On hot days, start early in the morning and lift until noon, start or restart early in the evening and work until late in the evening, bearing in mind the upper limit of 25 degrees Celsius.
In order to store potato lots as efficiently and for as long as possible, it is of the greatest importance that they reach the storehouse in the best possible condition, that the storage process is carried out with the utmost care, and that the potatoes are stored under appropriate conditions. It is also important to take measures when the potatoes are finally delivered. At various times during this process, the grower can give nature a helping hand in making potato storage as effective as possible.
An effective grower ensures that his crop has the time to mature
An immature crop will lead to sub-standard performance throughout the whole storage season. A similar effect can occur in the case of low temperatures during the field period, causing a kind of cold sweetening in the field. So storage already starts in the field. In order to better understand the whole story of sugars in the tuber, it is important to know how the sugars in the potato plant function. The light that the leaves absorb during growth, forms large quantities of sugars. Glucose is partially converted into fructose. These two sugars together form sucrose, the form in which sugars can be transported by the plant. This process is called photosynthesis. The sugars ensure growth and sustain the various parts of the plant, build up nutrient reserves and guarantee reproduction. The tuber is the reproductive organ, in which the sugars that are not needed for growth and maintenance are stored. Once in the tuber, the sucrose is again separated into fructose and glucose. The glucose is then linked to form long chains of starch. If a potato crop is still in full development when the haulm is killed, the content of reducing sugars in the tubers can be very high, because sugar is still being transported from the leaf to the tuber. In that case, the tubers are not yet matured and they will enter the storehouse with a poorer frying quality. In case of a fully-matured crop, the sugar transport has long been stopped and the reducing sugar content in the tubers is low.
An effective grower does not harvest at too high temperatures
Harvesting in the right way and at the right time is an important step that precedes optimal storage and helps, among other things, to prevent damage. If it is hot and dry and the soil contains hard clods, postpone harvesting until you have had a good rain shower. If the possibility of irrigation is available, an artificial shower can be used to minimise the risk of lifting damage. This also lowers the temperature of the tubers. Damage to the skin results in extra weight loss, while internal damage leads to loss of quality. After irrigation, the tubers not only enter the storehouse with less damage and at a lower temperature, but also with slightly adhering moisture. This moisture evaporates during storage and thus ensures further cooling. Never harvest potatoes at temperatures higher than 25 degrees Celsius. On hot days, start early in the morning and lift until noon, start or restart early in the evening and work until late in the evening, bearing that upper limit in mind. Also, never leave the potatoes lying in the field for more than a few hours nor in the tipper under the full sun, because there is the chance of damage to the skin, which causes extra weight loss.
An effective grower checks for rotten tubers and avoids bruising
Harvesting under warm conditions while there are rotten (mother) tubers present is very risky. This combination ensures that bacteria can strike very fast and affect healthy tubers quickly. Freshly-harvested potatoes are particularly susceptible to bacterial infection. It is therefore important to always check whether there are rotten tubers in the product and try to determine their percentage. It is preferable to store potatoes with more than 5 percent rot, for example from headlands or low parts in the field, in a separate space and treat them accordingly. If the amount of rot is limited, keep a close eye on the lot, at least from the moment of storage until it is certain that the rotten tubers have rotted completely. When storing in storehouses with only outside air ventilation, make sure that the (tuber) temperature in the first weeks is not too low, because it is important to continue the drying process, especially when it concerns a lot with rotten tubers. This is only possible when you have drying, colder outside air at your disposal.
When tubers arrive at low tuber temperatures, it requires energy and heat to dry the potatoes. Sometimes it is not possible to postpone harvesting. At the end of the harvesting season, the chance of rainfall increases and temperatures drop. When harvesting takes place under very wet conditions, a great deal of wet soil often comes in as well. It is then essential to dry the soil and the potatoes as soon as possible after storage. In such circumstances, heaters are indispensable. Wetness often goes together with low tuber temperatures. Drying causes moisture to evaporate, which requires energy and heat. This is extracted from the potatoes, which then cool down. To prevent this and to warm up the potatoes if possible, it is necessary to generate extra heat with the help of heaters. If heaters are not used, the potatoes will cool down further and the possibility of drying with outside air will decrease considerably. Harvesting in wet conditions requires a great deal of care. Important is to get the product in a stable condition into the storehouse. The best advice for this is to have the fans on constantly and the hatches set to full auto mode.
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