2017 journal article

Combining urease and nitrification inhibitors with incorporation reduces ammonia and nitrous oxide emissions and increases corn yields

Journal of Environmental Quality, 46(5), 939–949.

By: C. Drury*, X. Yang*, W. Reynolds*, W. Calder*, T. Oloya* & A. Woodley*

co-author countries: Canada 🇨🇦

Contributors: C. Drury*, X. Yang*, W. Reynolds*, W. Calder*, T. Oloya* & A. Woodley*

MeSH headings : Ammonia / analysis; Denitrification; Fertilizers; Nitrification; Nitrous Oxide / analysis; Urease; Zea mays
Source: ORCID
Added: June 17, 2020

Less than 50% of applied nitrogen (N) fertilizer is typically recovered by corn ( Zea mays L.) due to climatic constraints, soil degradation, overapplication, and losses to air and water. Two application methods, two N sources, and two inhibitors were evaluated to reduce N losses and enhance crop uptake. The treatments included broadcast urea (BrUrea), BrUrea with a urease inhibitor (BrUrea+UI), BrUrea with a urease and a nitrification inhibitor (BrUrea+UI+NI), injection of urea ammonium nitrate (InjUAN), and injected with one or both inhibitors (InjUAN+UI, InjUAN+UI+NI), and a control. The BrUrea treatment lost 50% (64.4 kg N ha −1 ) of the applied N due to ammonia volatilization, but losses were reduced by 64% with BrUrea+UI+NI (23.0 kg N ha −1 ) and by 60% with InjUAN (26.1 kg N ha −1 ). Ammonia losses were lower and crop yields were greater in 2014 than 2013 as a result of the more favorable weather when N was applied in 2014. When ammonia volatilization was reduced by adding a urease inhibitor, N 2 O emissions were increased by 30 to 31% with BrUrea+UI and InjUAN+UI compared with BrUrea and InjUAN, respectively. Pollution swapping was avoided when both inhibitors were used (BrUrea+UI+NI, InjUAN+UI+NI) as both ammonia volatilization and N 2 O emissions were reduced, and corn grain yields increased by 5% with BrUrea+UI+NI and by 7% with InjUAN+UI+NI compared with BrUrea and InjUAN, respectively. The combination of two N management strategies (InjUAN+UI+NI) increased yields by 19% (12.9 t ha −1 ) compared with BrUrea (10.8 t ha −1 ). Core Ideas Ammonia volatilization resulted in 50% loss of applied urea over 2 yr. When urease inhibitors were added with urea, ammonia volatilization was reduced by 64%. Injection of UAN reduced ammonia volatilization by 60% compared with broadcast urea. N 2 O emissions were increased by 30 to 31% when urease inhibitors were applied. Pollution swapping was avoided when both urease and nitrification inhibitors were used.