Enhancing nitrogen use efficiency and yield of maize (Zea mays L.) through Ammonia volatilization mitigation and nitrogen management approaches

Management of nitrogen (N) fertilizer is a critical factor that can improve maize (Zea mays L.) production. On the other hand, high volatilization losses of N also pollute the air. A field experiment was established using a silt clay soil to examine the effect of sulfur-coated urea and sulfur from gypsum on ammonia (NH3) emission, N use efficiency (NUE), and the productivity of maize crop under alkaline calcareous soil. The experimental design was a randomized complete block (RCBD) with seven treatments in three replicates: control with no N, urea(150) alone (150 kg N ha(-1)), urea(200) alone (200 kg N ha(-1)), urea(150) + S (60 kg ha(-1) S from gypsum), urea(200) + S, SCU150 (sulfur-coated urea) and SCU200. The results showed that the urea(150) + S and urea(200) + S significantly reduced the total NH3 by (58 and 42%) as compared with the sole application urea(200). The NH3 emission reduced further in the treatment with SCU150 and SCU200 by 74 and 65%, respectively, compared to the treatment with urea(200). The maize plant biomass, grain yield, and total N uptake enhanced by 5-14%, 4-17%, and 7-13, respectively, in the treatments with urea(150) + s and urea(200) + S, relative to the treatment with urea(200) alone. Biomass, grain yield, and total N uptake further increased significantly by 22-30%, 25-28%, and 26-31%, respectively, in the treatments with SCU150 and SCU200, relative to the treatment with urea(200) alone. The applications of SCU150 enhanced the nitrogen use efficiency (NUE) by (72%) and SCU200 by (62%) respectively, compared with the sole application of urea(200) alone. In conclusion, applying S-coated urea at a lower rate of 150 kg N ha(-1) compared with a higher rate of 200 kg N ha(-1) may be an effective way to reduce N fertilizer application rate and mitigate NH3 emission, improve NUE, and increase maize yield. More investigations are suggested under different soil textures and climatic conditions to declare S-coated urea at 150 kg N ha(-1) as the best application rate for maize to enhance maize growth and yield.