In the course of a long storage of large batches of potatoes, slow drying and cooling, condensate on products and storage structures, loss of turgor, germination, product spoilage due to the development of diseases and physiological disorders can be noted. Difficulties that arise must be prevented or quickly and skillfully eliminated, otherwise there is a significant decrease in the safety of products and the economic efficiency of long-term storage. Negative phenomena always have certain reasons. For example, loss of weight and turgor is a consequence of excessive ventilation, germination is the result of storage at high temperatures. The most difficult storage problems are slow drying, condensation and diseases.
The best results of long-term storage of potatoes are achieved when harvesting and loading dry, disease-free tubers into storage at a temperature of 10 to 15 ° C. However, the realities in large-scale production, in the soil and climatic conditions of the Russian Federation, are rarely so optimal. A wide variety of field and weather conditions during the main, autumn harvest often leads to the fact that the tubers are stored in a far from ideal condition. They may be damp, diseased, and/or too warm or too cold. In some cases, daily and hourly fluctuations in temperature and precipitation lead to the fact that in one batch of storage there may be both too warm and too cold, both dry and wet tubers. Fortunately, not everything is lost in such a situation: with timely and qualified use of technological capabilities, special care and attention, these tubers can also be successfully and long-term preserved. As a result, the result of long-term storage is provided in the first month after loading into storage, especially in difficult situations.
Let us consider the possibilities of solving storage problems not each separately, but with the imposition of real negative phenomena that can be observed in the example of the 2022 season. April - May were cold and rainy, on a large area, planting was carried out on insufficiently mature soil, which led to its overconsolidation and clod formation. In many regions (Non-Chernozem zone, Urals) there was a long summer drought, very high air temperatures were observed in July and August. The beginning of mass harvesting (the first ten days of September) took place with dry, hard soil. In the second decade, the situation with soil quality improved somewhat. The third decade of September brought excessive precipitation, air temperature is within 10 оC, waterlogging of the soil and tubers significantly complicates the digging of potatoes.
Slow drying. High-quality drying of products received in the storage is a paramount condition for the success of storage. Regardless of the initial moisture, complete drying of batches of tubers should be carried out no more than two days. If drying takes much longer, then this leads to moisture condensation, suffocation and the spread of diseases on the tubers. Often the reason for slow drying is a long or poor-quality formation of an embankment - at different heights, areas with a higher height are very difficult to dry. If the embankment is formed quickly and correctly, then the reason for slow drying is the presence of impenetrable zones, with a large admixture of soil, or insufficient power of the fans in terms of air flow pressure. Active ventilation systems for potato storage must have a capacity of at least 50-70 m3 per ton per hour at a pressure of 350-450 Pa, depending on climatic resources, storage method, storage design and air distribution system. This is a scientifically based criterion for the adequacy of ventilation during storage of potatoes. Widespread in recent decades, at the suggestion of European equipment suppliers, the ventilation standard in the amount of 100-125 m3 per ton per hour without reference to the need to provide sufficient airflow pressure is an amateurish approach. If the pressure created by the fans is insufficient, the air cannot overcome the resistance of the air distribution system and the product embankment, as a result of which the drying process is very slow with all the ensuing negative consequences. If drying takes more than three days, this indicates insufficient fan power or a large air leak in the air distribution system. This is also true for drying in containers. Poor drying is a traditional problem and the main cause of product spoilage from the subsequent development of diseases, also in refrigerators with no or insufficient ventilation. Machine cold storage of vegetables is effective only in combination with sufficient power of active ventilation.
Potatoes should ideally be harvested under the following conditions: good skin formation, cool air during the night, sufficient soil moisture to move in the combine without clods, tuber flesh temperature at or around 15 оC. Immediately after loading the chamber or part of the chamber, continuous ventilation with somewhat colder air is carried out. In many cases, soil conditions and temperatures can be less than ideal, which requires adjustment of the initial storage conditions. The rules for drying should be adjusted taking into account the prevailing weather conditions. In summary, the adjustments are as follows:
1. If the temperature of the soil and tubers is above 25 оC and soil dry at harvest: while the storage is being loaded, turn on the fans continuously until the temperature of the tubers reaches 15 °C (relative humidity should be 95%); supply air temperature during cooling should be 1-2 оC below the temperature of the tubers.
