Effectively managing canola residue by ensuring a uniform spread can improve canola stand establishment and increase profitability. Ideally, a combine should be able to spread residue evenly across the full width of the cut. When purchasing a combine, prioritize the performance of the spreader and chopper, and seek advice from dealers on settings to match spread width with cut width. Older combines may need after-market upgrades to enhance residue spread.

Other Combine Adjustments:

• Vanes or powered tailboard: Adjust the angle of vanes or control disk speed to improve spreading.
• Chopper knives: Regularly sharpen, flip, or replace the knives for optimal performance.
• Chopper speed: Adjust speed based on crop type and stubble density.
• Chaff spreader: Ensure it spreads chaff thinly and evenly.
• Straw conditions: Tough straw can hinder spreading, making adjustments necessary.
• Cut height: Taller stubble means less material for the combine to process, which can improve spreading. Optimal stubble height also helps with snow retention and spring moisture infiltration, particularly in dry regions.

Cut Height and Moisture:

Research shows that increasing stubble height from 10cm to 20cm can double the amount of snow trapped in dry conditions, which reduces moisture loss through sublimation and enhances spring moisture availability. Taller stubble also improves canola seed yield and water use efficiency.

Crop Establishment:

Stubble height and residue distribution affect the performance of seeding tools. Ideally, stubble should be cut to match or be shorter than the row spacing of the seeding tool. Research indicates that stubble height has no consistent effect on canola emergence, disease, or yield across different sites.

Harrowing and Tillage:

If combine performance is insufficient, heavy harrows can spread straw, but aggressive use can cause soil erosion. Tillage, while helpful in breaking up residue piles, is less effective than a well-set combine. Light harrowing is ineffective in heavy residue.

Farm Systems: Residue management varies by region:

• Semi-arid regions benefit from standing stubble to trap snow, protect against erosion, and conserve soil moisture.
• Moist regions may require harrowing, tillage, or specialized seeding tools to manage the higher volume of residue. Tillage can also help incorporate fall-applied herbicides or fertilizers while spreading residue.