Organic matter management is believed to solve many
chemical and physical problems of these soils including their low water holding and
low buffering capacity as well as their low nutrient reserves. Although it is widely
recognised that in sandy soils organic matter build up does not take place easily,
some recent research in Northeast Thailand has shown that it is possible to improve
soil organic matter content in land use systems that enable a continuous supply of organic
inputs with minimum disturbance (Wu et ai., 1998).