Proposal to Host Borlaug Fellow from Mexico on Greenhouse Gas (GHG) Emissions from Composting

Fellow 1 (Mexico) proposed the following research effort during the fellowship. It is a subproject from a major project intended to reduce the use of fresh cow manure in the traditional production of nopalito (tender cactus cladode) in Milpa Alta, D.F. and promote the organic production. The main goal of our team is to research on GHG emissions and to offer alternatives for reducing these emissions in agricultural crops. My objectives are to integrate a practical methodology for composting fresh cow manure with low costs and low methane, carbon dioxide and nitrous oxide emissions that can be transferred to low income producers of nopali. The Fellow has an interest that is very similar to research objectives of Dr Mark Coyne (Department of Plant and Soil Science) and Dr Joseph Taraba (Department of Biosystems and Agricultural Engineering) concerning GHG emissions from composting dairy manure with bedding in a compost bedded dairy barn. They will share the 12 week mentoring of the invited research Fellow. Dr Coyne also has and objective of studying GHG emissions from soils after application of plant nutrients. Drs Coyne and Taraba have collaborated on studying the release rates of P and N nutrients from composted dairy manure for plant uptake in soil culture. We are proposing a different tact to address his objectives. It is important to understand some of the controlling factors that lead to the generation of GHGs during the composting process: moisture content and particle size of the compost material. In a published paper from our efforts with biofilters, it was found that as the average moisture content of compost was above 50%, the maximum production rate of nitrous oxide was found. But when the moisture content fell below 45%, but greater than 40% (wb), the methane production rate was highest (Maia, GDN, GB Day V, RS Gates, JL Taraba and MS Coyne. 2012. Moisture effects on greenhouse gases generation in nitrifying gas-phase compost biofilters. Water Research 46 (9), 3023-3031. doi:10.1016/j.watres.2012.03.007). This phenomena is associated also with the oxygen gradient within a particle where the oxygen concentration at the center is zero. It is proposed, to understand the fundamentals of the GHG production in composting process, that a laboratory research project where batch reactors containing actively composting dairy manure, separated by particle size be used to determine the generation rates of nitrous oxide and methane gases. The other variables to be tested are moisture content and incubation temperature. Dr coyne laboratory is equipped with 3 gas chromatographs to analyze the gases in the head space of the batch reactors for nitrous oxide (ECD), methane (FID) and oxygen and carbon dioxide (TCD). His laboratory also is equipped with incubators to control temperature level. Significant, publishable data will be able to be collected during the 12 week Fellowship. Dr Taraba has an extension appointment and has extensive working knowledge of composting dairy manure with sawdust bedding. He will work with a dairy farm that is presently composting dairy manure with sawdust as the source material for the above experiments. The compost is being analyzed for plant nutrient release in soil cultures to determine plant availability of the compost. These results have been presented at a conference (Hammond, L, JL Taraba, MS Coyne, and JM Bewley. 2014. Compost Bedded Pack Dairy Barns: An Alternative Housing and Nutrient Management Strategy for Southern Dairies. Poster Presentation at Southern Sustainable Agriculture Working Group (SSAWG) 23rd Annual Practical Tools and Solutions for Sustaining Family Farms Conference. January 17-18. Mobile, AL.).