CULTIVATION AND TECHNOLOGY Proper ridging important weapon against green discolouration The most important part in the tare of chip potatoes of the 2007 Harvest was ‘green’. A repetition can be prevented. For soil cultivation specialist Jos den Boer of machinery manufacturer AVR from the Belgian village of Roeselare, the main cause of ‘green’ is as plain as a pikestaff; ridges that were not prepared with the necessary care. Proper soil cultivation prevents green tubers. be prepared easily in the Netherlands this year, it was really difficult last year. The consequences of that growing season, with a very dry start and quite a wet period later, were visible at various points during and after harvesting. Most problems were found on the heavy soils with crops of coarsely developing potatoes, with a higher green tuber percentage than in an average year. In the beginning of the storage season, green tubers formed the most important part of tare in the supply of chip potatoes. “Green’ in potatoes is by no means a new phenomenon in potato growing. People have already come up with various solutions over the years; they include plateau ridges, 90 cm wide ridges, rounded-up ridges and bed cultivation. And yet, recent studies and practical results have shown time and again that ordinary 75 cm ridges are the best for growing chip potatoes without any green discolouration. W Inter-row rotary cultivators are no remedy To prevent green discolouration in potatoes, it is of the utmost importance to loosen the soil sufficiently before planting. Proper ridging preparation is the only way to get sufficient loose soil for optimum ridging. Ideal is a tilling depth of 8 to 10 centimetres. Jos den Boer, who has already seen many different practical examples, realises that it is not always easy to fulfil this requirement, but the farmer has no other option open to him. ‘Even if the soil is hard and dry, it is still necessary to cultivate the soil at depth. On clay and loam soils, this often takes extra time, which requires lots of patience on the part of the potato grower.’ Some just cannot do it and just accept less intensive ridge preparation. But there are also growers, who think ’I can just manage it by working the cultivator a little bit more deeply’. The latter thought is an enormous misconception according to Den Boer. ‘Each centimetre less cultivation depth when preparing the beds needs 3 centimetres cultivation depth of the inter-row rotary cultivator in the untilled topsoil. This is necessary to have sufficient loose soil for optimum ridge filling, because an inter-row rotary cultivator only works on relatively narrow stretches. This means that, effectively, only a third of the tilled soil is around the tubers of the potato plant. On the heavier soils, it is virtually an impossible task to e may have almost forgotten it, but while the soil could Potato World 2010 • number 1 23 Pagina 22
Pagina 24Voor reclamefolders, online onderwijscatalogussen en drukwerk zie het Online Touch CMS beheersysteem systeem. Met de mogelijkheid voor een webwinkel in uw vaktijdschriften.
Potatoworld 2010/1 Lees publicatie 15Home