European agriculture produces an abundance of high quality food, but also massive amounts of waste from crops and farm animals, including about 1.4 billion tonnes of manure each year.

Farm waste is bursting with nutrients, but these are often in complex organic molecules, which take time to break down into minerals for crop plants to use. Manure is voluminous, difficult to transport and usually generated far from crop fields. Consequently, farmers rely on chemical fertiliser that is often imported into Europe.

While the EU market for fertiliser is valued at between €20 - 25 billion per year, synthetic fertiliser accounts for 80% of products. The nitrogen is made by taking the chemical from the air and using energy from fossil fuels to convert it into ammonium salts that plants easily consume. Phosphorous, the other main ingredient in chemical fertiliser, is made from rocks mined mostly in Morocco, but also China and the US.

Meanwhile, nutrients spread onto farmland can leach into rivers and lakes, causing algal blooms and fish deaths, or evaporate as greenhouse gases.

‘We have too many nutrients flowing around in Europe, causing environmental problems,’ said Professor Erik Meers, an environmental chemist at Ghent University in Belgium. ‘We also have an increasing amount of chemical fertiliser, nitrogen and phosphate, being used.’

Read the full article about green fertilizer at The Naked Scientist.