To maintain the quality of harvested canola, immediate conditioning and consistent monitoring are essential. Conditioning cools the seed, evens out temperatures within the bin, and removes moisture that can lead to spoilage. Even dry canola releases moisture through natural seed respiration in the initial weeks after harvest. Key factors influencing safe storage include moisture, temperature, dockage, and air movement.
Risk Factors and Recommendations
- Moisture and Temperature:
Safe long-term storage requires canola seed moisture of 8% or less. Moisture combined with higher temperatures (e.g., 25°C or above) increases the risk of mould and spoilage. Aeration can reduce grain temperature below 15°C at harvest and to 0°C in winter, mitigating these risks. - Hot Canola:
Even low-moisture canola requires aeration to cool and redistribute moisture. Air movement ensures a consistent temperature and minimizes concentrated moisture pockets that could trigger spoilage. - Green Canola and Dockage:
Green seeds and dockage, such as weed seeds, chaff, or stalk fragments, retain higher moisture and create airflow resistance. These materials often clump together, increasing the risk of hot spots and spoilage. - Insects:
While insects from the field do not feed on stored canola, their presence can increase mould risk. Conditioning grain with significant insect content is advised. Avoid using malathion for bin treatment, as its residues can persist and contaminate canola. - Bin Size and Airflow:
Large bins pose airflow challenges, especially when filled to capacity. Research shows that partially filling bins (e.g., 17,000 bushels in a 25,000-bushel bin) can significantly improve airflow and cooling efficiency. - Temperature Differentials:
Seasonal changes cause moisture migration inside the bin. In the fall, warm air rises from the bin’s core to the surface, where it condenses and increases spoilage risk. In spring and summer, external heat from the sun reverses this process, leading to moisture reabsorption by cooler canola in the center.
By adhering to these practices and monitoring conditions within the bin, producers can minimize storage risks and maintain canola quality for the long term.
