Influence of grass hedges on soil hydraulic properties, runoff and soil erosion in a small watershed.

摘要

Little is known about how a grass-hedge system influences soil properties important to infiltration and water movement in soil. The objective of this study was to measure differences in soil hydraulic properties at three positions within a small watershed: within the grass hedges, within a deposition zone 0.5 m upslope from the grass hedges, and within the row crop area 7 m upslope from the hedges. Laboratory analyses were conducted on intact soil samples to determine bulk density, saturated hydraulic conductivity, and porosity. In addition, x-ray computed tomography (CT) scan data were used to analyze soil density, porosity, and pore shape within intact soil samples from the three positions. The WEPP watershed model was used to compare predicted and measured runoff and sediment yield from the watershed. Results show that the grass hedge system influences soil hydraulic properties and porosity important to infiltration and sediment yield. Predicted runoff and sediment yield using the WEPP watershed model were found to be comparable with measured values for the small watershed.