Humus Composition of Paddy Soils in Central Plain

Abstract

The compositions of humus in the three great soil groups in the Central Plain, Fresh Water Alluvial soils (FWAS), Brackish Water Alluvial Soils (BWAS), and Low Humic Grey Soils (LHGS), were investigated. The amount of humic acids in both free and comples forms varied with kind of soil serices and great soil group. the contents of humic and fulvic acids in free forms were higher, but in complex forms were lower in FWAS than in BWAS. Free humic acids in FWAS and BWAS were mostly classified as B type and followed by A type whereas humic acids in complex forms in both soils were A type in nature.