Cover crops require careful planning and management to achieve objectives. On-farm research can help optimize cover crop species selection and planting methods. Records of cover crop planting dates, termination methods, and subsequent crop yields are important to evaluate effectiveness over time. Cover crops are not a silver bullet and require more management than other soil amendments.

1. Capturing the full
potential of cover crops
Dr. Joel Gruver
WIU – Agriculture
j-gruver@wiu.edu

2. Haphazard
cover cropping

3. What am I
supposed to do
now?

4. Very common question received
by CC seed vendors in early fall
“What cover
crop should I
plant ???”

5. Well… what do you
want your cover
crops to do for you?

6. Cover crops are not the missing puzzle piece(s)
in your current crop rotation(s)!
http://www.ncl.ac.uk/tcoa/files/breakcrops_orgagr.pdf

7. Overview of book contents
• Problems and opportunities for over 500 crop
sequences
• Characteristics of more than 60 crops and 70 weeds
• Crop diseases hosted by over 80 weed species
• Modes of transmission for 250 diseases of 24 crops
• Thirteen sample four- and five-year vegetable and
Rotations
grain crop rotations Managing Crop Rotation Chart
should evolve
with key tasks & steps
not revolve
•Sample worksheets and calculations
• Step-by-step procedure for determining crop rotation
plans

8. Overview of book contents
• Problems and opportunities for over 500 crop
sequences
• Characteristics of more than 60 crops and 70 weeds
• Crop diseases hosted by over 80 weed species
• Modes of transmission for 250 diseases of 24 crops
• Thirteen sample four- and five-year vegetable and
grain crop rotations Managing Crop Rotation Chart
with key tasks & steps
•Sample worksheets and calculations
• Step-by-step procedure for determining crop rotation
plans

9. Excellent information on integrating cover crops with agronomic crops
http://ohioline.osu.edu/sag-fact/pdf/0009.pdf

10. Start planning today!
• Anticipate planting windows
• Match objectives with species
• Confirm seed availability
• Make sure seeding equipment is ready
• Identify realistic termination methods
• Allocate labor
• Develop contingency plans

12. Crop
planted
on May 15
and harvested
on October 1

13. Opportunities for planting cover crops
• Dormant seeding early or late winter
• Frost seeding
• In the spring
• When planting summer crops
• Prevent plant scenarios
• At last cultivation
• After small grains
• After vegetables
• After seed corn or silage corn
• Aerial or high clearance seeding into standing crops in
late summer/early fall
• After long season crops

15. What is this CC?
Phacelia

16. http://calshort-lamp.cit.cornell.edu/bjorkman/covercrops/spring-mustard.php

17. Klaas and Mary Martens,
organic innovators in
Central NY State, are
reporting excellent results
with frost-seeded
confectionary mustard
ahead of dry beans

18. Mustard variety trial at the Allison farm in early June 2011
Pacific Gold Ida Gold
Slower to mature Faster to mature
More biomass Less biomass

19. Mustards are very responsive to N

20. Mustards are easy to kill with tillage

22. Sunflowers planted 7/17 and 7/29 in 2010 and 7/7 in 2011

23. JD 730 Air-Disk drill on Jack Erisman’s farm in Pana, IL
Jack uses this rig to drill soybeans on 6" rows (~ 280,000/ac)
while also dropping about 2 bushel of rye and some
micronutrients

24. Planted before heavy rain Planted after heavy rain

25. Small amount of foxtail… almost no broadleaves
~ 20 bushels more yield

26. Lots of weeds but very few
towering monsters of maternity :->

27. Match CC objectives with species
Grazing
GRAZING = #1 way to make cover crops pay!
brassicas, clovers, small grains, a. ryegrass, sorghum-sudan
Nutrient scavenging/cycling
brassicas, small grains, annual ryegrass
Bio-drilling
brassicas, sugarbeet, sunflower,
sorghum-sudan sweet clover, alfalfa
N-fixation
clovers, vetches, lentil, winter pea, chickling vetch, sun hemp, cowpea,
soybean
Bio-activation/fumigation
brassicas, sorghum-sudan, sun hemp, sesame
Weed suppression
brassicas, sorghum-sudan, cereal rye, buckwheat

