Main authors: F.A. Nicholson, J.R. Williams, R. Cassidy, D. Doody, A. Ferriera, A. Jamsek, Ø. Kaste, S., Langas, R. K. Laursen, P. Schipper, N. Surdyk, L. Tendler, J. van Vliet and K.Verloop
Editor: Jane Brandt
Source document: Nicholson, F.A. et al. (2018) Survey and Review of Decision Supports Tools. FAIRWAY Project Deliverable 5.1 166 pp

Representation of water quality

Very few of the selected DST were aimed explicitly at improving water quality or represented water quality directly (e.g. by the calculation of N or pesticide concentrations). Many are agronomic tools for farmers and advisors which aim to optimise the use of N and/or pesticides to obtain maximum crop yields. They are effectively farm management tools and their inclusion in this report is based on the assumption that the efficient use of N and pesticides will improve water quality. Using a fertiliser recommendation system or a manure management tool will facilitate the application of the correct amount of fertiliser/manure to meet crop needs at the appropriate time, thus minimize nutrient losses to water bodies. Most participants reported using this type of DST; examples delivered via a range of platforms include PLANET, MANNER and The Fertiliser Manual (RB209) (UK), Načrtovanje gnojenja (SI), Düngeplanung (DE), Načrtovanje gnojenja (SI), Skifteplan (NO) and Teagasc NMP online (IE).

Indeed Düngeplanung which is used in Lower Saxony (DE) was specifially developed to help farmers in water sensitive areas (e.g. for drinking water abstraction) with fertiliser planning and regulatory compliance. Supported by water suppliers, it brought together several parallel software tools that existed previously. It indirectly affects water quality by:

  • combining all the available information for a farm (soil analyses, crop rotation, fertiliser history, specific restrictions in water protected area)
  • optimising yields and thus the amount of N exported from the field
  • improving N-efficiency (e.g. well-balanced soil P, K, Mg, S levels help to make more efficient use of the N available)
  • providing practical information on amounts and timing of fertiliser applications

Farmers using Düngeplanung have reported reductions in fertiliser use of roughly 5-10% (L. Tendler, pers. comm.).

Whilst again not specifically designed to represent water quality, the French SIRIS decision support tool allows pesticides to be classified according to their potential to reach surface and ground water, and helps to organize monitoring of pesticides in waters at the regional or local scale (Le Gall et al., 2007).

Representation of mitigation methods

The ability of the DSTs to represent mitigation measures for diffuse nitrate and pesticide pollution, and the number of different measures represented by the DSTs, was assessed. However, only three of the shortlisted DSTs were explicitly developed to consider the impact of mitigation methods on water quality:

  1. FARMSCOPER (UK),
  2. Environmental Yardstick for Pesticides (NL) and
  3. Catchment Lake Modelling Network (NO).

FARMSCOPER (Gooday et al., 2014), first developed in 2010, is a DST that can be used to assess diffuse agricultural pollutant loads (nitrate, phosphorus and sediment) on a farm and quantify the impacts of farm mitigation methods on these pollutants. Inputs are at the farm scale, however the outputs can be scaled up to catchment, regional and national levels. It currently contains over 100 mitigation methods adapted from the User Guide for England and Wales (Newell-Price et al., 2011) and they can be tested either individually or in combination for 3 broad soil types defined according to the probability of having artificial under-drainage for conventional agriculture: i) not requiring under-drainage; ii) requiring under-drainage for arable use; and iii) requiring under-drainage for both arable and grassland. The testable mitigation methods include:

  • establish cover crops in the autumn;
  • establish riparian buffer strips;
  • integrate manure and fertiliser use;
  • increase use of clover;
  • extend/reduce grazing season
  • cultivate land for crops in spring not autumn
  • use correctly inflated low ground pressure tyres
  • cultivate and drill across the slope
  • install beetle banks
  • re-site gatewyas from high risk areas
  • cultivate compacted tillage soils
  • use a fertiliser recommendation system

FARMSCOPER is a tool mainly used by policy makers and catchment managers, with the potential to be used by advisors on farms. To date it has been used to study the impacts of various mitigation methods in the Wensum and Avon Demonstration Test Catchments (DTCs) in England.

