Slope effect of soil detachment capacity on yellow-soil hillslope
WANG Xinyue1, WANG Bin2,3, WANG Yunqi2,3, AN Xin1, WANG Xiaoping1, WANG Chenfeng1
1. College of Natural Resources and Environment, Northwest A&F University, 712100, Yangling, Shaanxi, China; 2. Three-Gorges Reservoir Area(Chongqing) Forest Ecosystem Research Station, School of Soil and Water Conservation, Beijing Forestry University, 100083, Beijing, China; 3. Three-Gorges Reservoir Area(Chongqing) Forest Ecosystem Research Station, Ministry of Education, School of Soil and Water Conservation, Beijing Forestry University, 100083, Beijing, China
Abstract：[Background] Soil detachment is the initial phase of soil erosion. Quantifying soil detachment capacity is crucial to establish the process-based soil erosion model. There is obvious difference in soil detachment mechanisms between gentle slope and steep slope, but the mechanism of slope effect is still unclear. Thus, the objective of this study is to reveal the slope effect of soil detachment capacity. [Methods] The soil samples from abandoned cropland on yellow soil slope in the upper and middle Yangtze River were selected as research object. The effect of hydrodynamic parameters (i.e., flow rate, flow depth, flow velocity, Darcy-Weisbach resistance coefficient, flow shear stress, stream power, unit stream power and unit energy of water-carrying section and so on) on soil detachment capacity were analyzed by Pearson correlation analysis and regression analysis under different slope gradients (1.75%-48.77%) and flow rates (0.21-2.63 L/s). [Results] 1) The stream power, which represented the flow energy, was the best parameter to describe the soil detachment capacity, followed by the flow shear stress associated with forces. However, the water depth and Darcy-Weisbach resistance coefficient were the worst to describe the soil detachment capacity. 2) Based on the calculation equation of soil detachment capacity of WEPP, the response of soil erodibility and critical shear stress to slope was relatively sensitive and not constant value. The soil erodibility decreased firstly and then increased as the slope gradient increased, and the critical shear stress changed from power function to linear function as the slope gradient increased. This result showed that the constant values of soil erodibility and critical shear stress for previous studies can be extended to different slopes has great limitations. 3) There was obvious slope effect in using the power function of flow shear stress or stream power to characterize soil detachment capacity. The coefficient a1 of flow shear stress changed from increased firstly and then decreased as a quadratic function to decreased as an exponential function with increasing slope gradient, and the maximum value reached at 17.63% of slope. The exponent b1 of flow shear stress showed a quadratic function relationship, which decreased firstly and then increased with the increase of slope gradient, and the slope reached the minimum value at 26.71% of slope. However, the coefficient a2 of stream power decreased as a power function with increasing slope gradient. The exponent b2 of stream power decreased firstly and then increased as a quadratic function, and it reached the minimum value when the slope was 28.10%. [Conclusions] This study illustrated that the results of gentle slopes cannot be directly generalized to steep slopes and reveal the slope effects and its thresholds of soil detachment capacity. The results of the study provide new insights into understanding soil detachment mechanism.
王馨月, 王彬, 王云琦, 安昕, 王小平, 王晨沣. 黄壤坡面土壤分离能力的坡度效应[J]. 中国水土保持科学, 2023, 21(3): 9-16.
WANG Xinyue, WANG Bin, WANG Yunqi, AN Xin, WANG Xiaoping, WANG Chenfeng. Slope effect of soil detachment capacity on yellow-soil hillslope. SSWC, 2023, 21(3): 9-16.
王晨沣, 傅旭东, 张玍, 等. 黄土高原植被作用下黄河数字流域模型坡面侵蚀模块改进[J]. 清华大学学报(自然科学版), 2022, 62(12): 1953. WANG Chenfeng, FU Xudong, ZHANG Ga, et al. Improved hillslope erosion module of the digital Yellow River integrated model considering the vegetation effects on the Loess Plateau[J]. Journal of Tsinghua University (Science and Technology), 2022: 62(12): 1953.
[2]
张光辉. 土壤分离能力测定的不确定性分析[J]. 水土保持学报, 2017, 31(2): 1. ZHANG Guanghui. Uncertainty analysis of soil detachment capacity measurement[J]. Journal of Soil and Water Conservation, 2017, 32(2): 1.
[3]
PARTHIZKAR M, SHABANPOUR M, KHALEDIAN M, et al. The evaluation of soil detachment capacity induced by vegetal species based on the comparison between natural and planted forests[J]. Journal of Hydrology, 2021, 595: 126041.
[4]
ZHANG Guanghui, LIU Baoyuan, LIU Guobin, et al. Detachment of undisturbed soil by shallow flow[J]. Soil Science Society of America Journal, 2003, 67(3): 713.
