Decomposition of 14C-labelled melanoid fungal residues in a marginally sodic soil

Abstract Three melanoid fungi, namely Alternaria alternata , Curvularia lunata and Drechslera australiensis were grown on 14 C-glucose and then fractionated into cell wall, cytoplasm and melanin. The decomposition of these fractions and their contribution to the stable organic matter fraction was studied in a marginally sodic soil. The rate of decomposition of fungal melanins was less than that of the cell wall or cytoplasm which had the highest rate of decomposition. However, the contribution of these fractions to the humic acid fraction was very low. Most of the 14 C-activity was recovered in the humin fraction.