Survivability and plant stand targets critical to seeding success

Photo credit: SaskOilseeds

‘Review the appropriate target plant stand’ is one of the 9 agronomy tips to help increase canola profit that the Canola Council of Canada (CCC) lists in a Canola Watch fundamentals article. Part of achieving this target plant stand is selecting the proper seeding rate for the field and the conditions. This blog examines the impacts of canola seeding rate choices, including recent on-farm research from Manitoba and Saskatchewan on this topic.

One investigation of best management practices in canola establishment and production systems highlighted that growers should take note of typical seed survival in their regions, and adjust their seeding rate accordingly to achieve the target plant stand since actual plant density is a better judge of canola productivity than seeding rates.

For these reasons, along with the significant of canola seed, canola farmers were very interested to see the results of the on-farm Canola seeding rate and survivability trials in Saskatchewan and the Seeding rate trials in Manitoba.

Saskatchewan seeding rate and survivability trials

As part of SaskOilseeds’ On-farm research trials program, Saskatchewan growers involved in the canola seeding rate and survivability trials wanted to determine the canola seed survivability values and the optimal seeding rates which would provide sufficient plant density and optimize yield on their operations, with their management and under their soil and weather conditions.

The three seeding rates used were:

• 6-7 seeds per square foot
• 8-9 seeds per square foot
• 10-11 seeds per square foot

Trials were set up in randomized strips with four replicates of each of the three treatments (totaling 12 plots).

As noted in the booklet, Kayla Slind (of Western Applied Research Corporation or WARC) was the program manager and worked with her team to analyze the data.

For the analysis, seven of the eight sites (locations) were combined into two groups based on the density groups at the 2-4 leaf stage, seeding rates and variability. The eighth site was completed and analyzed separately. Group 1 consisted of sites near Biggar, Unity, Cando, Landis, and Elbow, Saskatchewan and Group 2 was made up of the sites near Birch Hills and Kerrobert, Saskatchewan.

Saskatchewan seeding trial results

The following results are from the 2024 trials. SaskOilseeds will be investigating seeding rates and survivability again in 2025. Every additional year of data increases and strengthens the total dataset (ensures it is more likely to be representing the total population).

The analysis from the 2024 results indicated the following:

• The highest yields of the Group 1 sites were achieved at the medium-high plant densities (8-12 plants/ft²), which were measured at the 2-4 leaf stage.
  • The oil content was significantly higher in the low plant density groups than the high plant density groups. Although there was no significant difference in the oil content between the very low, medium and very high plant density groups, the oil content generally decreased at increasing density groups.
• The yields of the Group 2 sites were reached at the low to very low (3.8-5.7 (8-12 plants/ft²), which were measured at the 2-4 leaf stage.
• The economic analysis revealed which seeding rate ended up providing the best net revenue for each site, (which included seeding rates of 2.8, 2.8, 3.0, 3.2, 3.8, 4.1, 4.2 and 4.6lbs/ac at different sites) based on the costs, yield and target price.

Growing season measurements in the Saskatchewan on-farm research trials 2024 booklet, including seedling mortality, varied across plant density treatments and over time (between two weeks after seeding, the 2-4 leaf stage and post-harvest ). This could be due to the varying impact of different stressors at different times and locations. It also highlights the value of checking plant densities both at the 2-4 leaf stage and post-harvest to determine plant survivability throughout the season.

More Saskatchewan on-farm trials

For SaskOilseeds’ Foliar-Applied Nitrogen-Fixing Biological Products for Canola, Split nitrogen or Top-Up nitrogen and Enhanced Efficiency Nitrogen Fertilizer Top Notch Farming Trials, see the Saskatchewan on-farm research trials 2024 booklet. It also includes BarleyBin Field Lab by SaskBarley, Pulse Replicated On-Farm Independent Trials (PROFIT) by Saskatchewan Pulse Growers and Wheat Wise On-Farm Trial Program by Sask Wheat.

Manitoba seeding rate trials

Manitoba canola farmers also wanted to determine if they could reduce their seeding rates without sacrificing yield to increase return on investment, which is why the Manitoba Canola Growers Association (MCGA) Canola On-Farm Research Program ran a protocol to test this. It was the third year in a row for this trial, but since the protocol will run again in 2025, the following results should be considered preliminary.

A randomized complete block trial was conducted with three seeding rate treatments and four replicates (totaling 12 equipment-width-by-field-length-sized strips) at six different locations (sites) across the province in 2024.

The three treatments were:

• Reduced seeding rate (75% of what is normally used on that field)
• Standard seeding rate (normal seeding rate for that field)
• High seeding rate (125% of what is normally used on that field)

All site data, including treatments seeding rates in lbs/ac and seeds/ac, seeding and harvest dates, seeding equipment, row spacing, variety, seed treatment, seed TKW and plant counts in addition to monthly average temperatures and rainfall accumulations are available in MCGA’s 2024 Canola On-Farm Research Program Report.

