FORREST, Ill. — The physical and chemical characteristics of
soil has been a primary focus of crop production for generations, but the
biological aspects are as important.
Hans Kok, coordinator of the Indiana Conservation Cropping
Systems Initiative, said soil health now is on the radar because of the
increasing demand for food production on a limited amount of acres.
Meeting the demand of doubling food production over the next
40 years will require a systems approach to soil health management.
The CCSI promotes a systematic approach to production
agriculture, focusing on no-till production, integrating cover crops, precision
farming and nutrient and pest management.
“I worked most of my career at the university, and putting
out plots was an enormous undertaking with a lot of students, lots of flags to
lay out the plots and a lot of sampling,” Kok said in his presentation during
the recent Conservation in Action Tour of the Indian Creek Watershed Project.
“Now you don’t even have to get out the combine or the
tractor. You can lay out research plots, and it can tell you a lot of stuff
about changing practices on you farm.
“And, of course, one of our goals is to keep the water
clean, so buffers are very important in this whole system.
“It’s a systems approach. It’s not, ‘We’re just going to do
no-till, and now everything is cool.’ The whole thing around it needs to
Dan Towery, assistant coordinator with the CCSI and founder
of Ag Conservation Solutions in Lafayette, Ind., added that the systems approach
involves multiple years.
“So if we look at our soil properties, we’ve done pretty
good job on the physical elements, but the biological and there’s this
interaction that takes place and a lot of our soil health focus on the
biological part is very important,” he said.
“We’re very unfamiliar with the biological part of the soil.
We know a lot about the physical and chemical,” Kok said.
“Basically, since we started continuous row crop, we didn’t
know about the biology back then, but we had a diverse crop rotation,” Towery
“We kind of ignored the biological part, and that’s resulted
somewhat in a degraded soil — loss of organic matter, loss of aggregate
stability, loss of moisture-holding capacity, loss of nutrient cycling. We can
make the soil a recycler, if you will, on the nutrients.
“As our equipment has gotten bigger, we can get out there
sometimes not under the best of conditions and that can result in soil
“And our soils cannot handle that compaction like they used
to because they’ve lost a lot of that organic matter,” Kok said.
One example of soil health concerns over the years is data
collected from soil samples taken from the Morrow Plots at the University of
When those plots first were used in 1876, the soil contained
about 6 percent organic matter. By 1904, the organic matter fell to under 5
percent, and two years later it was less than 2 percent.
“They lost two-thirds of the organic matter in the soil that
was plowed up from the prairies. That makes an enormous impact on a lot of
things that impact those soils,” Kok said.
“For example, if we increase mycorhizae fungi, they produce
the glue that holds the particles together. If we have a storm event, that
allows that water to infiltrate through the soil,” Towery explained.
“If you have tillage out there, the soil is going to seal
over if we have a rain event, then we’re going to have increased runoff
occurring. It’s also taking soil and nutrients with it.”
“In the tilled soils, you have low aggregate stability, and
your soil biology is mainly bacteria. If you go in a no-till situation, you have
mainly fungi in your soil, and you have much better soil aggregation,” Kok said.
“We can increase that by reducing tillage – and, in fact,
the key components to soil health is minimizing soil disturbance,” Towery
“Cover the soil as much as possible. The microbes are
sensitive to temperature and moisture, and you want a diverse crop rotation or
cover crops. We’re not going to change from corn and soybeans, but by adding
cover crops, we can add more diversity.
“Also, when corn hits black layer, it’s done. Agriculture is
all about capturing sunlight, and we have a period in the fall and in the spring
where we could also capture as much as we can.”
“For seven months, we’re not using our fields, we just pay
taxes and we fight weeds. So Mother Nature is trying to tell us something with
those weeds,” Kok said. “Instead of having weeds out there, why don’t we plant
what we want out there, that’s actually going to benefit and do some stuff for
A demonstration was held during the tour showing how cover
crop seeds can be applied by an airplane through the corn canopy and to the
ground. Seed also can be applied with a highboy-type system.
