Evaluation of medical stone amendment for the reduction of nitrogen loss and bioavailability of heavy metals during pig manure composting

Abstract The purpose of this research was to evaluate the effect of medical stone (MS) on nitrogen conservation and improving the compost quality during the pig manure (PM) composting. Five treatments were designed with different concentrations of MS0%, 2.5%, 5%, 7.5% and 10% (on dry weight of pig manure basis) mixed with initial feed stock and then composted for 60 days. The results showed that MS amendment obviously ( p 3 loss and N 2 O emission were significantly reduced by 27.9–48.8% and by 46.6–85.3%, respectively. Meanwhile, the MS amendment could reduce the NO 2 − -N formation and increase the NO 3 − -N content. Finally our results suggested that 10%MS addition could significantly reduce the nitrogen conservation as well as improve the quality of compost.