Study the release pattern of nitrogen as ammonical and nitrate nitrogen from neem-coated and prilled urea in rice as a test crop

Abstract

Release pattern of nitrogen as ammonical and nitrate nitrogen from different levels of neem-coated and prilled urea applied in rice was conducted on vertisol during Kharif 2019. The concentration of ammonical and nitrate nitrogen was measured on 3, 5 and 7 days after each application of N fertilizer at 10, 30 and 50 days after transplanting. The effect of different levels of neem coated and prilled urea on concentration of ammonical (NH4-N) and nitrate nitrogen (NO3-N) in flood water were found significant. The increasing levels of neem coated and prilled urea increased the concentration of ammonical nitrogen and nitrate nitrogen in flood water on the different days. The peak concentration of ammonical and nitrate nitrogen in flood water was observed on 3 days after application of neem coated and prilled urea and decreased gradually on 5th and 7th days after the application. The highest concentration of ammonical and nitrate nitrogen was observed in T9(STCR based yield target 6t) treatment and the lowest was recorded in treatment T1-control. The concentration of nitrate in flood water was lower than ammonia due to the reductive condition of the flooded rice field. The results showed that neem coated urea slow down the conversion of nitrogen amide (urea) in to NH4+ and thus increases the time its availability for longer time as compared to the prilled urea.