2. If the temperature of the soil and tubers is above 25 оC and soil moist at harvest: continuously turn on the fans until all free moisture is removed from the tubers; supply air temperature should be 1-2 оC below the tuber temperature until it reaches 15 оC.3. If the temperature of the soil and tubers is 10 - 15 оC, and the soil is dry at harvest: periodically turn on the fans (relative humidity should be 95%); supply air temperature - by 0,5-1 оC below the temperature of the tubers.
4. If the temperature of the soil and tubers is 10 - 15 оC, and the soil is moist at harvest: continuously turn on the fans until the tubers dry; supply air temperature - by 0,5-1 оC below the temperature of the tubers.
5. If the temperature of the soil and tubers is below 10 оC and soil dry at harvest: periodically turn on the fan (aim for a relative humidity of 95%); supply air temperature - by 0,5-1 оC above the temperature of the tubers until the tubers are 10-13 оС
6. If the temperature of the soil and tubers is below 10 оC and soil moist at harvest: run fans continuously until tubers are dry; supply air temperature - by 0,5-1 оC above the temperature of the tubers until the tubers are 10-13 оС
The need to reduce or increase the temperature during the drying process, respectively, "hot" and cold potatoes to the level of 10-15 оC is due to the fact that this level is optimal for the fastest possible therapeutic storage period, which immediately follows the drying of products. Suberization of skin lesions takes place at the optimum temperature in 7-14 days (Table 1).
Table 1. Duration of various stages of healing of skin lesions (suberization)
Temperature, оC | Light suberization | Complete suberization | Beginning of periderm formation | Formation of two layers of wound periderm |
(2,5) 0 5,0 | 7-14 | 21-52 | 28 | 28-63 |
10 | 4 | 7-14 | 7-14 | 9-16 |
20 | 1-2 | 3-6 | 3-5 | 5-7 |
Overseas recommendations on potato drying regulations indicate the need to turn on humidifiers in dry soil and at any temperature. To do so in the climatic conditions of the Russian Federation is pointless, if not harmful. After all, drying is carried out by air, and the air must be able to bind the excess moisture of the tubers, which at this stage most actively breathe and evaporate the most moisture, especially against the background of the inevitable damage to the skin when harvesting in dry conditions. Humidification reduces the ability of the air to remove excess moisture. Also, with air humidification and unstable air temperatures in the storage during the cleaning period, the risk of condensation increases. BUT Condensation is the most dangerous phenomenon during storage of potatoes.
water condensation is an extremely undesirable process and one of the main problems of storing any vegetables. In closed storage, in just a few hours, potatoes can naturally (breath, evaporate) create an environment with a high relative humidity of 95% or more. With such a high relative humidity, condensation can occur on the product or structures if their surface becomes only slightly colder than the air. Condensed moisture is pure water, acting as a catalyst for the active development of microorganisms that always live on the skin of tubers or in wounds, lentils and eyes. A condensation period of just one hour is sufficient to start the development of decay diseases.
Air temperature and relative humidity are related. As the air temperature rises, the moisture content increases and the relative humidity falls. Conversely, if the air temperature decreases, then the relative humidity increases. Cold air in contact with warmer potatoes does not pose a risk of condensation. Condensation on the surface will inevitably occur if the air surrounding the potato is warmer than the potato itself and if the surface temperature of the potato is below the dew point temperature of the air. Typically, a temperature difference of 4°C or more between warm air and colder crops will cause condensation to form. But in some situations (for example, at low temperatures), this difference can be as little as 1°C for condensation to occur. The lower the surface temperature of the tuber compared to the dew point temperature of the air, the more moisture will be deposited. Typically, condensation occurs under the following circumstances:
- Warm outside air enters the cooler potato storage, for example through an open door. The crop next to the door will become wet;
- Warm potatoes enter the storage with a cool crop. If the temperature difference is not controlled, the warm air from the warm crop condenses on the colder potatoes;
— Recirculation of warm, moisture-laden air exiting the top of the stack back to the colder base of the stack carries the risk of condensation at the lower levels of the stack;
- After airing the top of the container storage with cold air, the fans turn off, allowing warm air to rise through the crop by convection. This warm air enters the cooler crop layer at the top of the storage and condenses on the underside of the tubers (Fig.1);
- During periods without ventilation, warm air rises by convection from the warmest part (usually the center) of the store and is replaced by colder air from below. Warm air enters this zone and condenses on the colder edge.
