209-5 Reducing Nitrous Oxide Emissions and Nitrate Leaching From Grazed Grasslands.
See more from this Division: ASA Section: Environmental Quality
See more from this Session: Nitrous Oxide Emissions From Agricultural Practices: II
Tuesday, November 5, 2013: 11:05 AM
Tampa Convention Center, Room 19
Abstract:
In grazed pasture systems, the nitrogen (N) contained in a cattle urine patch may be up to 1200 kg N ha-1. The majority of this N is in excess of plant requirements and is vulnerable to environmental loss. In this study, cattle urine was applied at 5 rates of nitrogen, 0, 300, 500, 700 and 1000 kg N ha-1 to soil monolith lysimeters in late autumn in Ireland in two separate years. Dicyandiamide (DCD) nitrification inhibitor was applied in solution form at 30 kg DCD ha-1 in two split applications following urine. Measurements of gaseous N emissions, nitrate (NO3-) leaching and pasture N uptake were made for a calendar year following urine application in two consecutive experiments. Increasing the rate of urine N applied increased the cumulative nitrous oxide (N2O) emissions, NO3- leaching and pasture N uptake in years one and two, and these relationships are described. The application of DCD reduced the cumulative N2O emissions and NO3- leaching in year one but not in year two. The pasture N uptake response to the increasing urine N rate was variable. We suggest the use of nitrification inhibitors and the reduction of urinary N content as two mitigation strategies for N loss from grazed pasture.
See more from this Division: ASA Section: Environmental Quality
See more from this Session: Nitrous Oxide Emissions From Agricultural Practices: II