It's part of reaching better yields
Canola plant stands below 3-4 plants per square foot are unlikely to reach their full yield potential. Your targeted plant stand is likely going to be a higher number than this, but it does vary depending on your field conditions.
Evaluating your plant stand helps you to determine whether you reached your plant population goals, and if not whether next year there might be things to change at seeding in order to reach that target. Knowing your plant stand can also help you make decisions around in-season threats – if your plant stands are critically low, you may consider lowering your thresholds for spraying insecticides and herbicides.
How to conduct a plant count
- Evaluate your fields between 2-4 leaf stage
- Take multiple counts across the field to create an average
- You will need either a plant count hoop, or a meter stick to conduct the plant counts
- With a hoop – use one with an area of two square feet (inner diameter of 49 cm)
- Count the number of plants inside the hoop and divide by 2 for the number of plants/sq foot
- With a meter stick –
- Count the number of plants in a row along the length of the meter stick, multiply by 100 and divide by the row spacing (in cm) to achieve plants per square meter. To convert to plants per square foot, divide again by 10
- Don’t include volunteer canola in your plant counts – look for blue seed coats when you dig up plants and don’t count plants outside of the seed rows
Comparing plant count to seeding rate
Once you’ve done a few plant counts and gotten an average for the field, you can compare this to your seeding rate. What percent of plants actually emerged? The Canola Council has a great tool for this. If your emergence rate was good, but you’re still below your target plant population, that can indicate a need for a higher seeding rate next year. Other reasons for being below your target plant population could be insect pressure, unfavourable field conditions, or harsh weather events like frost.
Implications of thin stands
This spring has thrown some tough conditions at farmers. Dry starts and heavy frosts have had a lot of growers out in their fields checking their plant stands and possibly thinking about reseeding. It’s always good to remember that canola plants are hardy and adapt to the conditions they’re put in. A thin stand will often create more side branches and can achieve close to it’s full yield potential, whereas a late reseeded field may not be able to reach that mark.
With thinner stands, it’s also important to note that in season management may have to change. The field will be more susceptible to pest and weed pressure, and spray decisions need to be made accordingly. Thinner stands also in general mean uneven, extended maturity.
Ideal plant counts
Every famer and field has a different ideal plant count based on their field conditions. However, research shows that highest yields come from plant stands of 5-8 plants per square foot. Achieving a close to ideal plant population is going to give your canola crop the best chance to reach its highest potential yield. Starting out with too many or too few plants immediately reduces a field’s yield potential and takes money out of your pocket. Going out and counting is the only way to know where your field sits, and if there’s anything you need to change this season or in future years to help maximize canola yields.