When it comes to stored grain pest management, prevention is always better than cure — aeration cooling helps by inhibiting insect development.
Aerating stored grain has four main purposes — preventing mould, inhibiting insect development, maintaining seed viability and evening out grain moisture.
Grain aeration maintains grain quality during storage and while aeration cooling may not eliminate the need for insect control, it dramatically slows insect development.
Without aeration cooling, grain is an effective insulator and maintains warm harvest temperature for a long time. Without circulation, air surrounding the grain reaches a moisture (relative humidity) and temperature equilibrium within a few days and is likely to maintain that temperature and moisture for months.
Aeration cooling moves the air pockets around the grain, which evens out any hot or moist areas, creating a ‘uniform stack’. This prevents hot spots forming — ideal locations for mould and insects to develop and spread through the storage.
Grain aeration systems are generally designed to carry out either a drying or cooling function — not both.
Grain dry enough to meet specifications for sale can be cooled with 2-4 litres of air per second per tonne, to slow insect development and maintain quality during storage. Grain of moderate moisture (up to 15 per cent for wheat and sorghum) will require aeration drying with 15-25 l/s/t to reduce the moisture content and maintain quality during storage.