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

Periodic Report Summary - N-TOOLBOX (Toolbox of cost-effective strategies for on-farm reductions in N losses to water)

The movement of nitrates into groundwater and surface water from agricultural sources has been identified as a major environmental and health issue within the European Union. The nitrates Directive was adopted in December 1991 as a tool to address this issue and the Water Framework Directive was more recently implemented. In spite of the best efforts of legislators in the European Union and member states, water quality in many European surface and groundwater bodies remains below the desired standard.

The N-TOOLBOX project was aimed at addressing the root causes of agricultural sources of water contamination and improving uptake of strategies to reduce losses of nitrogen (N) from agricultural sources to water. Project partners were the Newcastle University in the United Kingdom, the Louis Bolk Institute in the Netherlands, the Universidad Politecnica de Madrid in Spain and the University of Aarhus in Denmark.

The overall aim of N-TOOLBOX was to develop a 'toolbox' of cost effective technologies to be implemented at the farm level to protect water from nitrate pollution.

There was no 'magic bullet' to solve the problem of N losses to water from agriculture. We needed to identify 'networks of partial solutions' to the problem that, when summed up, could provide substantial gains in N conservation on farms.

The project general aim would be realised by:

1. producing a catalogue of innovative and cost effective technologies to be implemented in hotspots for N losses in the European Union
2. developing an improved NDICEA decision support tool for N management at the farm level
3. testing the N-TOOLBOX catalogue and decision support tool at the farm level
4. monitoring water quality, N use efficiency and costs and benefits on case study farms
5. documenting the implementation of the N-TOOLBOX approach at the farm level.

An extensive review of academic and non-peer reviewed literature was conducted during the reporting period. The N-TOOLBOX decision tree was developed and could be used by farmers and policy makers to identify strategies most appropriate for their specific system. Some key findings included the following:

1. feeding strategies could improve the efficiency of N use on livestock farms. On dairy farms milk urea testing could be used as a tool to indicate if N supply in feed was optimal.
2. manure management solutions should include 'thinking outside the box' approaches, e.g. anaerobic digestion which reduced manure volume, allowed for more targeted spreading of the digestate and reduced greenhouse gas (GHG) by producing energy.
3. farmers in northern regions could reduce N losses from grazed areas if simple monitoring tools were available that indicated the onset of net drainage.
4. similarly,N leaching could be reduced substantially by optimising N application rates to cropland using a combination of soil testing, in-field crop growth assessments and the use of dynamic simulation models.
5. catch crops offered the potential to trap N mineralised late in the year after the main crop was harvested.
6. strategies for irrigated cropland needed to include approaches that not only optimised fertilizer N application rates, but also the use of irrigation water.

In parallel with the compilation of strategies for N loss reduction from agriculture, the user friendly decision support tool NDICEA was adapted for use in Spain, Denmark and the United Kingdom. Case study farms were identified in the four partner regions and the N-TOOLBOX approach was tested by the end of the reporting period. This involved using the catalogue of N loss reducing strategies and NDICEA as a 'what if' tool to investigate and compare N management strategies at the field level.

The N-TOOLBOX project laid the groundwork for the development of grassroots' approaches to solving the problem of nitrate pollution from agriculture. In the following reporting periods the project would document successes and failures and use these experiences to produce a blueprint for use of the N-TOOLBOX approach at the farm and catchment level. More information on N-TOOLBOX was available on the project website, at http://www.n-toolbox.eu.

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