CULTIVATION AND TECHNOLOGY First experiences with Controlled Release Fertiliser in the cultivation of seed potatoes are promising For some years now, Everris International has been testing Agrocote in seed potatoes. The special quality of this coated fertiliser lies in the fact that it releases its nutrients gradually. If necessary, the controlled release lasts from the beginning to the end of the growing season. Sales Manager Roel Bloemert explains the process and tells us about the first, promising experiences. n the fertiliser world, the Everris Agrocote fertiliser is known as a Controlled Release Fertiliser (CRF). This is a fertiliser of which the nutrients are released gradually. The composition and thickness of the granule coating determine the period over which the fertiliser is released. This may vary from a few weeks to 18 months. The use of CRF fertiliser is still a fairly new phenomenon in crop farming. However, the fertiliser granules manufactured by Everris have already been used for some time now in horticulture and glasshouse farming, both in the Netherlands and abroad. Everris is part of ICL Specialty Fertilizers (Israel), which has been selling these special fertilisers for several years. The granules that Sales Manager Roel Bloemert is now promoting in crop farming is an NPK 38-0-0 and therefore contains nitrogen and some sulphur. I Not yet profitable for chip potatoes About five years ago, the Sales Manager happened to talk to a few potato growers who were interested in the horticultural fertiliser. They were chip potato growers, who grew the Innovator variety. As most growers know, this is a variety which needs special attention as far as the use of nitrogen is concerned. In order to bring about sufficient growth during the cultivation season, a considerable application of nitrogen is needed. A frequent point of discussion is whether you need to split the total amount of nitrogen into several applications, how many times and when, because absorption is not always optimal. Moreover, there are quite a few years in which the haulm of the Innovator dies off relatively early as a result of specific weather conditions. The thought among growers that appealed to Bloemert was: ‘If we could have a fertiliser that released nitrogen gradually, we might be able to keep the haulm green for longer in difficult years.’ This was indeed proven a during a three year period of trials. However, because of its relatively-high price, the use of Agrocote didn’t make cultivation more profitable than with the use of current fertilisers. ‘And you don’t conquer the market without any profit’, Bloemert knows from his own experience. The type of coating of the orange granules influences the level of permeability. There are granules for seed potato growing that have a time-release of two to three months and those that act for three to four months. Suitable for a poorer haulm performance Meanwhile, Bloemert got a tip from the French-fry potato growers and agronomists that he’d do better to take his fertiliser to the seed potato sector. As he now had contacts in the crop farming sector, he decided to seize the opportunity with both hands. So, he organised a meeting for seed potato growers and asked them to tell him what they still needed in the area of fertilisation and whether there was scope for a fertiliser such as Agrocote. And that hit the bull’s eye, because the seed potato growers told him that they lacked the possibility of spreading the nitrogen demand of the seed potato crop over a longer period of time. They said they preferred a crop with as little haulm as possible during the growing period, because the nutrients need to go to the tubers as much as possible. They prefer a somewhat poorer haulm performance rather than a lot of thick, green haulm. An additional advantage of a crop of seed potatoes with not too much haulm is that it is easier to select. As it is, in regular crops, it’s already difficult to determine the correct dosages for those one or two fertiliser applicaPotato World 2014 • number 3 29 Pagina 28
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