Farmer Trial: Green Manure Disc Down
Connecting Farmers To Soil Health
Hello, Friends.
Today we wanted to touch on the positive effects a Full Season Cover utilized as a green manure disc down can have on soil health and more specifically, increased yield the following year. This is a two-year study that will continue to be researched and measured (yield) going forward into 2022 and 2023.
Green manure is a crop grown strictly to boost soil health & fertility — not to harvest.
Effective green manures reduce weed pressure, improve water infiltration & holding capacity, increase organic matter, break insect and disease cycles, provide a habitat for pollinators, & stimulate soil biology.
How do we do this? First, by selecting plant species that will balance the Carbon:Nitrogen ratio at 24:1. In this case, we turned to the Full Season Cover.
Important Note: this is a different approach than your traditional green manure crop which is mainly grown for nitrogen production.
Green Manure Trial
The details of the trial
Farmer: Matthias Lehenbauer
Location: Arnaud, Manitoba
Soil Type: Heavy Clay
The Idea: Grow a multi-species full-season cover crop to be plowed down as green manure during maximum vegetation. Evaluate yield response the following year.
Year 1: 160 acre field selected. 80 acres of wheat planted & harvested. 80 acres of a full season cover planted & disced down.
Year 2: Plant canola across the entire quarter section. Evaluate yield difference.
Year 3: Continue to evaluate yield difference across the entire field.
Year 4: Continue to evaluate yield difference across the entire field.
Improve The Soil in 2020
Year 1: the green manure year (2020)
The Full Season Cover was grown on 80 acres of the quarter selected.
No fertilizer was applied.
Inoculant was applied.
The crop was disc downed at maximum vegetation.
Spring Wheat was grown on the other 80 acres of the quarter section selected & taken to harvest.
Image: Full Season Cover @ Maximum Vegetation
Picture Taken: May 19th, 2020 (not exact same spot in field)
Picture Taken: May 13th 2021 (not exact same spot in field)
the benefits of a green manure
Year 2: Evaluate cash crop (2021)
Canola was sown across the entire quarter. (see images below)
Soil moisture probe tests were conducted. See video.
Image Left: Wheat Stubble
Image Right: Green Manure Disc Down Stubble
Picture Taken: May 13th 2021
Image Left: Wheat Stubble
Image Right: Green Manure Disc Down Stubble
Picture Taken: June 24th 2021
“The green manure side flowered longer and was harvested 10 days later” - Matthias Lehenbauer
Green Manure Trial
The Yield Response
See below for some quick farmer math on the economics of this trial.
Canola Yield (Green Manure Side): 53 bu/acre
Canola Yield (Wheat Stubble Side): 45 bu/acre
Although given current commodity prices, the economics of this practice may not be a fit for everyone as you are sacrificing a “cash crop” for a year.
However, if you are serious about improving the soil health of your farm - this is looking like a great practice for those poor producing pieces of land or compacted headlands that tend to yield considerably less year over year.
Picture Taken of Green Manure Side of Trial: May 13th 2021
Green Manure Trial
Why did we see this response?
By balancing the Carbon: Nitrogen ratio at the ideal 24:1, we created the ideal home for soil biology to thrive and function as close to the natural system as possible. This means the plant (canola) had access to all nutrients required to physiologically mature as it should, in both the vegetative and reproductive stages of its life cycle. This is why we saw a longer flowering period.
Remember: Effective green manures reduce weed pressure, improve water infiltration & holding capacity, increase organic matter, break insect and disease cycles, provide a habitat for pollinators, & stimulate soil biology. What does that mean? It could have been one or many of these factors that contributed to the yield response.
Conclusion: This is why trying a full season green manure cover crop on a problem piece of land (poor water infiltration, disease cycle present, etc.) could yield an even greater response than the one we saw here if all or more of these conditions are present.
We understand that commodity prices are not helping the green manure march but we would challenge you to pull out a pen and paper and add up your input costs on those poor producing areas on the farm.
Contact us to discuss further.
From a water infiltration & soil health perspective, we saw similar results from a Compacted Headland Trial we conducted last year in Roland, Manitoba.
With Gratitude,
The Covers & Co Team
Joseph Gardiner, Travis Avery, Owen Taylor, Mark Fallis