Municipal Tropical Compost: Effects on Crops And Soil Properties

Three kinds of tropical soils (inceptisol, mollisol and oxisol: USDA) were amended with increasing quantities of municipal refuse compost. Prepared mixtures: 0, 1.2, 2.5, 5, 10 and 25.6 percent (by volume) of compost were utilized as growing substract (without mineral fertilizer) in pot vegetation trials including three successive plantations taking corn as the test plant. Plant yields and heavy metal concentrations were determined. Urban compost effects on soil chemical parameters were evaluated. Corn growth had been significantly enhanced by the presence of urban compost showing no toxic effects. However, this fertilizing effect decreases after successive harvestings. Cadmium and lead concentrations in the plants were found to be under detection concentration limits (0.5 and 5.2 ppm respectively). Concentrations of copper and zinc in the plants increased relative to the amounts of urban compost but never reached toxic concentrations.