Sheet erosion rates and erosion control on steep rangelands in loess regions

• Published in: Earth surface processes and landforms 2018-11, Vol.43 (14), p.2926-2934
• Main Authors: Wang, Dongdong, Wang, Zhanli, Zhang, Qingwei, Zhang, Qilin, Tian, Naling, Liu, Jun'e
• Format: Article
• Language: English
• Subjects: Agricultural land; Computer simulation; Dynamics; Erosion control; Erosion mechanisms; Erosion models; Erosion processes; Erosion rates; Grain; Grassland management; Grasslands; hydraulic parameters; Hydrodynamics; Laminar flow; Linear equations; Loess; loess region; Mathematical models; Model accuracy; Modelling; Plant cover; Rain; Rainfall; Rainfall intensity; Rainfall simulators; Range management; Rangelands; Rivers; Shear stress; Sheet erosion; sheet erosion rate; Simulated rainfall; Slope; Slopes; Soil; Soil dynamics; Soil erosion; Soil improvement; Soil management; steep rangelands; Vegetation; Vegetation cover; Water depth
• ISSN: 0197-9337; 1096-9837
• DOI: 10.1002/esp.4460

Numerous steep rangelands have been restored from abandoned steep croplands, and sheet erosion has become the dominant erosion process on rangelands since the Grain‐to‐Green Project was launched in 1999 on the Loess Plateau. Quantifying sheet erosion rates and dynamics on steep rangelands may aid soil erosion management strategies and improve grassland health. Simulated rainfall experiments were conducted on a rangeland plot under five vegetation coverages (30%, 40%, 50%, 60% and 70%), five rainfall intensities (0.7, 1.0, 1.5, 2.0 and 2.5 mm min‐1) and five slopes (7°, 10°, 15°, 20° and 25°). The results show that the sheet erosion rate decreased as vegetation cover increased, as described by linear or logarithmic equations under different rainfall intensities or slopes. Herbaceous vegetation can reduce and control sheet erosion by reducing the effect of rainfall intensity or slope, especially under sufficiently high vegetation cover. The sheet erosion rate was accurately modelled by a linear equation that included the three factors, i.e. rainfall intensity, vegetation cover, and slope. Among the different hydrodynamic parameters (shear stress, stream power, unit stream power and unit energy), stream power resulted in the best model for the sheet erosion rate. Velocity measurements and calculations, water depth calculations, and aggregative indicators of herbaceous vegetation for sheet flow should be explored in future research, which will be important in improving experimental accuracy and sheet erosion modelling. © 2018 John Wiley & Sons, Ltd. Sheet erosion rate decreased as vegetation cover increased, as described by linear or logarithmic equations under different rainfall intensities or slopes. Sheet erosion rate was accurately modelled by a linear equation that included rainfall intensity, vegetation cover and slope. Stream power resulted in the best model for the sheet erosion rate.