Vetiver grass for road slope protection through soil erosion and runoff reduction in a haor area of the Sunamganj district

Erosion control on slopes and embankments is a global concern, with vetiver planting emerging as an effective solution. This study investigated vetiver grass as a potential alternative for reducing runoff and soil erosion in protecting road embankments. In a small-scale model on a 1 V : 2 H slope, simulated rainfall was applied through a perforated sheet. The runoff was collected, and the eroded soil samples were dried using the sand bath method. The runoff and soil loss were compared with and without vetiver grass. The results showed that the vetiver grass significantly reduced the soil erosion, preventing about 87% more soil loss than the bare soil. During 60 min of simulated rainfall, the bare soil plot lost 27.056 kg.m-2 per unit area, whereas the vetiver-covered plot lost only 3.606 kg.m-2. This soil retention is due to vetiver's strong, deep root system and its hedge-like structure that effectively holds the soil. Additionally, the runoff was reduced by 14% in the plots covered with vetiver. For the 60 min of cumulative rainfall, the total runoff in the bare soil micro-plot was 81.15 cm, compared to 70.35 cm in the vetiver micro-plot. Therefore, vetivers are expected to be a sustainable and eco-friendly solution for runoff and erosion control within the lowland haor context.