Entomologist Johnnie van den Berg (Potchefstroom University, South Africa) found that larvae prefer to lay eggs on vetiver leaves planted around the crop instead of on the maize or rice crop itself. Vetiver leaves are hairy, the larvae that hatch on them cannot move around easily, resulting in about 90% of the eggs are dead. Vetiver also harbors many helpful insects that are predators of pests that attack crops.
Objectives of Vetiver hedgerows include reducing soil erosion, preserving plant nutrient, maintaining soil organic matter, stabilizing soil chemical and physical properties, and storing water in soil. Appropriate use of land or soil and water resources with wise and economic could preserve soil fertility for the highest yield and sustainability.
Deforested land area is degraded mostly because of the topsoil being washed away by water runoff. In Thailand, upland farming with contour planting of vetiver strips can increase crop yield by 20%, decrease runoff by 50%, and erosion by 70%. This paper shows some research results of demonstrations on farming households’ lands in Vietnam.
Vetiver System has been established for dike stabilization, erosion and sediment control, and water quality improvement by treating uneaten food and feces. The slides demonstrate this application in a Basa farm near Can Tho City of Vietnam.