What kind of cover
crops should I plant?
Cover crops may
not always give
farmers a big
return on invest-
ment. It’s not al-
ways about dollars
and cents, though,
says Liz Juchems,
conservation
outreach specialist
at Iowa Learning
Farms. “It’s about
how we value long-
term soil health,”
she says.
What is a
cover crop?
Farmers seed cover
crops to protect
and improve
short-term and
long-term soil
health. Farmers
don’t harvest cover
crops. Instead, they
grow them outside
the cash-crop
growing season.Benefits include:- Less erosion
- Recycled nutri-
ents - Increased soil
organic matter - Improved soil
structure - Better water
quality - More beneficial
soil organisms - Additional graz-
ing and forage
for livestock- Weed suppres-
sion
Properly man-
aged cover crops
can improve profit-
ability due to fewer
herbicide applica-
tions and lower
fertilizer costs, says
Juchems. Over
time, enhanced
soil health may
also spur higher
cash-crop yields,
she says.
How do you start?
“I recommend
seeding oats ahead
of corn acres,”
Juchems says. “Inthe fall, seed oats
where you harvest
soybeans and then
winter cereal rye
ahead of soybeans.
In part because the
oats will winter-kill,
you don’t have to
terminate ahead of
corn. Because the
traditional planting
window for soy-
beans is later than
corn, you have
a larger window
in the spring to
terminate winter
cereal rye.”
In addition:- Evaluate soil
needs and which
cover crop or
mix will provide
matching ben-
efits. - Start with just
one field on your
farm. Expand
as you learn the
best manage-
ment practices,
says Juchems.Characteristics
of common
cover crops
Cereal Rye- Grass species es-
tablishes quickly
and easily. - Scavenges
excess nitrogen
(N), prevents
erosion, adds
organic matter,
suppresses
weeds. - Requires spring
termination;
till, mow, roll, or
spray. - Seed from late
summer to
mid-fall.
Oats - Grass species es-
tablishes quickly
and easily. - Suppresses
weeds, prevents
erosion, scav-
enges excess
nutrients, and
adds biomass. - Winter-kills.
- Seed in late sum-
mer or early fall.
Radish - Brassica species.
- Winter-kills.
3. Cuts compac-
tion, scavenges
N, suppresses
weeds.
4. Seed between
mid-August and
September 15
for optimal sun-
light and heat.
Hairy Vetch- Legume species
- Can overwinter
(may be winter
hardy). - Fixes N, sup-
presses weeds,
reduces erosion
and compaction. - Can be hard to
control and ter-
minate in wheat
and corn. - Plant in fall
before a killing
frost.
Rapeseed - Brassica species
- Most species
winter-kill. - Scavenges N and
phosphorous,
adds biomass,
and can be
grazed. - Can be spring-
planted as a
summer cover
crop and in the
fall as a winter
cover crop.
Source: Liz Juchems, Conser-
vation Outreach Specialist, Iowa
Learning Farms
Where do I begin? Set goals when planting cover crops, recommends
Dwayne Beck, who manages Dakota Lakes Research Farm near Pierre, South
Dakota. “Do you want forage? Or do you want to improve organic matter? You have
to decide what you want to accomplish,” he explains. A cover crop – or blend of crops – is
another component in the crop rotation. As such, it can carry disease or attract insects.
Think ahead to what the impact on the next crop may be. “Using a mix of cover crops
meets several goals simultaneously,” says Beck. “Mixtures add more diversity by growing
at different times, competing with weeds, and optimizing nutrient cycling.”How do healthy soils and fertile soils differ?
Fertile soils contain many nutrients, but they aren’t
as productive as healthy soils that contain the same
amount of nutrients, explains Ray Ward, founder of Ward
Laboratories, Kearney, Nebraska. Healthy soils have more
soil life that makes the soil community hum. “A fertile soil
has plenty of nutrients,” he says. “Healthy soils produce high
yield, yet they may be high or low fertility.”48 Successful Farming at Agriculture.com |August 2019 Photography: Bill Spiegel