Effects of adding sulphuric acid on composting process of cattle manure and changes of main nutrients

In this study, to explore the effects of different concentrations of sulphuric acid on changes of pH and main nutrient elements during the windrow compost, an experiment of cattle manure composting was carried out for 43 days. Besides the control, three mixtures were treated with addition of different concentrations of sulphuric acid, 0.1 mol/L, 0.2 mol/L and 0.3 mol/L. The results show that during 43 days, the sulphuric acid addition treatments at 0.2 mol/L and 0.3 mol/L decrease the stage of initial high temperature, pH and carbon losses significantly, and increase the contents of total N, total K, total P, available potassium and available phosphorus effectively. The total N, total K, total P, available potassium and available phosphorus in the 0.2 mol/L sulphuric acid compost are increased by 19.51%, 13.49%, 6.07%, 21.39% and 9.03% respectively compared to the control in the 43 days. The germination index (GI) value is over 80% at the end of composting, implying that the phytotoxicity is eliminated completely. On the whole, the addition of the 0.2 mol/L sulphuric acid has the best composting effect. The addition of sulphuric acid can provide technical support and basis for cattle manure composting engineering.