The Environmental Yardstick for Pestcides (Reus & Leendertse, 2000) is a DST designed to quantify the environmental impact of the use of pesticides in outdoor and greenhouse crops. The mitigation methods represented are:

  • choice of pesticide;
  • dose rate;
  • application technique (drift);
  • width of untreated buffer zone.

For each pesticide the yardstick assigns environmental impact points for the risk to aquatic organisms, the risk of leaching to groundwater and the risk to soil organisms (depending on the user-specified soil organic matter content and season of application). The yardstick also shows the risk to pollinators, beneficials and applicators. It is used in the Netherlands (and Belgium) as a management tool for farmers and technical consultants, a tool for monitoring the environmental performance of farmers, a tool for setting standards for ecolabels, a tool for the supply chain to be able to purchase sustainable agricultural products, and as a policy evaluation tool.

The Catchment Lake Modelling Network, designed specifically for the Lake Vansjø catchment in Southern Norway, consists of a network of process-based, mass-balance models linking climate, hydrology, catchment-scale nutrient (phosphorus) dynamics and lake processes (Couture et al., 2014). The model network allows the effects of climate change to be disentangled from those of land-use change on lake water quality and phytoplankton growth, and includes the following mitigation methods:

  • land use change;
  • cultivation change;
  • crop rotation;
  • erosion risk reduction measures;
  • change in fertilizer application.

The model network can thus support decision-making to achieve good water quality and ecological status within the Lake Vansjø catchment. It was developed to model phosphorus and suspended sediment loadings, although it is also possible to include nitrate. The model network is transferable to other catchments; however, it is quite time-consuming to set up and calibrate for a new catchment.

Other DSTs: Whilst not directly evaluating the effects of mitigation methods, the UK SCIMAP model (Perks et al., 2017) provides a framework for generating catchment risk maps for sediment losses, so that the areas within a catchment where mitigation methods are most urgently required can be identified. SCIMAP is being used in the River Eden Demonstration Test Catchment project which is investigating the dynamics of water quality from agricultural land, and by Durham Wildlife Trust to identify areas with high fine sediment pollution risk within the River Wear catchment. In addition, Bedrijfswaterwijzer (NL) was developed to provide starting points for indicatively evaluating measures to reduce emissions to water, whilst STONE (NL) is a modelling tool wherin various policy measures to reduce nutrient emissions to ground water and surface waters may be specified.

Other DSTs identified during the literature search (but not shortlisted or assessed in detail) which may have the ability to represent mitigation methods include:

  • Agricat 2 (NO). An empirical, ‘management oriented’ GIS based model. Designed to assess the effectiveness of mitigation measures to reduce phosphorus losses from agricultural land.
  • DET (various countries). A practical, interactive tool to evaluate the risk of spray drift for specific weather and field situations, and propose effective measures to mitigate this risk.
  • EOS (various countries). EOS (Environmentally Optimised Sprayer) is an application evaluating the risk mitigation potential of sprayers based on their technological features.
  • IMAS (FR). The model of agricultural scenarios defines a “reference scenario” representing actual soil use and pesticide-spraying practices, and compares this with alternative scenarios defined by stakeholders targeting mitigation measures.

Representation of economic and financial aspects

The economic and financial implications of implementing mitigation methods were infrequently represented in the shortlisted DSTs. However, FARMSCOPER (UK; Gooday et al., 2013) estimates the cost effectiveness of mitigation methods as a cost-efficiency (C/E) ratio in terms of money (£) saved per % reduction in nitrate, phosphorus or sediment loss. The TargetEconN model (DK) is an integrated economic and biophysical social planner model which minimizes the costs of meeting a nutrient load reduction target in a specific water body. Some other DSTs do have the capability to represent economic aspects e.g. Düngeplanung (DE) allows cost-benefit comparison of different fertiliser use scenarios.

A recent research project investigated the economic benefits of diffuse pollution mitigation targeting using SCIMAP within a number of UK Demonstration Test Catchments to identify the optimal locations to install diffuse pollution measures. The economic benefit of the interventions was assessed using crop growth and yield models in terms of production profit, although the results have not yet been published.

 


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