Optimal vetiver hedgerow spacing for mitigating sediment and runoff erosion on steep slopes in Malawi

Abstract

This study assessed the optimum vetiver hedgerow spacing capable of reducing sediment and runoff erosion on a 17% slope. Three treatments were used: 2-meter vetiver hedgerow spacing, 4-meter vetiver hedgerow spacing, and a control plot without vetiver. Erosion pins were strategically placed on the plots and measured periodically over a period of 6 months, accompanied by daily rainfall measurements. The findings revealed the effectiveness of vetiver hedgerows in reducing sediment erosion and runoff from the plots. Notably, the 2-meter vetiver hedgerow spacing proved more efficient in reducing erosion and minimizing soil accumulation within the plot, with an average change in erosional pin height of 1.2 cm, whereas the 4-meter hedgerow spacing exhibited higher erosion rates at 2 cm, which was statistically significant. These results underscore the importance of optimizing vetiver hedgerow spacing to effectively combat soil erosion and runoff on steep slopes.