Crop production specialists, Hutchinsons, are recommending early doses of nitrogen where Soil Nitrogen Supply (SNS) levels are low.
Reb Jewers, Hutchinsons fertiliser and crop nutrition specialist, said that even fields with high SNS levels will require a good early nitrogen application of at least 60-80kg/ha: “Learnings from extensive trials at our Helix Farms and Regional Technology Centre’s over the past few years has shown us that crops need a good base foundation of soil applied nitrogen, granular or liquid, to grow biomass and retain tillers to maximise yield potential.
“Crops should receive a good base application of nitrogen anywhere between 120-180kg/ha depending on individual circumstances and final applications then tailored according to developments in the season, end market etc.”
SNS
Low winter rainfall and mild conditions in spring 2022 led to high SNS levels than in 2021, meaning that mineralisation of N continued throughout the winter and in many cases it was possible for nitrogen applications to be cut back without any noticeable impact on production.
Mr Jewers said: “The results that have been coming back from the laboratory this year are looking quite varied for SNS; the figures are generally lower than last year due to higher winter rainfall and cooler temperatures and are more in line with what we would expect to see in a ‘typical’ year.
“With more normal SNS results this year, RB209 predicted rates can be used along with any break even ratio (BER) adjustment for N & grain price. Where BER calculations or SMN Plus results suggest cutting back on nitrogen rates, for example from 200kg/ha to 160kg/ha, apply all nitrogen early – by the end of March.”
There are many tools and resources available to help with final nitrogen recommendations such as the AHDB Calculator or the automatic BER adjustment in Omnia.
Mr Jewers continued: “The important underlying message to this is that with generally lower SNS than last year, there might not be as much opportunity to cut back on nitrogen rates. Whilst crops may look good now, it’s important they don’t run out of ‘oomph’ later in the season when they need it. So it is important to know your baselines!”
Further recommendations from Hutchinsons include that those using urea should plan their first applications as soon as possible as it takes longer to convert to plant available nitrate. He said that the urea applications should be made around 10 days before ammonium nitrate.
