Building Better Soils with Cover Crops

Building Better Soils with
Cover Crops
Anne Verhallen
Ridgetown, OMAF and MRA

Why grow cover crops?
• Improved soil structure through increased stability,
biopores and organic matter.
• Improved trafficability.
• Improved pest management and vine nutrition.
• Reduced tillage.
• Protection of soil from water and wind erosion.
• Attraction of beneficial insects, spiders and soil borne
organisms.
• Potential reduction/suppression of some pests.
• Reduced weed population.
• Feed

From the SARE North Central cover crop survey
2012 (drought year Midwest US) 759 responses
- 11 % better yields on corn after a cover crop
- 14.3 % better yields on soybeans after a cover
crop
2013 1500 responses
- 5 % better yields corn or soybeans after a cover
crop

Soil Health
No-cover lower than with cover crops
% Cover
Visual differences
fall 2009
No difference in
cover rating
Soil Quality Scoring (Ontario Soil Health Project - Cornell Test)
No CC Oats OSR Peas Rye Vetch
64
66
68
70
72
74
76
78
SoilQuality(100pointstotal)

Let’s look at soil health to build a better soil
Chemical Physical
Biological
nutrients
infiltration
drainage
aeration
water
holding
disease suppression
diversity

Reduce Soil Erosion
• Nutrients in wind blown soil -
$1 to $10 /acre
• Can cut yield 50%
• Need 2-3 tons/acre residue for
effective control
• Water Erosion - $40/acre value
in eroded sediment
(soil loss/nutrient loss/ road and ditch
maintenance included in
formulating value)
Water and Wind Erosion –
What is it worth?

To build or maintain your soil
• add organic matter
– cover crops
– manure/compost
• crop rotation
• reduce tillage and
traffic/pressure

GrainYield(bu/ac)
2010 2011
Corn Yields after Wheat +/- Red Clover,
Ridgetown 2010-12
C-S-W
C-S-W(rc)
2012
C-S-W
C-S-W(rc)
C-S-W
C-S-W(rc)
C-S-W
C-S-W(rc)
Ave

Cover Crops as a Soil Builder –
Can Cover Crops Build Organic Matter?
• Illinois study 1996 – a
vetch/rye cover crop and
chemical burn down in snap
beans – in 3 yrs soil organic
matter went from 3.07 to
3.48%

Improved Water Holding Capacity
0.5 % in soil OM = 15% in nutrient holding ability
(ie K, Mg)
12 % in water holding capacity
(result possibly one week longer drought-stress free symptoms
on a sandy loam soil with low OM)
Adapted from work by Dr.
Sig Snapp, MSU

Contributions of Root hairs
From Czarnota, M, Weed Technology,200

Tap roots
From M. Ngouajio, MSU

To Achieve the Maximum Level of
Aggregate Stability
Clay
content (%)
10 20 40 50
Organic
matter
content (%)
3 4 7 9
Soil
Texture
sandy
loam,
sand
silt loam,
loam,
sandy
loam
clay loam clay

• Improved soil structure through increased stability,
biopores and organic matter.
• Improved trafficability.
• Improved pest management and vine nutrition.
• Reduced tillage.
• Protection of soil from water and wind erosion.
• Attraction of beneficial insects, spiders and soil borne
organisms.
• Potential reduction/suppression of some pests.
• Reduced weed population.

Earthworms – the soil health poster child

What about tillage and traffic
Compaction
• Fine textured, poorly sorted
• High silt content – fills voids
• Low OM
• Water content

What about tillage and traffic
From Spatial variability of soil compaction over a vineyard region in relation with soils and cultivation operations
P. Lagacherie a,*, G. Coulouma a, P. Ariagno a, P. Virat a, H. Boizard b, G. Richard c,d
a INRA, UMR LISAH, 2 place Viala, 34060 Montpellier Cedex 01, France
b INRA, Unite´ d’Agronomie Laon-Reims-Mons, B.P. 50136, 80203 PERONNE Cedex, France
c INRA, Unite´ d’AgronomieLaon-Reims-Mons, Rue Fernand Christ, 02007 Laon Cedex, France
d INRA, Unite´ de Science du Sol d’Orle´ans, Domaine de Lime`re, Avenue de la Pomme de Pin, Ardon, BP 20619, 45166 OLIVET Cedex, France

Reducing compaction, improving
trafficability
Compaction
Cover crops – acts as a
shock absorber

What do cover crops add to the soil?
• 20-50% of C fixed by
photosynthesis –
released to the soil
through rhizodeposition
• Added carbon stimulates
microbial community
• Adds diversity – a
different root system, a
different plant

