Changes in the organic matter mineralization rates of an arid soil after amendment with organic wastes

This study examined the changes in organic matter mineralization when sir amendment rates of municipal solid waste, sewage sludge, and compost were added to an arid soil. Short-time incubation assays were carried out in which the amount of CO2 emitted was measured. The kinetic and mineralization constants of the organic matter were studied, as was the influence, of this amendment on the soil organic matter content. Potentially mineralizable C (C-0) in the municipal solid waste-amended soil was significantly higher than in the soil amended by sewage sludge and compost and it increased (is the amendment rate of compost and savage sludge increased. There was no direct relation between the increase in organic matter decomposition rate and the amount of organic amendments that were applied to the soil. The CO2 loss/total organic carbon (CO2 loss/TOC) ratio in the soils amended with fresh organic waste was significantly higher than in that amended with compost. The CO2 loss/TOC ratio also differed with amendment rare between fresh and composted wastes. The ratio rose slightly as the amendment rate of fresh wastes increased up to 2%, after which it stabilized, whereas it decreased ar the amendment rate increased in the soils amended with compost. Linear fittings were made of the CO2 evoked as a function of dose for the different sampling rimes. The carbon mineralized increased in all treatments, more so in the soils amended with fresh wastes than in those amended with compost. The organic amendments resulted in a priming effect that was more pronounced during the first days of incubation and differs according to the nature of the material added.