Effect of aeration rate, C/N ratio and moisture content on the stability and maturity of compost

To estimate the order of importance of factors affecting the stability and maturation of compost, pig feces and corn stalks were co-composted at different aeration rates (AR: 0.24, 0.48, 0.72 L kg(-1) dry matter (DM) min(-1)), C/N ratios (15, 18,21), and moisture contents (MC: 65%, 70%, 75%). The thermophilic phase with all treatments was long enough to meet sanitation requirements. The oxygen content and N losses increased with increasing AR, but no significant differences were observed between the moderate and high treatments. The compost with the lowest initial C/N ratio was significantly different from the other treatments and had the lowest germination index (53-66%). AR was the main factor influencing compost stability, while the C/N ratio mainly contributed to compost maturity, and the MC had an insignificant effect on the compost quality. The recommended parameters for composting are an AR of 0.48 L kg(-1) DM min(-1) and a C/N ratio of 18 with MCs of 65-75%. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.