The harvest season in agricultural production is the most enthusiastic time when months of intense labor and waiting turn into a product. However, in some years, the yield is so high that the massive amounts of wheat, corn, cotton, hazelnuts, or dried figs obtained do not fit into existing closed silos and warehouses. In this case, tons of agricultural products have to be stored outdoors in massive "stacks" (bulk) in factory yards, port areas, or on the plains right next to the fields. This valuable crop waiting outdoors is an open target not only for rain and sun but also for birds, rodents, and especially microscopic stored product pests. An unattended pile of grain is rapidly invaded by moths and weevils in just a few weeks and rots quickly. In these harsh conditions where there is no enclosed warehouse, the only professional way to protect the harvest is "Stack Fumigation". In this article, we will examine the technical details and operational challenges of stack fumigation that protects products stored in open areas.
Pest Risks in Open Area Stacks
Left alone with nature without the protective walls of an enclosed silo, stacks are an inviting feast for pests:
- Stored Product Pests (Grain Weevil, Lesser Grain Borer, Moths): These insects, reaching the stack by flying with the wind or crawling from the soil, enter the product and multiply rapidly. Insects descending towards the center of the stack cause the product to heat up, hollow out, and produce aflatoxin (carcinogenic mold poison).
- Birds and Rodents: While birds perching on top of open stacks contaminate the product with their droppings, mice dig tunnels to the lower parts of the stack and consume tons of the product. The fumigation process destroys not only the insects but also the mice inside the stack.
Basic Principles of Stack Fumigation
Exterminating a silo or a container is relatively easy because they already have airtight steel walls around them. However, exterminating a massive hill (stack) on a soil or concrete floor in an open area requires great engineering and experience. The main purpose of stack fumigation is to prevent the gas from escaping by creating an artificial "enclosed space" (tent).
Process Steps:
- Floor Insulation and Preparation: If possible, before the stack is formed, thick, gas-tight tarpaulins are laid on the concrete or soil floor. This prevents the gas from leaking into the soil and blocks moisture/pests coming from the soil. The product is piled on this tarpaulin.
- Covering the Product (Pulling the Tents): The stack is completely covered with special fumigation tarpaulins (PVC or Polyethylene based) that are highly resistant to UV rays, wind, and rain, tear-proof, and lack microscopic pores.
- Ensuring the Seal: This is the most critical stage. The skirt parts where the upper tarpaulin meets the lower tarpaulin (or the concrete floor) are completely sealed with sandbags (sand snakes) or special adhesive mastics to prevent the gas trapped inside from blowing away with the wind.
- Gassing: Phosphine (Aluminum or Magnesium Phosphide) tablets, calculated according to the size of the stack, are placed in different parts of the stack under the tarpaulin. The gas slowly releases and penetrates from the top to the bottom of the stack.
- Ventilation: After a waiting (quarantine) period of 3 to 7 days, the tarpaulins are opened in a controlled manner, and the product is ventilated.
Operational Challenges and Safety Precautions
Stack fumigation performed in an open area is risky because it is directly exposed to natural conditions. The company carrying out the operation must analyze the wind speed, precipitation status, and soil characteristics of the region very well. If a severe storm tears the tarpaulin, all the toxic gas can spread into the environment, causing a fatal disaster for nearby workers, farm animals, or villagers. Therefore, security ribbons must be drawn around the stack, and warning signs must be hung.
Conclusion
Open area storages, where your labor and capital are piled up like massive mountains, cannot be left to their fate. The way to save your thousands of tons of agricultural products, which you have to keep outdoors due to a lack of warehouse space, from rotting, becoming infested with insects, and losing value is stack fumigation. You can secure your wealth in the open air by entrusting this challenging process to an expert fumigation team that reads the weather conditions correctly, uses solid insulation materials, and provides services at international safety standards.