When spring arrives, winter canola growers will have to scout their fields and answer 3 questions before applying fertilizer:
- Is the canola alive?
- Does it have strong yield potential?
- What is the population of healthy plants?
Scouting typically begins towards the end of March when plants start to green up. Assessments should be made after the risk of further losses from cold conditions, or fluctuating temperatures, has passed. Information from the canola breeding program at Kansas State University suggests that freezing tolerance is lost when temperatures are above 15°C for an extended period. Assessments could be made prior to temperatures reaching 15°C and above; however, if temperatures drop below that you may need to scout again.
In March, if you “scout” from your truck you might jump to the conclusion that everything looks dead if all the leaves have fallen off or turned brown. Some fields do not retain all the green leaves they put on in fall, especially if there was an abundance of vegetative growth. It has been observed that plants with fewer leaves (but adequate root growth) in the fall tend to retain those leaves through winter, whereas plants with many large leaves in the fall tend to lose those leaves through winter.
So, to answer Question #1 – is the canola alive: If there is any green tissue at the center of the rosette (plant crown) the plant is alive. You can also squeeze the stem just below the crown to confirm it is not rotten. By the end of March or beginning of April, dead plants will often be rotten and can be brushed away from the soil surface with your hand. If it is difficult to be confident in your assessments of which plants are alive vs. dead, wait a week and check again.
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