Kinetics of the Mineralization of Nitrogen In a Pig Slurry Compost Applied to Soils

Abstract

The influence of pedological variables (soil type and temperature) in the nitrogen mineralization of an organic fertilizer obtained by composting of pig slurry versus a conventional fertilizer was studied. The net nitrogen mineralization rate and mineralization half-time for the different treatments were determined. The final values suggest that the mineralization was more extensive at 30°C than at 15°C, independent of the treatment fertilizer. Similar observations were made for the losses of N. The results reveal that greater losses of gaseous N takes place when a conventional fertilizer is applied (urea) than when compost is applied, which shows a lower pollution potential with compost. The treatment with compost exhibited the greatest residual N effect. The statistical treatment of changes in the inorganic N content during the incubation period showed that the soil+compost treatment contained two N fractions, one of quick mineralization and another of slower mineralization. In the case of the Luvisol soil, the nitrogen fraction of slower mineralization presents a highest half time of mineralization compared to the nitrogen fraction corresponding to the Rendsina soil. Finally, in relation to the pedological variables considered, the soil type has a larger influence than temperature on N mineralization.