Vol. 11, Issue 6 (2022)

Author(s):
Kamlesh Kumar, Ashok Kumar, Hari Singh Meena B Raghavendra Goud, Vinod Kumar and Radheshyam

Abstract:
Rapid nitrification is one of the key factors of inefficient nitrogen use in maize and use of neem oil-coated urea holds immense promise to use fertilizer nitrogen efficiently. Therefore, a field experiment was conducted at the Research Farm of Division of Agronomy, ICAR-Indian Agricultural Research Institute, New Delhi to get insights on effect of the different doses of nitrification inhibitors and varying levels of nitrogen on the NH₄⁺ and NO₃^--nitrogen content in soil, nutrients uptake and nitrogen use efficiency of maize. The treatment consisted of three nitrification inhibitors (Dicynadiamide, neem oil and meliacin) each with two different concentrations (350 and 700 ppm of neem oil and meliacin and 5% and 10% of Dicynadiamide) and two levels of nitrogen (135 and 180 kg N/ha). Result showed that different parameters viz. grain yield, stover yield and harvest index were significantly influenced by levels of nitrogen and nitrification inhibitors. The meliacin coated urea (MCU) at 350 ppm @ N₁₈₀ recorded maximum grain yield and stover yield which was comparable with MCU₇₀₀@N₁₈₀. Uptake of nitrogen, phosphorus and potassium by grain, straw and total uptake was significantly higher with MCU₃₅₀@N₁₈₀. Highest agronomic efficiency and physiological efficiency were recorded with the application of MCU₃₅₀@N₁₈₀ and highest nitrogen harvest index (NHI) was obtained with MCU₇₀₀@N₁₃₅. Maximum concentration of NH₄⁺-N in soil was recorded with application of MCU₇₀₀@N₁₈₀ and it was significantly higher over all other levels of nitrogen and nitrification inhibitors. The higher amount of soil NH₄⁺-N for longer period with MCU₃₅₀@N₁₈₀ indicated that this treatment had the most durable effect on nitrification inhibition. It was concluded that the coating of urea with meliacin @ 350 ppm is effective in enhancing the nutrient uptake, nutrient use efficiency and yield of kharif maize.