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Sharing the Available Fertilizer Rate between Two Crops in a Limited‐Capital Situation 1
Author(s) -
Isfan Daniel
Publication year - 1986
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1986.00021962007800020026x
Subject(s) - crop , fertilizer , mathematics , yield (engineering) , crop yield , agronomy , profit (economics) , agricultural science , environmental science , economics , biology , physics , microeconomics , thermodynamics
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 ( S 1 ) and crop 2 ( S 2 ) can be calculated with equationsS 1 =P 2 A 2 b 2 ‐ P 1 A 2 b 1 + 2 P 2 c 2 k 2 ( P 1 A 1 c 1 + P 2 A 1 c 2 )andS 2 = k ‐ A 1 S 1A 2, where S 1 and S 2 are shared N rates for crop 1 and 2, in kg ha −1 ; P 1 and P 2 are the price of crop 1 and 2, in $ kg −1 ; A 1 and A 2 are the areas planted to crop 1 and 2, in ha; k is the total amount of N available for A 1 and A 2 in kg; and b 1 , b 2 , c 1 , and c 2 are the regression coefficients of the quadratic production functions for crop 1 and 2 ( Y = a + bN + cN 2 , where Y is the predicted yield and N the added N, in kg ha −)1 ).