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TRANSCRIPT
10/14/2014
1
Using Cover Crop Mixtures to Achieve
Multiple Goals on the Farm
Penn State Cover Crop Cocktails Research
J. LaChance, M. Hunter, J. Hinds, C. White
INSERT GROUP PHOTO HERE
Guidelines for cover crop mixtures:
1. Weeds: Have 1-2 species that provide fast ground-cover in
the fall, then add species to achieve other goals
2. Insects: To support beneficial insects for pollination or
biological control, manage mixtures to include flowers
3. Nitrogen: Combine a well-adapted legume with a low
seeding rate of a winterhardy grass or brassica
4. Overall: Aim for balanced biomass from all species in the
mix to benefit from a range of functions
Farmer use of mixtures aligns with ecological
theory
We
ed
su
pp
ressio
n
Nit
roge
n r
ete
nti
on
Be
ne
ficia
l in
se
cts
Pla
nt
bio
ma
ss
Nit
roge
n s
up
ply
Adapted from Hooper et al. 2005
# of species in field
FU
NC
TIO
N
High
Low
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2
Winter Cover Crop Mixtures in Pennsylvania
Corn Silage
Cover Crops
Soybean
WinterWheat
Cover Crops
Cover Crop Mixtures in a Corn-Soy-Wheat
Rotation for Organic Feed and Forage
Mid-Aug
Mid-early May
Mid-late Sept.
Mid-May
Red Clover Cereal RyeCanola
Austrian Winter Pea Forage Radish Oats
An example with six cover crop species
18lb, $52/A13lb, $40/A 142lb, $49/A
70lb, $42/A 11lb, $58/A 101lb, $27/A
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3
3-Species Nitrogen Mix = 3sppN
Cereal Rye
20% rate
69lb, $51/A
3 Species Nitrogen Mix (3sppN)
Austrian Winter Pea (35#)
Red Clover (6#)
Cereal Rye (28#)
Goal: Supply and retain N
=
Red Clover
50% rate
Austrian
Winter Pea
50% rate
3-Species Weed Mix = 3sppWGoal: Suppress weeds and supply and retain N
3 Species Weed (3sppW)
Oats (50#)
R.Clover (6#)
Rye (71#)
127lb, $58/A50% rate
Red Clover
=
Oats
50% rate
Cereal Rye
50% rate
4-Species Mix = 4sppGoal: Support pollinators & beneficial insects,
suppress weeds and manage N
50% rate
20% rate
Canola
4 Species (4spp)
Canola (9#)
Pea (35#)
78lb, $77/A
R. Clover (6#)
Rye (28#)
Cereal RyeRed Clover
50% rate
Austrian
Winter Pea
50% rate
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4
6-Species Mix = 6sppGoal: The “Insurance” Mix
6-Species Mix (6spp)
Radish (4#)
Oat (25#)
Canola (4#)
82lb, $70/A
A.Winter Pea (18#)
Red Clover (3#)
Cereal Rye (28#)
Adapted from Hooper et al. 2005
# of species in field
FU
NC
TIO
NHigh
Low
Fall Cover Crop BiomassPoor red clover establishment in cover crop mixtures
Dry
Bio
mas
s (L
bs
pe
r A
cre
)
0
500
1000
1500
2000
2500
3000
3500
pea
clover
canola
radish
oat
cereal rye
Spring Cover Crop BiomassRye dominates in cover crop mixtures
Dry
Bio
mas
s (L
bs
pe
r A
cre
)
0
500
1000
1500
2000
2500
3000
3500
4000
red clover
pea
canola
cereal rye
If planted after corn, then spring biomass is nearly 100% rye
10/14/2014
5
The Same “4 Species Mix” Varies by Farm
Shorter season Longer season
ResearchStation
Farm 1 Farm 2 Farm 3
Low N Moderate NHigh NHigh N
Rye dominated Canola dominated
Can mixtures achieve multiple goals on the farm?
1. Weed suppression and management2. Beneficial insects3. Nitrogen management
Mitch HunterPhD Candidate in Agronomy
Weed Management withCover Crop Mixtures
10/14/2014
6
Weed Management Goals:• Keep weeds from setting seed
• Grow cover crops, not weeds
– Get the benefits you paid for
• Bonus: Draw down the weed seedbank
Weed Management Questions:• Which cover crops work best?
• Do mixtures help?
• How do cover crops suppress weeds?
