Field experiment was conducted on a red calcareous clay-loam soil.testing low.medium and high for available N.P.and K respectively. Four levels each of N.P.and K.@0.60,120. and 180 Kg N/ha.0.15,30 and 45 Kg P/ha and 0.30.60 and 90 Kg K/hawere tried.Hybrid maize (Variety-Deccan)was grown as test crop.The crop responded significantly to N fertilization alone.The quadratic equation showed 193 Kg N/ha as physical optimum and 182 Kg N/ha as economic optimum.P and K didnot increase the maze grain yield.Nitrogen fertilization progressively increased the straw yield Straw yield decreased with increase P level and the influence of added K on the straw yield was not significant.The results of the investigation revealed further that it is not economical to apply phophatic and potassic fertilizers to the maize crop when the inherent availability of these nutrients in the soil is either under medium or high status according to soil Test Classification.I30to N.fertilization alone.The quadratic equation showed
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