Turning cow dung into green fertiliser

In an effort to reduce agriculture emissions, researchers around Europe are finding ways to turn nutrient-rich farm waste such as chicken feathers and cow dung into eco-friendly fertiliser.

According to an article in Horizon, an EU magazine on research and innovation, the European agriculture industry is responsible for producing massive amounts of waste from crops and farm animals. But instead of recycling this nutrient-rich farm waste into green fertilisers, farmers have mostly relied on imported chemical fertilisers.

Researchers across Europe now want to change this. “We aim to convert the linear chain we have today into a circular chain by recycling nutrients,” says Dr Victor Riau Arenas, a scientist at the Institute of Agrifood Research and Technology in Spain.

To do so, the researchers have to overcome two challenges. First, they need to process the waste to extract the nutrients that can be used to fertilise crops. Second, they need to turn those nutrients into products that can replace imported synthetic fertiliser.

Some scientists are taking the circular agriculture economy approach one step further and working on how these recycled nutrients can be used to grow animal feed. For example, a Nutri2Cycle project in Belgium will give treated pig manure in liquid form to duckweed, a floating plant that is high in protein. This could help replace some of the millions of tonnes of soybean, a protein-rich animal feed, shipped to Europe last year.

Other efforts to reduce the environmental footprint of the agriculture industry include the use of solar heating to process and dry manure to produce fertilisers, precision feeding of dairy cows to cut down on manure and emissions, and even recovering nitrogen and phosphorous from food industry waste.

“We will reduce the use of chemical fertiliser, which will reduce costs, but also the environmental impact of agriculture on soils and leaching of nitrates into groundwaters,” says Dr Riau.

Image credit: Genta via Flickr

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