If the controlled release fertiliser granules in your next batch of growing media are an unfamiliar colour, it may be because your supplier has recently switched brands to Basacote Plus.
Basacote Plus is a relative newcomer to the controlled release fertiliser market. The technology was developed 12 years ago by the chemical company BASF at its Agricultural Centre at Limburgerhof in Germany. The fully coated product was introduced in 2000 at about the same time that BASF decided to withdraw from marketing fertilisers, selling its distribution division, Compo, to K+S Group, a fertiliser multinational which owns resources in potash and magnesium.
Compo has operated in several mainland European countries for 30 years or more, but is a name largely unfamiliar to UK growers. That is set to change with Compo setting up a UK subsidiary headed by Mike Butler, who has many years’ experience in technical sales in the horticultural fertiliser market.
The principle of controlled release fertilisers is well established. Water penetrates coated granules of NPK, dissolving the nutrients, and the solution is released over set periods of time - three, six, nine or 12 months in the case of Basacote - to guarantee plants a constant source of nutrition. Where Basacote differs from other brands is in the granule’s flexible but resilient polymer coating, which is sprayed on, instead of the hard resin which coats other CRFs.
The coating is the key to Basacote’s performance, says product manager Ingo Müller. Release in response to temperature is precisely controlled because of the nature of the polymer - as temperatures increase, the coating becomes more elastic and the pores, through which the solution is discharged, expand. While the quantity of nutrients contained in the granules of each release rate is the same, the three-month product is released faster than the 12-month, for instance, because the coating is applied more thinly.
Comparative trials by Compo on Prunus laurocerasus, potted up with different six-month CRF products, suggest release of macronutrients can vary between brands, with between 15 and 40 percent of nitrogen released after one month. “Some products gave better growth at the start of the trial but it didn’t make a big difference by the end,” says Dr Müller.
“Growth produced by Basacote was good in the last two months, close to the selling point, giving plants a nice colour.” Analyses also showed that release of phosphate and potassium was particular poor by some products, for instance as little as 3 percent of potassium was released over the period of the trial by one brand compared to 64 percent of others including Basacote.
Tests to ensure the fertiliser will do exactly what it says on the bag, for instance release over the correct period, are given the highest priority at Compo’s production plant at Krefeld, western Germany. “There are five quality checks before it reaches the customer, from the raw material to the bagged product,” says Dr Müller. “A sample of every batch is kept for two years so we can trace back and check again if necessary.”
Trials have shown the coating is frost resistant, with no damage recorded down to -20C. “Nor was there any effect on nutrient release after temperatures warmed up,” he says. The coating’s elasticity resists mechanical impact, protecting the granules’ integrity ‘between the factory and you,’ he adds.
While BASF no longer has a role in the marketing and distribution of the fertilisers it develops, Compo continues to have access to BASF’s research expertise with 37 staff at Limburgerhof working exclusively for the company on product development and technical support.
Since it was first introduced, improvements to Basacote have included the addition of trace elements, which sit in a layer just under the coating for almost immediate release. “Research by Margaret Scott [at Efford Research Station] suggested that if you were going to feed trace elements to plants, you needed to give them straight away,” says Butler. “That’s the thinking behind it.”
Since last year, the granule size range has been tightened, to 2.5-3mm, for a more homogenous product, the granules screened for size before being coated. And among the advances BASF is currently working on are new coating materials.
At its research centre BASF is also studying new uses, too, such as a pre-planting application for fruit trees. “We want to find out if it gives the trees a better start,” says BASF researcher Anna Storm.
Agricultural centre
The Agricultural Centre at Limburgerhof is one of two BASF research centres worldwide and where BASF works on new fertilisers and application technology. Founded in 1914 following the discovery of how to manufacture synthetic nitrates from fixing atmospheric nitrogen, the site was chosen specifically for its poor sandy soil to show how the use of fertilisers could improve yields.
The biggest area of research at Limburgerhof is the development of new plant protection products - the site supports a fleet of lysimeters where the leaching behaviour of chemical products is studied over periods of years. It is also home to the company’s seed treatment technology centre and to BASF Plant Sciences, responsible for developing the world’s first potato variety with resistance to late blight disease. “We work closely with seed companies and other research organisations,” says researcher Anna Storm.
In terms of BASF’s total R&D spend on all the sectors it is involved in, agriculture absorbs the most even though it accounts for the smallest share of sales.
Along with Basacote Plus controlled release fertiliser, slow release fertilisers are an important line for Compo, its flagship product Floranid first introduced more than 30 years ago. Floranid is mainly used on turf, keeping the grass growing at a constant rate.
Compo also markets Entec, a fertiliser for the arable and field vegetable markets developed by BASF in the 1990s, which contains an ammonium stabiliser. The stabiliser slows the breakdown of ammonium in the early days after the fertiliser application, reducing the risk of nitrate leaching.
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