Distribution of Native Fixed Ammonium and other Forms of Nitrogen in Different Soils of West Bengal

All the soils representing different agroclimotic regions of West Bengal contained native fixed NH₄+ which ranged from 0.61 to 2.28 m.e./l00g and contributed 61 to 100% of the mineral nitrogen of the soils. As a fraction of total nitrogen, it varied from 4.90% to 54.06%. Inorganic nitrogen contributed substantially (6.30 to 54.70%) to total N. Organic C/Organic N values were found to be considerably higher than organic C/total N. Significant correlation was observed between native fixed NH₄+ and clay+silt, CEC and inorganic N.