Frost, wind, cold soils and in some cases excess moisture have reduced canola stands. Some growers are thinking about reseeding. This week’s quiz provides some background to help with the decision.
When growers have canola stands of fewer than 4 plants per square foot — due to low seeding rates, poor seed survival, insects, crusting, frost, wind, etc. — they grapple with the question whether to reseed. An established canola stand with as few as 1-2 plants per square foot generally has higher economic potential than if were to reseed that crop in June. This population is far below the minimum 4-5 per square foot required to meet yield potential, but a thin stand seeded early has greater economic potential (considering yield, quality and cost of production) than an adequate stand that doesn’t get established until mid to late June.
However, reseeding may be the better option if…
After a frost, it can take a few days to accurately determine how many plants survived, and whether the stand is still uniform. Be patient before making any decisions. Check the whole crop the day after a frost and then again 3-4 days after a frost to assess the situation.
Flea beetle don’t change with frost, but frost may have changed the crop assessment situation. Here’s how….
In dry soil conditions, growers may be tempted to seed deep enough to reach moisture. This is not necessary from April to mid-May, and may create more harm than good at any time. The common recommendation to seed no deeper than 1” still applies in dry conditions. Here’s why:
Weeds will be going strong with the sun, especially if they have established roots that reach moisture while newly seeded crop battles dry topsoil conditions. A second pre-seed burnoff may be in order or — if emergence is likely to be slow — the post-seeding pre-emergence window may be a little wider than usual. Either way, early weed control remains important to maximize profit potential of the crop.
Canola is quite susceptible to water logging and shows a yield reduction after only 2-3 days in excessive moisture. Wait to see how the crop recovers before making decisions on reseeding or fertilizer top ups.
canolaPALOOZA — June 23, Lacombe, AB
International Rapeseed Congress – July 5-9, Saskatoon, SK.
Crop diagnostic school — July 28-30, Outlook, SK.
Crop diagnostic school — July 7-9 and 14-17, Carman, MB
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