• Developing the EU Farm Accountancy Data Network to derive indicators around the sustainable use of nitrogen and phosphorus at farm level.

      Buckley, Cathal; Wall, David; Moran, Brian; Murphy, Paul N. C.; Department of Agriculture, Food and the Marine, Ireland (Springer, 2015-07)
      This study uses a national farm survey which is part of the European Union (EU) Farm Accountancy Data Network (FADN) to develop environmental sustainability indicators in the use of nitrogen (N) and phosphorus (P) across a range of farm systems in the Republic of Ireland. Farm level micro data were used to calculate all inputs and outputs of N and P that cross the farm gate and to derive balances (kg ha-1) and overall use efficiencies across 827 farms in 2012. The sample is populated weighted to represents 71,480 farms nationally. Results indicated an average N balance of 71.0 kg ha-1 and use efficiency of 36.7% across the nationally representative sample. Nitrogen balances were between two and four times higher across specialist dairy farms compared to livestock rearing and specialist tillage systems. Nitrogen use efficiency was generally lowest across milk producing systems compared to livestock rearing and tillage systems. Phosphorus balance and use efficiency averaged 4.7 kg ha-1 and 79.6% respectively across the sample. Specialist tillage and dairying farms had higher average P balances compared to other livestock based systems. The approach developed in this analysis will form the benchmark for temporal analysis across these indicators for future nutrient balance and efficiency trends and could assist other members of the EU FADN to develop similar nationally representative indicators.
    • Farm-gate N and P balances and use efficiencies across specialist dairy farms in the Republic Ireland

      Buckley, Cathal; Murphy, Paul N. C.; Wall, David (Teagasc, Oak Park, Carlow, Ireland, 2013)
      This study establishes farm gate N and P balances and use efficiencies based on the average of 2 years of Teagasc National Farm Survey data in 2009 and 2010. The weighted average farm gate N surplus for this nationally representative sample of specialist dairy farms was 143.4 kg N ha-1. Average farm gate nitrogen use efficiency was 23.2%. For dairy farms operating under an EU Nitrates Derogation, the average N surplus was higher at 181.8 kg N ha-1 and averageN use efficiency was slightly lower at 22.2%. The total average farm gate P balance was 4.1 kg ha-1 in surplus, and P use efficiency averaged 83.9%. P balance ranged from -7.3 to 23.0 kg ha-1. A total of 27% had a negative P balance. The average P surplus for farms with a Nitrates Derogation was below the average of all farms at 3.5 kg P ha-1 and average P use efficiency for these Derogation farms was above the average of all farms at 90%.
    • Phosphorus management on Irish dairy farms post controls introduced under the EU Nitrates Directive

      Buckley, Cathal; Wall, David; Moran, Brian; O'Neill, Stephen; Murphy, Paul N. C.; Department of Agriculture, Food and the Marine, Ireland (Elsevier, 08/11/2015)
      The Republic of Ireland was one of a minority of EU member states to include direct controls on chemical phosphorus (P) fertilisers in its EU Nitrates Directive National Action Plan, first introduced in 2006. This study estimates farm gate phosphorus balances and use efficiencies across 150 specialist dairy farms over the seven year period since these controls were introduced (2006–2012) using nationally representative data. Results indicate that P balances declined by 50% over the study period from 11.9 in 2006 to 6.0 kg ha− 1 in 2012. This decline was driven by a reduction in chemical fertiliser imports of 6.5 kg ha− 1. This is equivalent to a reduction of 281 kg of P and represents a cost saving of €812 per annum across the average farm. Phosphorus use efficiency also improved over the period from 60% in 2006 to 78% in 2012, peaking in 2011 at 88.3%. This was achieved while increasing milk solids output per hectare and per cow. Results of a random effects panel data model indicated that P balance and use efficiency are significantly influenced by factors such as fertiliser prices, stocking rates, land use potential, use of milk recording technology, contact with extension services and rainfall patterns.