Potential of Lemongrass as River Siltation Control Associated with Water Runoff

Erosion is the natural process in undisturbed ecosystem for a natural geochemical cycle to maintain and balance between the rates of soil formation. However, due to the land disturbance which mainly from anthropogenic activities cause soil erosion become the main problems to be face. Soil erosion induced the process of siltation to occur by transporting particle silt and clay that will accumulated at the bottom of the river when the particles being loaded in excessive flow. This gave huge impact to the quality of water and also aquatic life. The existing prevention method in controlling erosion such as concrete embankments was high in cost, difficult to maintain and also not biological. Prevention method by using natural barrier was conducted in this study to overcome erosion problem by using vegetative barrier to filter the sediments and silts. Lemongrass being planted at Agro Park, Universiti Malaysia Kelantan with 17.6% degree of the slope to analyze its effectiveness in preventing runoff of sediment. Fifty samples of water runoff were collected during rainy day in April and May before and after surface runoff passing through lemongrass to know the amount of Total Suspended Solid. Water samples were analyzed using spectrophotometer to see the reduction of its value after passing vegetative barrier. Highest percentage of reduction of sediments after passing through vegetative barrier was 51.28 % while the lowest reduction was 11.19%. The value of TSS after passing lemongrass is significantly reduced which show that planting lemongrass can effectively help in filtering sediments of surface runoff during rainy days and can be said as one of the environmental friendly mechanisms in controlling erosion. It also can give benefit towards the soil stabilization and at the same time lemongrass can be harvest for the other beneficial use.