To minimize condensation when loading storage, the temperature difference between incoming and stored potatoes should be minimized. In bulk storages, place sensors 100mm and 300mm down from the top surface. The top surface (100mm) should be no more than 0,5°C colder than 300mm below. In container storage, control the difference between the bottom and top container in the stack. Keep the temperature difference below 4°C during loading and wound healing and below 1,5°C after the crop has dropped to main storage temperature. If germination occurs, make sure it is not the result of condensation. Prevent warm air from entering storage rooms by sealing structural gaps and keeping storage doors closed, especially in warm, humid weather.
During the drying or cooling phase of the crop, introduce outdoor air into the storage only if the temperature difference between the air and the potatoes is less than 4°C. It is possible to ventilate with warmer air than the crop only if the crop temperature is higher than the dew point temperature of the air. Where outside air is suitable (eg 1-4°C below crop temperature), ventilation rather than recirculation can be used to equalize crop temperature differences. Recirculation occurs only if the temperature sensors indicate a difference and if the air temperature at the top is lower than the temperature of the potatoes at the bottom of the stack.
Harvest heating. The dew point temperature of the air used for heating must be higher than the temperature of the product. If possible, warm the product with heaters to meet this condition. When returning warm sorted material to the cold store (for example, after sorting seeds), pre-cool it so that it is no more than 4 ° C warmer than the product in storage.
structural condensation. The formation of condensate on the storage structures is dangerous for the crop. On the roof, it forms from the underside, flows down to the purlins, and then flows in rows onto the potatoes below. Wet potatoes may start to rot or develop diseases on the skin. Condensation on the walls is only dangerous in bulk stores, where moisture can accumulate on the floor, wetting the tubers at floor level.
Condensation on the structure will occur if the temperature of the inner surface falls below the dew point of the air temperature near the surface. This can happen for one or more of the following reasons: the insulation is insufficient or has failed because it is damp, there is not enough air movement over the inside surface of the roof to localize high relative humidity on the roof surface, cold weather causes heat but not steam, exit the storage, the internal atmosphere of the storage has reached a very high humidity. For example, a closed storage has an inside temperature of 8°C and a humidity of 92% (pic 2). At an outside air temperature of 8°C, there is no heat and humidity transfer, the situation is stable. If the ambient temperature rises to 12°C, heat will flow into the storage, raising the air temperature to 10оC and reducing humidity to 82%. When the outside temperature drops, heat can pass through the insulation, but the steam is trapped inside. If the outside air cools down to 3°C, the heat will leave the store, the air temperature in the store will drop, and its relative humidity will rise to 100%. Condensation will occur on the coldest surfaces inside the store, usually on the roof, but it can also occur on cold areas of the crop. Although this is a temporary phenomenon, it can cause disease and product rot. Condensation can also form inside the structure and behind the insulation. If moisture penetrates the structure, the quality of the insulation is significantly reduced.
Structural condensation is minimized by:
– Good thermal insulation with low thermal conductivity. (Refrigerated warehouses - 0,3 W / m 2 °C for roof, 0,38 W/m2 °C for walls; conventional storage -0,4 W/m2 °C for roof, 0,45 W/m2 °C for walls).
— Recirculation of air in storage rooms using fans to prevent temperature fluctuations in the layers of still air under the insulation, which can lead to localized cooling and an increase in relative humidity. The fans must be installed so that the air movement is horizontal.
— Installation of roof heaters to compensate for heat loss during cold periods of weather. They can be used in combination with attic fans and/or polyethylene distribution pipes. Heating of the roof space can be carried out using an electric heating cable suspended from the roof, or electric heating elements installed in air circulation fans in the under-ceiling space. Heat output should be 10 W/m2 roof area.
