Decomposition of tropical peat soils .1. Decomposition kinetics of organic matter of peat soils

Malaysian tropical peat soils were examined for their microbial decomposability by incubation under aerobic conditions at 35 degrees C. Incubation data fitted well into the one compartment exponential decay model. Decomposition rate constants ranged from 0.0000241 to 0.000388 day(-1), equivalent to a half-life time of 78.6 and 4.89 years. No promotive effect of pre-air-drying on the decomposition rate was detected. The decomposition rate tended to increase with the increase of the soil pH and/or ash content of soil. The promotive effect of pH amendment of strong soil acidity by liming on the decomposition rate was confirmed, while no effect of NPK fertilizer application on the decomposition rate was observed. The inhibitory effect of sulfate salts of Cu, Zn and a highly polymerized hydroxyaluminium chloride solution on the microbial decomposition was observed.