Major Soils of Southeast Asia and the Classification of Soils under Rice Cultivation: Paddy Soils

Abstract

Legends of the soil maps of the Southeast Asian countries were presented and the soil units were correlated in terms of the great soil groups as proposed by Dudal and Moormann. As there are many great soil groups which are utilized for rice cultivation in Southeast Asia, problems associated with the classification of paddy soils were discussed. Because of the confusion in the usage of the term paddy soils and in order to make clearer the relationship of "paddy soils" with other soil groups in the general soil classification system, a new term "Aquorizem" was proposed for this soil group. This new term, "Aquorizem" has as its basic concept, an acquisition of specific morphological characteristics under rice cultivation and it is set up at the great soil group level. Classification of the soil group at both higher and lower categories was also discussed.