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Autumn N – Let it Grow – not Flow


Grass growth reduces from September onwards, the capacity to take up nitrogen (N) reduces steadily. All farmers are advised not to delay spreading the remainder of their slurry this autumn.

Pat Murphy, Head of the Teagasc Environment Knowledge Transfer Department advises that grass growth rates are currently strong, and existing grass covers are generally high. There is an opportunity on most farms to save on chemical fertilizer. Farmers should focus on earlier spreading of the remainder of slurry.

The nitrogen in slurry spread in September can have a higher impact on grass growth. Any N not used by grass is susceptible to leaching when autumn and winter rains come – particularly in free draining soils.

Good Practice this autumn

  • Look at your grass covers and identify if your farm has a sufficient supply of grass
  • Identify paddocks that are likely to respond to additional Nitrogen based on soil conditions, grass covers and soil fertility
  • At this point no more than 20Kg N per hectare is justified. In situations where there are significant grass covers and moderate to low stocking rate, it’s likely that no chemical fertiliser is required.
  • Apply remaining slurry as soon as possible using low emissions slurry equipment where available. This will lead to:
    • Good uptake of the Nitrogen in slurry by the plant and avoiding losses to water from late applications
    • Avoiding the risk of not being able to empty tanks if weather conditions worsen
    • Save money by getting effective use of slurry nutrients
    • Empty tanks to protect your storage capacity for the spring.

Important closing dates for spreading:

  • Chemical Fertiliser – Midnight September 14th
  • Slurry – Midnight October 14th
  • FYM: Midnight October 31st

Reducing nitrate loss to water is an essential part of protecting our environment and farm income.