Profits on intensively stocked dairy farms could be slashed by as much as 29% due to the combined impact of banding and reducing organic nitrogen (N) from 250kg/ha to 220kg/ha.

A Teagasc report on the impact of the new nitrates rules has warned that profits are likely to fall by at least 17% or €438/ha.

However, the Teagasc study warned that the reduction in profitability could exceed €700/ha in “the most extreme scenarios”.

The reduced profitability was due to factors such as a forced cut in cow numbers, increased land rental costs and higher feed bills.

The study – which is titled ‘The Impact of Nitrogen Management Strategies Within Grass Based Dairy Systems’ – argues that the cut in organic N from 250kg/ha to 220kg/ha should be delayed until the full impact of the latest Nitrates Action Programme (NAP) and the reduced fertiliser usage included in the Food Vision strategy are established.

The Teagasc work estimated that the revised NAP and reduced fertiliser usage targets could cut N leaching by between 5.9kg/ha and 9kg/ha.

However, it claimed that cutting organic N from 250kg/ha to 220kg/ha would only reduce N leaching by an additional 2.2-4kg/ha and was not an attractive option from a cost-benefit standpoint.

The study warned of a possible switch to more “high input” milk production systems in the event of cow numbers being constrained.

It also argued that stocking rate was not a primary driver of N concentrations in groundwater and streams.

N concentrations

It maintained that N concentrations in streams and rivers were influenced primarily by the physical characteristics of the catchment areas, meteorological conditions and agronomic practices.

The report pointed to the results of the Agricultural Catchment Programme for the Timoleague area of Cork, where the N concentration levels fell to a 12-year low last year of 4.95mg/l despite cow numbers in the area increasing significantly.

However, the report accepted that this was still above the 2.6mg/l being sought by the Environmental Protection Authority.