TRAPPED MULCH INCREASES SEDIMENT REMOVAL BY VEGETATIVE FILTER STRIPS: A FLUME STUDY

摘要

Vegetative filter strips and crop residues are effective methods of soil erosion control on agricultural land. When crop residues become detached and move downslope in runoff, their on-site soil erosion protective effect is largely lost. When a filter strip traps residues, the filter strip's erosion control effectiveness may be increased. Few investigations have been conducted concerning this subject. In this study, we investigated the impact of upslope-detached and transported surface mulches on the sediment-trapping capability of simulated filter strips. Results showed that mulches (pine needles) added in random orientation floated parallel to the direction of flow and then turned perpendicular to the flow when they accumulated in front of a filter strip. The width of the resulting mulch barrier depended on the amount and length of the needles supplied to the flow. Shorter needles resulted in denser mulch barriers