[5]
何小武, 张光辉, 刘宝元. 坡面薄层水流的土壤分离实验研究[J]. 农业工程学报, 2003, 19(6): 52. HE Xiaowu, ZHANG Guanghui, LIU Baoyuan. Soil detachment by shallow flow on slopes[J]. Transactions of the CSAE, 2003, 19(6): 52.
[6]
王凯, 王玉杰, 王彬, 等. 黄壤坡面土壤分离速率研究[J]. 长江流域资源与环境, 2018, 27(9): 2114. WANG Kai, WANG Yujie, WANG Bin, et al. Study on soil detachment rate on a yellow-soil hillslope[J]. Resources and Environment in the Yangtze Basin, 2018, 27(9): 2114.
[7]
MORGAN R P C, QUNINTON J N, SMITH R E, et al. The European Soil Erosion Model (EUROSEM): A dynamic approach for predicting sediment transport from fields and small catchments[J]. Earth Surface Processes and Landforms, 1998, 23(6): 527.
[8]
DE ROO A, WESSELING C, RITSEMA C. LISEM: a single-event physically based hydrological and soil erosion model for drainage basins. I: Theory, input and output[J]. Hydrological Processes, 1996, 10(8): 1107.
[9]
NEARING M A, FOSTER G R, LANE L, et al. A process-based soil erosion model for USDA-Water Erosion Prediction Project technology[J]. Transactions of the ASAE, 1989, 32(5): 1587.
[10]
SU Zilong, ZHANG Guanghui, YI Ting, et al. Soil detachment capacity by overland flow for soils of the Beijing region[J]. Soil Science, 2014, 179(9): 446.
[11]
LI Tianyang, LI Siyue, LIANG Chuan, et al. Erosion vulnerability of sandy clay loam soil in Southwest China: Modeling soil detachment capacity by flume simulation[J]. Catena, 2019, 178: 90.
[12]
史志华, 刘前进, 张含玉, 等. 近十年土壤侵蚀与水土保持研究进展与展望[J]. 土壤学报, 2020, 57(5): 1117. SHI Zhihua, LIU Qianjin, ZHANG Hanyu, et al. Study on soil erosion and conservation in the past 10 years: Progress and prospects[J]. Acta Pedological Sinica, 2020, 57(5): 1117.
[13]
LIU B Y, NEARING M A, SHI P J, et al. Slope length effects on soil loss for steep slopes[J]. Soil Science Society of America Journal, 2000, 64(5): 1759.
[14]
王晨沣, 王彬, 王玉杰, 等. 不同土壤前期含水率和坡度下黄壤分离临界水动力特性[J]. 农业机械学报, 2017, 48(4): 224. WANG Chenfeng, WANG Bin, WANG Yujie, et al. Critical hydraulic characteristics of yellow soil detachment under different antecedent soil moisture contents and slope gradients[J]. Transactions of the Chinese Society for Agricultural Machinery, 2017, 48(4): 224.
[15]
NEARING M A, BRADFORD J M, PARKER S C. Soil detachment by shallow flow at low slopes[J]. Soil Science Society of America Journal, 1991, 55(2): 339.
[16]
张光辉, 刘宝元, 何小武. 黄土区原状土壤分离过程的水动力学机理研究[J]. 水土保持学报, 2005, 19(4): 48. ZHANG Guanghui, LIU Baoyuan, HE Xiaowu. Study on hydro-dynamic mechanism of natural soil detachment in loess region[J]. Journal of Soil and Water Conservation, 2005, 19(4): 48.
[17]
NEARING M A, SIMANTON J R, NORTON L D, et al. Soil erosion by surface water flow on a stony, semiarid hillslope[J]. Earth Surface Processes and Landforms, 1999, 24(8): 677.
[18]
张光辉. 对土壤侵蚀研究的几点思考[J]. 水土保持学报, 2020, 34(4): 21. ZHANG Guanghui. Several ideas related to soil erosion research[J]. Journal of Soil and Water Conservation, 2020, 34(4): 21.
[19]
张光辉, 刘宝元, 张科利. 坡面径流分离土壤的水动力学实验研究[J]. 土壤学报, 2002, 39(6): 882. ZHANG Guanghui, LIU Baoyuan, ZHANG Keli. Experimental simulation of hydraulic mechanism of soil detachment by surface runoff on slope land[J]. Acta Pedologica Sinica, 2002, 39(6): 882.
[20]
牛梦飞, 孙三祥, 龚正威. 低含沙坡面薄层水流垂线流速特征试验分析[J]. 兰州交通大学学报, 2022, 41(6): 96. NIU Mengfei, SUN Sanxiang, GONG Zhengwei. Experimental analysis on characteristics of vertical velocity of overland flow on low sediment concentration[J]. Journal of Lanzhou Jiaotong University, 2022, 41(6): 96.
2023, Vol. 21 