— Painting of metal structures reduces the formation of condensate on them.
— Regularly check for condensation in cold weather (>6°C below storage temperature), watch closely for signs of structural condensation on surfaces such as the underside of a roof. Check for signs of dripping or sagging roof insulation caused by condensation. Check the thickness of the polypropylene insulation (usually at least 100 mm for cold stores and more than 75 mm for externally cooled stores). Replace damaged insulation.
— Automation of the anti-condensate action program. Adjust the fine settings according to the particulars of the vault. Ideally, use a controller that can independently control ventilation, air recirculation and under-ceiling space heating. Condensation in the refrigerator. Cold stores have less risk of condensation in the surface layers of containers, since the cooling air is always about 1,5-2,5°C colder than the crop. But too rapid cooling, i.e. >0,7°C/day, often aimed at limiting the development of diseases, can lead to significant temperature changes that can lead to condensation. At high cooling rates, it is advantageous to cool for fewer hours with air recirculation for the rest of the time. If condensation is observed, shorten the cooling period and increase the recirculation period. Attempts to slow down the onset of disease must not lead to inadvertent condensation and disease. Condensation and freezing of moisture in the evaporator increases as the storage temperature decreases (Fig. 3).
The need for defrosting is reduced when an even temperature is maintained in the storage. The temperature difference between the air entering the evaporator and leaving it should not exceed 2,5-3°C. Condensate control costs can be reduced if the warehouse is well sealed. Only one small door is left for winter access. Close and seal all doors or shutters not required for access or ventilation.
Prevention of moisture condensation during the entire period of storage is possible on the basis of accurate accounting of the temperature and humidity of the product mass, the air in the storage and the temperature and humidity of the ventilation air. These parameters are included in a special psychrometric table (Fig. 4). The analysis of the psychrometric diagram is carried out specifically for the possibility of condensation. Condensation means that the air in the prevailing conditions is or cooled to the dew point temperature.
For example, a pulp temperature of 16°C for incoming freshly harvested tubers requires a store supply air temperature of 15°C, and a sudden change in weather reduces the temperature of the store entering pulp to 10°C. The psychrometric diagram shows that supply air at 15°C at 70% relative humidity, cooled to 10°C, will reach the dew point (saturated humidity) and water will condense on potatoes at that temperature. And this is at a relative humidity of 70%, which is very rarely observed in the climate of the Russian Federation. And ventilation with warmer than potatoes and humid air in any case will lead to abundant condensation on the tubers. It is absolutely impossible to blow colder potatoes with warm and humid supply air. The ventilation system operating in such a situation with the storage doors open, figuratively speaking, practically means watering the tubers with water from a hose.
Analysis of the psychrometric chart provides information on what happens at the start of early storage when moisture-laden supply air enters warmer produce at harvest time. If the seeds are warm enough compared to the temperature of the supply air, then the tubers are treated with air of relatively low humidity, even if the cold supply air is close to moisture saturation. This is because the relative humidity of the air decreases as it warms up. For drying tubers, such a process is favorable, with regard to the treatment period, not everything is so simple.
The achieved degree of healing of skin damage predetermines the level of weight loss of tubers during the entire storage period. Most authorities agree that a supply air relative humidity of 90 to 95% provides good suberization. During harvesting, the relative humidity of the supply air is usually in this range simply due to the surface humidity. Once the storage is full, it is best to keep the temperature of the tubers at 10-13°C for two to three weeks so that the potatoes are cured (suberization = healing of wounds), this with the necessary period of time to bring the temperature of the pulp to 10-13°C . Periodic forced ventilation is needed during curing to get rid of respiratory heat and carbon dioxide and provide oxygen to all tubers. The relative humidity of the supply air at this time of the year is usually 85-95% without the need for additional humidification. While the above conditions are optimal for healing skin lesions, exceptions are often necessary. Yes, during the first month and a half of storage, the rate of tuber weight loss is highly dependent on the relative humidity of the supply air. But the relative humidity of the air during the treatment period should be maintained at 90-95%, unless the tubers are wet or diseased. If problems with diseases are foreseen, then significant adjustments must be made to the modes of storage, temperature and humidity, and ventilation.
