生物结皮对黄土高原坡面流水动力参数有较大影响,未来应加强生物结皮对坡面流水动力参数的研究。研究对于黄土高原生物土壤结皮坡面流水动力参数特征具有重要意义,可对精准侵蚀预报模型提供理论支撑。
【Abstract】 [Objective] The aims of this study are to elucidate the vital role of biological soil crust in slope flow dynamic parameters under different rainfall intensities, and evaluate the soil and water conservation function of biological soil crust. [Methods] Cyanobacteria and moss crusts were chosen as the typical model crusts to assess the effects of biological soil crusts on slope flow dynamic parameters under rainfall intensities of 60 mm/h, 90 mm/h, 120 mm/h, 150 mm/h, and 200 mm/h, respectively. [Results](1) Under all the tested rain intensifications, both flow patterns on the slopes with the Cyanobacteria and the moss crust present a laminar type. In addition, the flow patterns on the slopes with Cyanobacteria and moss crust show a rapid type under all tested rain intensities except for rapid flow type on the slope with the bryophyte crust flow under 200 mm/h rain intensification.(2) At 90, 120, 150 and 200 mm/h rainfall intensity, the velocity, runoff, and runoff coefficient on the slope with the Cyanobacteria under other rain intensities are 1.76~3.9, 4.89~9.26, and 3.91~4.13 times of those under the rainfall intensity of 60 mm/h, respectively, while the same evaluation is applied to the moss crust, the parameters are 1.34~2.56, 5.86~13.81, and 2.46~4.26, respectively. Additionally, the flow velocity and runoff increase linearly with the rainfall intensity(R~2≥0.85, p<0.01), and the runoff coefficient increases linearly with the power function(R~2≥0.49, p<0.05).(3) Under the rainfall intensities of 60, 90, 120, 150 and 200 mm/h, the drag coefficient and Manning roughness coefficient on the slope with Cyanobacteria vary in the range of 0.15 to 0.74 and 0.01 to 0.03, respectively, while the drag coefficient and manning roughness coefficient the slope with moss vary from 0.82 to 3.02 and 0.03 to 0.06, respectively. With increase of rainfall intensity, the drag coefficient and Manning coefficient decrease exponentially(R~2≥0.47, p<0.05).(4) Rainfall intensity and biological crusts are strongly correlated with slope hydrodynamic parameters. Under all the tested rainfall intensities, the velocity of Cyanobacteria is much higher than that of moss crust(11.77%~118.31%), while the runoff, drag coefficient, and Manning coefficient of algal crust are significantly lower than those of moss crust(1.41%~37.55%, 53.32%~90.42%, and 38.08%~73.00%). [Conclusion] The results of this study are of great significance to the characteristics of flow dynamic parameters on the slope with biological soil crust on the Loess Plateau, and provide the theoretical support for the accurate erosion prediction model.
【Key words】 Cyanobacteria; mossy crust; rainfall intensity; hydrodynamics; Loess Plateau;
- 【文献出处】 水土保持研究 ,Research of Soil and Water Conservation , 编辑部邮箱 ,2024年03期
- 【分类号】S157
- 【下载频次】126