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1: Corn |
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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.
| Year 2: Soybean |
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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.
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.
| Year 3: Small
grain |
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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 4: Hay
or pasture |
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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 5: Corn |
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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 6: Soybean |
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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 7: Rye
(land left idle) |
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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 next crop.
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.
| Years 8-12:
Same as Years 2-6 |
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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).
| Year 13: Small
grains |
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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 14: Grass/legume
mix |
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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 soybean.
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