Generalization of Yield Equations in Two or More Variables: I. Theoretical Considerations 1

Synopsis Particular quadratic yield equations which define crop yields in the restricted sense of given fixed soil fertility levels may, in theory, be generalized to other forms of the quadratic equation which define crop yields over a range of initial soil fertility levels. The similarity of the coefficients of the terms derived from different generalized equations may be tested by assuming appropriate null hypotheses and testing them by applicable statistical methods.