Effects of wetting rate and simulated rain duration on soil crust formation of red loam

Abstract

The characteristics of crusts are closely related to soil erosion in red loam under a rainfall condition. To better manage crust-prone soils and to accurately predict hydrological processes, it is necessary to understand the mechanism of crust formation. Wetting rate is an important factor influencing soil aggregate stability and crust formation. In this study, we considered two factors, wetting rate (slow 2 mm h -1 , fast 50 mm h -1 ) and rainfall quantity (intensity of 60 mm h -1 with every 5 min as a treatment from 0 to 60 min). The results show that soil in the fast wetting treatment had higher bulk density, stronger crust strength and lower infiltration rate. Therefore, the fast wetting treatment had higher ability to resist the damage caused by raindrops and to resist soil erosion, and higher runoff rate than slow wetting treatment. Crust formationdestruction-formation process appeared sharp in fast wetting treatment but gentle in slow wetting treatment. Surface morphology and profile microstructure show that crusts were formed earlier in fast wetting treatment. The aggregates in slow wetting treatment had higher stability than those in fast wetting treatment. The crust strength of the soil pretreated by slow wetting was weaker than that in fast wetting case due to the persistent presence of stable aggregates, albeit microaggregates, and, consequently, reduced levels of compaction.

Effect of Mulching with Vegetative Residues on Soil Water Erosion and Water Balance in an Oxisol Cropped by Cassava in East Cameroon

“…In contrast to the results of soil loss, the amount of runoff water in this study was not affected by the presence of surface mulching. The direct impact of the rainfall did not decrease the infiltration rate of the surface layer in BA and CA plots, which might occur by the formation of crust or clogging (Han et al, ). This result is clearly different from the results in other studies that showed surface mulching decreased runoff coefficient compared with that in the control plots without mulch (Gholami et al, ; Keesstra et al, ; Prosdocimi et al, ).…”

Spatial and Temporal Evolution of the Infiltration Characteristics of a Loess Landslide

“…Eldridge believed that this process requires one year in situations of suitable rainfall [29], while Bresson believed that a physical crust is likely to form after one or two rainfall and drying events [22]. In Han's study, the crusts formed rapidly under laboratory conditions (within one hour) [44]. Regardless, these researchers all agree that a physical crust can dramatically decrease the infiltration rate.…”

“…First, to better study the temporal evolution of infiltration on recent landslides, it is necessary to understand the formation mechanism and duration of physical crusts. Previous studies have assumed that raindrop impacts are the main driver of physical crust formation [44,45] and that the rainfall intensity influences the physical crust thickness. Simulated rainfall experiments have shown that the crust thickness slowly increases with increasing rainfall intensity [45,46].…”

Physical Crust Formation on Sandy Soils and Their Potential to Reduce Dust Emissions from Croplands

“…For this study, crust strength was measured with two instruments, commonly used to describe soil resistance to erosion: a fall cone penetrometer for both fields-as experimental crusts, and a torvane for only the field crusts. Fall cone penetrometer measurements have been used by several studies [68][69][70][71][72]. The major advantage of using a fall cone penetrometer was the small scale of the measurement, both in surface and in depth.…”