Plant Competition and Crop Yield

Abstract

Shinozaki and Kira¹ by combining a logistic equation of population growth (equation (1)) with the law of constant final yield (equation (2)) derived equation (3) to describe the relationship between plant density and yield. or where at a given time t, w is the dry weight of each plant and W is the asymptote of w, λ is the coefficient of growth which is independent of plant density ρ, k is the integration constant, determined by the initial conditions and independent of plant density, Y is the final yield/unit area, and independent of density, and W₀ is w at t = 0. The law of constant final yield, however, may not always be satisfied (data to be published elsewhere) and the yield in higher densities may decline. In these conditions, equation (3) cannot describe the yield–density relationship. The validity of the logistic equation (equation (1)), as tested for different crops^1,2, has proved to be justified so far, and it seems that it is the law of constant final yield which needs further modification.