International innovation needed for efficient nitrogen management

Nitrogen is an essential element in the formation of proteins and an integral part of our RNA and DNA. However, the amount of nitrogen available to plants, released through the natural fixation of airborne nitrogen is not enough to produce food for the current global population. As Prof. De Vries explained in his inaugural speech entitled Nitrogen and Ecosystem Services, ChaNgES and ChalleNgES, it is partly thanks to the discovery in 1909 of chemical nitrogen fixation, transforming airborne nitrogen to ammonia used in chemical fertiliser that the world's population has risen from 1.6 billion in 1900 to almost 7 billion today. In his opinion, this discovery was a blessing for humankind. Artificial fertiliser has increased crop yields three to six-fold and ensured that half of the global population has enough to eat.

But, argues De Vries, this blessing also has a downside. Only twenty percent of the nitrogen produced is consumed in case of a vegetarian meal, and in the case of meat, it is less than ten percent. The rest finds its way into the environment, where it is detrimental to public health, nature and the climate.

Increased concentrations of nitrogen oxide in the lower levels of Earth's atmosphere (the troposphere) restrict agricultural yield by approximately 5-10 percent and cause an estimated 21,000 premature deaths in EU member states as a result of respiratory problems. Furthermore, together with ammonia, it contributes to higher concentrations of particulate matter which reduce the life expectancy of Europeans up to 1 year. And in the higher levels of Earth's atmosphere (the stratosphere), nitrogen oxides break down ozone, increasing the risk of skin cancer induced by solar radiation.

High nitrate concentrations in drinking water also lead to health problems. And in surface water, they stimulate the growth of toxic algae and in extreme cases, create anoxic 'dead' zones. Nitrogen in rain water has caused a ten to fifteen percent drop in diversity among plants species and therefore in ecosystem services such as productivity and carbon sequestration. The sum total of all these effects puts the price of nitrogen impacts at between 70 and 230 billion euros, or 150 to 740 euro per European citizen.

The scope of the nitrogen problem demands an urgent global strategy aimed at finding more efficient ways of using nitrogen, states De Vries. The objective should be to increase food production while reducing the burden on the environment. and The nitrogen use efficiency should be increased by measures such as precision fertilisation and the development of more nitrogen-efficient crops. Nitrogen can also be reused, for example by recycling nitrogen in human waste . Technology for converting harmful nitrogen compounds into harmless airborne nitrogen is also available.

Finally, human behaviour is immensely important. The western world should aim to minimise food wastage and cut down on the consumption of animal proteins. The expected rise in meat consumption in countries like China and India is making this increasingly urgent.

De Vries argues that solutions through integrated nitrogen management should get more attention. He is therefore putting forward a case for an international nitrogen innovation project aimed at devising measures to increase food production, while simultaneously improving soil fertility, protecting air and water quality and tackling climate change. And he thinks that Wageningen UR can and must play a major role in this.