Questions of the Week

Does the crop have enough fertility for top yield?

Growing conditions so far this year are quite similar to 2016, which was the highest yielding canola year in Canada. What may stand in the way of great yields this year, however, is soil fertility: following multiple years of drought, many producers have cut back on nutrient rates. In extremely wet soils, N losses may contribute to nutrient deficiency. Consider the potential benefits of top-dressing. If wind limits opportunity for herbicide spraying, consider using the time to bump up the crop’s fertility and its corresponding yield potential, if suitable for your scenario. (Tips to apply nitrogen and sulphur in season) (Volatilization losses from surface applied nitrogen) (Canola Encyclopedia: nitrogen)

Spring frost: what next?   

Temperatures dipped below zero in multiple regions in the last few days. Wait four or more days to assess damage. Canola seedlings will usually recover from a light spring frost. After a heavier frost (below -2°C for a few hours) look for survival of the stem, green color at the growing points in the centre of the frozen leaf rosettes, and for hypocotyls to appear thick and not pinched off. Frost stress makes weeds less susceptible to herbicide, which is why it’s best to wait three to four days for weeds to resume growing after a frost before applying herbicide. (Spring frost: when to resume weed control) (Spring frost: did the crop survive) (Canola Encyclopedia: frost)

Why count plants? (And what if there are too many?)

Counting canola around the 2-4 leaf stage gives important insight into seeding success (seed placement, seeder consistency), early season crop health (emergence percentage, insect feeding), and later season crop uniformity. Here’s how to count plants. If plant counts are at the high end or exceed the recommended 5-8 plants/foot2, use this year’s emergence as a ‘top end’ benchmark to influence future years’ management choices. A very dense stand will have thinner stalks, may self-thin, and is likely to reach maturity early due to less branching. A thick plant stand, especially in combination with high moisture / high humidity, can also provide an excellent microclimate for sclerotinia development. Email if you’d like a Canola Counts 1/4m2 ring to help take plant counts. (Canola Counts) 

How to tackle weeds despite challenging spraying conditions?

Field access continues to be an issue in many acres due to wind and excess moisture. To maximize herbicide efficacy when it is possible to get into the field:

  • Prioritize the highest potential fields,
  • Scout to know what kinds and stages of weeds are present,
  • Consider bumping up herbicide to a higher labelled rate if it’s likely there will only be opportunity for one pass,
  • Ask: is it worth spraying? If a first pass was applied, how successful was it? Could canola growth outpace weed growth?
  • Time it well: the interval between passes is generally 5-7 days. Are weeds up and growing enough to justify tightening that window?
  • If a second pass is possible and necessary, is the target late-emerging weeds or weeds that didn’t die the first time?

(Spraying tips for tough conditions) (Weed control strategies for each HT system) (Spray early – economics of early weed control)