The method that farmers use to apply manure to their fields can affect emissions of greenhouse gases during the winter, say researchers from the University of Vermont. Their study, published in the Soil Science of America Journal, is one of the first to look at greenhouse gas emissions from Vermont farmland and highlights the consequences of different manure-spreading methods.
Injecting manure into the soil, an approach that reduces surface runoff and foul odors, resulted in the largest wintertime release of greenhouse gases, such as carbon dioxide and nitrous oxide, said the researchers in a news release. “By injecting manure, farmers are trying to do the right thing and keep manure on the farm, in their soils and crops, and out of waterways,” said lead researcher Carol Adair. “These results, in conjunction with our previous research that found injection to also increase emissions during the growing season, suggest that there may be important tradeoffs to consider when deciding on a method of manure application.”
The method that resulted in the lowest emissions was broadcast spreading of manure followed by plowing. Simply spreading the manure on the surface without further treatment led to more greenhouse gases than with plowing, but less than injection.