H. van Grinsven

Nitrogen as a threat to European water quality

Grizzetti, B., Bouraoui, F., Billen, G., van Grinsven, H., Cardoso, A. C., Thieu, V., Garnier, J., Curtis, C., Howarth, R. W. and Johnes, P. (2011) Nitrogen as a threat to European water quality. In: Sutton, M. A., Howard, C. M., Erisman, J. W., Billen, G., Bleeker, A., Grennfelt, P., van Grinsven, H. and Grizzetti, B. (eds.) European Nitrogen Assessment. Cambridge University Press, UK, pp. 379-404. ISBN 9781107006126 Available at http://centaur.reading.ac.uk/20869/

Lessons from temporal and spatial patterns in global use of N and P fertilizer on cropland

In recent decades farmers in high-income countries and China and India have built up a large reserve of residual soil P in cropland. This reserve can now be used by crops, and in high-income countries the use of mineral P fertilizer has recently been decreasing with even negative soil P budgets in Europe. In contrast to P, much of N surpluses are emitted to the environment via air and water and large quantities of N are transported in aquifers with long travel times (decades and longer). N fertilizer use in high-income countries has not been decreasing in recent years; increasing N use efficiency and utilization of accumulated residual soil P allowed continued increases in crop yields. However, there are ecological risks associated with the legacy of excessive nutrient mobilization in the 1970s and 1980s. Landscapes have a memory for N and P; N concentrations in many rivers do not respond to increased agricultural N use efficiency, and European water quality is threatened by rapidly increasing N:P ratios. Developing countries can avoid such problems by integrated management of N, P and other nutrients accounting for residual soil P, while avoiding legacies associated with the type of past or continuing mismanagement of high-income countries, China and India.

Potential of extensification of European agriculture for a more sustainable food system; the case for nitrogen and livestock

Most global strategies for future food security focus on sustainable intensification of production of food and involve increased use of nitrogen fertilizer and manure. The external costs of current high nitrogen (N) losses from agriculture in the European Union, are 0.3–1.9% of gross domestic product (GDP) in 2008. We explore the potential of sustainable extensification for agriculture in the EU and The Netherlands by analysing cases and scenario studies focusing on reducing N inputs and livestock densities. Benefits of extensification are higher local biodiversity and less environmental pollution and therefore less external costs for society. Extensification also has risks such as a reduction of yields and therewith a decrease of the GDP and farm income and a smaller contribution to the global food production, and potentially an i0ncrease of global demand for land. We demonstrate favourable examples of extensification. Reducing the N fertilization rate for winter wheat in Northwest Europe to 25–30% below current N recommendations accounts for the external N cost, but requires action to compensate for a reduction in crop yield by 10–20%. Dutch dairy and pig farmers changing to less intensive production maintain or even improve farm income by price premiums on their products, and/or by savings on external inputs. A scenario reducing the Dutch pig and poultry sector by 50%, the dairy sector by 20% and synthetic N fertilizer use by 40% lowers annual N pollution costs by 0.2–2.2 billion euro (40%). This benefit compensates for the loss of GDP in the primary sector but not in the supply and processing chain. A 2030 scenario for the EU27 reducing consumption and production of animal products by 50% (demitarean diet) reduces N pollution by 10% and benefits human health. This diet allows the EU27 to become a food exporter, while reducing land demand outside Europe in 2030 by more than 100 million hectares (2%), which more than compensates increased land demand when changing to organic farming. We conclude that in Europe extensification of agriculture is sustainable when combined with adjusted diets and externalization of environmental costs to food prices.

Developing integrated approaches to nitrogen management

Oenema, O., Salomez, J., Branquinho, C., Budnakova, M., Cermak, P., Geupel, P., Johnes, P., Tomkins, C., Spranger, T., Erisman, J. W., Palliere, C., Maene, L., Alonso, R., Maas, R., Magid, J., Sutton, M. A. and van Grinsven, H. (2011) Developing integrated approaches to nitrogen management. In: Sutton, M. A., Howard, C. M., Erisman, J. W., Billen, G., Bleeker, A., Grennfelt, P., van Grinsven, H. and Grizzetti, B. (eds.) European Nitrogen Assessment. Cambridge University Press, UK, pp. 541-550. ISBN 9781107006126 Available at http://centaur.reading.ac.uk/20872/

Nitrogen use and food production in European regions from a global perspective.

Current production systems for crops, meat, dairy and bioenergy in the European Union (EU) rely strongly on the external input of nitrogen (N). These systems show a high productivity per unit of land. However, the drawback is a complex web of N pollution problems contributing in a major way to degradation of ecosystems. European Union Directives and national policies have improved nutrient management and reduced fertilizer N use in most European countries, which has curbed the N pollution trends particularly in regions with high stocking rates of animals. However, improvement is slowing down and environmental targets for N are not within reach. Building on the 2011 European Nitrogen Assessment, the current paper reviews key features of the complex relationships between N use and food production in Europe in order to develop novel options for a more N-efficient, less N-polluting and secure European food system. One option is to relocate feed and livestock production from Northwestern to Central and Eastern Europe. This would allow a reduction of N rates and N pollution in cereal production in Northwest Europe by 30% (50 kg N/ha), while increasing total cereal production in Europe. Another option is a change towards legume-based cropping systems to produce animal feed, in order to decrease dependence on N fertilizer and feed imports. The greatest challenge for Europe is to decrease the demand for feed commodities, and thus for land and N, by a shift to more balanced (and healthier) diets with less animal protein. These drastic changes can be stimulated by targeted public–private research funding, while the actual implementation can be enhanced by smart payment schemes using, for example money from the Common Agricultural Policy, certification and agreements between stakeholders and players in the food and energy chain. Involving networks of consumers, producers and non-governmental organizations is critical. An effective strategy starts with convincing consumers with aWestern diet to eat less meat and dairy by communicating the associated health benefits and smaller ecological footprints. Internalizing the cost of N pollution leading to increased prices for N-intensive food products may also enhance involvement of consumers and provide financial resources to compensate farmers for loss of income and extra costs for stricter N measures.