Influence of organic matter on the chemical and electrochemical properties of some flooded soils

The influence of organic matter added in the form of gliricidia (Gliricidia sepium Steud.) leaves and rice straw on the chemical and electrochemical kinetics of three flooded soils was studied in a pot experiment. Soils after submergence differed markedly in the properties studied. With addition of organic matter not only the peaks of CO₂ production and maximum concentrations of water-soluble Fe²⁺, Ma²⁺ and other cations occurred earlier but their concentrations were also significantly higher as compared to controls (no organic matter addition). The high concentration of CO₂ appeared to influence pH, the accumulation of cations in the soil solution, and to be chiefly responsible for the death of the rice plants. The lethal effects of CO₂ and other reduction products can be avoided and nutritional gains to rice can be achieved by planting 3–4 weeks after the addition of quickly-decomposing organic materials.