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June 16, 2005: In real estate, experts say,
there are three key factors: Location, location, location.
I like to say there are three key factors in sustainable
farming: Rotation, rotation, rotation!
Rotate your crops, rotate your cover crops, and rotate your
tillage. Sounds simple enough, but in practice it takes thought,
planning and a mind open to observation.
I have a friend in Mississippi who says jokingly, “We
have a long term rotation down here—one year of corn,
then 99 years of cotton, then another year of corn.”
But that's not exactly what I have in mind for this discussion.
A few years back I visited some friends in Argentina who
were planting soybeans one fine November day. I asked them
what their rotation was. They responded by asking me what
I meant by the question. I said, “Well, you’re
planting soybeans here today; what was here last year?"
They said, “Soybeans.” Like a fool, I persisted:
“And the year before?” By now I’m sure they
thought I was just plain stupid because they said, “SOYBEANS
– it’s a soybean field.”
They had been planting soybeans in that field for over 40
years. They were experiencing severe problems with insects
and weeds. Nature had responded to the presence of soybeans
on an annual basis. The micro-environment was very predictable,
and insects, diseases and weeds that found that environment
to their liking knew where to find it, year after year.
There are all types of rotations for all types of cropping
sequences. For example, some folks in our area grow agronomic
crops (corn, soybeans, small grains and hay) but also grow
vegetables. They often rotate their vegetable production into
and out of various parts of their farm, confusing insects
and taking advantage of “clean spots” in the rotation
where weed management will be less difficult. For other, smaller-scale
growers, a rotation can be as simple as moving the tomatoes
to another part of the garden.
I think the longer the rotation the better. Of course that
means you need to grow a diversity of crops. Here on our farm
I’d like to have a 10-year rotation but 5 to 7 years
is more realistic given the crops we grow. I also like to
rotate my cover crops into the mix.
All solid rotation plans have some basic principles in common.
First, they all take into consideration the nutritional requirements
of the crop. For example, corn in my rotation is a heavy user
of nitrogen while soybeans will actually fix nitrogen from
the air into the soil. Alfalfa removes phosphorous at a much
higher rate than other crops in my rotation.
Second, a solid rotation should take into account the agronomic
and cultural practices associated with the crop. For example,
some crops are grown as row crops, planted in rows from 15
to 42 inches apart, while others like oats or wheat are drilled
in rows that are only 7 or 8 inches apart. And others like
hay grow in a thick stand, get mown as a harvest method, and
may last several years. Third, cover crops can be used in
the rotation to break weed cycles, supply nutrients and protect
the soil. And finally, a solid rotation takes tillage into
consideration.
Taking a closer look at tillage is as important as any other
factor in your plan. For example, planting winter wheat entails
late summer or early fall tillage, which helps break weed
cycles. Consistent spring tillage encourages annual weeds
to sprout and grow. Mixing up tillage dates can be a big help
to your overall weed management program. There may even be
points in the rotation where no tillage is required to establish
a cash crop or cover crop, as with the no-till roller system
I’ve been talking about lately.
While we use several crop rotations on our farm, the one
we use most for agronomic crops goes something like this:
CORN – RYE COVER CROP – OATS – SOYBEANS
– RYE , OATS OR WHEAT – VETCH OR ALFALFA/TIMOTHY
– CORN. I also grow potatoes and pumpkins, substituting
them for corn in the rotation. For vegetables, things can
get a little trickier due to the large diversity of crops.
We often grow up to 20 different types of vegetables. The
main thing to keep in mind is to separate vegetable families
by time and distance.
The benefits to rotations are many – improved soil
health, easier weed and insect management, and overall improved
ecology of the farm. Add to those the benefit of increased
yields and you have to ask, “Why wouldn’t I have
a diverse rotation?”
Email me with
your own rotations or rotation ideas. I’d like to learn
more from you about how you’ve designed your own system
so that we can all improve our farming operations.
From one farm to another,
Jeff
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