GRACEnet: Trace Gas Fluxes from Irrigated Soils Amended with Anaerobic Digested Dairy Manure.

Dairy production in Eastern Washington has shown a steady increase (-4 % per year) over the past eight years, with a farm gate value exceeding 280 million dollars.  This increase has also been accompanied by management challenges associated with the production of large concentrations of dairy animal wastes.  Challenges include: land use management, soil nutrient imbalances (N, K and P), and insect and odor problems generated from animal manures. In addition, a decline in surface and subsurface water quality has been attributed to the land application of dairy manure as well as a a potential increase in the production trace gases. The effect of N-fertilization, dairy manure and anaerobic digested manure on trace gas emissions within a corn-triticale sillage cropping system was evaluated under irrigation in Eastern Washington.  Sillage production with manure amendments is a common practice for dairy management in eastern Washington. Research findings, using indirect N-budget estimates, suggest greater loss of applied N fertilizer either through nitrification-denitrification or/and volatilization in irrigated soils. Trace gas flux was measured an hour after irrigation, using vented chambers, twice a week during the cropping season.