In recent years, demand for sweet potatoes has been growing rapidly in the EU countries, and the desire of producers to learn how to grow it is understandable. Already, it is grown in Italy, Spain, Israel and Egypt, and every year more. Sweet potato manufacturers are interested in both Belgium and the Netherlands. In 2017, several tests were carried out at the Fredepel Experimental Station, owned by the University of Wageningen (Netherlands).
Although sweet potatoes are often referred to as sweet potatoes, these two crops differ not only botanically, but also in the cost of growing them. In the production of sweet potato, the main cost items are manual planting and harvesting, the cost of planting material, as well as storage and processing. In 2016, varietal trials were started at the experimental station in Craischautem (Belgium), and trials in the Netherlands began this year.
At the Fredepel station, various cultivation methods, the use of mulch were studied and varietal tests were also carried out. As you know, sweet potato is a thermophilic plant and does not tolerate frost at all, this determines the start date of cultivation. For even growth, sufficient moisture and heat are also needed. In addition, harvesting should be carried out before the temperature of the soil drops below 10 degrees. C (in Holland this usually happens in early October).
At the Fredepel station, sweet potato was planted with cuttings directly into the ground on May 29, 2017, and seedlings in cubes were planted on June 21. By mid-July, the aboveground mass of plants from potted seedlings was significantly less than that planted with cuttings, possibly due to a later date of planting. This observation contradicts the assumption that potted seedlings provide a more friendly start to growing. In the test, varieties O`Henry, California, Beauregard (cuttings), Innosweet and Orata Orange (seedlings in peat bricks) were used, not so much for comparison among themselves, but for familiarization with the varieties.
Plants were grown in spread out on a flat surface. Alternatively, comb cultivation was tested, which may be good for quickly warming the soil, especially in combination with mulching. In the experimental field, mulching with a black film and brown paper was used. Temperature sensors measured it at a depth of 10, 20, 30 and 40 cm.
It turned out that mulching with a black film gives the best result, increasing the soil temperature by 3-4 degrees. C compared to brown paper and preventing the destruction of ridges by rain. Plants in cubes were planted in pre-made holes in the film, and cuttings stuck directly through the mulch. As an alternative, special wire hooks were used, around which the stem was wrapped twice, and then stuck it into the soil. Which is better depends on the quality of planting material and the availability of working hands. It is important that the cuttings come into contact with the soil heat as soon as possible, which stimulates the onset of root formation. The Belgian sweet potato producer Van de Bole, who planted sweet potato cuttings using a transplanting machine, believes that 1 man-hours are needed to plant 100 ha.
At Fredepel station, 125 kg / ha of kieserite and 200 kg / ha of potassium sulfate, as well as about 150 kg / ha of nitrogen with cattle manure, were introduced into the main dressing. In other countries, it is believed that sweet potato is enough 60 kg / ha of nitrogen. There are currently no products registered for sweet potato cultivation in Belgium and the Netherlands. Weeds do not create big problems, because plants quickly cover the entire surface of the soil. Of the pests, the most dangerous are mice and other rodents, as well as nematodes.
Sweet potato is very well stored under a number of conditions. Harvest must be harvested before the temperature of the soil drops below 10 degrees. C. The skin of the tubers is very thin and delicate, so harvesting should be done using a potato digger and manual labor.
According to the 2016 test, yam yield in Belgium reaches 20-50 t / ha, depending on the variety and growing conditions. Storage begins with a treatment period of one week at a temperature of 29-30 degrees. C and as high as possible relative humidity. The skin thickens and becomes stronger. Heat activates the work of enzymes, as a result, the taste of tubers improves. After the treatment period, the tubers can be stored for a year at a temperature of 13 degrees. C and high relative humidity.
One of the serious problems of growing sweet potatoes is planting material. In trials in Fredepel, seedlings from Spain were used. The most widely grown varieties in the world are Beauregard and Covington, both bred at US universities, while Covington is not allowed to grow outside this country. For cultivation in Europe, especially in its northern countries, it is necessary to select suitable varieties. The cost of cuttings is approximately 0,10-0,20 euro / pc., Seedlings in cubes - about 0,50 euro / pc.
A source: http://www.fruit-inform.com