Change in maize yield, N use efficiencies and climatic warming potential after urea combined with Nitrapyrin and NBPT during the growing season in a black soil

Abstract

Increasing nitrogen (N) utilization and reducing N losses are a globally accepted strategy for N fertilizer application. However, little information has been reported on the fate of N when urea (U) and nitrification and/or urease inhibitors are used in black soils. Therefore, a two-year field experiment was conducted with three N fertilizer application treatments, including urea-only, urea combined with nitrification inhibitor (U+NI), urea combined with NI and urease inhibitor (UI) treatments. Maize (Zea mays L.) yield, N use efficiency, gas emissions, global warming potential (GWP), and apparent N loss were determined. Compared to the other treatments, the U+NI+UI treatment had the significantly (P < 0.05) highest maize yield (11.2 t ha-1), N recovery efficiency (44.5%), agronomic N efficiency (28.7 kg kg-1) and N partial factor productivity (75.8 kg kg-1). Moreover, the U+NI+UI treatment significantly (P < 0.05) reduced the peak of Ammonia (NH3) volatilization and nitrous oxide (N2O) emissions, cumulative NH3 volatilization and N2O emissions, and apparent N loss compared to the U treatment. Although there was no significant difference in cumulative N2O emissions between the U+NI+UI and U+NI treatments, the U+NI+UI treatment significantly (P < 0.05) reduced cumulative NH3 volatilization by 55.3%, GWP by 16.2%, and apparent N loss by 28.2% compared to the U+NI treatment. Overall, the combination of urea with urease and inhibitors is a good practice to improve maize yield and N use efficiency while reducing environmental impacts in black soil.