Abstract

The deterioration of water quality in Ireland over the past thirty years and the nutrient losses from agriculture are of particular concern to policy makers. Agri-environmental schemes (AES) are designed to improve the environment and water quality. One such measure is to exclude cattle from watercourses. The 4th NAP of the Nitrates Directive will make it mandatory for intensive farms to fence off watercourses. Cattle exclusion provides a number of benefits in addition to reducing nitrogen, phosphorus and sediment run-off such as river bank stability and improved vegetation cover and biodiversity. Using GIS methods, a new national farm boundary spatial database utilising national administrative data and a spatial data storage model is created – T-farm. This database is used to examine cattle exclusion and cost effectiveness at the farm level. Benefits are measured in the form of reduced in-stream faecal deposits. The spatial distribution of cost-effectiveness at the sub-catchment level highlights the differences between areas in terms of costs, benefits and extent. There are clear patterns with the most cost effective areas located in the south of Ireland. These spatial distributions however only explain some of the variation. Utilising the I2 index shows that the majority of variation occurs within areas rather than between. Introducing a cluster analysis yields similar results. The analysis of the clusters show that the mid and high intensity farms are the most cost effective to fence and exclude cattle access. Any scheme which ensures the placement/replacement of a permanent fence along watercourses is worthwhile. This study is an important contribution and broadens our understanding of the impacts of policy decision making at the individual farm level and also the costs and scale of agri-environment scheme measures