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SOIL HEALTH IN PRACTICE - REAL SOLUTIONS FROM REAL FARMERS

Interseeding

Since many farmers struggle to incorporate diversity into
their crop rotation, some are looking to add diversity by
growing cover crops within their cash crop. Before pre-emer-
gence herbicides, it was common to seed cowpeas, clovers,
or other crops in between rows of corn to gain an additional Left Photo by Jeremy Wilson • Right Photo by Dean Krull
crop in the season at “layby” time. Modern experimentation
with this interseeding concept has been going on for the last
several years, but this technique is still in its infancy and suc-
cessful interseeding has a number of challenges to overcome.
Stand Establishment Left: Jeremy Wilson seeded this 14-way blend into V6 corn in Jamestown, ND
No crop can ever be better than the initial stand that is using a modified Yetter dry fertilizer coulter. Great stand establishment, excellent
achieved. For interseeding into growing corn fields, getting growth, and lots of diversity. Picture was taken when corn was fully tasseled. Cost
of seed mix was around $12 per acre as rates were calculated for intercropping.
the seed in the ground always outperforms broadcasting.
Companies like Hiniker, Dawn, and Interseeder Technolo- Right: Ken Seims and sons of Chapman, NE planted this blend of ryegrass, red
clover, and radish into irrigated corn at V6 with a Hiniker cover crop seeding
gies have developed equipment just for this purpose. system. Good stand but growth is being suppressed by lack of sunlight, but wait till
harvest and watch it take off!
Lack of Sunlight The methods employed by producers to achieve successful in-
Interseeded companions always struggle to get enough sun- terseeding are as varied as the producers themselves. If you are
light. Best results have occurred when covers are interseed- interested, we encourage you to experiment on a small scale,
ed at V3-V6 and a stand gets established before the corn but proceed with caution and check with your crop insurance
canopies. Once a plant is established it can survive better in agent to maintain compliance. For a great on-line resource on
partial shade. Corn varieties with more upright leaf struc- this topic, go to www.interseedingcovers.com.
ture can also help. This practice tends to work better as you
move north where the summer days are longer (more hours
of sunlight) and the maturity of the corn tends to be short- Photos by Lowell King
er. Some innovators are also experimenting with wider row
corn while not sacrificing plant population.

Herbicides and Weed Control
If planting a diverse mix of covers (grasses and broadleaf),
most post-applied herbicides will not work without hurting
the companion crop. Penn State research shows that some
pre-plant applied short residual herbicides like Resolve, Prowl,
Sharpen, and Verdict may work with companion interseeding.
Do not try interseeding in fields where you know you have Above: Lowell King of Fruita, CO is using his Interseeder drill to place three rows
of companions between each row of V4 corn.
difficult weed issues that will require post-applied herbicides.
Below: Here is what the companions look like late in the season - and this is espe-
Crop Insurance cially impressive as this is a gravity irrigated field!
Because intercropping into growing corn is a relatively new
practice, there are some gray areas of interpretation when it
comes to crop insurance. The guidelines can vary from zone
to zone so it is best to always check with your crop insurance
agent. The bottom line is that insurance will not cover loss
of production resulting from cover crop interference with
the agronomic management and harvest of the main crop.
With interseeding into corn that is at V4 or later maturity,
we are not aware of any studies that show the companion is
a threat to the cash crop.

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