Abstract

                                Efforts to evolve a quantitative relationship between the final yield and growth factors were made from time to time by soil investi- gators. In Mitscherlich's equation log (A-Y)= log A-C (b + x) where A = maximum yield, Y = yield obtained when epsilon_{b} ^ * units of the nutrient are originally present in soil and 'x' units of it are added as fertilizers while 'C' is the efficiency factor of E * b' and ' x ^ * the soil growth factor 'b' was not analysed, but was calculated in terms of 'x' Spillman's modified equation X = A(1 - 10) also falls in the same line of conception.

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