Knowledge Based Bio-Economy


Reducing nitrogen migration from farms to water sources

Project acronym: N-Toolbox

Title of project: Toolbox of cost-effective strategies for on-farm reductions in N losses to water

Research area: Agriculture & Forestry (Novel approaches for reducing nitrogen losses)

Contract No: 227156

EU contribution: €994 000

Start date: March 2009

Duration: 42 months


Current intensive farming methods result in significant levels of nitrogen, as nitrates, polluting natural sources of water, such as lake and rivers. This arises from various sources, including the spreading of nitrogen fertiliser, the run-off from animal husbandry, and the deposition of treated sewage or animal sludge on land.

The aim of this supporting action is to develop a ‘toolbox’ of cost-effective technologies to be implemented at the farm level to protect water from such nitrate pollution. The first activity will be to catalogue available technologies for reducing N losses on the farm generated from previous research results and local experience. The technologies identified will be prioritised based on their cost-effectiveness and efficiency at reducing N losses. They will be listed according to geographical regions where they are being implemented and production systems to enable easy identification of the best management option for specific local conditions.

The second activity will be the development of an enhanced decision support tool (NDICEA) which can be used at the farm level to illustrate options for improved N management and assist farmers in reaching their goals of complying with the Nitrates Directive. NDICEA, which has been developed by the Louis Bolk Institute, has been calibrated for a number of long-term crop-rotation experiments and validated using data from more than 35 organic farms. The model is used to calculate soil-specific mineralisation rates in precision applications and has been further developed in order to design and evaluate crop rotation performance. Hence, it may be used to judge the sustainability of various farming systems. It will be further enhanced using outputs from ongoing and previous projects carried out by the project partners. The resulting toolbox will be implemented through case study farms, and the results documented in the form of a ‘blueprint’ for implementing water protection policy at the farm level across the EU.

Expected impacts

N-Toolbox will lay the foundations for improved implementation of water protection policy at the farm level throughout the EU. The Nitrates Directive (91/676/EC) seeks to limit nitrogen levels to 50 mg/l in ground and surface waters across the Union. Agriculture has been blamed as the main cause of levels rising above this. EU Member States have to designate Nitrate Vulnerable Zones (NVZs) and monitor water quality to assess the effectiveness of their action programmes which are designed to meet the targets. This has led to changes in farm practices, including those related to animal husbandry and slurry disposal, crop choice and fertiliser management. Application of the results from this project will put farmers in a stronger position to adapt to these regulations by increasing their understanding of the causes and control of nitrate loss into the environment.

Expected results

This project will produce a detailed analysis of innovative and cost-effective technologies that have proven effective means of reducing loss of nitrogen into the environment across a range of N-losses environments and production systems. It will produce quantifiable estimates of average reductions in N losses that can be achieved, resulting in a catalogue of technologies ranked in terms of cost-benefit for different productions systems operating in various macro-climatic backgrounds.

An enhanced version of NDICEA, a decision-support tool for reducing N losses in commercial farming, will be produced to cover a wider range of regions and production systems within Europe. The catalogue of innovative and cost-effective technologies, combined with the improved NDICEA support tool, will form the N-Toolbox. Results from farm-level case studies in the UK, the Netherlands, Spain and Denmark are expected to validate the N-Toolbox approach.

Case studies will be reported for the UK concerning an area already designated as an NVZ due to the country’s concentration of dairy farms. Here, periodic heavy rainfall combined with light, loamy topsoil may result in the leaching of nitrogen from farmyard manure and slurry. Similar studies will characterise large-scale vegetable production systems on dry sandy soils which have lead to excessively high nitrate contents in groundwater in the Netherlands. Vegetable crops need heavy levels of nitrogen over a short period but, since not all of the application is utilised, residual inorganic nitrogen is easily lost from the sandy soil during long fallow periods between crops.

Other results will cover integrated vegetable and arable cropping systems in Denmark that result in contamination of groundwater with nitrates during their wet winters. As the vegetables are typically grown in rotations with cereals, specific options for improving N management – by optimising rotation, use of catch crops and adapting cereal cropping to optimise use of N residues from the vegetable crops – will be identified. Farm-level assessments of N-Toolbox in Spain will focus on irrigated maize production that is likely to cause groundwater pollution where crops are abundantly fertilised and overwatered. These studies will result in suggested nutrient- and water-management strategies that need to be implemented so that the leaching of nitrates into groundwater is prevented.

Website of


Coordinator: Julia Cooper,

Organisation: University of Newcastle upon Tyne, UK,


The Louis Bolk Institute, The Netherlands,

Polytechnic University of Madrid, Spain,

The University of Aarhus, Denmark,