Date
Jul Aug Sep Oct Nov
gravimetricsoilmoisture(%)
0
2
4
6
8
10
12
14
16
18
dailyprecipitation(inches)
0
1
2
3
4
strip till oat
strip till no cover
chisel plow oat
chisel plow no cover
precip (in)
Oats surface
residue
Increased soil
moisture 1-
2%
Benefits:
Soil Moisture Retention

7/17/10 7/18/10 7/19/10 7/20/10
Betweenrowsoiltemperatureat1"(ºF)
65
70
75
80
85
90
95
100
strip till oat
strip till no cover
chisel plow oat
chisel plow no cover
Benefits:
Soil Temperature Moderation
Oats surface
residue
reduced soil
temp by 5-
10oF on hot
days in early
season
From D. Brainard
MSU

Weed Suppression
California research
As seeding rates
Weed biomass
Rye, brassicas effective at
normal seeding rates
Legume/rye mixtures –
needed 3x seeding rate to
be effective

Total Weed biomass
0
50
100
150
Corn OSR Pea Vetch Oats Mustard
COVER CROP
ABOVEGROUNDBIOMASS(G/M2)
a c b b b c
Robinson, Van Eerd – Ridgetown Campus

Nitrogen cycling
Nitrogen fixers
• Clover
• Alfalfa
• Peas
Nitrogen scavengers
• Grasses – oats, corn,
rye
• Brassicas – oilseed
radish, mustard
• Buckwheat
• Even legumes

How well do they capture N?
0
5
10
15
20
25
30
35
40
soilnitrateppm
Sep-03
Oct-03
Nov-03
0-30cm
Apr-04
30-60cm
Apr-04
Soil Nitrate Levels under Cover Crops
(planted Aug.15, 2003 after cucumbers)
Bare soil
Oats
Peas
Oilseed radish
Wheat

-40
-20
0
20
40
60
80
100
Red Clover-Fall Control
-40
-20
0
20
40
60
80
100
Red Clover-Spring Control
1
2
-40
-20
0
20
40
60
80
100
No Cover
LSD=27.99
LSD=28.99
Actual
Nitrate
Actual
Ammonium
Relative
Nitrate
Relative
Ammonium
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Red Clover-Fall Control
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Red Clover-Spring Control
1
2
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
No Cover
LSD=27.99
LSD=28.99
LSD=27.99
LSD=28.99
Actual
Nitrate
Actual
Ammonium
Relative
Nitrate
Relative
Ammonium
Actual
Nitrate
Actual
Ammonium
Relative
Nitrate
Relative
Ammonium
-40
-20
0
20
40
60
80
100
Perennial Ryegrass
-40
-20
0
20
40
60
80
100
Oilseed Radish
-40
-20
0
20
40
60
80
100
16/9/03 6/10/03 23/10/0314/11/03 12/4/04 26/4/04 10/5/04 26/5/04 9/6/04 21/6/04 19/7/04 1/9/04 29/11/04
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
Oats
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Perennial Ryegrass
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Oilseed Radish
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
16/9/03 6/10/03 23/10/0314/11/03 12/4/04 26/4/04 10/5/04 26/5/04 9/6/04 21/6/04 19/7/04 1/9/04 29/11/0416/9/0316/9/03 6/10/036/10/03 23/10/0323/10/0314/11/0314/11/03 12/4/0412/4/04 26/4/0426/4/04 10/5/0410/5/04 26/5/0426/5/04 9/6/049/6/04 21/6/0421/6/04 19/7/0419/7/04 1/9/041/9/04 29/11/0429/11/04
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
0
200
100
Oats
Oats
Perennial Ryegrass
Oilseed Radish
Red Clover Spring Control
Red Clover Fall Control
No Cover
Timing of
Kill
and
Timing of N
Release
Mid Sept 03 mid Nov 04
From work by W.
Deen, University of
Guelph

The bad news - N credits and cover crops
“These corn yield responses to either oat or oilseed
radish cover crops suggest that fertilizer N
requirements were not reduced compared to when a
cover crop was not planted. The Maximum Economic
Rate of Nitrogen (MERN) estimates clearly indicate that
either oat or oilseed radish cover crops, on average, did
not reduce corn fertilizer N requirements when manure
was or was not applied the previous summer.”
Crop Advances Report 2008 – based on 17 sites comparing cover crops
planted after wheat with and without manure

20
40
3 6 9 12 15 18
60
80
Years
Tonsofcomposttosupply150lbsofN/acre
From a nutrient management perspective,
application rates of slow release organics should
diminish over time
Adapted from Magdoff and Weil (2004)
Single season N availability = 25%
From Dr. Joel
Gruver SWAC 2009

•Source of carbon for
food for “critters” in soil.
•Protects soil life from
sudden cold spells
(once temperature is
below 50ºF, a lot of soil
bacteria become
dormant).
“catch” or “trap’ crops for
nitrogen, phosphorus,
macro and micronutrients.
Earl and Bill Elgie,
Fairview Fams,
Dresden, Ontario –
comments…

Managing cover crops starts with
What are your goals with cover crops?
Why are you planting them?

