Optimising nitrogen use to meet milling wheat protein specifications without overstepping economic thresholds is a key factor to balance this season, particularly as grain prices remain feeble.

Winter wheat crops have significant potential, but growers must be realistic about whether milling requirements can be achieved on farm, explains Tim Kerr crop nutrition manager at agronomy firm Hutchinsons.

“A well-timed application of nitrogen after the flag leaf final-dressing will increase the amount of nitrogen available to crops during that crucial stage of protein development,” he says.

See also: Farmer Focus: Don’t treat symptoms, look at cause of problem

Without a well-timed late application of nitrogen, crops may struggle to contain enough protein to satisfy the requirement for yield and quality.

The later this dressing is applied, the more influence it will have on grain protein up to ear emergence. After flowering, the uptake of nitrogen declines.

Farmers Weekly asks three pivotal questions about late season nitrogen requirements for a Group 1 milling wheat established in autumn 2024, with the aim of being sold for a milling premium.

1. What is the likelihood of achieving milling wheat spec this season?

This is an important starting point and should be based on the historical success of meeting milling spec weight with a particular variety, notes Tim.

“If milling spec has regularly or occasionally been achieved, then it would be sensible to follow past nitrogen fertiliser strategies.

“If not, do not apply the additional nitrogen. It simply doesn’t make economic sense,” he says.

These recommendations shift with low spring rainfall and the prolonged dry periods much of the UK has witnessed over the past couple of months.

“If the weather stays dry, later applications of foliar urea at the milky ripe stage will become more important.”

However, Tim says that growers should be aware of the terms and conditions of some milling wheat contracts that exclude the use of foliar urea.

Alternatively, growers can consider forms of methylene urea applied with the T3 fungicide which is now a well-established practice, it is very crop safe and reduces the need for extra field passes.

2. Should growers consider a late nitrogen application to push for protein?

A simple way for growers to find out whether a late application of nitrogen is needed to hit the magic 13% protein mark is carrying out a protein prediction test.

Northamptonshire arable farmer and Hutchinson’s Helix National Farm host Andrew Pitts routinely uses the test for his milling wheat samples, carried out by Hill Court Research laboratory.

The test involves digging up 5-10 wheat plants from across a field and then sending off to a lab. 

The test is based on root extracts which are an accurate indicator of the current N status of the crop.

Samples can be taken from the third week in May onwards. The test retails at £37.50/sample.  

Further details about protein prediction tests can be found on the website. 

3. How can growers calculate the effect of more nitrogen on breakeven costs?

In general, Tim explains that milling wheat requires 5kg extra nitrogen per tonne of wheat than the equivalent feed wheat crop.

This means a 10t/ha milling crop needs about 50kg extra N than a feed wheat.

Taking into account the reliability of achieving milling spec and depending on the fertiliser product used, this is an additional variable input cost of £5-£6.50/t of wheat.

Tim says when the crop is sold for an additional milling premium that is money well spent.