April 16, 2024 – Farmers can’t control the weather but they can control their weather preparedness. Can farmers actually “drought-proof” the crop? No. A long drought will result in significant yield drop no matter what. The following steps can however give canola a better chance at moderate success when dry conditions occur.
1. Leave tall stubble.
Research from the Prairies shows that, in dry conditions, moisture from snow trapped in stubble increases until stubble is about 12” tall.
2. Seed between the stubble rows.
This works in tandem with tall stubble. Precision seeding tools that work between the rows of tall stubble will result in fewer complications from the tall stubble. Farms get the moisture gain from the snow trap without the issues of poor seed placement. A combine that achieves uniform residue spread also helps.
3. Choose weather-tolerant cultivars.
Cultivars that yield consistently well in a broad range of conditions may provide an advantage when drought conditions occur. Ask around to see which cultivars performed best in recent dry seasons. More on choosing the right cultivar for each field.
4. Select fields with low herbicide carryover risk.
Canola is extremely sensitive to Group 2 herbicide carryover. Areas with moisture accumulation through the previous June, July and August of 4” or less will be at highest risk of herbicide carryover. That risk will be even higher in areas with multiple dry years in a row. Residual herbicides need moist soils and warm temperatures for breakdown to occur within the expected time frame. Listen to an episode of the Canola Watch podcast on herbicide carryover risk.
5. Provide balanced nutrition.
Crops with access to an adequate supply of all necessary nutrients will have lower stress and increased health. Recent research from Agriculture and Agri-Food Canada shows that adequate sulphur can improve results in drought conditions. Read this Canola Watch fundamentals article on ‘how much fertilizer does canola need?’
6. Use very low rates of seed-placed fertilizer.
Even a small amount of fertilizer can damage seed and seedlings in dry conditions. Higher seed-bed utilization can increase the spread between seed and fertilizer, and lower the risk from seed-placed fertilizer, but these high disturbance openers also dry out the soil. Learn more about the right rates for seed placed fertilizer.
7. Consider a split fertilizer application.
The simplest approach is to apply fertilizer at the time of seeding using rates based on the usual yield expectation. An alternative is to fertilize for low-moisture yield targets, then add an in-crop application if moisture and yield outlook improve.
8. Achieve the recommended plant stand.
The recommended range is five to eight plants per square foot. Emergence rate may be lower than anticipated in dry conditions and farmers will need enough seed to achieve the five-plant minimum.
9. Seed at around 1” depth.
When seeding early into dry soils, seed around 1” – even if seed is not placed in moisture. Rain, when it does come, can provide the moisture needed for germination and emergence. Seeding deep to chase moisture can result in lower vigour, delayed emergence, uneven stands and more flea beetle susceptibility. If seeding to reach moisture, place seed at the top of the moisture and pack well to prevent further moisture loss.
10. Keep other stress to a minimum.
Remove weed competition. Weeds take up moisture and nutrients while the crop struggles to establish. For flea beetles, the action threshold of 25 per cent leaf area loss could be lowered with a thinner, dryer stand.
For more information, read the full Canola Watch fundamentals article: 10 tips to improve canola yield in dry conditions. While there, please sign up to receive the weekly Canola Watch e-newsletter, answering the top canola agronomy questions from across the Prairies.
