Fine Tuning Canola Seeding Rates and Row Widths

Achieving target canola seeding rates can be a challenge with some drills. Over-seeding can be a costly mistake, with hybrid seed costing $8 - $10/lb. One approach that some growers are adopting to improve seeding rate accuracy while saving on seed costs, is switching to planting canola in 14 inch row width.

Potential advantages with this approach include:

• improved calibration of seeding rate
• reduced seeding rate
• improved emergence on soils prone to crusting due to higher number of seeds per foot of row
• opportunity to band starter fertilizer in alternate rows
• reduced potential of serious sclerotinia stem rot (white mould) by improved air flow through the canopy.

Ontario research on row widths dates back to the 1970’s, when narrow rows significantly outyielded wider row widths. The most recent row width research conducted was in North Dakota, which concluded that there was no yield advantage to narrow (7 inch) over wider row widths.

Georgian Soil & Crop Trial

In 2005, the Georgian Regional Soil & Crop Improvement Association undertook a project to compare seeding hybrid canola in 18 cm (7 inch) vs 36 cm (14 inch) row widths. Seven sites were established, but only 4 were harvested due to the extreme heat and drought stress that impacted emergence, growth and yield. The target seeding rate was 5 lbs/ac in 18 cm (7 inch) rows, and 3.5 lbs in 36 cm (14 inch) rows. Seeding in 36 cm row width was accomplished by blocking off alternate rows on the drill.

Results of the 4 locations harvested are shown in Table 1. Canola in the 36 cm (14 inch) row width, took approximately 5-7 days longer to canopy over than the 18 cm (7 inch) rows. Canola plants displayed more branching in the wider row width. All plots showed considerable moisture stress at flowering, and flower blasting was very evident. Variety varied by location. Except for one site, the seeding rate for 36 cm row width averaged 3.9 lbs/ac vs. 5.3 lb/ac for 16 cm row width. Final plant population in the 36 cm rows ranged from 45% to 90% of that in the 16 cm row width. Given the reduced canopy in 2005, this may have impacted final yield.

Results from 2005 should not be viewed as a recommendation, with only 1 year of data, but hopefully encourage other growers to conduct a trial on their own farm in 2006.

Note: average of 4 trials