Management
Cover crop management starts with:
System approach
• Selection
• Planting
• Control

Making the plan – crop rotation
Acres Field 2012 2011 2010 2009 2008 2007 2006
96 Caron sweet corn soys Wheat SWW Soy Sugar Beet RR RRSoy seed Sweet Corn
82 Dewolf Corn/Malcom sprout50/pep30corn/Malcom Tomato/pep 25 Corn/ Malcom Brussel sproutCorn
51 EVS CemeteryCorn P1184 sprouts soy LL Peas Brussel SproutsSweet Corn Beets
51 EVS Shop Corn P1184 sprouts soy LL Brussel Sprout Soys RR Corn Beets
51 Terpac Corn P1184 beets ach 808 corn Brussel Sprout Peas/ soy RR Sweet Corn Beets
73 Griffore sprouts Corn/Malcom Brussel sprout Corn Beets RR Tomato/pep Wheat-Malcolm
98 HJH Wheat SWW beets ach 824Tomato 75 Corn/MalcomRR Brussel SproutsCorn Malcom 84 Cucumber
HJH pepper 22 Corn25ac DVS RRE pep 25ac Snap bean 14
104 Hunter Corn DKC52-62 sweet corn Brussel Sprout Sweet corn HRW /alfalfa Sugar Beets Sprouts
51 Hunter RailRoad Sweet corn HRW /alfalfa Sugar Beets Sprouts
34 Lauber 78 Tom20/SoyLL corn LL 35F43 Beets Wheat/SoyRR soy E corn W
85 Lauber River Soy LC2399 LL corn LL 35F43 Wheat HR/tile Soy RR wheat/soy peapursuitsoy
21 M River wheat HR Soy RR Sweet Corn Soy (Wheat)
48 Moninger peppers corn LL 35F43 Brussel sprout Corn RR Sweet Corn Wheat/Barley (Soy)
50 Bourdeau peascovercrop soys/SWW beets Wheat Sugar Beets RR Soy seed Wheat
50 Myers West peascovercrop soys/SWW beets Soy RR Corn Wheat soy
50 Myer East peascovercrop soys/SWW beets Soy RR Wheat SRW soy corn
72 Dreveny Soy LC2399 LL beet64ac-SW78soy VanDammecorn wheat

When do they fit for cash crops?
• Seed RC
• Adjust chaff spreader to
enhance volunteer wheat/small
grains
• Interseed Peas or Crimson
clover into RC bare spots
• interseed rye into corn
• Plant OSR, Oats, Rye
Peas etc
interseed cover crop soybeans

Cover crop seeding into corn
Timing (MSU)
A - clover, vetch*, ARG*
B – clover, vetch*, ARG*, oats, radish, rye
C – rye, triticale, wheat
* - avoid if going to wheat in rotation
Apr May June AugJuly NovOctSept
A B C

June 30th : manure ? Seeding.. Uneven
density

Quebec plots - Yield (bu/ac) in 2010
Field
seedingrate
#
ofrepetition
rye
grass
raiting*
Yield
(bu/ac)
m
oisture
atharves
154 0 lb 3 0 181 17.6
11 lb 4 1.75 173 17.4
22 lb 3 2 167 17.1
156 0 lb 3 0 194 18,7
11 lb 5 1.3 191 18.8
22 lb 2 2 196 18.9
* 0 to 3 (3 = ideal stand rye grass)

Cover crop seeding into soybeans
Timing (MSU)
Overseed at early leaf drop
A - clover, vetch*, ARG*, oats/barley, rye,
triticale, wheat
* - avoid if going to wheat in rotation
Apr May June AugJuly NovOctSept
A

Cover crop selection
• Cover crop type
• Growth habit
• Cover crop variety?

MCCC Cover Crop Decision Tool
• http://mccc.msu.edu/SelectorTool/2011CCSelectorT
ool.pdf

Feed the soil life
Cover Crop Mixes
• Diversity – “ crop rotation on
steroids”
• ND research – 6 species critical
point
“When you farm in nature’s
image – everything gets easier.”
Gabe Brown

Creating diversity
Cover Crop Mixes
• Oats/OSR
• Rye or ryegrass/OSR
• Rye/vetch
• Peas/oats/OSR
• OSR, sunflower, blue
lupin, AWP, fava
bean, fenugreek etc.
Consider:
warm vs cool season,
grass vs legume

Cover Crop Selection – Variety?

