As a storage guy, I regularly get asked by producers what changes they can make through the storage season that would have the biggest return to their business. There are the obvious watch items – humidity, temperature, condensation, shrink and pressure bruise – but the vast majority of producers are already well aware and very on top these factors. That’s why I’d say, for most farmers, one of the biggest money-saving storage management opportunities is improving carbon dioxide (CO2) management to maximize fry colour bonuses.
Carbon dioxide is all around us. It’s a natural biproduct of respiration of all living things; it’s produced every time we burn fossil fuel; it’s released from decomposing organic matter, volcanoes and even the ocean. At normal levels, it’s harmless. When it builds up, however, it can cause problems.
When CO2 levels are high (over 0.2 per cent or 2000 parts per million) for an extended period in potato storages, the fry colour may shift, resulting in darker fry colour that may impact colour bonuses.
Here’s how to best manage CO2 in storage:
- Adjust ventilation schedules to suit the weather — Ventilate at night during warm weather; ventilate during the day during cold weather. Watch the inlet hours versus fan run time hours to determine if inlets are active during fan run time. If you have fan run time without inlet activity, reduce fan run time (recreational ventilation).
- Keep CO2 sources to a minimum — Loaders, trucks and other fuel burning equipment release CO2 and other byproduct emissions. Ventilate the storage well when using this equipment or find electric alternatives.
- Trick your system — During very cold weather, place an electric heater in the mixing chamber or aimed at the return air to fool the system into opening the louvers, which will bring in fresh air.
- Conduct a timed/manual CO2 flush — Set your panel to run a timed CO2 flush, opening the air inlet for five minutes every four hours. Set the door opening percentage to correspond with the weather outside (two per cent open on colder days; 10 per cent open on warmer days).
- Monitor your CO2 — Install a CO2 sensor that will sound an alarm when air quality is poor (CO2 above 2500 ppm). The Simplot Raw Department also offers instruments for monitoring CO2, contact us for more information about testing.
- Bring in an expert — consult with your local storage representative to understand your building’s storage and ventilation capabilities and to optimize your system, including its CO2.
There’s a lot farmers can’t control during the growing season. From excessive heat to thrashing hailstorms, from pests that blow in to the timing of disease, farmers constantly have to react to whatever their environment throws at their growing plants. Luckily, that’s not the case once potatoes are tucked into storage. While managing potatoes from harvest to shipping requires time and thought, it’s very possible to avoid the biggest robbers of ultimate return – including excessive CO2 – through careful management.