Nitrogen inputs by irrigation is a missing link in the agricultural nitrogen cycle and related policies in Europe
Irrigation, one of the 28 agri-environmental indicators defined in the European Common Agricultural Policy, is often neglected in agricultural nitrogen (N) budgets, while it can be a considerable source of N in irrigated agriculture. The annual N input from irrigation water sources (NIrrig) to cropping systems was quantified for Europe for 2000–2010 at a resolution of 10 × 10 km, accounting for crop-specific gross irrigation requirements (GIR) and surface- and groundwater nitrate concentration. GIR were computed for 20 crops, while spatially explicit nitrate concentration in groundwater was derived using a random forest model. We show that although GIR were relatively stable (46–60 km3 yr-1), the Nirrig in Europe increased over the 10-year period (184 to 259 Gg N yr-1), approximately 68 % of which occurred in the Mediterranean region. The main hotspots appeared in areas with both high irrigation requirements and high groundwater nitrate concentration, reaching up to averaged values of 150 kg N ha-1 yr1. These were mainly located in Mediterranean Europe (Greece, Portugal and Spain) and to a lesser extent in Northern Europe (The Netherlands, Sweden and Germany). By not including NIrrig, environmental and agricultural policies are underestimating the real extent of N pollution hotspots in European irrigated systems.
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article/Letter to editor biblioteca |
| Language: | English |
| Subjects: | Agrienvironmental indicator, Irrigation water, Nitrate pollution, Nutrient management, Water balance, Water management, |
| Online Access: | https://research.wur.nl/en/publications/nitrogen-inputs-by-irrigation-is-a-missing-link-in-the-agricultur |
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