Effective fertilising

Fertiliser spreading
Fertiliser spreading

The beautiful weather which we enjoyed in February is well and truly in the past and while grass is still plentiful in the fields it is still too soon to think in terms of an early Spring.

Hopefully the preparations for the new season have been made - soils should have been analysed and a fertiliser plan produced which will ensure that every field can be balanced for the essential plant nutrients which will ensure a good yield of grass for cutting or grazing. The all – important lime status needs to be considered to ensure that the nutrients applied can be used efficiently.

The fertiliser plan should take account of the manures available on the farm and ensure these are directed to the fields with the lowest phosphate status. The method of application of these manures is another consideration - with trailing shoe and dribble bar equipment producing the best response from the nutrients applied but also reducing the loss of nutrients to the atmosphere – particularly in the form of Ammonia. This “Low Emission” slurry application has been shown to increase grass growth by up to 25% while reducing emissions to air by 50 to 60% and is likely to become a requirement of future policies for sustainable farming.

Applications of chemical nitrogen are also under the spotlight and while there are no concerns about Nitrate levels in our waterways the level of ammonia in the atmosphere attributed to livestock farming, and particularly from dairy herds, is very much in the spotlight. Nitrogen losses vary significantly between different types of fertiliser – with urea typically losing up to 50% of its Nitrogen as ammonia.

The most commonly used nitrogen fertiliser in Northern Ireland, Calcium Ammonium Nitrate (CAN) is also susceptible to denitrification with significantly higher emissions of Nitrous Oxide. The current thinking points towards Urea, treated with a urease inhibitor to reduce emissions, as the most cost effective and sustainable source of chemical Nitrogen for the future.

Applications of phosphate fertilisers which had reduced very significantly over the last twenty years are now trending upwards again and this is reflected in increased phosphate enrichment of waterways. Research would suggest that phosphate fertiliser applied to soils at level two or above will produce no yield response, simply adding to the phosphate surplus in the soil and incurring an unnecessary cost to the farmer. The crop will be more likely to respond to additional nitrogen, potassium or Sulphur – refer to those soil analysis results to see where the limitations to yield actually are - and don’t forget the lime!