storage diseases include those that can progress significantly in the post-harvest period and the development of which significantly depends on storage conditions: common late blight and pink rot, anthracnose, bacterial rot - ring, dikeya, pectobacterium, tuberculate scab - oosporosis, wound watery (pithy) rot - pytium, silver scab, anthracnose, phomosis, fusarium. Keeping hot or cold but moist and disease-infested potatoes is challenging, but with the right care and attention, it's possible. Wet tubers, combined with painful pressure and high temperatures, are especially dangerous.
A good and thorough pathogen risk assessment for potatoes to be stored is a must as it gives an accurate picture of the development and spread of the presence of specific diseases in the crop. It is necessary to assess in a timely manner all the facts that caused concern during the growing and harvesting period: the quality of seed material, weather characteristics, the effectiveness of chemical control, problems in neighboring fields, symptoms of diseases on plants and tubers, comments on the quality of pre-selected samples, the quality of desiccation, tuber maturity, cleaning damage, temperature and humidity during cleaning. Reviewing the agronomist's records for each field during the growing season, and especially in the weeks immediately before harvest, provides a solution to problems through the correct implementation of the main stages of storage or rationally refuse long-term storage if the risks are excessive. Most experts believe that it is not practical to store potatoes with more than 4% of tubers infected with late blight or 1% with soft rot. With a lower level of disease in the crop entering storage, the spread of diseases can be controlled, i.e. hold back. Managing temperature and humidity against an infectious background requires a very fine line. There is definitely a conflict between optimal conditions for suberization and for disease control. To minimize losses, it is necessary to implement a clear plan and a set of measures. The possibilities for controlling all diseases at the stage of potato storage have been published in detail earlier (1-3). Universal measures at the initial stage of storage are as follows:
• Avoid problems by picking dry potatoes with a pulp temperature between 7 and 13 оC.
• For lots showing symptoms of wet rot, dry rot, late blight, if possible, wait until harvest until symptoms are fully manifest before harvesting.
• Sorting diseased tubers on the harvester; this requires additional people.
• Sorting out diseased tubers as they are being loaded into storage, ensuring there is enough light, people and time to do the job properly.
• Prepare a storage facility with a working active ventilation and control system. Make sure there is sufficient air flow in the chambers and storage areas. Good ventilation is absolutely essential for storing problem potatoes.
• Do not spend the traditional treatment period. Because problem potatoes are usually wet and infested with rotting organisms, the goal is to cool and dry the crop as quickly as possible.
• Cool quickly to final storage temperature (3-4оFROM). Do not moisten the potatoes and prevent condensation in storage.
• Ventilate continuously (install additional fans if necessary) until the crop is dry and rot is under control. During the problem period, air must be constantly supplied to the mass of potatoes, even if outside air is not used.
• To ensure the movement of air through the entire mass of products, for which a local increase in power makes sense, since rotting potatoes and dirt impede the movement of air.
Monitor storage status daily. Thermometers located in different areas of the storage lots provide a good indication of the average temperature. Infrared scanners help detect localized temperature rises before they smell and spread.
• Do not expose cold potatoes to warm outside air. A layer of free water will condense on the tubers. Contact with water on the tubers leads to their suffocation, while at the same time promoting the reproduction of soft rot bacteria.
Two examples of special disease-specific interventions.
1. Soft rot during storage, caused by pectobacteria:
— there is information on the use of bactericides or disinfectants to directly control bacterial soft rot in storage. This will be discussed below;
- storage and containers should be thoroughly cleaned (and disinfected if diseased potatoes were previously stored) before use;
- to achieve the formation of a strong peel and its maturity before harvesting;
- harvest carefully and avoid bruising, do not harvest in the rain;
— if soft rot infection is suspected in only part of the lot, then place it closer to accessibility so that it can be quickly removed if it starts to deteriorate;
- use air with low humidity with a constant air flow during drying, suberization, early storage.
