Canola Harvest Losses May Lead to Costly Soybean Problems

By Blake Jackson

Canola acreage is steadily increasing across western Kentucky as more farmers adopt the crop as an alternative to wheat. Favorable market prices and strong profit potential have made canola an appealing option for crop rotations, according to Dr. Mohammad J. Shamim, UK Extension Associate Grain Crops. However, harvest practices can have a major impact on the success of the next crop, particularly double-crop soybean.

Canola differs from wheat because its small seeds are highly prone to shattering when pods are disturbed during harvest. Throughout this year’s harvest season, field observations were conducted in Christian County and across Kentucky’s Purchase Area to evaluate seed losses.

Environmental conditions caused very little natural pod shattering before harvest, even in the more susceptible PT-303 variety.

Most harvest losses occurred during combining, making equipment settings and operating practices critical. Faster ground speeds and excessive fan speeds resulted in more seed being left behind, while harvesting at approximately 2 to 3 mph with properly adjusted combine settings significantly reduced losses.

Although PT-303 produced higher yields and offered stronger resistance to white mold, lodging, aphids, and spring frost, PT-314 demonstrated better resistance to seed shattering during harvest. Because canola seeds are extremely small, even minor losses can quickly become significant.

As few as 115 seeds per square foot can equal roughly one bushel of yield lost per acre.

Beyond reducing canola yields, leftover seed can create problems for the following soybean crop. Seeds remaining on the soil surface often germinate after rainfall, emerging alongside double-crop soybean.

In addition, plants cut during harvest may regrow from surviving stems, increasing the number of volunteer canola plants.

Volunteer canola competes with soybean for moisture, sunlight, and nutrients while also making weed control more difficult. Depending on the herbicide program and canola variety, additional post-emergence herbicide applications may be required, increasing production costs.

Reducing harvest losses through proper combine adjustments, moderate operating speeds, timely harvest, and appropriate desiccation practices can protect canola yields while minimizing volunteer canola in subsequent soybean fields, improving both productivity and profitability.

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