Towards a nutrient export risk matrix approach to managing agricultural pollution at source

Abstract

A generic Nutrient Export Risk Matrix (NERM) approach is presented. This provides advice to farmers and policy makers on good practice for reducing nutrient loss and is intended to persuade them to implement such measures. Combined with a range of nutrient transport modelling tools and field experiments, NERMs can play an important role in reducing nutrient export from agricultural land. The Phosphorus Export Risk Matrix (PERM) is presented as an example NERM. The PERM integrates hydrological understanding of runoff with a number of agronomic and policy factors into a clear problem-solving framework. This allows farmers and policy makers to visualise strategies for reducing phosphorus loss through proactive land management. The risk of pollution is assessed by a series of informed questions relating to farming intensity and practice. This information is combined with the concept of runoff management to point towards simple, practical remedial strategies which do not compromise farmers ability to obtain sound economic returns from their crop and livestock.

Evaluating the risk of non-point source pollution from biosolids: integrated modelling of nutrient losses at field and catchment scales

“…Ultimately, it is hoped to evaluate the role of spatiallydynamic runoff zones or critical source areas (CSAs) within model predictions by linking INCA together with complimentary field scale models developed under the EPSRC SEAL project using a smart export coefficient approach to derive fine-scale DEMs that predict CSA behaviours (Heathwaite et al, 2005) and a practical risk matrix approach described by Hewett et al (2004).…”

“…Hence, it provides an ideal tool for testing hypotheses about the mechanisms controlling nutrient transport at a range of scales. Most importantly, it can provide generic information on fluxes and can be used to inform the Nutrient Export Risk Matrix (Heathwaite et al, 2003a;Hewett et al, 2004;Burke et al, 2003). The field research carried out so far suggests that where agricultural land is subjected to nutrient loadings for agricultural benefit this may not lead immediately to a problem unless the nutrient is in a form to be transported and connectivity exists to a receptor.…”

Catchments, sub-catchments and private spaces: Scale and process in managing microbial pollution from source to sea

“…Attention has been focussed primarily on farm-to-fork risk (Havelaar et al, 2007) because of the direct potential impact on human health. Making informed decisions at the field scale is crucial because agricultural land is heterogeneous, and inherent spatial variability in soils and hydrological flow pathways influences the loss of pollutants from land to water, often at sub-field scales (Hewett et al, 2004). So while IRBM involves assessing the bigger picture, it risks ignoring the focus of site specific management issues which can be critical to catchment functioning.…”

Eutrophication control in river-systems: an application of INCA-P to the River Lugg

“…As such, INCA-P represents an advance towards a generalised framework for simulating water quality determinands in heterogeneous river systems which started with the INCA model. The Kennet model has been used previously to investigate management options, such as the impacts of flow and the removal of P from effluent on macrophyte biomass (Wade et al, 2002c, d;Wade et al, 2004), and INCA-P was used to assess the integrated effects of variable hydrological connectivity, soil P conditions and bio-solid applications (Hewett et al, 2004).…”