— do not heal injuries at high temperatures (>15 оFROM);
- maintain a low temperature of the tuber pulp at the stage of main storage (below 4°C);
- if the disease does not appear immediately, but during the treatment, the decrease in temperature to the conditions of exposure should be rapid, with a large amount of air;
- prevent the formation of condensate on the tubers, use a continuous but low-velocity air supply to better equalize the temperature in all stacked storage areas;
- use additional ventilation of severely severely affected lesions, isolate them, if possible, for this treatment.
2. Dry rot caused by Fusarium sambucinum and other Fusarium spp..:
- minimize the formation of bruises during harvesting and processing;
Avoid harvesting potatoes at low pulp temperatures because cold potatoes are very susceptible to bruising.
- before harvesting, make sure that the skin and maturity of the potatoes are in good condition;
- remove excess dirt and clods during harvest and before storage;
- post-harvest treatment of tubers without contamination.
– temperature of 13°C and relative humidity of 95% promotes wound healing, wound healing is completed in 2-3 weeks;
- After suberization is completed, gradually reduce the temperature at a rate of 0,5 °C per day until the conditions of the main storage period are reached.
In order to reduce the infectious background during storage, reduce the spread of diseases, it is advisable to treat tubers before storage or, as necessary, directly during storage with fungicides or disinfectants. The decision-making algorithm for treatment depends on many circumstances and is specific for each disease (Fig. 5).
The active ingredients used to treat potatoes against storage diseases are azoxystrobin, fludioxonil, difeconazole, sedaxan, mancozeb, flutalanil, penflufen, prothioconazole, thiophtanate-methyl, phosphorous acid, potassium phosphite, chlorine dioxide, hydrogen peroxide, benzoic acid, peroxyacetic acid. There are no universal means of suppressing all pathogens, it is necessary to use active substances that are effective for the target object (Tables 2, 3).
Table 2. Some commercial tuber fungicides
Active ingredients | Rhizoctonia stolons and stems | Tuber rhizoctoniosis | Fuzarioz | silver scab | Scab Obyknov | Fitoftoroz |
Thiaftanat methyl + mancozeb + cymoxanil | 5 | 2 | 5 | 3 | 5 | 5 |
fludioxonil | 5 | 5 | 5 | 5 | 2 | 2 |
Fludioxanil MZ | 5 | 5 | 5 | 5 | 5 | 4 |
Thioftanatmethyl 2,5D | 5 | 2 | 5 | 2 | 2 | 4 |
Thioftanatmethyl 5D | 5 | 2 | 5 | 2 | 2 | 4 |
Thioftanatmethyl MZ | 5 | 2 | 5 | 4 | 5 | 4 |
Thioftanate methyl MZ + imidacloprid | 5 | 2 | 5 | 4 | 5 | 4 |
5 - excellent; 4-excellent; 3- good; 2 - weak |
High-quality treatment with fungicides and disinfectants is an ultra-low-volume spraying with a working fluid consumption of not more than 3 l / t. This is possible when using disc atomizers on any rotating surface - hopper rollers, inspection tables or Mafex special equipment. Permissible flow rate of the working fluid of 10-20 l/t at the hospital is erroneous and unacceptable. In the modern phytopathological situation, the obvious wetting of tubers is a conscious provocation for the development of bacterial diseases. After processing at the hospital, even on the eve of planting, the potatoes must be dried .. Otherwise, problems with germination and rotting of tubers are inevitable.
So far there are no fungicides with antibacterial activity. For valuable batches of potatoes in difficult situations in Germany in order to localize wet bacterial rot, tubers are dusted before storage with finely ground dry slaked lime at a dosage of 20-50 kg per ton. Lime does not impair the table quality of the tubers, but after that the appearance becomes unusual. It is clear that in this case, the potatoes must subsequently be washed or the consumer must agree to purchase lime-coated potatoes.
Washing potatoes before storage is a very rare agricultural practice.. It makes sense to wash potatoes to save valuable lots when wet rot slime has spread throughout the whole lot during the harvesting process. In this case, you can not use submersible containers, only sprayers. It is necessary to have several directions of nozzles so that the entire surface of the tubers is washed clean. Washed potatoes before immediate and mandatory quick drying must be treated with a disinfectant (hydrogen peroxide, benzoic acid, sodium hypochlorite, etc. with a full rate).
