Nitrapyrin reduced nitrous oxide emissions from beef cattle urine patches on a semiarid tame pasture

Urease and/or nitrification inhibitors applied to urine patches or pastures may increase N retention in the soil-plant system, but how N2O emissions respond to these N stabilizers in semiarid regions is poorly understood. The objectives of this research were (i) to quantify N2O emissions and the associated emission factors, based on the percentage of applied urine-N emitted as N2O-N, from beef cattle urine patches (urine) and (ii) to test the N2O reduction potential of three N stabilizers [2-chloro-6(trichloromethyl) pyridine (nitrapyrin), N-(n-butyl)-thiophosphoric triamide (NBPT), and NBPT plus dicyandiamide (DCD)] on a semiarid tame pasture over two grazing seasons in western Canada. A deionized water control was also included. Nitrapyrin reduced cumulative N2O emissions by 39% and the N2O emission factor by 50% compared with untreated urine in a dry grazing season and reduced cumulative N2O emissions by 58% and the N2O emission factor by 68% compared with untreated urine in a grazing season with normal precipitation. The NBPT and NBPT + DCD had similar cumulative N2O emissions compared with untreated urine patches. The N2O emission factors ranged from 0.03 to 0.08% over 103 d in 2015 and from 0.06 to 0.21% over 119 d in 2016, all lower than the 2% Intergovernmental Panel on Climate Change default 365-d value. Extrapolating over 1-yr periods, N2O emission factors ranged from 0.11 to 0.64%. Based on the N stabilizers tested, nitrapyrin most effectively reduced N2O emissions from beef cattle urine patches on a tame pasture in a nonirrigated semiarid region of Canada.