Effective potato storage is a critical step in preserving harvest quality, minimising losses, and ensuring a consistent supply to the market. It’s a complex process that goes far beyond simply putting potatoes in a shed; it involves creating and maintaining precise environmental conditions adapted to the specific needs of the crop. Drawing on insights from experts in the field from Agrovent, a leading provider of potato storage solutions, we delve into the core technologies and stages required for successful potato storage.
Diverse Approaches to Storage
There isn’t a single “right” way to store potatoes; the choice of technology is influenced by numerous factors. These can range from the design of the storage building itself and the initial condition of the potato harvest to the available technological equipment and the company’s financial capabilities. Common methods include bulk storage or container storage, often employing technologies like the “Aspiration System” or “Every Air,” among others. Regardless of the specific method chosen, the fundamental principle remains the same: the creation and maintenance of optimal microclimate conditions.
The Crucial Role of the Microclimate System
Maintaining the right microclimate – specifically air temperature and relative humidity – is paramount throughout the storage period. An effective microclimate system must be automatic to ensure these parameters are consistently met. It also needs to manage the removal of excess CO2, a natural byproduct of storing potatoes, and this should happen without constant human intervention. Control of temperature conditions, limiting water losses in tubers, controlling humidity, and maintaining CO2 levels are all managed through ventilation systems within the facility. These automatically controlled systems are excellent at maintaining any preset parameters required for a particular situation.
Understanding the Storage Stages
Potato storage is not a static process but rather a series of distinct stages, each with its own required microclimate parameters. For both seed and table potatoes, these stages include therapeutic (often referred to as healing), drying, healing, cooling, stamina, and finally, heating before the potatoes are unloaded. Harvesting potatoes involves specialised techniques that can inadvertently damage tubers and partially destroy the peel. Such damage creates favourable conditions for the penetration and development of phytopathogenic organisms, potentially leading to dangerous diseases like dry and wet rot. Peel damage can also cause moisture loss, reducing the tuber’s original weight.
The Healing Stage: Repairing and Preparing
A vital initial stage is damage healing. This typically occurs over 8 to 10 days at a temperature no lower than +15 degrees Celsius and high relative humidity, approximately 90-95%. It’s crucial to note that these conditions are ideal for tubers with only minor damage. For harvests with significant damage or traces of bacterial diseases, such conditions can be detrimental, accelerating the disease’s progression.
Healing should incorporate ventilation and drying of the tubers. The duration and intensity of this process depend on the quality of the crop, the humidity of the tubers themselves, and the temperature during harvesting. A dry tuber surface is essential for maintaining its health. Bacterial and fungal diseases, in particular, can spread rapidly on wet tuber surfaces, especially when temperatures exceed +20 degrees Celsius.
The Importance of Dryness
Potatoes entering storage must be dry. Ideally, they should be harvested from dry soil and allowed to dry in the field. If there is liquid water present on the surface of the tubers upon arrival at the storage facility, they should be dried as quickly as possible after loading. Excessive ventilation during drying, however, must be monitored carefully, as it can lead to crop weight loss or dry rot. Monitoring humidity levels is a very important factor for successful long-term storage. High humidity is generally beneficial in potato storage, but the formation of liquid or condensation on the tuber surface poses a serious threat of bacterial rot, which spreads quickly and degrades the stored crop. Experts strongly recommend using meteorological equipment, such as humidity sensors, to ensure the necessary storage conditions are maintained at each stage.
Cooling for Long-Term Preservation
Following the healing stage, potatoes must be cooled to establish conditions suitable for extended storage. This is a crucial period where significant temperature fluctuations in the product should be avoided. Careful control of the product temperature is essential to reduce respiration, evaporation, and germination. Cooling should be a gradual process until the temperature reaches somewhere between +3 and +10 degrees Celsius.
The optimum storage temperature varies depending on the potato variety and its growth conditions. For seed and table potatoes, a temperature of 3-5 degrees Celsius is often recommended. Potatoes intended for fries are best stored at 5-8 degrees Celsius, while those destined for chips require a warmer temperature range of 7-11 degrees Celsius.
Technology and Facility Design
Beyond environmental control, the physical infrastructure and technological equipment of a potato storage facility are key. The facility should be equipped to receive the crop after harvesting and facilitate its processing. During the design phase of a vegetable storage building, consideration must be given to enabling disinfection measures and creating conditions that maximise the automation of product loading and unloading processes.
Successful potato storage relies on a combination of appropriate technology, meticulous microclimate control through automated systems, careful management through specific storage stages, and a well-designed facility. By adhering to these principles, drawing on expert knowledge, storage operators can significantly enhance the longevity and quality of their potato harvest.
