Opinie: stikstof, teveel van het goede

Door Jan Willem Erisman, directeur van het Louis Bolk Instituut en hoogleraar Integrale Stikstofproblematiek.

In 1898 Sir William Crookes called upon England and all other civilised nations to help solve the food-security problem. The production of food depended too much on natural resources, such as guano, which were rapidly depleting. Now, more than 100 years later, we again face the challenge of food security for the fast-growing population. Now, though, we talk about different natural resources, such as fertile land, water and phosphorus. We have solved Crookes nitrogen shortage by establishing a large chemical industry. But is this a good thing?

"Nitrogen pollution has become one of the most important global environmental issues"

The use of fertilisers ensures sufficient food to feed half of the world's population. Furthermore, the meat industry has increased tremendously, which is also partly due to the availability of fertilisers. However, there are appreciable leakages of nitrogen into the environment owing to agricultural practices. An over-abundance of nutrients in the environment leads to acidification of soil and water. Nitrogen emissions and deposition cause poor air quality and have impact on climate stability through N2O emissions. Nitrogen pollution has become one of the most important global environmental issues, affecting food security negatively because of its effects on ecosystems.

Nitrogen emissions need to be reduced in order to meet the needs of the growing population with its changing diets while improving the environment. We are gradually realising that we need to ensure that our food production, transport, retail models, food preparation and waste management become more sustainable. Although each link in the food-supply chain is currently attempting to make its own contribution more sustainable, the overall result will not necessarily ensure a sustainable chain. Footprint modelling assesses the whole chain of nitrogen emissions for consumer products. This might serve as a starting point for an integral approach to sustainable agriculture and healthy nutrition. (See www.N-print.org to calculate your nitrogen footprint).

According to the Dutch Council for Integral Sustainable Agriculture and Nutrition, food production has, to a large extent, been removed from its ecological and social context. From an ecological point of view, agriculture has been reduced to systems with disrupted cycles and low biodiversity, in which little self-regulation takes place. Such agricultural systems are highly dependent on the external inputs of fertilisers, pesticides and veterinary medicines. The distance between producers and consumer's of food has increased, as has the number of links in the food-production chain. Much of our food is processed, with the result that it has become anonymous to the consumer. As a result, consumers feel little responsibility for production methods and the agro-ecosystem.

Food must once again be reconnected with visible ties to its ecological and social context. Food production must be removed from its situation of anonymity, and once again acquire a face and an identity. Such a development is often simpler if food originates from a consumers own region. The linear food-supply chain must give way to a circular food cycle. A cycle enables consumer and producer to re-establish some form of communication with one another, and a sense of responsibility towards one another. This could result in increased ecological resilience and improved food quality, as well as a strengthened food culture. Eventually, this will also solve most of our nitrogen problems.

08 mei 2012

Deze column is eerder verschenen in Change Magazine, Floriade Dialogue (nummer 1 2012)