Crusting effects on erosion processes under simulated rainfall on a tropical Alfisol

Abstract

Abstract:Sealing and crusting of soil surfaces have dramatic eects on water in®ltration into and runo from soils, thereby greatly in¯uencing erosion processes. This study focused on the eect of the initial stage of crusting on inter-rill erosion processes for a crust-prone Al®sol sampled from south-central India. Soil aggregates ranging from 2 . 4 to 8 mm collected from ploughed (PL) and naturally vegetated (NV) treatments were subjected to rainfall simulation under laboratory conditions. Runo from PL soil aggregates was 2±2 . 5 times higher, while percolation was 20±100% lower, than for NV aggregates. Soil wash and splash losses were 0 . 5±3 times greater for PL than for NV soil. Runo and inter-rill erosion were signi®cantly higher during the wet simulation run compared with the dry run. The results indicated that NV soil aggregates were more resistant to breakdown from raindrop impact and slaking, and subject to less rapid sealing, than PL soil. Total soil loss was in¯uenced most by initial aggregate stability and the extent of seal development. Splash and wash losses of soil both increased as a result of surface sealing regardless of soil condition for short (30±60 min) rainfall durations. High drying rates resulted in the highest crust bulk densities. Increased crust strength for PL soil compared with NV soil re¯ected the greater susceptibility of cultivated soil to surface sealing and crusting. #

Effects of vegetation cover on phosphorus loss from a hillslope cropland of purple soil under simulated rainfall: a case study in China

“…This is because the vegetation cover reduced the kinetic energy of raindrops so as to prevent surface soil sealing, and soil surface roughness in the vegetation-covered plot impeded overland flow and increased the infiltrating time. Vegetation roots increased the soil infiltration capacity (Li et al 1996;Bajracharya and Lal 1998). Moreover, rainfall interception by vegetation shoots and runoff reduced by prolonged infiltration resulted in greater contributions to runoff reduction and the observed differences in the initial and stable subsurface flow rates (Johansen et al 2001;Benito et al 2003).…”

Simulated watershed scale impacts of corn stover removal for biofuel on hydrology and water quality

“…The stream flow at the watershed outlet reduced with stover removal; reductions were 1.4%, 2.0% and 2.7% in flow from the baseline scenario for 38%, 52% and 70% stover removal rates, respectively. This would be contrary to the principle of increase in runoff with residue removal due to soil crust formation (Bajracharya and Lal, 1998;Wells et al, 2003). To understand the physics behind stream flow reduction, a detailed HRU level monthly analysis was done comparing baseline and the 70% stover removal scenario.…”

Role of selected riparian herbs in reducing soil erosion and nutrient loss under simulated rainfall

“…Low water run-off and soil loss from the Leonotis stand (40.0% and 85.6 gm -2 ) may be ascribable to the reduction in raindrop energy by the multilayered (3-6 leaf layers) canopy cover (92.3%), whose cushioning effect was further increased when the plants blocked under the impact of the initial application of simulated rain and protected the ground more closely (Young and Wiersma 1973). This is probably due to the increase in the interception of raindrops which may reduce raindrops energy approaching to soil surface, prevent soil crusting, and reduce runoff (Bajracharya and Lal 1998;Li et al 1991). The plant roots bind the soil and reduce erosive power and increase infiltration capacity (Pan and Shangguan 2006).…”