Canola Oat Radish 3SppN 4Spp
02
00
400
600
800
YRs 1−2 Spring Weed Biomass by Treatment
Spri
ng
Wee
d B
iom
ass
(lb
/ac)
Most cover crops controlled spring weeds
Results:• Mixtures worked as well as the
best monocultures• Legumes were laggards• Winterkilled can work
Fall Radish
Spring Radish
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7
Early Fall Percent Cover(5-6 weeks after cover crop planting)
Rapid fall growth is key to stopping weeds
Spri
ng
Wee
d B
iom
ass
(lb
/ac)
YEAR 1
20 40 60 80 100
02
00
400
600
800
BC YRs 1−2 CC1 v. S.Wd.KgHa
BC$CC1.1
BC
$S
13.W
D.K
gH
a
Year1Year2
Fall Mixture
Fall Clover
Weed Take-Homes:• Many cover crop treatments can be effective
– Watch out for slow-growing legumes on their own
– Start from a weed-suppressive base, build out
• Winter-killed cover crops can suppress weeds through the spring
• Rapid fall growth is key
– Focus on getting a good stand
• Manage tillage timing to draw down weed seedbank
10/14/2014
8
Jermaine HindsPhD Candidate in Entomology
Cover Crop Mixtures and their Influences on
Beneficial Insects
Beneficial Insects
• Provide valuable ecosystem services on farm.– Pollinate crops
– Suppress pest insects
• Pollinators provide approximately $29 billion in pollination each year.
• Natural enemies provide estimated $4.6 billion in pest
suppression service each year.
http://blogs.discovermagazine.com/d-brief/files/2013/03/honeybee-flower1.jpg
http://www.freshplaza.it/images/2013/0717/aphidius1.jpg
Photo: Jermaine Hinds
Insects and Cover Crops
• Plants represent a valuable resource to beneficial insects.– Food
• Nectar, Pollen, Alt. Prey
– Shelter
• Egg laying sites, ground-dwellers
• Cover crops may support insects when insect prey numbers are low.
• Can we use cover crop mixtures to support beneficial insects?
10/14/2014
9
Insects Have Preferences, Too!
• Insects exhibit preferences for specific floral resources
• Different insects may appear depending on plant characteristics:– Flower:
• Shape
• Size
• Color
• Smell
• More diverse mixtures may support a more diverse group of beneficial insects
Need to consider cover crop termination and crop establishment if a goal is to provision beneficial insects
April May June AugustJuly Sept.
CC + Canola
CC + Red Clover
CC + Winter Pea
Pink Spotted Lady Beetle
Minute Pirate Bug
In rotations where cover crop mixtures must be terminated before flowering, are there alternative ways to use them to promote beneficial insects?
Conservation of Bees for Pollination Services
0
0.5
1
1.5
2
2.5
3
Monoculture 4 Species Mix 6 Species Mix
Ave
rage
no
. b
ee v
isit
s p
er2
min
s.
*
6 Species Mix
*
**
0.5
m
Canola 4 Species Mix
Nu
mb
er O
pen
Blo
om
s p
er 0
.25
m2
A diverse group of wild bees visit canola plants in cover crop mixtures:
• More frequent visits in the monoculture plots where floral density was highest
Slide Credit: Katie Ellis
10/14/2014
10
What about our natural enemies?!•Cover crops can be used as “insectary” strips
Buckwheat CowpeaBuckwheat-Cowpea
Mixture
•Nectar/pollen for beneficial insects
•Early extrafloral nectaries for beneficial insects
•Floral nectar/pollen AND
•Extrafloral nectar for beneficial insects
Can Mixes Be Tailored to Attract Specific Natural Enemies?
Would a biculture of buckwheat and cowpea provide combined benefits from both plant species? In progress, stay tuned……
Flower presence and flower density may be more important than cover crop diversity
• Compatibility with farm goals and crop:– Timing
• Establishment, flowering, termination
– Alternative
• Insectary strips
• Mixture design:– Diversity of flower types
– Be aware of potential crop pests in your system and if cover crop species will support them
Insect Take-Homes:
10/14/2014
11
Charlie White Penn State
Extension Associate & PhD Candidate
Nitrogen Management withCover Crop Mixtures
Goals
• Prevent Nitrate Leaching“N retention”
• Supply N to the next cash crop
Behavior of Mixtures is Affected by Species Characteristics
• Grasses, Brassicas, Legumes
• Winterhardy vs. Winterkilled
Nitrogen Management with Cover Crop Mixtures
• Grasses and brassicas only acquire N from the soil• Legumes can acquire N from the atmosphere through N fixation
Species Characteristics: Nitrogen Acquisition
NodulesForage Radish
Cereal Rye Austrian
Winter Pea
10/14/2014
12
Species Characteristics: Growth Period
Forage Radish
Cereal Rye
Oats
Win
terh
ard
yW
inte
rkill
ed
Canola
0
20
40
60
80
100
120
Fallo
w
Clo
ver
Pe
a
Oat
Rad
ish
3Sp
pN
Can
ola
6Sp
p
4Sp
p
3Sp
pW
Rye
Nit
rate
Le
ach
ing
Be
low
12
Inch
es
(lb
s N
/acr
e)
Red Clover vs. Austrian Winter Pea
Species Characteristics Affect N Retention
Winterkilled and/or fast
growing legumeIncludes Winterhardy
grass or brassica
No cover crop or slow growing legume
Rye
(20
% s
ee
d r
ate
)
Rye
(20
% )
+
Can
ola
(25%
)
Rye
(20
% )
+C
ano
la (5
0%)
Rye
(50
% )
0
10
20
30
40
50
60
Frost Seeded RedClover
Red Clover+Ladino Clov.+Sweet Clov.
