On average, only 40 to 60 per cent of canola seeds put in the ground actually survive to become plants. If a grower spends $50 an acre on seed, typically only $25 of that seed survives to contribute to the success of the crop.
Growers can use the following tips to increase seed survival, achieve a healthy target of at least seven plants per square foot, and get more from their seed investment.
Half an inch to one inch below the packer furrow is the recommended seed depth for canola. This will reduce days to emergence and reduce the seed energy required for emergence.
Seed at a consistent depth
The more consistent the better. For some drills, the overall average may be one inch, but the range could be zero inch to two inches. Too shallow or too deep both contribute to seed and seedling mortality, and those that do emerge will have highly variable emergence dates, creating an uneven field.
Seed slower to ensure good and even seed depth from all openers. The ideal speed will vary by drill and soil conditions. In general, at higher speeds, rear openers tend to throw more soil over the front rows. Seed in these front rows will be buried deeper, making them slower to emerge — if they emerge at all.
Recheck depth when moving from one field to the next.
Limit seed-placed fertilizer. Nitrogen fertilizer placed in the seed row can increase seedling loss due to toxicity and salt effect. Safe rates of seed-placed nitrogen range from zero to 50 lbs./ac. (over and above N in P fertilizer) depending on soil type, soil moisture conditions and seedbed utilization.
The best practice is to place only phosphate fertilizer with the seed at rates up to 30 to 40 pounds of phosphate per acre, and then put the rest of the N and other nutrients away from the seed row. The more fertilizer put down at seeding, the farther away it should be from the seed row.
Spread residue evenly in the fall, and have a drill that can penetrate trash so all openers place seed into the soil.
Leave a firm seedbed
Openers that fracture the seedbed to place fertilizer lower than the seed may not provide the firm, moist seedbed that canola needs. Worn openers that do not provide a defined seed ledge and high fan speeds that cause seed bounce can also reduce an opener’s ability to place seed precisely.
In wet conditions, reduce packing pressure to limit hard crusting. In dry conditions, pack more to conserve moisture in the seed row. Packing pressure can be a delicate balance, and often changes by soil type as well as moisture conditions.
A tight canola rotation will increase the risk from seed and seedling diseases that can prevent emergence.
Seed into warmer soils
This can greatly increase survival but this needs to be balanced against the benefits of early seeding. Canola seeded early May yields higher, most years, than canola seeded late May, but this yield benefit depends on stand establishment. The best plan is to aim to seed early and use the other tips listed above to increase seed survival. Seeding into warmer soils speeds up emergence and makes it more uniform. However, the yield benefits of seeding early May versus late May are too important (most years) to ignore.