The latest crops update from the College of Agriculture, Food and Rural Enterprise (CAFRE) in Northern Ireland has confirmed the high cost of fertiliser relative to current grain price.

According to CAFRE crops advisor, Leigh McClean, this means that growers are again questioning optimum fertiliser rates and cropping decisions this spring.  

Winter crops in Northern Ireland range from strong, well-developed, to thin and backward. Growers are being advised to assess fields on an individual basis.

Highest yield potential crops are more likely to give a financial return if ‘normal’ fertiliser rates are applied compared to lower yield potential crops which may justify an overall reduction in nitrogen (N) rates.

Fertiliser application

CAFRE has said that growers should not delay fertiliser application, particularly for thin crops, as early N encourages plants to respond by producing more shoots while still at the tillering stage.

According to McClean, farmers should make any reductions in N rates on subsequent dressings once yield potential has been re-assessed later in the spring.

He points out that the Agriculture and Horticulture Development Board (AHDB) nitrogen fertiliser adjustment calculator, available on that organisation’s website, is a useful tool for working out optimum rates.

Winter barley needs at least one third of its total N during late tillering, while winter wheat the same proportion before the end of March.

Growers are advised to include at least 20-30kg/ha of sulphur in early fertiliser dressings and to top up remaining phosphate and potash.

Where herbicide was not applied in the autumn, growers should prioritise winter barley, as the few grass weed herbicides effective for this crop will only work on small grass weeds.

Generally, latest application dates are earlier than for winter wheat, so farmers should consult product labels for latest application date or growth stage.

Reducing bills

CAFRE advisors point to the potential of reducing fertiliser bills by making changes to planned spring cropping.

Using organic manures, substituting spring wheat with barley or oats, letting land for potatoes and vegetables or growing a protein crop could all help in this regard. However, growers should consider the pros and cons of each option before deciding.

Northern Ireland’s pilot Protein Crops Scheme has been extended for another year to 2023.

According to Leigh McClean, spring beans generally yielded higher last harvest than the previous year due to more favourable summer weather, with many growers achieving over 5t/ha.

Higher yields were also reported in cereals following protein crops due to their ability to fix atmospheric nitrogen for the following crop.

CAFRE advisors confirm that spring beans perform best drilled early into good conditions. Growers should take advantage of an early drilling window by being prepared.

This means getting seed on farm and applying pre-emergence herbicide immediately after drilling. This is essential to ensure that crop gets off to a good start.