Model for accumulation of dry matter and plant nutrient elements by tobacco

Abstract

Accumulation of dry matter by warm‐season annuals depends upon time of season, including planting time. A mathematical model has been developed to simulate the growth process. The model contains a Gaussian environmental function and a linear‐exponential intrinsic growth function. Previous work has shown the applicability of the model to data for the perennials bahiagrass (Paspalum notatum) and bermudagrass (Cynodon dactylon), and to the warm‐season annual corn (Zea mays). This article applies the model to field data for the warm‐season annual flue‐cured tobacco (Nicotiana tabacum), demonstrating that it applies to a broad‐leafed crop. A hyperbolic relationship between plant nutrient element accumulation [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), or magnesium (Mg)] and dry matter accumulation has been included. Since total plant dry matter accumulates at a faster rate than plant nutrient elements, plant nutrient element concentrations for N, P, K, Ca, and Mg all decrease rapidly with age. A consequence of the growth model is an equation for estimating optimum time of transplanting in terms of the parameter values assumed. Optimum time of planting precedes the mean of the environmental function by nine weeks due to the exponential term in the intrinsic growth function.

Notes

Florida Agricultural Experiment Station Journal Series No. R‐06285.