The IFA has called on the Minister for Agriculture Simon Coveney and the Minister for the Environment Phil Hogan to ensure greater flexibility on the closure dates for the spreading of organic fertiliser this autumn.
Under EU regulations the deadline for spreading chemical fertiliser is September 15, with the cut-off date being October 15 for slurry and farmyard manure.
However, farm organisations maintain that there is no justification for enforcing a simplistic 'calendar-date' deadline this year.
"Unfortunately, the heavy rain which has been a feature of this summer has not cleared away and sodden ground conditions have made it impossible for many farmers to empty their slurry tanks," said Harold Kingston, chairman of the IFA's environment and rural affairs committee.
He said ministers Hogan and Coveney had to make a "convincing case" to Brussels for greater flexibility this autumn on the rules governing the spreading of organic fertiliser.
"There must be maximum flexibility in the autumn to carry out the spreading of organic fertiliser at the optimum time.
"Organic fertiliser is a valuable nutrient and farmers will want to identify the best opportunity to use it," said Mr Kingston.
"This year has been an extremely difficult one and proves that the inflexible calendar farming regime is simply not working.
"Farmers have made the right agronomic and environmental decisions and not spread in unsuitable conditions.
"The Government must recognise this by providing fertiliser spreading flexibility, and it must go beyond an extension of a few weeks."
Mr Kingston said it would be totally unreasonable to force farmers to spread slurry on good grass covers and spoil this feed, in order to meet an inflexible deadline.
"I am calling on both ministers to look at this issue now, and provide some direction to the thousands of beleaguered farmers who find themselves battling with both deplorable weather conditions and escalating feed bills."