Mathematical model and computer simulation for release of nutrients from coated fertilizer granules

Controlled release of nutrients from coated fertilizer granules is desired for optimal uptake by plants and crops. We study the saturation and release of nutrients from a coated spherical fertilizer granule having varying contact areas with the soil using the techniques of mathematical modeling and computer simulation. The effects of granule radius, diffusion coefficient and contact area on saturation time as well as on the release time of nutrients are studied. The effect of evaporation loss on the saturation time is also investigated. Understanding these effects quantitatively is very useful in determining the radius and coating width while manufacturing such granules and also educating the farmers about selection of the granules.