Successful Farming – August 2019

Will yields suffer?

Based on two years of

field research from dozens

of working farms across the

Midwest, well-managed

cover crops tend not to affect

yield of cash crops like corn

and soybeans, according to

the Soil Health Partnership

(SHP). The SHP col-

laborates with more than 140

farmers to conduct side-by-

side research involving soil

health practices.

Planting cover crops did

not affect soybean yields,

although there is more

variability with cover crops

before corn, says Shefali

Mehta, director of the SHP.

“These are working

fields,” she says. “They get

all the shocks and issues

that you do as an active

working farmer. It was

great to see that yield trend

staying steady.”

Moreover, the majority of

farmers participating in an

Iowa State University (ISU)

project reported no yield dif-

ferences. The 10-year cover

crop study at ISU evaluated

cereal rye in a corn-and-

soybean rotation. ISU trials

also show the same results

from a five-year research

study on cover crop mixtures.

Finally, a 2016-2017

annual survey of 2,012

farmers conducted by the

Conservation Technology

Information Center with

help from Purdue University

and funding support from

Sustainable Agriculture

Research & Education and

the American Seed Trade

Association reported that

after cover crops: 

• Corn yields increased an
  average of 2.3 bushels per
  acre, or 1.3%.


• Soybean yields increased 2.1
  bushels per acre, or 3.8%.


• Wheat yields increased 1.9
  bushels per acre, or 2.8%.
  “If you understand the
  system and apply (proper)
  management strategies, that
  is when you will see yield
  increases,” says Keith Berns,
  who co-owns Green Cover
  Seed near Bladen, Nebraska. 

How rapidly can I expect
to improve soil if I reduce
tillage? Add cover crops?
Add grazing?
“Normally, we say the first five
years are the hardest when
transitioning from conventional
tillage to no-till,” says Ray Ward,
Ward Laboratories. “However,
with good residue manage-
ment and cover crops, we
generally see improvement in
the soil’s granular structure in
three years.”

Can I reduce the use of
commercial herbicide and
fertilizer by adopting
these principles?
No one talks about net
revenue per acre at the coffee
shop, but Ray Ward says
that’s the most important
statistic on any farm. In
time, farmers who adopt soil
health practices tend to be
able to reduce fungicide and
herbicide applications, and
perhaps eliminate insecticide
expense. In fact, except for
controlling grasshoppers at
field edges, the Dakota Lakes
Research Farm has not had a
foliar insecticide application
on it for nearly 20 years,
Dwayne Beck says.
Fertility, however, is
trickier. “You can use legumes
to replace some nitrogen, but
you can’t replace phosphorous
and potassium with cover
crops,” Ward adds.

Cover crops can even

key cash-crop yield

increases, says Keith

Berns, who co-owns

Green Cover Seed near

Bladen, Nebraska.

However, proper

management strategies

must occur for this to

happen, he says.

Photography: Bill Spiegel August 2019 | Successful Farming at Agriculture.com 49