Efficiency of Vegetative Filter Strips in Mitigating Soil Erosion and Surface Runoff

Abstract

Vegetative filter strips (VFS) are widely used in agriculture to reduce soil erosion and sediment transport during heavy rainfall events. This study assessed their effectiveness in controlling surface runoff and sediment transport under controlled field conditions. Experiments were conducted on plots of varying lengths (4 and 8 m), slopes (5° and 10°), and vegetation cover (grass, bare soil, and mixed). A suspension of micronized sand and water (40 g·L−1) was applied at a flow rate of 0.5 L·s−1 to simulate surface runoff. The results confirmed that vegetation cover significantly reduced runoff (up to 91%) and sediment transport (up to 98%). The plot length played a dominant role in sediment and runoff reduction, while the slope had minimal effect within the tested range. Runoff and sediment transport were significantly higher on bare soil plots, providing evidence of the importance of vegetation in erosion control. A key methodological contribution of this study was the differentiation of VFS efficiency based on calculation methods. Two efficiency metrics were applied: (1) RE (the ratio of inflow to outflow), and (2) RE2 (comparison with a bare soil plot). While sediment reduction differed only slightly (4.7%) between the methods, runoff reduction varied more significantly (19.9%), highlighting the impact of the calculation method. Additionally, VFS preferentially trapped coarser sediment, allowing finer particles to pass through and resulting in a reduction of the median grain size (D50) from 33 to 6 μm in the transported material. This study underscores the effectiveness of VFS in mitigating sediment transport, highlighting the importance of vegetation cover and filter strip length. It further emphasizes that VFS performance can be optimized through methodological consistency, even when only a minimal land area is allocated for implementation.