Don’t ask what it costs, but ask what it brings in CULTIVATION AND TECHNOLOGY can see exactly how the space system works. For each unit, three big towers blow ventilation/cooling air across 23 rows of boxes via a six-metre-long blower outlet. The air drops down at the back of each row and is sucked back towards the heat exchanger between the rows and the pallet openings of the boxes. The cooled air is then blown back into the space. Demota has opted for a heat exchanger with a large surface, which makes it possible to cool at a low speed during the storage season. This provides the most efficient cooling energy in such a big cooling block. As the fans are equipped with a speed regulator, they can also run at a lower speed. As a result, we can run a lot of hours with a low ventilation capacity and subtle differences in temperature in the space and product. The advantage is that you keep the RH high, thereby avoiding weight loss in the potatoes. In addition, as a result of the cooling block and speedregulated fan combination, you have the capacity to cool down the relativelywarm newly-harvested potatoes quickly to about 8 degrees Celsius. This means that you can quickly get rid of any clinging moisture, but keep the moisture content in the potatoes in tact’, Huiberts explains. During the season As soon as the potatoes have reached the right temperature, they are treated once with CIPC. This is to stop the table potatoes from germinating, also after delivery. ‘Before my table potatoes reach the consumer’s plate, they’ve been on the road for at least a week. And the quality has to be retained during this period as well’, Moll explains. The storage system can be controlled from both the storehouse and the computer. The computer gives more information about the statistics. You can see exactly what’s happening in the storage. For example, you can see that the first potatoes of this year were stored in unit 1 on 25 October at a temperature of 15 degrees Celsius and that it had reached 4.5 degrees on 19 December. The temperature dropped by 0.4 degrees a day. ‘We only used mechanical cooling this year THE GROWING SEASON For Demota, the potato season usually starts in mid April. It’s definitely not the earliest one in the region. ‘We prefer to start a little bit later. By then, the soil is slightly warmer, which gives the crop a good start and rapid initial development. It means that we have less chance of soil-bound diseases’, Moll explains. The Demota plots all have 90 German soil points and a humus content of about 2.2 percent. ‘That’s a type of soil that’s perfect for tasty table potatoes. It’s why we prefer growing table and not industrial potatoes. What’s important is the taste, the presentation alone is not enough’, Moll emphasises. Every year in the autumn, Demota applies 25 tons of Champost before ploughing. ‘This supplier of organic matter also supplies potash, phosphate and trace elements. Nitrogen is applied separately before planting, the quantity is based on what the variety needs. The gross yield doesn’t really come into this. What’s important is what we’ll be able to sell as table potatoes in the following year. This variety yields between 50 and 60 tons per hectare. Harvesting starts at the end of October and continues until approx. 15 November. The potatoes are subsequently delivered in June. The cost price upon delivery is approx. 20 cents per kilogram, 12 cents for cultivation and 8 cents for storage. The Antonia, Bellana, Toscana and Melody table potato varieties are mainly bought by the nearby, small-packaging firm Böhmer. The Demota plots all have 90 German soil points and a humus content of about 2.2 percent. to avoid fluctuations in the RH and too keep dry outside air from coming in. So the mechanical cooling is the heart of the storage process’, Moll emphasises. ● Jaap Delleman Potato World 2014 • number 2 43 Pagina 48

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