Fractional nutrient uptake model of plant roots.

Most nutrient uptake problems are modeled by the convection-diffusion equation (CDE) abiding by Fick's law. Because nutrients needed by plants exist in the soil solution as a form of ions and the soil is a typical fractal structure of heterogeneity, it makes the solute transport appear anomalous diffusion in soil. Taking anomalous diffusion as a transport process, we propose time and space fractional nutrient uptake models based on the classic Nye-Tinker-Barber model.