Planting
Seeding rate
Drill/planter versus broadcast or other?
Planting date
Consistency
Timing
Speed of emergence
Fertility?

Planting – Seeding Rate
Oats and radish after
wheat, planted August 22

Planting – Drill vs Planter vs Broadcast

How – seeding options – beyond the norm
Slurry Seeding
• Manure as a carrier
• Similar to broadcast
• Less moisture dependent
• Not all seed types

How – seeding options – beyond the norm
High Clearance Seeder
• Seed into a standing crop
• Needs moist soil or rain for
good germination
• May knock some crop
around

Interseeding into Seed Corn12 lbs/A ryegrass 2 lbs/A alfalfa

Planting Date
Heavier clay soil, about 2 weeks difference in
planting - oats and radish.

Nitrogen and Cover Crop Growth
58
Soil nitrate level 5ppm or less
Soil nitrate level 8-10ppm Soil nitrate level 20ppm
No N applied
No N applied
No N applied

Control of Cover Crops
Consider during selection
Options :
• Winterkill – frost/freeze
• Tillage
• Roller crimper, mowing
And combinations

Water Infiltration (seconds to drain 2.5 cm)

Other options – roller crimper
Pelee Island 2013
- Last field
planted – June
14
- Heavy clay soils
- Dry summer
- 68 bu/a
- For 2014 -500
acres in rye

Other options – strip till
Laurent Van Arkel,
Dresden Nov. 2011
Matt Van Tilburg, Ohio, 2011

Cover Crops – it’s a prescription
“It depends”
• Soil type/topography
• Amount of residue
• Tillage/planting system
• Patience
And of course weather

More Cover Crop information
OMAFRA website
http://www.omafra.gov.on.ca/english/crops
/facts/cover_crops01/covercrops.htm
Midwest Cover Crop Council
http://www.mccc.msu.edu/

Questions
Anne Verhallen anne.verhallen@ontario.ca 519 6741614

"Land, then, is not merely soil; it is a
fountain of energy flowing through a
circuit of soils, plants, and animals."
- Aldo Leopold, A Sand County Almanac, 1949

So let’s talk about…
Oats
• Seed easy to obtain
• Winter kills
• Beautiful root system – soil structure
• Early planting = lots of growth – slugs?

Red Clover
• Underseed in small
grains
• Nitrogen release curve
fits well with corn
• High quality feed for soil
life!
• Inconsistent stands?
• Slugs?

What about Red Clover?
3900 kg/ha October 12!

Oilseed Radish
• “rock star of cover crops”
• Easy way to start into cover
crops
• The fit – Aug/early Sept, after
manure – high N need
• Cautions – smell, nitrogen loss,
hard seed, setting seed
• Winter kills

Austrian Winter Peas/Peas
• Large seed
• Inconsistent winter survival
• N cycling?

Austrian Winter Peas/Peas
• Do not seed late

Cereal Rye
• Can be planted later
• Excellent nitrogen
scavenger
• Won’t head out
• Will not winter kill
Caution: fast spring growth
– be prepared!

What else might you see out there…
Annual Ryegrass
• Slow to establish
• Large varietal
differences
• Roots create a
beautiful sod
• Kill early to reduce
nitrogen tie up

What else might you see out there…
Crimson Clover
• Fast growing clover
• inconsistent winter hardiness

And there are more…
• Vetch, chickling vetch
• Buckwheat
• Phacelia
• Lupins
• Faba Beans, Lentils
• Cowpeas
• Warm season
grasses – millet,
sorghum
• Sunflower
• And others

Sunn Hemp – a new possible cover crop?

Research – Darren Robinson
• Herbicide carryover – impact on cover crop establishment and function – caution
- first year data
Broadstrike
RC
Integrity Converge
Flexx
Pursuit Callisto
Primextra
Fall
planted
oats
injury injury injury injury injury
Hairy
vetch
injury No injury injury injury No injury
OSR
(daikon)
injury No injury injury injury Delay
emerge,
no injury
Fall rye Delay
emerge, no
injury
injury injury Delay
emerge,
no injury
injury
Fall cover crops – 4 Months after Application

Research – Darren Robinson
• Herbicide carryover – impact on cover crop establishment and function –
caution - first year data
Broadstrike
RC
Integrity Converge
Flexx
Pursuit Callisto
Primextra
Buckwheat injury No injury No injury injury Delay
emerge,
no injury
Annual
ryegrass
No injury No injury injury injury injury
Sorghum
sudan
injury No injury No injury injury injury
Spring
wheat
No injury No injury No injury No injury No injury
Spring cover crops – 1 Year after Application

Building Better Soils with Cover Crops

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