The cover crop is then killed with a herbicide application
in the spring, and corn can be planted in field.
“Is it as easy as planted in a moldboard-plowed field? Yes,
it is, but it is different. Your planter needs to be set different. But even
corn on corn in no-till, we can put cover crops in there and have good results,”
“People complain about the residue accumulating. If you get
the soil biology going when this corn gets knee-high, it’s looking for more
residue,” Towery added.
“Our long-term no-tillers are complaining about not having
enough residue in their fields because the earthworms eat it all,” Kok
“Last year was a good example, where we were very worried
about cover corps. We had cover crops using moisture in the spring and we were
going to plant corn in it and it turned dry.”
He referred to yield tests in adjacent fields near the
Indiana-Illinois border last year. One field had conventional tillage and no
cover crop. A neighboring field with the similar hybrid featured no-till and a
cereal rye cover crop.
The conventional tilled field with no cover crop yielded 65
bushels per acre, and the field with the cover crop had a yield of 109 bushels
“The cover crop had broken up the soils for the corn root to
go down and get to moisture,” Kok said.
“A healthy soil can somewhat act as an insurance policy.
We’re making the soil more resilient, especially if there’s a dry summer. We can
increase the organic matter. Most of the increase is going to be in the top
couple of inches, and it’s slow — it takes time,” Towery added.
“It took a long time to breakdown the organic matter, and
it’s going to take a long time to build it up,” Kok said.
“We can build it up faster than we broke it down, though,
because we’re adding fertilizer to the soil, and we have much higher crop yields
in the soil than we used to have, so we’re putting a lot of materials in the
soil to start building organic matter.”
“But, remember, most of the organic matter is actually
coming from the decaying roots. You can’t increase organic matter if you’re
having any erosion at all,” Towery said. “By increasing the organic matter, we
can easily pick up after a couple of years five to seven inches more
“Some farmers really can cut back on their fertilizer. I’m
not promoting anybody cutting back on their fertilizer until you have been in
the system like this for 20 years with probably five or 10 years of cover
crops,” Kok added.
“Some guys are doing this because the crops root deeper.
They can go to nutrients that a normal crop can’t go after. Plus, the cover
crops can actually carry nutrients from one year to the next.
“Last year was a great example. We had half the crop or less
in a lot of fields. We put a cereal rye cover crop out there. All the rows were
sidedressed and showed up beautifully because all the nitrogen was in the
ground. The crops never got to it and carried it into this year.
“In looking at the soil biology in a healthy soil, we
estimated that the amount of weight under your feet of the soil biology equates
to 22 cows per acre. You have a lot of soil biology in a healthy soil.
“Everybody can think about what a field does when you graze
cows in there. Now, think about feeding 22 cows per acre underneath the fields
in a no-till system.
“So hopefully if we improve our soil, we improve our water
quality in our rivers and streams and increase profitability for
Greg and Ryan Myers of Fairbury have been using no-till for
soybeans for more than 20 years and strip-till for corn for five years. They
have used cover crops for three years.
Ryan Myers explained their farming operation and its
relationship to soil health issues.
“We apply anhydrous in strip-tills in the fall,” he said.
“One of the benefits we’ve seen in our strip-till and no-till is equipment
costs. We don’t have large tillage costs. We’re not making extra trips across
fields, and that leads to fuel-cost saving.
“Another benefit is less labor. With our strips, if we got
into a field in the spring and half of it was fit and half of it was not, which
we ran into a lot this year, we’re able to pull out of the field and come back
later since we were on our strips. We didn’t have to worry about a field
“When we started this in 2001, we did a lot of trial and
error. By 2003, 2004, we committed ourselves. We updated our guidance systems,
and that made it very enjoyable. Your strips are there, and you’re set.
“Some of the things we’ve noticed with our soil structure is
in wetter conditions like this spring, we didn’t rut it up as much as we used
to. Obviously, there were some tracks there, but it held up the sprayer or
whatever we were doing.
“We also noted less erosion when the gully-washing rains
came. Everything kind of held together.”
Myers added the corn and soybean yields are competitive to