Progressive terracing technology is established through successive deposits of sediments behind (upstream) any anti-erosional structure, in this case contour strips of vetiver grass (vetiveria zizanioides). To better stabilize the slopes in the long-term, trees are planted downstream of the vetiver hedges.
Afforestation is planting trees on previously non-forested land. Trees hold the soil and reduce runoff, and thus prevent erosion of the most fertile layers. It is an effective way to rehabilitate degraded lands, being a nature-based solution which addresses flood and soil erosion impacts.