title: Economic gains from targeted measures related to non-point pollution in agriculture based on detailed nitrate reduction maps.
abstract: From 1990 to 2003, Denmark reduced N-leaching from the root zone by 50%. However, more measures are required, and in recent years, the focus has been on how to differentiate measures in order to ensure that they are implemented where the effect on N-loss reductions per ha is the greatest. The purpose of the NiCA project has been to estimate the natural nitrate reduction in the groundwater more precisely than before using a plot size down to 1ha. This article builds on these findings and presents the possible economic gains for the farmer when using this information to reach a given N-loss level. Targeted measures are especially relevant where the subsurface N-reduction varies significantly within the same farm and national analyses have shown that a cost reduction of around 20-25% using targeted measures is likely. The analyses show an increasing potential with increasing variation in N-reduction in the catchment. In this analysis, the knowledge of spatial variation in N-reduction potential is used to place measures like catch crops or set-a-side at locations with the greatest effect on 10 case farms in the Norsminde Catchment, Denmark. The findings suggest that the gains are from 0 to 32€/ha and the average farm would gain approximately 14-21€/ha/year from the targeted measures approach. The analysis indicates that the economic gain is greater than the costs of providing the detailed maps of 5-10€/ha/year. When N-loss reduction requirements are increased, the economic gains are greater. When combined with new measures like mini-wetlands and early sowing the economic advantage is increased further. The paper also shows that not all farms can use the detailed information on N-reduction and there is not a clear link between spatial variation in N-reduction at the farm level and possible economic gains for all these 10 farms.
authors.affiliation: Department of Food and Resource Economics (IFRO), University of Copenhagen, Rolighedsvej 25, 1958 Frb. C. Electronic address: brian@ifro.ku.dk.
authors.forename: Brian H
authors.initials: BH
authors.lastname: Jacobsen
authors.affiliation: Department of Hydrology, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350, København K, Denmark. Electronic address: alha@geus.dk.
authors.forename: Anne Lausten
authors.initials: AL
authors.lastname: Hansen
mesh_terms: D000383:Agriculture / Q000379:methods*; D003718:Denmark; D004784:Environmental Monitoring; D009566:Nitrates / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000517:prevention & control* / Q000706:statistics & numerical data
chemical_list: D009566:Nitrates; D014874:Water Pollutants, Chemical
keywords: Cost-effectiveness; N-risk mapping; Nitrate reduction; Non-point pollution; Site specific regulation; Spatial distribution; Targeting