Better recycling of nutrients in the agricultural ecosystem would cut demand for fertilisers and reduce our dependence on Russian phosphorus imports, write a group of scientists from the Baltic Sea Centre.
By Gun Rudquist, an advocacy and analysis officer and Dr. Michelle McCrackin and Dr Annika Svanbäck, research scientists at the Baltic Sea Centre at Stockholm University.
One would have guessed that the new regulation on fertiliser trade, recently proposed by the EU Commission, would be followed by intense discussions about things like green economy and agricultural practices. But instead the whole deal has turned into a geopolitical debate.
The Commissions’ longed-for legal initiative is now jeopardised by a looming fear among member states of increased dependence on Russia – amply demonstrated by the current debate on cadmium thresholds in fertilisers.
The proposal suggests increased trade of organic fertilisers and stricter thresholds for a number of toxic metals, including cadmium, which is toxic to humans. Cadmium is easily taken up by plants from the soils, and humans can absorb it through food such as grains and vegetables.
It so happens that Russia sits on a huge natural resource of phosphate rock that has lower content of cadmium than the phosphate in Morocco, which presently supplies the EU fertiliser industry with raw material. The fear seems to be that the proposed new cadmium thresholds would disqualify Moroccan phosphate rock – and make the EU dependent on Russia to maintain its agricultural production.
Phosphate rock is a finite resource, and the European Commission has added it to the list of 20 Critical Raw Materials for which supply security is at risk and economic importance is high. Still, phosphorus is an essential plant nutrient, and the EU needs it to maintain yields in agriculture.
So the key question is, what can be done to save the proposed regulation on fertiliser trade, and thereby reduce the import of new cadmium to the agro-ecosystem to mitigate the risks for human health – and at the same time reduce dependence on phosphate rock from abroad?
One answer is: use available nutrients more efficiently.
The regulation on fertiliser trade is not only about thresholds of cadmium; the key objective is to implement the concept of circular economy by facilitating trade (and use) of organic fertilisers – like manure. Using manure more efficiently would reduce the need for imported mineral fertilisers.
But presently, manure is poorly handled in many agricultural regions throughout Europe. Its full potential as a plant nutrient is far from being exploited. This results in a huge waste of crucial nutrients, as well as polluted waters – not only seas and rivers but also groundwater.
The Baltic Sea region is unfortunately a good example. There, eutrophication is a severe environmental problem, with agriculture as the single largest source of new nutrients to the Baltic Sea contributing about half of the total waterborne nitrogen and phosphorus inputs. Mineral fertilisers and feed imports represent most of the new nutrients brought into the Baltic Sea region through trade, and makes nutrient flows in the livestock sector especially large. About 70% of crop production is fed to animals, while only 30% is consumed directly by people. And each year, 23 million pigs, 16 million cows, and 244 million chickens in the region together produce manure containing two million tons of nitrogen and 0.4 million tons of phosphorus. Each year.
Most of the manure is used in agriculture. But new research from the Baltic Sea Centre at Stockholm University show that nutrient use efficiency (NUE*) can be greatly improved in many agricultural regions in the nine countries surrounding the sea – by using manure more efficiently and recycle nutrients more. In fact, in many regions the crops’ nutrient demand could be fully supplied by the amount of manure produced there.
But manure is bulky and expensive to transport long distances. So instead of being an important source for nutrients, for example phosphorus, manure is often seen as a waste product. As a result, too much manure is put on many farmlands, which creates huge nutrient surpluses.
Agricultural systems can never be perfectly efficient. There will always be unavoidable nutrient losses. But in the Baltic Sea region an average of only 43% of nitrogen and 62% of phosphorus in mineral fertilisers and manure are converted to harvested crops.
Such low NUE-values are not unique for the Baltic region. The EU imports around 1.5 million tons of phosphorus in fertilisers every year. Scientific studies estimate that the NUE for phosphorus in crop production is 70%. If efficiency was increased to 80%, the EU could reduce fertiliser imports by 25% (about 0.4 million tons of phosphorus annually).
This shows that the way manure is handled in the agricultural production system is key to reaching the goals of avoiding nutrient surpluses – and reducing fertiliser import.
In practice, this requires:
- only applying as much nutrients as the plants need
- more nutrient recycling
- better manure handling
- promoting increased trading of manure
- more even distribution of animals in relation to the available agricultural area
Applied throughout the EU, these practices would lead to increased nutrient use efficiency, and the possibility to substantially reduce the import of mineral phosphorus from abroad.
So, instead of arguing about which country to buy mineral phosphorus from, the member states and the European Parliament should focus on adopting the fertiliser regulation. With clear rules on fertiliser trade in place, manure can be handled better, and trading between regions can be stimulated. This will in turn improve nutrient use efficiency, reduce dependence on imported mineral fertilisers – and put less new toxic cadmium in our soils.