Fully-biodegradable controlled release coatings for fertilizer

A new, fully-biodegradable material and method of preparation of slow release fertilizers.
Technology No. 2019-366
IP Status: PCT Patent Application Filed; Application #: PCT/US2020/045216


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

Biodegradable microporous coating

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.

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 microporous coating. Moreover, the new material may offer other advantages such as improving product integrity, flowability and preventing agglomeration.

Key Benefits & Differentiators

  • 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

Phase of Development

Proof of concept. The researchers have created microporous layer around commercially available fertilizer granules and characterized its release properties.

Eric Singsaas, PhD
Initiative Director, Wood Products and Bioeconomy
External Link (www.nrri.umn.edu)
Tim Hagen, PhD
Researcher, Natural Resources Research Institute
External Link (www.nrri.umn.edu)
Stéphan Barbe, PhD
Faculty of Applied Sciences, TH Köln
External Link (www.th-koeln.de)

Desired Partnerships

This technology is now available for:

  • License
  • Sponsored research
  • Co-development

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