50yearsofOsmocote
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Controlled-release fertilisers FOUR GENERATIONS OF APPLIED SCIENCE AND INNOVATIVE TECHNOLOGY
As professional growers will appreciate, a lot of hard work goes into creating the environment that container nursery stock, perennials, pot plants and bedding plants require. Fortunately, controlledrelease fertilisers (CRFs) offer a convenient way of helping them to achieve this aim by ensuring that their plants gain the right kind of nutrition at the right time. While such useful products may seem like a fairy tale, they are in fact a very real result of applied science and innovative technology. Andrew Wilson is technical manager for ICL Specialty Fertilizers, which produces the established CRF brand Osmocote. He explains: “A CRF is a granule containing nitrogen, phosphorus and potassium (NPK) — and, depending on the product, they can also contain magnesium and other trace elements. These are then covered in a coating.” He notes that Osmocote features an organic, resin, semi-permeable coating. “As water penetrates through the coating it dissolves the nutrients inside the granule. The osmotic pressure inside the granule releases the dissolved nutrients through the coating. It sucks water in because it’s very concentrated inside and then, as the pressure builds up, it pushes out the fertiliser through the coating.” CRFs are also influenced by temperature. Wilson explains: “They are temperature-related. The only thing that affects the release of the fertiliser is the temperature. The warmer it gets, the more it releases. That’s the basics of it. It’s not affected by pH levels, salinity, water quality and rain.” Wilson adds that, when all the nutrients have been released, the resin coating breaks down gradually. Higher temperatures will speed up the nutrient release and therefore shorten the product’s longevity, while lower temperatures will slow 37
September 2017
As Osmocote celebrates its 50th anniversary this year, Rachel Anderson examines how the brand’s continuous product development is helping commercial growers to finetune their crops’ nutritional needs
down the release of nutrients and extend longevity. Cleverly, this means the plants are getting the nutrients they need for the conditions they are experiencing. OSMOCOTE: A FINELY-TUNED PRODUCT ICL usefully offers the industry a range of different Osmocote products for ornamental crops of many shapes, sizes and species. This year, the brand celebrates its 50th anniversary. Wilson says: “We are constantly developing our products and over the years we’ve constantly improved them. We have been making Osmocote since 1967 which was the first-generation product — a coated NPK granule. And then we produced a secondgeneration product, Osmocote.” Wilson explains that CRFs are
calibrated products: “The thickness of the coating and the chosen ingredients reflect how fast the fertiliser will release. For example, a 3-4 month product will have a thin coating, while a 12-14 month product will have a thicker coating. It’s the thickness of the coating that
gives it the longevity.” Osmocote products offer growers a choice of longevities. For example, Osmocote Pro includes NPK, magnesium and trace elements (the micronutrients that the plant requires in small amounts) and is available in several longevities, from 3-4 months up to 12-14 months. PATTERNED RELEASE TECHNOLOGY While second-generation products such as Osmocote Pro have an efficient release of nutrients, ICL’s third- and fourth-generation products are even more finely tuned. The third-generation Osmocote Exact features patterned release technology, which gives a guaranteed release pattern due to its unique production process and extended quality control process. The steady and continuous nutrient release ensures crop safety and ensures nutrients are available exactly when the plant needs it. Osmocote Exact with Double Coating Technology (DCT) is the fourth generation, featuring programmed nutrient release, when ICL can actually specify the release pattern that the grower needs. Understanding that a young plant’s nutrient demand is initially quite low after potting but much higher after establishment has led to the development of a unique Double Coating Technology (DCT). These second coatings have a
Working principles of Osmocote
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