Abstract

Field experiments were conducted during Kharif and rabi seasons of 1991-92 to study the effect of nitrogen (N) sources on the availability of different inorganic N forms in Typic Ustropept Wetland rice soil. The results indicated that the NH4 - N, NO3 - N and available N content of the soil declined with crop growth during both the seasons. Increasing levels of N application up to 175 kg N ha increased the NH4-N, NO3-N and available N content of the soil. Application of neem cake coated urea (NCU) recorded the lowest content of NO3-N in the soil during both the seasons. Among the applied N sources, NCU followed by urca gypsum, prilled urea + green leaf manure recorded the highest NH4-N and available N content of the soil in both the seasons.

Keywords: Inorganic Nitrogen Forms, Neem Cake Coated Urea, Urea gypsum, Wetland Rice.