The seeding sheet for your canola says 120 seeds per square meter (about 11 per square foot). That is the one number you already hold for the field. Write beside it the plants per square meter that came up, counted on a day, with a tool and in a number of spots that you fixed before the drill moved. On 130 hectares (320 acres), reseeding costs about C$ 12,350 in the example below, so pay it only on a count you could repeat next season the same way. Taken the same way each year, the count also lets you set this year’s stand beside last year’s.
What do I write beside the 120 seeds per square meter?
The plants that came up, and the share of the seeds they make up. The Canola Council of Canada defines that share, emergence, as the “average number (percentage) of seedlings that have grown out of the number of seeds planted this spring”. The Council counts the plants inside a hoop of a quarter of a square meter and tells you to “multiply by four to get plants per square meter”.
In the example, 16 plants fell inside the hoop. That is 64 plants per square meter, and 64 of 120 seeds is 53 of every 100. The Council gives 50 to 80 plants per square meter as the optimum for an established canola stand, so a count of 64 sits inside that range. Write both numbers, the seeds sown and the plants counted, and the date.
On which day do I count, and in how many spots?
On a day counted from seeding, the same day in every field and every season. The Council tells growers to start monitoring “10 days after seeding if conditions are good, or 15 days if conditions are cool”. The day matters because plants do not come up together. In ten maize experiments in farmers’ fields, Albarenque and colleagues recorded individual plants emerging anywhere from 3 to 31 days after planting. A field counted on day 8 and again on day 20 can show two different stands. Which day suits your crop is for you and your agronomist to settle; the sheet only fixes it.
For the spots, use more than one, picked by chance. Iowa State University Extension tells the person counting to repeat the count “multiple times across the field”, and to choose the places at random without avoiding “areas that have missing plants or gaps”. The Council adds that “several counts per field are required to get good representative average plant density and emergence percentage”. Write the number of spots once, as your agronomist advises, so every field gets the same.
If one count does not fit the others, Iowa State says to keep it “separate and make a note of where that area is in the field”. In the example, four spots read 68, 64, 72 and 60 plants per square meter, and the fifth read 28 in a wet low corner. The four that fit average 66. The 28 goes on the sheet apart, with its place.
Who counts, and what goes on each line of the sheet?
One named person, with the same tool, in every field. The FAO makes the point in a guide to farm data. Knowing that the data “is from a reliable source and that it was collected using reliable methods” can often matter more than how neatly the numbers are stored. When the person counting changes and nobody writes it down, a different count can look like a different field.
On each line, write what Iowa State tells the person walking the field to watch: “emergence uniformity (differences in crop stages), plant spacing, and seedling vigor”, in your own words. Add the plants per square meter, the emergence percentage, the date, the days since seeding, the counter and the spots. Leave a column for last season’s line. Where a field was not counted, write “not counted”, so a blank is not read later as a good stand.
Your agronomist advises on the stand and on reseeding, and the written count stays with you. There is a separate article on where the agronomist’s advice ends and the farm’s own record begins.
| Line | What it fixes or records | What happens without it |
|---|---|---|
| Counting day | Days from seeding, the same in every field | One season counted early, another late, and the two cannot share a row |
| Spots per field | The number, picked at random | One good corner stands in for a patchy field |
| Who counts | One named person with one tool | A change of person reads as a change in the field |
| What is written | Plants per square meter, emergence percentage, uniformity, spacing and vigor | The single word good hides which one went wrong |
| Last season’s line | Beside this season’s | An impression that cannot be set against another year |
| Not counted | The words not counted | A gap read later as a good year |
What does a thin or late stand cost, and what does the count decide?
Use the count to judge whether a field needs a second look. Whether to reseed is a call for you and your agronomist. The Council puts the critical level for canola at “somewhere between 30 and 40 plants per square meter”, below which stands tend not to reach full yield. It also warns that “seeding late tends to produce lower yields”, so reseeding does not always pay.
Iowa State works the same trade for corn. A stand of 24,000 plants per acre (about 59,000 per hectare), seeded on April 15, still has “94% of the maximum yield potential”. Replanting on May 25 at 35,000 plants per acre is expected to reach 87%. In that example the stand already in the ground wins.
Timing counts too. In the corn experiments above, final crop yield fell by 8.5 percent per day of emergence delay on average, and the effect was generally larger in low-yield areas. In soybean trials in the United States and Argentina, Pereyra and colleagues found uneven spacing cost yield in low- and medium-yield environments, while “High-yielding environments were unaffected”. These are corn and soybean figures. They show how the decision is shaped, not what your canola field will do.
How the crop came up is also part of why each field’s yield year by year moves as it does, and a harvest number cannot show it alone.
What goes on the sheet first, and how long does it take?
Start with two lines, the seeding rate and the counting day. You already have both, in the drill setting and the calendar. The rest of the sheet takes about an hour before seeding, and one pass through each field on the counting day.
Written down, this year’s count sits beside last year’s, and whoever counts next season can read what you counted. The reseeding call is then made on a number, inside the window your agronomist gives you. Deciding before the season how the crop will be checked is part of running a farm.