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.
In 2009 3300 out of 25,000 farm businesses were dairy farms. With an average farm size of 65 ha they occupy 22% of the agricultural area. Currently on specialist dairy farms there are over 80 cows per farm, although over 55% of cows are now in herds of 100 cows or more. Their levels of economic output are high. Around 50% of the value added by agriculture (gross margin of outputs less inputs) in Northern Ireland over recent years has been from milk production. The average yield in 2005 was 6500 litres per cow. Since then yields have fluctuated around this value.
There has been a continued trend in the use of imported concentrate feeds, which increased from 1.7 tonnes per cow in 2005/06 to 1.9 tonnes per cow in 2008/09. Over the same period milk production per cow did not increase, implying a lower reliance for milk from grass for grazing and/or grass silage and this is reflected in lower rates of chemical nitrogen fertilisers which decreased from 151 kg N/ha in 2005 to 139 kg N/ha in 2009.
The typical or traditional management system is to operate an autumn to winter calving herd, with cattle being housed for the winter (October/November to March/April) and grazed during the summer. A few herds have moved to a total confinement management with no grazed grass.
In 2007 a new Action Programme under the Nitrates Directive came into operation in Northern Ireland. The regulations in this Programme covered the whole area of Northern Ireland and limited livestock manure applications to the maximum of 170 kg N/ha/yr set by the Nitrates Directive. For the first time closed periods for spreading organic manures (between 15 October – 31 January) and chemical N fertiliser (between 15 September – 31 January) were introduced. Minimum standards for the capacity to store livestock manures were set, which for dairy farms was 5 months.
An option for intensive grassland farmers to apply for a derogation that would allow organic manures application rates of up to 250 kg N/ha/yr provided certain criteria was obtained. The most significant criteria is a requirement to ensure that a farm-gate phosphorus surplus of 10 kg P/ha is not exceeded. Additionally a new phosphorus regulation was introduced that required that the use of chemical phosphorus fertilsers be validated by defined crop need as defined by a soil phosphorus test and the availability of organic manures.
Water quality in Northern Ireland is dominated by the prevalence of eutrophication, as defined by high phosphorus concentrations. Approximately 70% of lakes are either eutrophic or hypertrophic including the two largest lakes: Lough Neagh and Lough Erne.
In contrast nitrate concentrations are low with an average concentration in rivers of less than 7 mg NO3/l and no rivers exceed the nitrate concentration of 50 mg NO3/l set by the Nitrates Directive.
|Agriculture area||67 ha|
|% others crops||3.2|
|% Rough grazing (moorland)||4.4|
|Mineral fertilizer per ha||139 kg N/ha|
|Other cattle (young stock, cattle for slaughter, breeding, heifers)||121|
|Milk per cow||6,600 kg|
|Milk quota||99.8% owned / 0.2% leased|
|Main diet of the cows||38% grazed grassland|
|28% grazed silage+hay|
|<1% maize silage|
|1,700 kg concentrates|
|Time in pasture||8-5 months (March/April to September/November)|
9 Pilot Farms in Northern Ireland