Pushing wheat seeding rate on marginal ground
Target plant stand of 25 versus 32 plants per square foot.
Producer field, Southeast SK · Producer identity withheld
The question
Does a higher target plant stand compensate for thin, low-organic-matter ground, or does it simply add seed cost?
The thin ridges on this quarter have historically produced uneven, weedy stands. The theory was that a denser stand would close the canopy faster and shade out kochia.
Trial design
How it was run
- Two seeding rates run in alternating passes across the whole quarter.
- Plant counts taken at the three-leaf stage in twelve locations per treatment.
- Weed biomass sampled at herbicide timing; yield resolved by combine monitor.
Results
What the numbers did
What if prices change?
Yield and rates are fixed observations from the field. Move the price and cost assumptions to see whether the result still holds on your farm.
| Treatment | Yield | Revenue/ac | Cost/ac | Margin/ac |
|---|---|---|---|---|
| 25 plants/sq ftControl | 46.2 | $369.60 | $117.00 | $252.60 |
| 32 plants/sq ft | 45.1 | $360.80 | $124.50 | $236.30 |
At these assumptions the treatment returns −$16.30/ac against the control.
The story
What the season looked like
The higher rate did what it was supposed to agronomically — plant counts came in at 31 per square foot against 24, and canopy closure was about five days earlier.
Kochia biomass at spray timing was roughly a third lower in the dense stand.
But the ridges ran out of moisture in mid-July, and the denser stand ran out first. Kernel weight dropped enough to erase the stand advantage.
What we learned
Takeaways
- 01Canopy competition worked. Moisture was the binding constraint, not weed pressure.
- 02On this soil, extra seed is buying a bigger crop than the water can finish.
- 03The kochia problem is real but needs a chemistry or rotation answer, not a seeding rate answer.
Would we do it again?
No — not on this soil type.
The agronomy behaved exactly as expected and the economics still went the wrong way. Worth repeating on heavier ground where moisture is less limiting.
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