Northern Thailand covers about one third of the country (17 million ha) and is comprised for 52% of
highlands, for 33% of uplands and for 15% of lowlands. Particularly, the upper northern part (8.58
million ha) has 72% of highlands, 16.7% of uplands and 11.3% of lowlands and water areas. Due to an
increase in hill-tribe population pressure and land pressure in lowland agriculture, forest encroachment
has increased markedly in the highlands where slash-and-burn shifting cultivation is practised. Soils
are degraded because erosion increases rapidly as a consequence of the traditional cropping system,
which knows neither soil and water conservation nor proper crop management. As soil fertility and
crop yields decrease, farmers’ lives are impeded and ecological balance is under threat. Particularly
soil, water and forest are destroyed rapidly.
His Majesty the King has long realized the problems of soil degradation on sloping lands due to soil
erosion and runoff. He has recognized the value of vetiver grass as a simple, cheap and efficient
technology to fight against erosion. At his suggestion, the Land Development Department has
undertaken vetiver experiments in the upper north of Thailand since 1990. Research has concentrated
on finding the best-performing varieties and the best management methods.