Canola +Rye +
A. W. Pea +Red Clover
Nit
rate
Le
ach
ing
(lb
sN
/ac)
Lancaster County Farm 2013
Frost seeded red clover allows significant nitrate leaching
On-Farm Results
Lancaster County 2013 Photos
Fro
st S
ee
de
d
Re
d C
love
r
Sum
me
r Se
ed
ed
3
sp
eci
es
Clo
ver
(Red
, La
din
o, S
wee
t)
Nitrogen Uptake By Weeds = 40 lbs N/ac
10/14/2014
13
Nitrogen Supply: N is released from cover crop residues by microbial decomposition
C:N ratio of cover crop residues regulates N supply vs. N tie up
5:1 10:1 15:1 20:1 30:1 40:1
Car
bo
n:N
itro
gen
Rat
io
N mineralization-Microbes release excess N to soil
N immobilization-Microbes tie up N from soil
Clovers
Peas
Radish
Canola
Cereal Rye, Triticale
Annual Ryegrass
Oats
Sorghum sudangrass
Research Station Mixtures
On-Farm Mixtures
Ne
utr
al
min
eral
izat
ion
/im
mo
bili
zati
on
High Nitrogen Concentration
Low Nitrogen Concentration
0
5
10
15
20
25
Pe
a
Rad
ish
Clo
ver
Fallo
w
4Sp
p
3Sp
pN
6Sp
p
Can
ola
Oat
3Sp
pW
Rye
Co
rn S
ilage
Yie
ld (
T/ac
)
Corn Yield Declined with Increasing C:N Ratio of Cover Crop
Rye
(20
%)
Rye
(20
% )
Rye
(20
% s
ee
d r
ate
)
Rye
(50
% )
Rye
(10
0% )
C:N 10 12 27 28 27 28 39 41
10/14/2014
14
Acceptable Compromise?
Prevented N leaching,
moderate yields
Tradeoff:Prevented N
leaching, but lower yields
Tradeoff:Higher yields, but
moderate N leaching
0
5
10
15
20
25
Pe
a
Rad
ish
Clo
ver
Fallo
w
4Sp
p
3Sp
pN
6Sp
p
Can
ola
Oat
3Sp
pW
Rye
Co
rn S
ilage
Yie
ld (
T/ac
)
Tradeoffs Between N retention and N supplyNitrogen Management with Cover Crop Mixtures Rule of Thumb
To balance N retention and supply, combine a well-adapted legume with a low seeding
rate of a winterhardy grass or brassica
Can mixtures achieve multiple goals?
Guidelines:1. Weeds: Have 1-2 species that provide fast ground-cover in
the fall, then add species to achieve other goals
2. Insects: To support beneficial insects for pollination or
biological control, manage mixtures to include flowers
3. Nitrogen: Combine a well-adapted legume with a low
seeding rate of a winterhardy grass or brassica
4. Overall: Aim for balanced biomass from all species in the
mix to benefit from a range of functions
Yes – but make a plan
Identify the functions you want from the
cover crop mixture
• Build organic matter
• Nitrogen fixation
• Nitrogen retention
• Weed suppression
• Beneficial insects
• Fall and/or spring forage production
Identify the planting window• Late summer
• Early fall
• Late fall
Making the most of cover crop mixtures
Fine-tune for an even mixture on your farm
10/14/2014
15
Thank you!
Jason Kaye
Nancy Ellen Kiernan
Jim LaChance
Dawn Luthe
Dave Mortensen
Jeff Moyer
Christy Mullen
Puneet Randhawa
Rebecca Robertson
Meagan Schipanski
Brian Snyder
Dayton Spackman
Alexandra Stone
Charlie White
Dave Wilson
Leslie Zuck
Bucky Ziegler
Project Team
Mary Barbercheck
Brosi Bradley
Mike Brownback
Mac Burgess
Alan Cook
Sarah Cornelisse
Dan DeTurk
Tianna DuPont
Katie Ellis
Wade Esbenshade
Denise Finney
Scott Harkcom
Abbe Hamilton
Dave Hartman
Mena Hautau
Jermaine Hinds
Mitch Hunter
Shan Jin
Organic Research and Extension Initiative (OREI)
For more information, please contact:Jim LaChance - [email protected]
http://agsci.psu.edu/organic/research-and-extension/cover-crop-cocktails
Questions for the panel?
Mary Barbercheck
Entomology
Penn State
Extension
Jason Kaye
Soil Biogeochemistry
Penn State
David Mortensen,
Weed Ecology
Penn State
Jermaine Hinds
Entomology
Penn State
Mitch Hunter
Agronomy
Penn State
Jim LaChance
Ecosystem Science &
Management
Penn State
Charlie White
Sustainable Agriculture,
Penn State Extension