Different characteristics of greenhouse gases and ammonia emissions from conventional stored dairy cattle and swine manure in China

Livestock manure emits considerable amounts of greenhouse gases (GHGs) and ammonia (NH3), inducing climate change and air pollution. However, there remains a lack of knowledge in the literature related to GHGs and NH3 emissions from the manure of various livestock species. This study reports on a field observation we conducted to analyze GHGs and NH3 emissions of solid stored manure from dairy cattle and swine, which represent the two main livestock species raised in China. Results showed that although dairy cattle manure emitted 521.9% more methane (CH4) than swine manure, they separately emitted 50.8% and 40.9% less nitrous oxide (N2O) and carbon dioxide (CO2) emissions, respectively. With respect to their global warming potential, the GHGs emission from dairy cattle manure was similar to that from swine manure. NH3 emissions from swine manure were significantly higher, namely, greater by a factor of 2.4 compared to dairy cattle manure. Differences in gas emissions between dairy cattle and swine manure can be explained by differences in the physicochemical characteristics of their manure and their associated microbiological, chemical, and physical processes that produce gas during storage periods. Based on our results, this study highlights the necessity for prospective mitigation strategies to simultaneously decrease GHGs and NH3 emissions from livestock manure. Our findings provide useful implications for understanding GHGs and NH3 emissions, which can be used to develop corresponding mitigation strategies for livestock manure management in China. (C) 2020 Elsevier B.V. All rights reserved.