Nutrient cycling

Phosphorus (P) and nitrogen (N) along with other mineral nutrients are essential to all life. They are needed in crop production. There is no alternative for phosphorus and the mineral phosphorus resources are rapidly shrinking. Nitrogen fertilizers for their part are produced in highly energy intensive processes that accelerate climate change. Nitrogen compounds originating from nitrogen fertilizers are emitted into the atmosphere causing global warming. In the Baltic Sea the nutrients cause eutrophication and end up creating more dead zones on the sea bottom.

Right now only a fraction of vital nutrients end on our plates. The valuable resources are lost along the entire food chain: from primary production, processing and consumption. Because of the leaks in different stages, only 20 – 25 % of the mined P-rock ends up in the food we eat. After consumption of the food, nutrients are then lost in the waste water treatment processes.

Leaked nutrients from various sources end up in water courses causing eutrophication. The nutrient cycle needs to be closed and leakage prevented. Valuable nutrients contained i.e., in organic household waste, food industry’s side streams, manure and municipal wastewater need to be recovered. Agricultural practices should focus on sustainable nutrient management and preventing nutrient leakages. The next step is to produce precise, tailored fertilizers from human and animal organic waste and create real market for them.

Recycling of nutrients would not only save the water systems but would feed the world. The UN has estimated the world’s population growth to require a 60 % growth in food production by 2050. Without recycling of nutrient this can’t be done.

LINKS:

BSAG policy paper May 2015

Nutrient cycling at the core of circular economy

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