Simulating Low-Mobility Nutrient Uptake by Crop Roots Systems Growing in Variable Soil Volumes

We study the absorption of low mobility nutrients by root systems of crops growing in variable soil volumes (such as field conditions in intensive crops) through a moving boundary model. For this model, each individual root in the root system has an accessible volume of soil that varies according to the density of the root system varies in the total variable volume of soil. The resulting equations are solved by the adaptive finite element method. Results obtained from simulations for a same crop growing in fixed and variable volume are shown as a function of the characteristic parameters of the soil-plant system. Unlike the moving boundary model for the same growing crop in a fixed volume, the moving boundary model for a growing crop in a variable volume predicts a greater absorption of nutrient, which depends strongly on the rooting speed in depth of the root system.