Nutrient issues on Irish farms and solutions to lower losses

Abstract

Agriculture in Ireland utilizes 63% of total land area and has a big environmental impact accounting for 70% of phosphorus and 82% of nitrogen in surface waters, and for 97% of ammonia, 81% of nitrous oxide and 86% of methane emissions to air. Phosphorus loss to water is Ireland's most serious pollution problem. The deterioration of water quality that has been evident since the 1970s has been halted and reduction targets for ammonia and greenhouse gas emissions from agriculture are being achieved. These achievements are largely attributable to declining ruminant livestock populations and declining inputs of manufactured fertilizers as a result of increasing emphasis on extensification of production practices in the Common Agricultural Policy during the past decade. Nevertheless, substantial improvements in water quality are needed by 2015 to meet the requirements of the Water Framework Directive. To meet this and a broad range of environmental targets and to comply with the Nitrates Directive, a wide ranging set of regulations governing agricultural practices was implemented into law in 2006. These include general limits on stocking rates on farms of no greater than 170 kg/ha of N in livestock manures applied mechanically or deposited by grazing livestock. There are periods between September and January when the application of fertilizers and manures is prohibited and minimum winter storage requirements apply for manures generated on farms of between 16 and 26 weeks depending on location and agricultural enterprise. The use of phosphorous is stringently curtailed; there are limits on phosphorous concentrations in soil as determined by a soil test and limits on imports of phosphorus onto farms, which generally cannot exceed exports. These regulations are likely to make an important contribution to achieving environmental targets in Ireland, particularly the improvement in water quality required by the Water Framework Directive.