A rotation is a repeated sequence of crops, and in reality any year
can be tagged as “year 1,” with that crop being the first
in the series. The current year-1 crop in Jack Erisman’s long
and complex rotation is corn. Corn grows well in the Midwest. This
swath of middle America is not called the “Corn Belt”
for nothing. The deep-rich soils, adequate and timely rainfall and
moderate temperatures constitute ideal growing conditions for corn,
and yields are high. Jack’s organically grown corn yields on
average 160 bushels per acre. The corn grown predominantly in Illinois
is #2 dent field corn. Jack grows some #2 but also grows blue corn,
food-grade corn and even popcorn. The food-grade and blue corn is
grown on contract, with the field corn sold on the thriving organic
market where prices are typically at least twice that of conventional
corn. On-farm storage allows Jack to keep the different types segregated
and allows greater control over when to sell and when to hold. Whereas
many Illinois farmers plant corn as early as possible, Jack waits
for the soil temperatures to warm with no risk of frost. Corn is planted
in 30-inch rows at planting populations that vary according to corn
type. He relies heavily on the harrow and rotary hoe for mechanical
weed control in corn. Optimal harvest date will also vary depending
on corn type, contract requirements and weather.
After corn is harvested in the fall, Jack sows a rye cover crop.
The formal definition of “cover crop” is a crop grown
but not harvested. There are many benefits derived from a properly
grown cover crop. The soil is “covered” and therefore
protected from the harsh elements of weather that result in soil
erosion. One of the best ways to build up soil is to keep what you
have from being washed or blown away. A cover crop provides that
protection. The growing roots promote the formation of soil structure
–stable aggregates that hold together (again resisting erosion),
allow exchange of air and water, and increase organic matter. For
organic and sustainable farmers in Illinois, rye (Secale cereale)
has been found to be a well-suited species for these purposes. It
is easy to establish, even in less than optimum seeding conditions.
It grows well in the cool fall temperatures and goes dormant in
the dead of winter, but begins growing again in spring.
Jack usually sows his rye after corn harvest in the fall, but sometimes
he waits until early spring to plant rye, double-disking it into
the soil to kill it a short time before planting the following crop.
Some years he will sow the rye with the following soybean crop as
a companion crop. The rye and soybeans grow up together, the rye
inhibiting the growth of weeds in the soybean crop. Even after harrowing
and rotary hoeing, enough of the rye survives to inhibit the growth
of other grasses.
After year-1 corn, Jack grows soybeans. Soybeans are also planted
in 30-inch rows to allow ample cultivation for weed control. Controlling
weeds in an organic soybean crop is a real challenge. Timing of cultivation
is crucial. Jack uses a rotary hoe, specially designed for use in
high-residue. The rotary hoe is used early and often (if weather permits)
while soybeans are just emerging. This controls weeds early on and
gives the crop time to grow up and shade out future weeds.
|Year 2: Soybean
Jack typically harvests soybeans in the fall after corn. In the
fall of year 2, after the soybean crop is removed, a small grain
is typically planted which will be the crop for year 3. Jack plants
a variety of small grains; all are planted in the fall, except oats,
which are spring-seeded.
The small grain stage of Jack’s rotation has considerable variation
depending on the year and the market. Small grains work well at this
stage because rapid early season growth and a thick crop stand smother
out the weeds that may have been a problem during the previous soybean
season. Most of the small grains used by Jack – wheat, rye,
spelt, barley and triticale – are sown the previous fall after
the soybean crop is harvested. The crop overwinters and gets a good
early start the following spring. Another benefit of this year’s
crop is that it is harvested early in the growing season – usually
in July. This spreads out the workload, and allows plenty of growing
season for the following hay or pasture crop to become established.
This grass/legume mix is overseeded into the year-3 small grain crop.
Growth is well established by the time the small grain is harvested.
|Year 3: Small grain
Jack’s hayfields and pastures consist of a mix of species, with
both grasses and legumes. Grasses used at this stage are typically
rye or timothy. Legumes include alfalfa and red clover. The crop is
cut for hay or grazed by the cow-calf beef herd that Jack maintains.
If the field is to be grazed or cut for hay, Jack will plant a mix
that is heavier on the grasses – 60 percent by volume (seed
count). In some fields and in some years Jack will plant alfalfa or
clover to harvest for organic seed. Organic clover seed has doubled
in price over the past few years. In these fields he will plant a
pure alfalfa or clover crop. Jack also grows orchard grass for seed.
In these fields he sows a small amount of some legume to provide nitrogen
for the orchard grass.
|Year 4: Hay or pasture
Corn grown at this stage of rotation is indiscernible from corn grown
in the first year of the rotation. The fertility, particularly nitrogen,
required in great amounts by corn is provided by the previous hay
crop. The hay or pasture mix Jack uses is heavy with legumes. These
special species work with bacteria that live on the roots of legumes
and are capable of drawing nitrogen from the atmosphere, making it
available to its plant host. They are a vital tool for the organic
farmer. Much of the residual nitrogen builds up in the tissue of the
bacterial structures (called nodules) that form on the roots and in
the tissues of the plants themselves. If the field has been pastured
the previous year, fertility has been directly applied by grazing
cattle. The four-year time span since the last corn crop breaks up
insect life cycles and allows the soil to build up nutrients to levels
required by the heavy-feeding corn.
|Year 5: Corn
Soybeans grown in year 6 are treated the same as year-2 soybeans.
Jack never grows corn two years in a row in the same field. Continuous
corn – corn grown year after year in the same field –
is practiced by some conventional farmers in Illinois, but research
has shown that even with adequate fertilization, yields decline over
time. Insects and disease also become more problematic in continuous
corn. This is a powerful demonstration of how valuable crop rotations
can be in helping farmers maintain fertility in soils, as well as
in keeping pests and diseases in balance with beneficial species that
provide natural controls.
|Year 6: Soybean
Rye is planted in the fall after soybeans are harvested. It is left
idle and allowed to go to seed and eventually disked in before the
|Year 7: Rye (land
At this point, the Erisman rotation gets complicated. The sequence
outlined above is what is currently being used. When Jack first
started, he only included corn one year in the seven-year rotation.
“We just didn’t have the fertility,” he explains.
Now, testing has confirmed, the land is building fertility, enough
to include a second corn crop in the seven-year cycle. That is why
corn is planted in year 1. Economics also played a role in this
decision. The organic soybean market was even better when Jack started
than it is now. There was a strong incentive to put more acres of
the rotation into soybeans. Still, Jack strives to let his fields
lay idle once every seven years.
The rotation in essence starts again, but leading off with soybeans.
The next four years are small grain (year 9); grass/legume hay, pasture
or seed (year 10); corn (year 11); soybean (year 12).
|Years 8-12: Same as
As before, wheat, rye, spelt, barley and triticale are sown the previous
fall after the soybean crop is harvested. Oats, when grown, are sowed
in the spring of year 13.
|Year 13: Small grains
This pasture mix is inter-seeded into the previous small-grain crop
and used for hay, grazing or seed production. Under certain conditions,
the pasture, if healthy and productive, might be kept for multiple
years before resuming the rotation at year 1, with either corn or
|Year 14: Grass/legume