28. Forage kale Oats, turnips, annual ryegrass and wheat
Oats, turnips and cereal rye Mystery brassica

29. OATS & PEAS
Spring Planted/Summer grazing

30. Have you used any forage brassicas
as cover crops?
Hunter

31. Franzluebbers AJ and JA Stuedemann. 2008.
Soil physical responses to cattle grazing cover
crops under conventional and no tillage in the
Southern Piedmont USA.
Soil and Tillage Research 100, 141-153.
• Cover crops (winter or summer) can provide high-
quality forage and increase economic return and
farm diversity, but some farmers have been
reluctant to take this advantage due to perceived
“compaction” caused by animal trampling.
• Grazing of cover crops can compact soil, but
not to the detrimental levels often perceived.

32. Terminating spring planted oats with a soil finisher
~ 3 weeks before planting corn

33. Are you equipped to handle a situation like this?

34. 10’ Howard Rotavator tilling ~ 3” deep with C blades

35. Complete kill after 1 pass
and 2 days of sun

36. Typical weather in spring 2009-2011 :-<

37. Moldboard plowing can be the best option

38. Are you familiar with the fence post principle?
Zone of maximum biological
activity and rapid residue decay
Deeper burial does not optimize decay but sends weed
seeds into deep dormancy and brings deeply dormant
weed seeds to the surface where they germinate slowly

39. Performance over Price
• Buy CC seed on value not price
Cover crop seed price survey from 2010 ($/lb)
Vendor Cereal rye Annual Hairy vetch Medium red
ryegrass clover
WI 0.188 0.52 (0.69) 1.60 (1.98) 1.22 (1.62)
IL1 0.147 (0.179) 0.47 (0.63) 1.42 (1.65)
MN 0.153 (0.171) 0.50 (0.56) 1.70 (1.90) 1.66 (1.84)
NE1 0.157 (0.179) 0.55 (0.65) 2.10 (2.50) 1.65 (1.95)
IL2 (0.213) (0.75) (2.20) (2.60)
IL3 0.188 (0.214) (0.70)
MO 0.197 0.46 1.47 1.21
IL4 (0.20) (0.60) (1.80) (1.75)
IA (0.195) (0.62) (2.00) 2.00
IN (0.239) (0.75) (2.20)
(IL farmer) 0.125 0.48 1.05

40. The cheapest seed available is
frequently VNS – variety not stated
Do you know the difference
between “variety name” and
“brand name”?
How important is uniform seed
size and vigor to you?

41. How much
is good
technical
support
worth to
you?

42. Reduce Risk
• Enroll in programs that pay you to plant CCs
• Use time tested CC methods
• Use more than one method of planting CCs
• Plant mixtures/cocktails
• Grow some crops e.g. small grains,
vegetables, corn silage, shorter season
hybrids/varieties that are harvested early
• Irrigate

44. Traditional cover cropping in the Midwest
The
most tried and true
cover cropping system
in the Midwest region
Frost seeded red
clover

45. Drilling CC after small grain harvest

46. There are many options other than drilling

47. Annual ryegrass & radishes aerial
seeded into soybeans at leaf drop.
Aerial seeding is fast and relatively cheap
but more sensitive to weather

48. Effective multi-tasking or cover crop chaos???

53. Beware of hype!
• Cover crops are not a silver bullet solution
to any problem

54. The rock
star of
cover
crops!!!

55. With lots of space, moisture, fertility and time to
grow, individual radishes can get huge!
but a good stand of 1” radishes
will probably do more for your soil!

