Harvesting Cereals For Quality

Cereal harvest is not that far away. The winter wheat crop is well into pollination in the south-western part of the province. Current high temperatures and dry weather stress have greatly increased the speed of crop development, and it is ahead of normal this year. Spring cereals were seeded 1 to 2 weeks earlier than normal in many areas. This means that cereals will be ready to harvest 1 to 2 weeks earlier than normal. Grower experience and research shows that cereal quality can drop as harvest is delayed past 13-14% grain moisture. The micro-organisms that cause weathering and quality decline flourish under cool, moist conditions. Timely harvest is important to maintain a food grade quality product.

Quality Factors & Downgrading

Mildew can be a problem in spring wheat if harvest is delayed due to rain, and can result in discounting due to downgrading. There are several other quality factors that can be negatively affected by delayed harvest. “Falling number” is a quality factor measured by the millers when they receive wheat from elevators or directly from growers. Research done by the University of Guelph and C&M Seeds showed that a decline in falling number can happen as harvest is delayed. The rate of decline varies depending on variety. Sprouting (chitting) or fusarium can result in downgrading of both wheat and malting barley. Sprouting is the result of moisture and delayed harvesting. Fusarium and DON levels can also continue to increase with delayed harvest.

Premium Oat Markets

For the premium quality oat horse and milling markets, weathering or discolouration prior to harvest is a major issue. The horse market demands a white, bright oat, with no discolouration. The milling market requires an oat with no discolouration of the groat (the core of the grain beneath the hulls). Oats that have dark tips on the hulls are not acceptable for the horse markets, but may be acceptable for milling if the groats are not discoloured. Research by John Rowsell at the New Liskeard Agriculture Research Station found that colour, whiteness and brightness begins to deteriorate with delayed oat harvest. The rate of weathering and discolouration is greater when swathed than with direct harvest. Using a fungicide did not affect the amount of weathering.

If the harvest weather looks to be unfavourable, you are better to harvest grain when it reaches 16% moisture and artificially dry it down to 13-14%, than to wait for it to dry in the field and risk weathering damage. Grain at 13-14% moisture will maintain its food quality and make it safe for storage. The $5 to $10 per tonne drying charge can be easily lost if harvest is delayed and this results in lower grades.

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