As soybean harvest gears up across eastern Canada, many growers are reporting uneven maturity in fields.
On this episode of RealAgriculture’s Soybean School, Bernard Tobin catches up with Horst Bohner, OMAFRA soybean specialist, to find out why fields are not ripening or senescing evenly.
The first potential explanation is uneven spring emergence, says Bohner. This often results when soybeans sitting in drier areas of the field take longer to emerge. In a wetter planting scenario, the drill may sink lower in areas of the field with higher soil moisture levels, again creating inconsistent emergence. He notes that some growers have purposely switched to a planter to achieve more even soybean senescence.
Bohner says growers are also seeing a higher number of parthenocarpic or seedless plants. In this case, the whole plant or the stem stay green and there are often fewer pods present. Most often this results from a genetic mutation, which prevents the plant from pollinating properly. Carbohydrates then become trapped in the top of the plant and it remains green. (Story continues after the video.)
Bohner also comments on the role that poor fertility can play in uneven and slow maturity. Plant genetics is another suspect. In the past, many varieties have displayed parthenocarpic symptoms, but breeders have been successful in eliminating the trait. However, if growers are seeing significant numbers of these plants in their fields they need to consider other varieties.
When it comes to managing these fields, practicing patience is likely the best course of action. Bohner notes that pre-harvest aids or burndowns are meant to speed up leaf drop and drying of stems, but they don’t solve this problem. In this situation, the seed inside the pod doesn’t dry any faster when the plant is desiccated.
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