Use of Multi-Diffusion Model to Study the Release of Urea from Urea Fertilizer Coated with Polyurethane-Like Coating (PULC)

Controlled release fertilizer (CRF) play an important role in nutrient loss prevention and plant's uptake efficiency. This
study uses a multi-diffusion model to simulate urea release from urea fertilizers coated with polyurethane-like coating
(PULC). In this model, finite element method (FEM) and 2D geometry are applied for three sizes of urea granule using
COMSOL Multiphysics software. Modeling results are in agreement with the experimental data for the "constant release"
stage. Standard error of estimate (SEE) ranges from 0.00417 to 0.02084 in these simulations. Besides, relationship of
coating thickness with release time and percent of urea released at the end of "constant release" stage has also been
established.