Fertility Improvement of Sandy Soil by Vetiver Grass Mulching and Compost

Abstract

To improve the productivity and fertility of Hupkapong sandy soil, fresh vetiver grass was used in mulching and vetiver grass compost was applied in combination with chemical fertilizer. Soil fertility and productivity were evaluated from the yields of Insee 1 super sweet corn hybrid grown on the soil, and soil moisture determined using a neutron probe. The results indicated that super sweet corn hybrid gave a maximum growth and yield when it was fertilized with 75-75-75 kg N-P₂O₅-K₂O ha^-1 in combination with soil mulching of 31.25 t ha^-1 of fresh vetiver grass. Reducing the application of N-chemical fertilizer and vetiver mulching by 50% resulted in a decrease in super sweet corn hybrid yields. This decrease, however, was not statistically significant. Mulching was found to conserve topsoil moisture and increase plant growth and production. Soil incubated with vetiver grass or its compost released approximately the same amount of available-N. However, fresh vetiver grass mineralized higher levels of available-P and extractable-K than vetiver grass compost. One ton of vetiver grass yielded 1.32 kg t^-1, 0.24 kg t^-1 and 6.73 kg t^-1 of available-N, avetiver grassvailable-P and extractable-K, respectively.