Modeling individual nutrient uptake by plants: Relating demand to microclimate

Abstract

This paper proposes an approach for modeling plant uptake of individual nutrients based on incident microclimatic variables and independent of water uptake. Current nutrient uptake models, though quite complex, have not been developed in a form directly applicable to nutrient management systems for greenhouse crop production. This paper proposes an approach for predicting plant nutrient use based on the assumption that plant nutrient demand, as determined by photosynthetic rate, determines the required rate of nutrient uptake for optimal growth. This general model allows specific models to be developed with direct functional relationships between individual nutrient uptake rates and incident microclimatic variables. A simple model is presented which applies nutrient demand directly to photosynthetic photon flux density.