Nitrous Oxide and Carbon Dioxide Emissions During the Nongrowing Season from Manured Soils under Rainfed and Irrigated Conditions

Abstract

This study investigated CO2 and N2O emissions from soil receiving long-term cattle feedlot manure applications under rainfed and irrigated conditions in semi-arid southern Alberta, Canada. Soil available N and CO2 and N2O fluxes were measured after fall crop harvesting and prior to next spring's seeding from plots that had received 0 and 60 t ha−1yr−1 cattle feedlot manure application with (Mi0 and Mi60) or without irrigation (Mr0 and Mr60) for 27 years. Both CO2 and N2O fluxes varied considerably over the 7-month nongrowing season. Cumulative CO2 emissions from manured treatments (Mr60 at 2.20 t ha−1 and Mi60 at 2.36 t ha−1) were 2.6 times values from nonmanured treatments (Mr0 at 0.83 t ha−1 and Mi0 at 0.92 t ha−1). Similarly, cumulative N2O emission from manured treatments (Mr60 at 4.54 kg ha−1 and Mi60 at 5.34 kg ha−1) were 8–12 times values from nonmanured treatments (Mr0 at 0.40 kg ha−1 and Mi0 at 0.70 kg ha−1). Growing season irrigation had no effect on CO2 and N2O emission over the nongrowing season.