Similar to the drying and curing steps, the schedules for the next cooling step should also take into account the condition of the potato batches, i.e. temperature, humidity, risks and issues. In a normal situation, the ventilation air temperature is reduced at a rate of 0,3-1,0 ºC per day until the conditions of the main long-term storage period are reached. Measuring the pulp temperature is a more accurate method of process control. The best time to measure cooling results is in the early morning because the cooling is done using the low night outside temperatures. Ventilation must always be on during cooling. Once conditions inside the store have stabilized, daily ventilation should be long enough to maintain a difference of no more than 1,0 ºC between the bottom and top containers or fill layers, and in the back and front of the storage chambers. It is better to run fans with shorter cycles (2-4 hours on and at least 2 hours off). This schedule reduces temperature fluctuations within the vault. If the fans are stopped for a long time, the tubers tend to heat up; therefore, it will take more time to cool down to the holding temperature.
Lowering the storage temperature quickly helps reduce the damage from most diseases. However, this procedure is not without risks for normal, mature tubers. One of the disadvantages of rapid cooling is that tubers at the bottom of the containers and in the lower layers of the mound can lose turgor, flatten under pressure and shrink excessively. This is due to a significant increase in the temperature of the too cold air used for rapid cooling, which leads to a decrease in relative humidity. As a result, the air around the tubers is characterized by a deficit in vapor pressure compared to the internal water content of the potato. This causes internal water to come out of the tubers to make up for the deficiency. The loss of moisture weakens the strength of the internal cellular structure of the potato. The second disadvantage of rapid cooling is that during prolonged warm weather in autumn and even early winter, after cooling, it is necessary to minimize the use of fresh outdoor air for a long period (so that the temperature in the store does not rise), which deprives the tubers of oxygen and leads to the accumulation of carbon dioxide. gas. Overripe seeds will be especially sensitive in this situation. Also, low temperatures and elevated levels of carbon dioxide slow down the healing process of wounds. At the same time, rapid cooling is required if there is a risk of early germination of tubers. This risk is also typical for the current season, since the tubers received a large amount of heat in the process of growth during the growing season. For this reason, varieties with a short dormant period will be able to germinate already in October - November, which is undesirable for both table and seed potatoes.
Finally. It is practically impossible to exclude the possibility of problems during long-term storage of potatoes. Every professional potato grower experiences them firsthand as they are grown and harvested under unregulated and often sub-optimal conditions. Good temperature and humidity control during the first few weeks of storage is the single most important factor in the success of all long-term storage. The first month of storage is crucial, as it is during this time that you need to quickly dry, heal damage to the peel and cool the product properly. Whether the problems are related to weather or diseases, temperature or humidity, attention must be paid to each of these factors in order to preserve the maximum mass and quality of the tubers. Sufficient supply airflow at the right temperature and humidity is vital for problem potatoes. Actual procedures for conducting the first stages of storage may require compromises to minimize losses. In order to preserve the quantity and quality of potatoes in every possible way, highly qualified specialists should be responsible for storage and promptly make the necessary decisions, and potato storage facilities should be properly built and equipped with powerful active ventilation equipment.
References:
1. Storage of seed potatoes / S.A.Banadysev. - M .: Knihizdat, 2020. -292 p.
2. Technologies of active ventilation of vegetables (2nd ed.) / S.A.Banadysev, Yu.V.Patsyuk. - Minsk: Witposter, 2016. - 148 p.
3. Banadysev S.A. Potato storage diseases. - "Potato system", 2021. - No. 4, p.42-47
4. XieT, Shen S, HaoY, LiWandWangJ. Comparative Analysis of Microbial Community Diversity and Dynamics on Diseased Tubers During Potato Storage in Different Regions of Qinghai China. front. Genet., 2022.-13:818940. doi: 10.3389.
5. Problem Potatoes at Harvest./Suberizer Inc. — 2019
Author: Sergey Banadysev, Doctor of Agricultural Sciences Sciences, "Doka-Gene Technologies"