Results The research indicated that almost all of the plants grown in T1 without vetiver grass died or had withered and were expected to die soon. This is because the soil is still compact hardpan soil, which prevents root penetration resulting in the death of all plants. Other treatments revealed the following results: Fruit trees and economic trees in Plots 1 and 2 yielded the best result in T2. Legumes and fast growing plants in Plots 3 and 4 yielded no significant difference in T2 to T5. It can be concluded that T2, where vetiver grass was grown in a circle with an 80-centimeter radius surrounding the plants with eight additional holds of vetiver grass in the circle covered with mulching of 15 kilograms, yielded the best result because the soil has been rapidly improved based on two factors. The first factor is the deep penetration of the roots of the vetiver grass reducing the density of the soil. The second factor is the mulching which changed the physical, chemical and biological nature of the soil and thus helped make the soil components suitable for plant growth. T2 thus yielded the best results. Agricultural plants such as cut-flower plants grown in the circles of T2 to T5, T3 were found to yield the best result because the water and air tubes together with mulching covering the circle helped make the soil suitable for growing agricultural plants and flowers. Recommendations Based on the results of the experiment, it was agreed that the time spent for the research should be extended. A learning centre for the benefits of vetiver grass for the improvement of compact hardpan soil should be established. Research on the potential and benefits of vetiver grass in improving compact hardpan soil should be supported to cover extended areas which should likewise be promoted as study centres at the local and national level. Strategies for public relations and information dissemination should be carried out to encourage target groups to use vetiver grass in production. An analysis where production can break-even in relation to investments made should be studied to systematically create incentives. Study on calculation of break-even point should Figure 8. Produce from compact hardpan soil. 6 THE ASIA REGIONAL FORUM ON BIODIVERSITY
In Celebration of His Majesty the King of Thailand’s 84th Birthday Anniversary
To see the actual publication please follow the link above