How to store potatoes

I. Chemical and physiological changes during storage

When potatoes are harvested, tubers generally contain about 75% moisture. During storage, temperature, humidity, light and air conditions are strictly required, such as improper regulation, causing adverse changes in physiological state and chemical composition.

The physiological and chemical components of potato are constantly changing during storage. With the change of temperature, humidity and light, the respiratory intensity changes accordingly, and the weight can be reduced by 6.5% due to respiration, such as insufficient maturity, excessive nitrogen fertilizer, potassium chloride alone, etc., the weight loss will be even greater. With the change of temperature, the starch content decreased rapidly, and with the extension of storage time, the starch content decreased gradually, and a series of other nutritional and chemical components also changed.

Second, loss during storage

The loss of potato during storage is relatively high, generally divided into high natural loss, generally divided into natural loss and waste products. Natural loss is the loss of water and dry matter caused by respiration and evaporation. Reasonable regulation of storage conditions can reduce natural loss to a minimum. The waste products are caused by decay, abnormal temperature, hypoxia and light, which promote the value of eating, processing and planting of tubers. In order to avoid and reduce the occurrence of waste products, it is necessary to strictly prevent the infection of pathogens, control the abnormal temperature too high and too low, adjust humidity, air and light, and prevent serious damage such as rot heat, freezing injury, hypoxia, asphyxia, water loss and so on.

III. Environmental conditions for storage

The environmental conditions in the cellar mainly include: heat, temperature, humidity, carbon dioxide, light and ventilation.

Heat: there are four sources of heat during storage: original heat (original heat of the tuber itself), respiratory heat (heat generated by the respiration of the tuber), external heat (heat from the air outside the cellar flowing into the cellar) and soil heat (the warm current transferred from the ground to the soil). Among them, land heat is the main source of heat for cellar utilization.

Temperature: storage is closely related to humidity, freezing at-5 ℃ for 2 hours, freezing through for 4 hours, and weakening bud growth for a long time under the condition of 0 ℃. The highest yield of seed potato is obtained at the suitable storage temperature of 1 ℃.

Humidity: the safe range of temperature change during storage is 80%, preferably between 85% and 90%. Proper humidity can reduce the natural loss and facilitate the preservation of tubers, too wet can easily promote the early germination of tubers and form fibrous roots to reduce the quality of edible and seed use, while too dry can easily cause tubers to lose water and soften, wrinkle and lose plumpness.

Ventilation: it can adjust the ventilation in the cellar, breathe in fresh air, increase oxygen, eliminate accumulated carbon dioxide, ensure tuber breathing, and then ensure field germination and seedling health of tubers.

Light: although it has little relationship with seed potato storage, it also has some effects. Poor storage conditions can create certain light conditions, make the epidermis green, inhibit bacterial infection, inhibit the healthy growth of young buds and form short and strong buds, which is conducive to the increase of yield. On the other hand, the processing of commercial potatoes should not be illuminated, so as to avoid the increase of eggplant and the decrease of quality.

IV. Management of storage period

After entering the cellar, we should strictly carry out scientific management, and by regulating the temperature and humidity of the cellar, ventilation, inverting the cellar and other measures to prevent diseases, frost damage caused by decay, no shrinkage, no sprouting, according to food, processing, seed use to ensure different needs of excellent varieties.

1. Pour the cellar

It is necessary to often check the change of pit temperature and the occurrence of diseases. When the original low temperature in the pile rises to more than 8 ℃, the cause should be found out in time and tried to control, such as falling into the cellar in time due to rotten fever. When the temperature is normal, 35% of the pile is infected with soft rot, more than 10% is susceptible to dry rot, and when the temperature is more than 34%, the cellar should be emptied. When pouring out the cellar, pick out all the susceptible and frozen rotten potatoes. During storage, it is found that the above conditions can be returned to the cellar for 1 / 2 times. If the cellar is ventilated for a certain period of time before entering the cellar, it is not necessary to control the temperature and humidity after entering the cellar.

2. Control of temperature and humidity.

First, the regulation of the cellar: in principle, it is appropriate to keep the pit temperature at 1 Mel 3 ℃. Pay attention to heat protection when entering the cellar for the first time, block the pit door when the temperature outside the cellar drops to-5 ℃, and ventilate for a short time at noon every day. Before the Beginning of Spring, put grass or plant stalks on the heap and on the cellar door and gas hole to keep warm, and after the weather changes, it is necessary to prevent hot gas from entering the cellar.

Second, the control of reactor temperature: the heap height in the cellar is generally more than 1.5lu 2m, 5m is suitable, and in the cellar depth of 1m, 2m, 1am, 3m, which is beneficial to air circulation. Into the pit potato had better be packed in a net bag, neatly placed, leaving a certain gap. If the bulk pile should dig a cross-shaped ventilation ditch at the bottom of the pit, the width and depth should be 20cm, lay tree strips, leave some space, the trench is connected with the pit wall, and the ventilation handle with 20cm diameter should be inserted in the pile, which is higher than the height of the pile 30cm.

Third, the humidity in the cellar is made by changing air through the cellar door. Keep the humidity in the cellar at 80ml 93%. The main reason is the "sweating" phenomenon of water droplets in the upper pile tubers after spring, which will promote the spread of the disease. By laying grass or straw curtains on the pile, the sweating phenomenon can be solved and heat preservation can be kept.

5. Calculation of cellar capacity

The number of tubers in the cellar should be related to the cellar capacity. When the maximum height of the potato pile is 2 / 3 of the cellar depth, the available cellar accounts for 65% of the cellar volume. Generally, the weight of the tuber per cubic meter is 650m 750 kg. The larger the tuber is, the lighter the weight per unit volume is, and vice versa. As long as the cellar volume is measured, the cellar capacity can be calculated. Calculation method: total cellar volume × (650 × 0.65) = suitable cellar volume (kg)

For example: when the cellar is 10 meters long, 5 meters wide and 4 meters deep.

Suitable pit size = (10 × 5 × 4) × (650 × 0.65) = 84500 kg