Harvesting Cereals For Quality

Harvest time is not that far away. The development of the winter wheat crop is ahead of normal, and in parts of the province the spring cereals were seeded 1 to 2 weeks earlier than normal. Frost seeded spring cereals are advanced by 2 to 4 weeks over conventional seedings. This means that cereals may be ready to harvest 1 to 2 weeks earlier than normal. 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

In 2003, mildew was a problem in some spring wheat because harvest was delayed due to rain. This resulted in some discounting and downgrading because of mildew. There are several other quality factors that can be negatively affected by delayed harvest. Falling number is a quality factor measured by the millers. Research by the University of Guelph and C&M Seeds showed a decline in falling number can occur as harvest is delayed. The rate of decline varies depending on the 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.

Quality Oats

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 determined 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% and plan to dry it down to 13-14%, than to wait for it to dry in the field. Grain at 13-14% moisture will maintain its quality and make it safe for storage. The $5 to $10 per tonne drying charge can be easily lost if harvest is delayed.

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