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This article in AJ

  1. Vol. 78 No. 2, p. 346-347
    Received: Feb 19, 1985

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Sharing the Available Fertilizer Rate between Two Crops in a Limited-Capital Situation1

  1. Daniel Isfan2



Fertilizer recommendations are usually based on the maximum economic rate, which gives the greatest profit per unit area. When the capital is limited, this fertilization rate obviously cannot be applied to all crops. In this case, a method to calculate the most profitable fertilizer rates for each crop is needed. The objective of this work is to develop such a method for nitrogen (N) fertilizer applied in the same year to two different crops or else the same crop in two different crop sequences where the fertilizer needs are not the same. The shared economic rates (SR) of N for crop 1 (S1) and crop 2 (S2) can be calculated with equations and where S1 and S2 are shared N rates for crop 1 and 2, in kg ha−1; P1 and P2 are the price of crop 1 and 2, in $ kg−1; A1 and A2 are the areas planted to crop 1 and 2, in ha; A is the total amount of N available for A1 and A2 in kg; and b1, b2, c1, and c2 are the regression coefficients of the quadratic production functions for crop 1 and 2 (Y = a + bN + cN2, where Y is the predicted yield and N the added N, in kg ha−)1).

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