Considering Row Widths in Canola

  • Canola acreage can be expanded to farmers who have equipment for crops with wider rows.  

  • Lower canola populations can be used with wider row spacing. 

  • Narrow rows maintain more equidistant plant spacing and have quicker row closure to aid weed management.  

Background

Canola farming is a way to increase diversity in crop rotations.  Diverse crop rotations break up pest cycles and can improve soil health.  Traditionally, canola has been solid seeded with a drill and has a row spacing of six to 10 inches.  The canola industry supports the expansion of canola acreage into regions that primarily plant row crops: sugar beets, dry beans, soybeans, and corn.  Farmers with row crop equipment could introduce canola to their rotations if they utilize current row crop equipment. Researchers are also investigating if canola revenue increases with wider row spacing and lower seeding rates. 

 

Benefits of Narrow and Wide Rows

Most past research supports narrow rows (six-inch spacing), and one study did not show an effect on yield until row spacing was as wide as 30-inches.1  More uniform plant spacing from narrow rows can help the crop efficiently use moisture, nutrients, and light. Canopy closure is usually faster with narrow rows making the crop more competitive with early weeds.  

Adoption of wide rows is desirable for some farmers as there may be reduced machinery costs.  Less power is needed for pulling lighter row equipment.  Season-long weed management should be planned to reduce weed competition that could last into summer with delayed closure of wide rows.  Seeds are placed closer together within the row when row spacing is wider.  This can lead to thinner, weaker stems when plants compete for resources in the row.  

 

Figure 1. Narrow rows allow fast canopy closure and equidistant plant spacing for canola to efficiently use water, nutrients, and sunlight.   

Seeding Rate and Plant Population

Canola can branch out and fill open spaces.  The Canola Council of Canada has determined plant densities ranging from four to 19 plants per square foot usually have similar yields.2 In studies with increased row spacing, plant density can be reduced by 26 percent: 11 plants per square foot (9-inch row spacing) to eight plants per square foot (24-inch row spacing).2 

A recent two-year study in North Dakota determined six- to 12-inch row spacing was optimal at Langdon and a six-inch row spacing optimal at Prosper.  Complimenting these row spacings, seeding rate was optimal at six or nine seeds/ft2 for both sites.  Agronomic traits of flowering, maturity, plant height, kernel weight, percent oil, and lodging had little or no response to changes in row spacing and seeding rate.2

 

Fertility

Canola is good at taking up phosphorus (P) from the soil and can take up more P than is applied through fertilizer.  Regardless of row spacing, a canola crop requires 1.3 to 1.6 lbs of P2O5/bushel of yield.  Phosphorus should be positioned for early roots to reach it.  Cool, wet soils limit phosphate solubility and diffusion into the soil, and applications of 15 to 20 lbs P2O5/acre can be placed close to seeds to supply P critical to the first weeks of canola growth.3  Required fertilizer amounts can be split; a pre-plant band of fertilizer can be placed deeper in the soil to be available to roots as roots grow down into the soil profile.

 

Summary

Raising canola is a way to increase diversity in crop rotations.  Diverse crop rotations break up pest cycles and can improve soil health.   Farmers interested in adding canola to their rotations have options for row widths and seeding rates.  Wider rows can be successful with proper management; however, this new practice should be approached with caution as live plants per square foot may be reduced.  The bulk of research suggests narrow rows (12 inches and closer) are best for canola.