57. control Ohio State
University
Tillage
Radish®
plots
Soil compaction
decreased by >40%

58. Crop root density as affected by previous cover crop
Chen and Weil (2006)

59. Roots at ~ 40”
after 45 days

60. Radishes are not the only good bio-driller!!
• much less top growth but deeper roots than cereal rye
• much less winter hardy than cereal rye
• can be difficult to kill with tillage
• can be a serious weed in small grains

61. Learn from cover crop innovators
• Attend field days/host a field day
• Attend conferences
• Participate in internet forums

62. Field day at Steve Groff’s farm

63. Field day at Steve Groff’s farm

65. ~ 120 profiles including ~ 20 organic farmers since 2008

66. Read about CCs in on-line forums

67. Subject Replies Views
> 100 threads and > 200,000 views in 2011

68. Use precision planting

70. Bio-strip till
September 2008

71. September 2009 Attempt #2

72. Tillage radish on 30” rows with oats on 7.5” rows
November 2009

73. Attempt #3
Radish planted on 30” rows using milo plates
in mid-August 2010

74. Attempt #4

75. Cultivating
radishes on 30”
rows

76. Ridges with
dead radishes in
spring 2011

78. Planted
beautifully
but we decided
to replant after a
month of rain :-<

80. Keep good records
– Date of planting
– Seeding rates, drill settings…
– Take lots of photos!

81. Optimize fertility
• Inoculate legumes
• Inoculate non-legumes?
• Fertilize cover crops when
residual fertility is low

83. Do all legumes add N to the soil?
Soybean seeds
often contain
>25% more N than
was fixed within
their nodules

84. 133 lbs of K/ac 52 lbs of Ca/ac
Hairy Vetch
3,260 lbs of DM/ac
141 lbs of N/ac
18 lbs of P/ac 18 lbs of Mg/ac

86. ?

89. Learn from research
On-farm research
• Leave check strips - replicate if possible
• Work with universities/NRCS
Research station trials
• Make suggestions
• Pay attention to results

90. Practical Farmers of Iowa
Field Crops Project on-farm research questions
1. Can cover crop seed planted using a modified
highboy have better establishment then an
airplane?
2. How can we improve use of spring cover crops?
3. What other species of cover crops work in IA?
What are the yields of improved organic and non-GMO
corn hybrids?
5. What are the yields and aphid counts of aphid-
resistant soybeans?

91. Cereal rye inter-seeded with soybean for
in-row weed control at the Allison Farm
No significant differences in yield between 20&40
lbs of rye in row vs. 60 lbs broadcast vs. control
(all trt means > 40 bu/a)
Cereal rye and several other CC species that require
vernalization will be planted over soybeans rows
using the insecticide boxes on our planter in 2012

93. Joe Rothermel’s new rig

94. Cover crops planted with
insecticide boxes while stripping

95. Wheat + radish trial at the Allison farm
November 2010
3 lb/a = 2 lb/a = 1 lb/a > 0 lb/c
~ 2.5 bu/a yield boost

96. Annual ryegrass variety trial
at the Allison farm
November 2010
Bruiser, Bounty and KB Royal had the most top growth

97. > 36”

98. ARG is tough to kill
mechanically

99. Organic No-till research
at the Allison Farm
Early July 2009

100. Early August 2009

101. Early November 2009
Plot yields ranged from 51.6 to 58.6 bu/ac
No significant differences between systems

102. November 2010
Significant foxtail pressure
but almost no broadleaf weeds
Plot yields ranged from 42-52 bu/ac

103. August 2011

104. November 2011

105. Soybean health experiment – 6 locations across IL
November 2010
Mustard
Rapeseed incorporated
Canola pre-plant
Cereal rye
Cereal rye no-till
Soybeans no-till drilled into cereal rye
were the top yielder by ~ 10 bushels

106. Corn following cover crop experiment in 2011
Relative
Cover crop system
corn yield
Volunteer oats 79%
Radishes planted on 30” 99%
Radishes drilled on 7.5” 91%

107. Radishes on 30” rows with volunteer oats in fall 2010

108. Wow...cover crops
are not idiot-proof!
Cover crops generally require more management
than manure or purchased nutrient amendments

109. Good advice from Steve Groff…
TREAT
YOUR
COVER
CROPS
LIKE YOUR
CASH
CROPS!