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Ways with Residue

Crop residue is as good as
gold. The more there is, the bigger the bank of stored fertility.

“If we can get that residue
to break down by natural processes, the nutrients going back into the soil will
feed a crop in the future,” says Bill Kuehn, who farms with his wife, Laurie,
near Turtle Lake, North Dakota.

The Kuehns no-till spring
wheat, durum wheat, winter wheat, corn, canola, peas, and flax. Managing
residue from those crops helps reap future fertility, soil quality, moisture
savings, and wind and water conservation benefits.

“Of all the crops, cereal
grains present the greatest challenge to managing residue,” says Cal Hoff, a
Richardton, North Dakota, no-tiller who farms with his wife, Julie, and son,
Casey.

However, the challenge is limited
mainly to the year the residue was produced. In mature no-till systems, the
increasing soil biological activity accelerates residue breakdown.  “As
the health of our soil improves, the soil microbes help the residue to
disappear more quickly,” says Hoff.

Here are five practices they
and Greg Endres, Extension agronomist at the North Dakota State University
Carrington Research Extension Center, use to mange no-till residue.

1. Leave tall residue

In fact, the taller the
better. “Especially with wheat and corn residue, the more of it that can be
left standing, the easier it is to plant the next crop,” says Endres.

The taller the stubble, the
less crop aftermath to be spread by the combine’s chopper. This lowers the
chance of excess residue sealing the ground surface and keeping it cold and
wet.

“Such conditions make it
hard to get a crop off to a good start the next spring,” says Endres.

Bill Kuehn’s present
knife-opener seeding system handles wheat stubble of 12 inches and canola
stubble of 2 feet.

2. Spread finely cut straw
and chaff evenly   

This promotes an even stand
in next year’s crop. “Our goal is to spread straw and chaff in a pattern that’s
as wide as the combine header,” says Kuehn.

Uneven crop emergence
results when some areas of the field are covered by less residue than others.

“The residue holds the
moisture in the soil and keeps it cool. Those areas that didn’t get straw
spread across them tend to warm up faster, causing faster germination and crop
emergence,” adds Kuehn.

Kuehn faults his present
harvesting system because his combine’s fine-cut chopper does not spread as
wide as the combine’s 36-foot header. When he trades machines, he may go back
to a 30-foot header to try to better match spreading and cutting capability.

“There are machines that
will take a 39-foot cut and spread in a 39-foot pattern,” he adds.

Cal Hoff’s newest combine
cuts and spreads in a balanced pattern. He modified choppers on older combine
models to do the same.

“We have our local machinist
reinforce the choppers with added weight and balance them,” says Hoff. “Most of
the time, that lets the combine spread in a pattern as wide as the header.”

3. Eliminate harrowing of
standing stubble

Thinking that harrowing
would best handle the residue from a bumper crop of durum, Kuehn harrowed 300
acres in the spring of 2008. But the harrowing caused its own problems. During
planting, the seeder’s knife openers tended to rake up and bunch the bent-over
straw.

“When we leave the stubble
standing and attached to the soil,” he says, “the shanks on our seeder slide by
the stubble better than if the material is bent over or lying on the ground.”

Seed in a pattern that
offsets the previous crop Seeding at an angle or slightly offset to the
previous crop row helps seed openers pass more easily through standing stubble.
Kuehn expects his recently installed GPS systems on the combine and tractors
will help with this practice.

“We’ll be able to seed
through a lot taller stubble,” he says.

4. Be a patient seeder

Studying soil and residue
conditions at seeding is key. This can halt seeder plugging.

“Waiting until it’s dry
enough in the morning” to seed is one way Hoff helps his seeder deal with
residue. After the residue dries off from the morning dew, the 22-inch blades
on his disk-opener seeder cut right through the straw instead of just bending
it.

5. Boost crop diversity

A diverse crop mix also
plays a vital role in successfully managing residue under no-till.

“Diversity and a good
rotation are key to building soil health,” says Cal Hoff, a Richardton, North
Dakota, no-tiller.

“Once that soil health
starts building, the risk of having too much surface residue is reduced because
the soil microbes break it down,” he adds.

Hoff has observed this
benefit occurring in wheat. “Our wheat yields have increased, but the straw
residue carried over from year to year has not,” he says. “There’s no question,
healthy soil will absorb residue.”

A little bit of everything

Hoff’s crops include wheat,
oats, corn, flax, and sometimes peas and canola. He has also planted radishes
as a cover crop. His typical rotation comprises two types of cool-season crops
grown in consecutive years, followed by two years of two kinds of broadleaf crops.

“But we don’t always stick
to that sequence,” he says. “We will mix it up because Mother Nature can always
figure out predictable patterns and catch up to you.”

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