Results from the 2024 seeding rate trials

While plant stands generally increased with increasing seeding rates, four of the six sites used very low standard seeding rates (< 3lbs/ac) which led to their resulting plant stands being below the recommended 5-8 plants/ft².

The two sites with the lowest standard seeding rates (2 lbs/ac) and lowest resulting plant populations (3.1 – 3.4 plants/ft²) produced significantly higher yield at the high seeding rates. Conversely, the two sites with plant stands above the recommended range (at 7-9.5 plants/ft²) reported an increase in grain yield when their seeding rates were reduced.

Therefore, it appears that choosing a standard seeding rate which targets a plant stand 4.5 plants/ft² or greater can prevent yield reductions due to insufficient plant populations. The value of knowing emergence rates (especially if they are lower than expected) and all the factors that could impact them was also highlighted by these outcomes.

Multi-year seeding rate trial summary

As stated in the 2024 Canola On-Farm Research Program Report, there was no significant influence of seeding rate on grain yield when combining results from the three growing seasons. But seeding rates that didn’t achieve the recommended 5-8 plants/ft² had room for optimization.

Furthermore, when averaged across all three years of datapoints, reducing seeding rates by 25%, resulted in increasing emergence by 13%. This highlighted that in most cases when seeding rates are lowered, more of the seeds resulted in a canola plant at the 3-leaf stage. Therefore, on average, seeding rates can potentially be lowered without a large reduction in plant stand to increase economic return on investment.

Alternatively, when seeding rates were increased by 25%, emergence was reduced by 4% compared to the standard seeding rates.

More Manitoba on-farm trials

To find out the results of nitrogen rate, phosphorus source and seed-placed fertilizer toxicity trials from the Manitoba Canola Growers’ Canola On-Farm Research Program, check out the On-farm evaluations to help inform product and practice decisions blog and MCGA’s 2024 Canola On-Farm Research Program Report. The report also includes an update on the cover cropping for flea beetle management trial.

In addition, MCGA’s Canola Variety Evaluation Trial Results 2024 booklet summarizes the Manitoba Canola Variety Evaluation Trials (CVET) that had their inaugural year in 2024. The program was launched to provide farmers with independent third-party testing data for commercial canola hybrids. All seed companies were approached to enter varieties in the six testing locations across Manitoba and results from the four successful sites are included in the booklet.

This booklet also covers a helpful 2024 growing season recap, a Manitoba canola variety market share graph for 2024, a graph of 2014-2024 canola production in Manitoba, a useful ‘Understanding the results’ section and list of factors farmers can consider when choosing a canola variety.

Support on seeding rates and stands

There may be certain instance (such as portions of a field) where a reduced seeding rates is useful. This Canola Digest article notes that reducing seeding rates one of the top three management recommendations from agronomy providers in Saskatchewan and Alberta to manage low-producing and non-profitable acres. For all other scenarios, using seeding rates that achieve target stands are best.

Tools to help with seeding calculations

The Canola Council of Canada offers three seeding-related tools to help optimize canola plant establishment:

• The Target plant density calculator – suggests a target plant density that fits individual field conditions and a grower’s situation and appetite for risk. It does this by assessing stand uniformity expectations, early season frost risk, weed control intensity required, anticipated in-season insect damage (or preferred buffer for insect damage) and length of growing season at any field location.
• The Seeding rate and seed cost calculator includes a Seeding rate, Emergence and Plant density calculator:
  • Enter seed size (thousand seed weight, TSW), target plant density and estimated emergence values to generate a recommended seeding rate.
  • Enter your planned seeding rate in lbs/ac, the TSW of your seed lot in grams and your estimated emergence % to find out how many plants/ft² or m² you should end up with.
  • Enter the actual plant density in a field, the Thousand Seed Weight (TSW) in grams of the seed lot seeded in that field and the seeding rate in lbs/ac that the field was seeded at to get your emergence in %.
• The Canola Counts survey tool – enter plant densities and calculate emergence in this survey of crowd-sourced canola plant establishment data. Plant density and emergence values entered in the tool can be saved for spring assessments and for late season or annual comparisons.

Supplemental seeding support

For helpful tips on optimizing seed survival and plant stands, check out these Canola Watch fundamentals articles:

• The 8 best practices to maximize canola seed survival
• How to count canola plants and explain low numbers
• The five Agronomy priorities: More canola, more profits, lower emissions 
• Quick tips for on-farm trials, including seeding rate trials

Published February 21, 2025