The huge cost of nitrogen and the environmental concerns surrounding its use mean that advances claiming to minimise losses and maximise efficiency should be investigated further in the UK, according to Velcourt’s technical director Keith Norman.
Seven different systems to help growers make better use of nitrogen fertiliser will be displayed at the Cereals event (see box). “These technologies could enable growers to reduce the number of applications or the total amount of nitrogen applied, or both,” he says. “They also offer different ways of managing nitrogen, something which is very relevant in dry springs.”
Furthermore, the greenhouse gas (GHG) emissions associated with fertiliser manufacture and use can be reduced with some of the technologies, he points out, helping to minimise agriculture’s GHG contribution.
The technologies are mainly aimed at urea-based nitrogen fertiliser. They include nitrification inhibitors, a complex nitrogen/sulphur compound containing a bio-accelerant, stabilised urea, urease inhibitors, nitrogen uptake optimising bacteria and coated urea products.
The range clearly demonstrates the innovation that is taking place in this sector, says Mr Norman. Four are currently available commercially, together with explanation boards summarising how they work.
Some act on the enzyme urease, which drives the urea hydrolysis process, while others having an effect on microbes that influence nitrification, he explains.
“Urea has a reputation for being more difficult to manage. The perception is that it isn’t taken up by the crop as well and that it is more susceptible to losses from volatilisation. So there’s a mindset that needs challenging.”
It is, however, often better value for money, something which has taken on far greater significance in the last few years as costs have risen, he notes.
His colleague, Nick Shorter, regional farms manager in the south, points out that nitrogen is normally applied in three splits on Velcourt farms.
“So the opportunity to reduce the number of splits, which is one of the possible benefits of these advances, would represent a cost saving. A contractor will charge around £12/ha to apply nitrogen.”
But he believes that a far greater potential benefit from the new technologies is the ability to apply nitrogen early in the season, when moisture is available. “It takes some of the risk and guesswork out of the operation.”
Mr Shorter adds that farmers also have a social responsibility where fertiliser use is concerned. “Application timings will vary from season to season, according to the weather, but we do need to know what the product is doing and how much is getting into the crop, rather than being lost to the environment.”
Some 30% of all nitrogen applications made to the 11 farms for which he has responsibility are urea-based, he reports. “It often has a price advantage, it comes in a more concentrated form and it helps to spread the machinery workload.
“But it can be a logistics challenge. And that will only increase if we are given a method of putting it all on in one hit.”
Currently, the technologies add 10-20% to the price of urea. “The Velcourt business as a whole spends around £10m on nitrogen fertiliser, so it will have to stack up for us.”
New N technologies in a nutshell
Bacterial nitrogen uptake enhancer (Cleveland Biotech)
A liquid formulation of bacteria that aids and enhances the plant’s nitrogen uptake process, making nitrogen and other nutrients more available to the crop.
Nitrification inhibitor – Didin Fluid (Omex Agriculture)
This nitrification and urease inhibitor can be tank mixed or applied to the soil, where it slows down nitrate production. Allows a single application of nitrogen, as it is released gradually over a three-month period and reduces NO emissions from the soil.
Stabilised urea – Koch Advanced Nitrogen (Koch Fertiliser)
Contains Agrotain nitrogen stabiliser in a single fertiliser product, which reduces volatilisation and prevents losses. Claimed to give comparable performance to ammonium nitrate.
Nitrification inhibitor – GF2747 nitrapyrin (Dow AgroSciences)
A micro-encapsulated nitrogen stabiliser, which keeps applied nitrogen in the preferred ammonium form, minimising losses and environmental impact. Sold in the US as Instinct, known as GF2747 in the UK
Combined urease and nitrification inhibitor – Nutrisphere (Origin)
Uses polymer and cation exchange technology to inhibit both urease and nitrification, optimising nitrogen availability throughout the spring from granular and liquid urea.
Complex nitrogen/sulphur compound containing a bio-accelerant – N-Process (Nutrifertil)
Three different technologies in one product – meta membrane, soil enzyme activator and Npro molecule. Together, they reduce losses from volatilisation and leaching, increase enzyme activity and stimulate the absorption and assimilation of nitrogen.
Slow-release, polymer-coated and perforated urea – ESN (Agrium)
A physical polymer protective coating with perforations which is applied to the urea granule, reducing losses and allowing gradual release of nitrogen from one application.
Precision Farming Update
Using soil zones to predict a crop’s nitrogen requirement is the focus of latest precision farming work at Velcourt.
Two fields with contrasting soil types are being used to vary nitrogen applications in zones, in an effort to improve the efficiency of nitrogen use.
The effect of zones on fungicide and PGR rates will also be explored, says Mr Norman.
“This complements our on-going work with the N sensor. To date, we’ve found that the success of the N sensor depends on the original estimate of total N to be applied to the crop and the % variation either side of this the sensor has to apply. This manual intervention can sometimes lead to inaccuracies.
“New software will hopefully mean less reliance on guesswork and more on plant-based sensing data to dictate total N and % variance.”