Hi I’m Aaron Silva, associate professor and State Extension specialist in organic
agriculture at the University Wisconsin-Madison.
The reliance on tillage in cultivation in organic grain systems is one of the biggest
challenges facing organic farmers.
But here at the UW-Madison, in collaboration with Dr. Brian Luck’s program from the Department
of Biosystems Engineering, we've been looking at alternative strategies to allow organic
grain farmers to reduce tillage and use alternative methods for weed management and soil building
during the corn phase of the organic grain rotation.
Here behind me isn an organic no-till corn field.
We used as a strategy, of a summer sown cover crop to create a killed mulch the following
spring, we directly seed corn into that terminated cover crop to provide the weed management
that we need to grow a productive corn crop the following year.
The cover crop that we used here was a combination of winter cereal rye and hairy vetch.
This crop was sown in late August at a seeding rate of 70 pounds per acre of the cereal rye
and 35 pounds per acre of the hairy vetch.
The cover crop was grown after an oat crop harvest and after the application of dairy manure.
The cereal rye and the vetch started to grow in the fall, went dormant through the winter,and
resumed growth again in the spring.
We wait until a very specific time to terminate the cereal rye and the hairy vetch.
We want to wait until the hairy vetch is at late bloom, early pod set and the cereal rye
is past anthesis, to the soft dough stage.
At these stages, using mechanical means such as a roller crimper, we can terminate the
cover crops without reliance on herbicides.
At the same time of crimping we planted the corn directly into this cover crop in late
June, and at that time as well we applied about 1 ton of composted poultry manure over
the top of that cover crop.
You can see here the killed mulch.
The addition of the cereal rye adds a lot of biomass as well as allelopathy properties
that adds considerably to the weed suppression of this system.
While the addition of hairy vetch helps compensate for any nitrogen tie-up in the rye and helps
mitigate the need for additional supplemental nitrogen to grow a productive corn crop.
You can see that within the corn crop rows there are very few weeds that have grown.
And there has been no additional weed management done to this crop.
We applied no herbicides and there's no cultivation nor any other weed management activities done
in this field.
One of the challenges that historically faced the organic no-till corn system, has been
a later planting.
Which as I mentioned occurred here in June.
But we're looking at new tools and strategies to allow for earlier planting.
Such as between row mowers and between row crimpers that could allow for later termination
of the cover crops.
While we want an earlier emergence and stand establishment of the corn, allowing us more
Growing Degree Days to benefit us before harvest.
I do want to stress that this is a system that we are still doing a lot of research
on, not only here at the UW-Madison, but in collaborations with organic farmers throughout
the state.
There is still a lot of risk in terms of adopting this system: getting good cover crop growth,
getting adequate nitrogen fertility to the corn crop, getting adequate termination of
the cover crop, and getting enough Growing Degree Days to make sure the corn matures.
And additionally, this crop behind me, we did have to treat for armyworms, which can
be a significant risk using a cover crop-based organic no-till corn system.
However we're excited that we're seeing good results with the initial applications of these
treatments and strategies and look forward to doing more research to share out with you
as we develop organic no-till systems for grain farmers across the Upper Midwest.
For more information you can visit our website, OGRAIN, and you can also contact me directly
Erin Silva via email or phone.