Influence of bare soil and cultivated land use types upstream of a bank gully on soil erosion rates and energy consumption for different gully erosion zones in the dry-hot valley region, Southwest China

Abstract

This study assessed temporal variation in soil erosion rates in response to energy consumption of flow (DE). It employed an in situ bank gully field flume experiment with upstream catchment areas with bare (BLG) or cultivated land (CLG) that drained down to bare gully headcuts. Water discharge treatments ranged from 30 to 120 L Min -1 . Concentrated flow discharge clearly affected bank gully soil erosion rates. Excluding minimal discharge in the CLG upstream catchment area (30 L min -1 ), a declining power function trend (p B 0.1) was observed with time in soil erosion rates for both BLG and CLG upstream catchment areas and downstream gully beds. Non-steady state soil erosion rates were observed after an abrupt collapse along the headcut slope after prolonged scouring treatments. However, as the experiment progressed, DE and energy consumption of flow per unit soil loss (DEu) exhibited a logarithmic growth trend (p \ 0.1) at each BLG and CLG position. Although similar temporal trends in soil erosion and infiltration rates were observed, values clearly differed between BLG and CLG upstream catchment areas. Furthermore, Darcy-Weisbach friction factor (f) values in the CLG upstream catchment area were higher than the corresponding BLG area. In contrast to the BLG upstream catchment area, lower DEu and higher soil erosion rates were observed in the CLG upstream catchment area as a result of soil disturbances. This indicated that intensive land use changes accelerate soil erosion rates in upstream catchment areas of bank gullies and & Donghong Xiong increase soil sediment transport to downstream gullies. Accordingly, reducing tillage disturbances and increasing vegetation cover in upstream catchment areas of bank gullies are essential in the dry-hot valley region of Southwest China.

Variation in the vertical zonality of erodibility and critical shear stress of rill erosion in China's Hengduan Mountains

“…Following this initial high erosion rate, runoff samples were collected to measure the soil Dr and to calculate Kr and Ʈc using Equation . As observed in previous studies, steady state hydraulic properties were often achieved following an initial period of adjustment (Franti et al, ; Su et al ., 2015a, b).…”

“…Vegetation in the dry‐hot valley section is dominated by herbs, such as Heteropogon contortus and Bothriochloa pertusa , as well as sparsely distributed Leucaena leucocephala and Dodonaea viscosa shrub species. This section subsequently resembles a tropical savanna ecosystem (Su et al ., 2015a, b).…”

“…Various studies from a number of research areas have obtained data related to the effects of land-use type on soil erosion (Galang et al, 2007;Capolongo et al, 2008;Zhang et al, 2009b;Bouajila and Gallali, 2010;Su et al, 2015a). Bouajila and Gallali (2010), for example, reported that the conversion of native forests to cultivated land was accompanied by a decline in SOM and nutrients as well as the deterioration of soil structure, which resulted in the acceleration of soil erosion processes.…”

Impacts of headcut height on flow energy, sediment yield and surface landform during bank gully erosion processes in the Yuanmou Dry‐hot Valley region, southwest China

“…The frequent erosive precipitation events in the rainy season and special lithological conditions are the major causes of the well‐developed gullies in this region (Zhong, ). An experimental programme supported by the Institute of Mountain Hazards and Environment (IMHE) of the Chinese Academy of Sciences (CAS) has obtained some significant observations for gully erosion research in recent years (Chen et al ., , ; Dong et al ., , ; Su et al ., , , ; Yang et al ., , ; Zhang et al ., , ).…”

“…Su et al . (, , ) examined the headward erosion of bank gullies under different water discharges, including headcut erosion rates and hydraulic properties. Zhang et al .…”