The impact of organic amendments on soil hydrology, structure and microbial respiration in semiarid lands
Abstract Few studies have considered the effect of organic amendments on soil microbial activity and its contributions to hydraulic conductivity under field conditions in semiarid region soils with different textures and degrees of aggregate stability. This study was performed to investigate the relationship between selected soil properties and hydraulic conductivity in response to different types and application rates of organic amendments. For this purpose, urban municipal solid waste (MSW) compost and alfalfa residue (AR) were applied at different rates of 0 (control), 10 Mg ha− 1 and 30 Mg ha− 1 to clay loam and loamy sand soils under field conditions. Results show that after two years,…
WEPP calibration for improved predictions of interrill erosion in semi-arid to arid environments
Abstract Modeling soil erosion contributes to the understanding of the erosion processes and needs to predict accurately the erosion rates under different environmental conditions. Few studies have investigated the WEPP's applicability for arid and semi-arid conditions that differ from those where the model was developed. This research was carried out to evaluate and improve the WEPP model for arid and semiarid regions for interrill erosion using a rainfall simulator at plot scale. The results showed that measured interrill erosion rates ranged from 9.3 × 10− 6 to 89.6 × 10− 6 kg m− 2 s− 1. In comparison, the WEPP-interrill erosion prediction values were on average 14.5 times lower than the…
The use of barley straw residues to avoid high erosion and runoff rates on persimmon plantations in Eastern Spain under low frequency-high magnitude simulated rainfall events
[EN] Soil and water losses due to agricultural mismanagement are high and non-sustainable in many orchards. An experiment was set up with rainfall simulation at 78 mm h(-1) over 1 hour on 20 paired plots of 2 m(2) (bare and straw covered) in new persimmon plantations in Eastern Spain. Effects of straw cover on the control of soil and water losses were assessed. An addition of 60% straw cover (75 gm(-2)) resulted in delayed ponding and runoff generation and consequently reduced water losses from 60% to 13% of total rainfall. The straw cover reduced raindrop impact and thus sediment detachment from 1014 to 47 g plot(-1) h(-1). The erosion rate was reduced from 5.1 to 0.2 Mg ha-(1) h(-1). The …
Sediment transport mechanisms and selective removal of soil particles under unsteady-state conditions in a sheet erosion system
Abstract Selective removal of particles and nutrients by water erosion is a key factor in soil erosion studies. Most agricultural soils are located on gentle slopes where fertility is high; however, until now, the main attention on sediment transport mechanisms was paid to high-slope gradients, where soil erosion is intense, but soils are less productive. Despite the importance of sediment size distribution (SSD) and transport mechanisms under unsteady-state conditions, few studies have been done on this issue. Higher sediment concentrations in the early stages of the runoff indicate the need to deal with unsteady-state conditions. To address this issue, sheet erosion experiments were done …