In order to establish standards for soil classification in Thailand and make soil types easier to understand , LDD has set up a soil classification system and grouped several soil series together. Soil series that have similar characteristics , properties and crop productivity potentials have been grouped together. A total of 62 "soil groups" have been definded for Thailand.

          Soils groups No. 1-25 and 57-59 are found in lowland areas , with predominantly flat , flood - prone topography with shallow water table. Such soils are suitable for rice paddy.

          Soil groups No.26-56 and 60 are usually found in upland areas with good drainage and normally low risk of flooding. However , they may also be found on flat land , hillside slopes or undulating areas. Most of these soil groups are used to grow filed crops , tree fruit and other trees / bushes. These soil groups are divided into 2 subgroups , i.e upland dry zone soils upland humid zone soils.

          The last soil group , soil group No.62 is found on complex slopes or mountainous areas , usually with slopes greater than 35%. The characteristics of the soil group are not consistent , depending greatly on type of terrian , parent materials and vegetative cover. Sush areas are unsuitable for agriculture and be kept under forest to prevent erosion.