Effects of Dicyandiamide, Phosphogypsum, and Superphosphate on Greenhouse Gas Emissions During Pig Manure Composting

Abstract

This study investigates the effects of dicyandiamide, phosphogypsum, and superphosphate on greenhouse gas emissions and compost maturity during pig manure composting. The results indicate that the addition of dicyandiamide and phosphorus additives has no negative effect on composting, and it can increase the maturity of the compost. Adding only dicyandiamide reduces the emissions of ammonia (NH 3 ), methane (CH 4 ), and nitrous oxide (N 2 O) by 9.37%, 9.60%, and 31.79%, respectively. Dicyandiamide combined with phosphogypsum or superphosphate could enhance mitigation of the total greenhouse gas (37.46% and 29.55%) and NH 3 emissions (18.28% and 21.48%). The combination of dicyandiamide and phosphogypsum exhibits the most pronounced emission reduction effect, simultaneously decreasing the NH 3 , CH 4 , and N 2 O emissions by 18.28%, 38.58%, and 36.14%, respectively. The temperature and C/N content of the compost were significantly positively correlated with greenhouse gas emissions. The N 2 O emissions can be effectively reduced by inhibiting nitrification during composting.

Keywords: composting, Dicyandiamide, Phosphogypsum, Superphosphate, greenhouse gas, Ammonia