Fertilizer timing affects nitrous oxide, carbon dioxide, and ammonia emissions from soil

The impact of interactions between management and climate on nitrous oxide (N2O), carbon dioxide (CO2), and ammonia (NH3) emissions are not well understood. This study quantified the effect of urea fertilizer application timing on inorganic N movement, immobilization, and the gaseous emissions of N2O‐N, CO2‐C, and NH3‐N. Urea was applied once, at two rates (0 and 224 kg ha−1) on six dates (early fall, 20 Sept. 2017; mid‐fall, 11 Oct. 2017; early winter, 1 Nov. 2017; early spring, 1 May 2018; mid‐spring, 22 May 2018; and early summer, 12 June 2018). Gaseous emissions, soil temperature, and soil moisture were measured every 4 h for 21 consecutive days following urea application. Changes in soil inorganic N contents were used to determine the amount of inorganic N remaining in the soil, nitrification, immobilization/fixation, and leaching. For all fertilizer application dates, the cumulative fertilizer derived N2O‐N emissions for the 21 days following application were 60%). These findings indicate that intergovernmental panel on climate change (IPCC) default value of 1% of applied N for N2O emissions improved by considering the fertilizer application date.