INFLUENCE OF POTASSIUM ON NITROGEN MINERALIZATION OF SEWAGE-SLUDGE IN2 CALCAREOUS SOILS

Two calcerous soils were used to make mixtures with sewage sludge. Thr ee potassium levels were established to study nitrogen mineralization processes. After 180 days, the contents of NO3--N and NH4+-N were much lower than those at the beginning. Results show that K has a clear in fluence on nitrifiocation and ammonification. At the same time, we obs erved that no differences in the degradation process of the sewage slu dge were found from on soil to another, but they existed for the diffe rent K levels.