NITROUS-OXIDE LOSS FROM POULTRY MANURE-AMENDED SOIL AFTER RAIN

Land application of poultry wastes in Kentucky will increase as the broiler industry grows. If poultry manure stimulates N2O loss from soil it will reduce the fertilizer N value of this waste. In contrast, stimulated N2O loss in grass filter strips receiving the runoff from manured fields could help reduce contamination of surface water by NO3-. Our objectives were to determine (i)if poultry manure stimulated N2O loss in soil after rainfall and (ii) if there was an edge-of-field effect on N2O loss in grass filters intercepting runoff from amended soil. Soil covers were used to measure N2O loss from a well-drained, poultry manure-amended, silt loam soil immediately after simulated rainfall and were also used to measure N2O loss from grass filters intercepting their surface runoff. Nitrous oxide loss from manure-amended soil was greater than from unamended controls and ranged from 5 to 13 mg N2O-N m(-2) h(-1). The maximum N2O loss was equivalent to 3.2 kg N2O-N ha(-1) d(-1). Nitrous oxide loss from grass filters intercepting runoff ranged from 0.1 to 1.4 mg N2O-N m(-2) h(-1) and was significantly greater than portions of the grass filters that did not intercept runoff. Nitrous oxide loss from poultry manure-amended soils was greater than N2O loss typically measured from waste-amended agricultural soils. However, it only represented up to 0.7% of the total N in the applied manure.