A NEW OECD report has said that in Ireland agriculture has been harmful to the environment but things are now improving.
The projected contraction of agriculture should further reduce environmental pressure with decreased stocking levels and lower nutrient pollution of water, the report emphasised.
It also pointed out that the implementation of the nitrates directive which limits nitrogen use to protect groundwater, should yield results in reducing agricultural pollution of water bodies. The report, Environmental Performance of Agriculture in OECD Countries Since 1990, found excess levels of nitrates, phosphorus or pesticides in more than one out of 10 monitoring sites in 13 OECD countries.
In its report on Ireland, it said that about one-third of slight and moderate eutrophication - enrichment of water with nutrients - of rivers was due to agriculture with over 70 per cent of phosphorus and 80 per cent of nitrogen reaching inland waters originating from farmland in 2004.
It said that most drinking water quality in Ireland meets required standards but between 1998 and 2005, there was a rise in the share of ground-water monitoring sites with nitrate levels greater than the Irish drinking water guide level of 25 mg/1N03, mainly related to agriculture.
"Ground-water accounts for over 15 per cent of drinking water nationally and more than 85 per cent in some rural areas. Drinking water contamination from pathogens, some resulting from land spreading of manure, is a problem in certain locations especially those using groundwater," it said.
"But between 1995 and 2005 there were less faecal coliforms monitored in groundwater, with a rise in the share of samples showing zero contamination," it said.
The adverse impacts of eutrophication on water bodies included damage to aquatic ecosystems, such as algal growths and fish kill events and also higher costs for water treatment.
"Nevertheless, the share of agriculture in total fish kills declined from nearly 60 per cent in 1992-94 down to 22 per cent by 2005, partly due to the effect of measures by local authorities, the Central and Regional Fisheries Board and the Department of Agriculture and Food," it said.
It said that nitrate levels had risen between the 1980s and 2005 in nine of the 11 large rivers that were monitored which has led to the depletion of the nitrate sensitive pearl mussel in some rivers.
Overall, it said that in Ireland agri-environmental policies have started to improve since about 2000 and this was reflected in the strengthening of the Rural Environment Protection Scheme (Reps).
It concluded that the increase in part-time farming could lead to greater biomass production through afforestation and while Reps had some recent success in addressing biodiversity concerns, large scale, intensive farms were significantly under represented.