Fully-biodegradable Controlled Release Coatings for Fertilizer

University of Minnesota Background
Fertilizers applied to land dissolve quickly resulting in a spike in the fertilizer concentration and subsequently, runoff into water bodies. Fertilizer leaching and runoff results in fertilizer waste, fertilizer burn of plants due to overfertilization, increased cost, and serious environmental issues due to contamination of water bodies. A viable solution to this issue is to use Controlled Release Fertilizers – fertilizer granules that are coated with a porous outer layer to promote slow and steady release of nutrients over a course of time. The outer coating that helps mitigate the leaching and runoff problem, however, is typically made up of plastic resin or sulfur-based polymers, which are not biodegradable and therefore linger in the soil, adding to the plastic footprint. There is increasing regulatory pressure to replace existing controlled-release polymers that have poor biodegradability with polymers that readily and rapidly bio-degrade.
Technology Overview
To address this issue, researchers at the University of Minnesota, in collaboration with TH Köln, have developed a fully-biodegradable microporous coating material suitable for creation of slow-release fertilizers. This coating material is 100% naturally-derived as opposed to the currently used synthetic materials. This new material is prepared in a liquid solvent and can be conveniently sprayed onto surfaces or fertilizer granules to create a microporous coating. Moreover, the new material may offer other advantages such as improving product integrity, flowability and preventing agglomeration.
Stage of Development
Proof of concept. The researchers have created a microporous layer around commercially available fertilizer granules and characterized its release properties.


100% naturally-derived and biodegradable
Microporous layer facilitates slow and sustained release of nutrients
Residual material degrades over time without adding significant nutrition to soil
Easy application by spray-coating


Agricultural and landscape fertilizers
Solid Insecticides
Solid Herbicides
Water treatment chemicals
Road de-icing

This technology is now available for:

Sponsored research

The University is excited to partner with industry to see this innovation reach its potential.
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