Thailand's first soil survey was initiated in 1935 by renowned American soil and production of soil scientist , Dr. R.L. Pendleton. The study of soils and production of soil maps across the country followed in 1960 , initially with a scale of 1:2,500,000 with reference to the soil survey and soil classification of the U.S. Department of Agriculture system (USDA , 1938). Subsequently , soil surveys at provincial level were initiated , beginning in the northeast and central regions. The work progressed continued until 1963 , when the Land Development Department (LDD) was established. Since then , soil survey and soil classification work have become the responsibility of LDD.

          In Thailand , soil survey and soil classification are conducted following the soil taxonomy developed by the US Department of Agriculture (USDA). This taxonomy provides a classification of soil types at 6 levels: Order , Suborder , Great Group , Family and Series.

          Soil survey and soil classification work comprise both field and laboratory work , beginning with a study of preliminary data and examining soil characteristics and properties in the field. The next steps involve developing descriptions of soil profiles , drasting maps showing boundaries of soil types , then checking the accuracy of the soil map. Finally , the process concludes with pubilcation of the soil maps and soil survey report.