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Testing a von Liebig Crop Response Function against Polynomial Specifications
Author(s) -
AckelloOgutu Christopher,
Paris Quirino,
Williams William A.
Publication year - 1985
Publication title -
american journal of agricultural economics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.949
H-Index - 111
eISSN - 1467-8276
pISSN - 0002-9092
DOI - 10.2307/1241829
Subject(s) - polynomial , function (biology) , limiting , crop , mathematics , substitution (logic) , crop production , agricultural engineering , plateau (mathematics) , agronomy , computer science , agriculture , mathematical analysis , mechanical engineering , ecology , evolutionary biology , engineering , biology , programming language
Crop responses to fertilizers traditionally have been specified as polynomial functions. Recently, criticisms were raised against such specifications because they force substitution between nutrients and overestimate the optimal fertilizer quantity. With those criticisms, an alternative crop response function was presented in the form of a minimum function which equates the realized output to the production potential associated with a limiting input. In this paper a nonnested test is performed to discriminate between the two rival specifications. The results of this test reject the hypothesis that a crop response is of the polynomial type, while they do not reject the hypothesis that it is of the minimum and plateau type.