CRF Technology proven successful in wider Agriculture

Advanced fertiliser technology that delivers precise amounts of nutrients to closely match crop needs during the growing cycle could have a major role to play in helping UK agriculture meet its future sustainability goals.

January 23, 2024
6 mins

Controlled Release Fertiliser (CRF) technology, proven in independent trials and commercial crop production across the world, could bring major productivity and environmental benefits to UK growers, say crop nutrition specialists ICL.


A nitrogen use efficiency (NUE) of over 90%, some 50% more than the UK average of around 60%, is just part of the story, says ICL UK speciality fertilisers manager Andrew Judd.

“Other benefits seen include cutting ammonia volatilisation in half and reducing nutrient leaching by nearly 60% compared to other fertiliser practices.

“Unlike other fertilisers, CRFs are temperature-based fertilisers that are designed to release optimum daily quantities of nutrients to crops over a specific timescale.

“This ensures nutrient availability can be matched to the specific crop requirements more effectively, which leads to higher NUE and reduces nutrient losses.

“This more efficient use of nitrogen results in higher yields per tonne of fertiliser applied whilst also giving growers the option to reduce nitrogen inputs if they wish to, such as when they are farming in nitrate vulnerable zones (NVZs).

“Another major advantage of CRFs is that they can reduce the number of fertiliser applications required through the season. This reduces farm traffic, labour costs and time as well as helping to reduce potential soil compaction problems.”

The combination of reduced environmental impact and improved productivity, means CRFs could play a key role in helping UK agriculture meet its future sustainability goals, he believes.

“Whether it’s reducing ammonia emissions required by the UK’s Clean Air Strategy, addressing concerns over nutrients entering water courses or the need to reduce the carbon footprint of food production, CRF technology brings a range of benefits to growers and the wider food supply chain.”


How do Controlled Release Fertilisers work?

CRFs work by covering granules with a semi-permeable coating that allows water to pass through it to dissolve the nutrients contained within, Andrew Judd explains.

“The process is temperature sensitive. As soil temperature rises, cracks develop in the coating, drawing in water to dissolve the nutrients inside.

“The water then carries these out into the soil for the plant roots to take up. When soil temperature decreases, nutrient release slows down.

“This process can last for many weeks with the release of nutrients specifically tailored to individual crop requirements.”


Proven benefits

According to ICL agronomist Scott Garnett, an extensive set of trials carried out on CRF have been pretty conclusive on the benefits of the approach.

“ICL’s CRF technology has been rigorously tested on a range of crops with consistent results being seen.

“For a start, conventional nitrogen fertilisers average around 60% NUE, but in a recent UK winter wheat trial, we saw an NUE of 97% resulting from our CRF technology.

“Other UK trials with Alliums and Brassicas have shown similar benefits from CRFs with yield increases of 8%.

“We’ve also seen reductions in ammonia volatilisation of 32 – 54% and 54 – 61% less nutrient leaching combined with 11% less denitrification, so these are major real world gains from both production and environmental perspectives.”

Potatoes are another crop where particular benefits of CRF technology have been seen, he says.

“In one trial carried out in Yorkshire the controlled release of nitrogen from CRF increased NUE by 82% and boosted seed potato yield by 10%. In Belgium, a 26% increase in potato yields for CRF compared to the grower’s usual ammonium nitrate (AN) based regime, was recorded.

“In other trials in Holland, the income gain from such benefits was 14% for CRF compared to a conventional CAN-based two-application approach and we’ve seen similar yield lifts over regimes using urea treated with DMPP nitrogen inhibitors.

“Furthermore, independent analysis of 19 trials in Holland showed the combined benefits of CRF technology to reduce the carbon footprint of potato production by 11%.”


CRF products now available to UK growers

Two ICL CRF product ranges now being made available to UK growers, Andrew Judd says.

“Agrocote is a 100% coated nitrogen fertiliser designed to provide crops with a continuous supply of nitrogen throughout the growth cycle. The longevity of the release can be tailored depending on the needs of the crop.

“Agrocote contains 44% nitrogen and can be used either as a straight nitrogen fertiliser that can be directly applied to crops or blended with other nutrients.

“Agrocote is particularly effective in lighter soils where N is prone to losses from leaching, as well as areas where the use of Nitrogen is restricted. Using Agrocote can also help reduce the amount of Nitrogen applications during the season.

“One application at sowing or drilling, can supply the entire nitrogen needed for the growing year in many crops.”

The other range is Agromaster, which combines Agrocote N with ICL PKPluS, he explains.

“Agromaster effectively combines two leading ICL technologies to provide tailor-made NPK formulas for a range of applications.

“Agrocote provides the controlled release nitrogen and the PKpluS delivers the other key nutrients, phosphorus, potassium sulphur, magnesium, and calcium.

“Products can again be tailor made to crop specific formulations and trace elements can be added by request.”


Building on Polysulphate success

The introduction of CRF technology builds on the success of ICL’s prolonged release multi-nutrient fertiliser Polysulphate which has seen increasing use in UK agriculture over recent years, says the company’s Richard Ward.

“Polysulphate fertiliser is rapidly establishing itself as one of the best ways of getting vital sulphur into crops in the most efficient manner possible.

“Whereas most sulphur applied to crops in the UK has been in the form of nitrogen sulphur (NS) compounds historically, decoupling N and S offers growers increased flexibility in their fertiliser management allowing them to match nutrient applications to crop needs better.

“Polysulphate is a naturally occurring multi-nutrient sulphate fertiliser mined by ICL from under the North Sea and processed into an easy-to-apply product with excellent physical properties and performance right up to the widest spreading widths of 36.0m and more.

“In its standard form, Polysulphate contains 48% S03 with the additional benefits of providing potassium (K2O), magnesium (MgO) and calcium (CaO). Polysulphate is also a key building block of PotashpluS and PKpluS, as used in Agromaster CRF.

“All have Polysulphate at their core and it is this that sets them apart from all other sulphur fertiliser products available in the market.

“It’s a multi-nutrient product with UK trials showing yield lifts of over 5 – 8% in winter wheat and as much as 33% in oilseed rape with a clear 0.5t/ha advantage over the commonly used NS products.”


Prolonged release benefits

Scott Garnett adds that many of the benefits of Polysulphate come from its prolonged release characteristics.

“University of Nottingham trials have shown over 50% of the sulphur contained in Polysulphate is available in the first 12 days after application with the remainder released over the following 6 – 8 weeks.

“This matches nutrient availability precisely to crop needs through the growing cycle which is in contrast to traditional NS products, where 100% of the sulphate is released within just 5 – 6 days after application.

“This sudden release not only means many of the applied nutrients will never be taken up by crops, it also increases the possibility of soil nutrient loss and potential environmental problems.

“Polysulphate’s prolonged release nature also means a single application at the start of the season is usually all that is required by most crops.

“The fact that Polysulphate contains no nitrogen also allows producers to take full advantage of the most environmentally friendly nitrogen sources such as the latest inhibited or control release fertiliser urea fertilisers and foliar products.

“In fact, Rothamsted Research estimates that by breaking the link between nitrogen and sulphur, use of Polysulphate alongside alternative low emission nitrogen fertilisers could decrease ammonia emissions from sulphur fertiliser applications by 90%.”

“Polysulphate also has the lowest carbon footprint of all equivalent fertilisers at just 0.034 kg CO2e which is less than 6% of the carbon footprint of nitrogen sulphur products.”