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

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

Why grow cover crops?

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

So

il Q

uali

ty (

100 p

oin

ts t

ota

l)

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

Gra

in Y

ield

(b

u/a

c)

2010 2011

Corn Yields after Wheat +/- Red Clover, Ridgetown 2010-12

C-S

-W

C-S

-W(r

c)

2012

C-S

-W

C-S

-W(r

c)

C-S

-W

C-S

-W(r

c)

C-S

-W

C-S

-W(r

c)

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,2001

Tap roots

From M. Ngouajio, MSU

Fibrous roots

Soil structure

Aggregate Stability

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

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.

Earthworms – the soil health poster child

Earthworms and Cover Crops

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

gra

vim

etr

ic s

oil m

ois

ture

(%

)

0

2

4

6

8

10

12

14

16

18

da

ily p

recip

itatio

n (in

ch

es)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 Betw

een r

ow

soil tem

pera

ture

at 1"

(ºF

)

65

70

75

80

85

90

95

100strip 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

AB

OV

EG

RO

UN

D B

IOM

AS

S (

G/M

2) 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?

05

10152025303540

so

il n

itra

te p

pm

Se

p-0

3

Oct-

03

No

v-0

3

0-3

0cm

Ap

r-0

4

30

-60

cm

Ap

r-0

4

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

100No Cover

LSD=27.99LSD=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

100No Cover

LSD=27.99LSD=28.99

LSD=27.99LSD=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 20

010

0 0 200

100 0 20

010

0 0 200

100 0 20

010

0 0 200

100 0 20

010

0 0 200

100 0 20

010

0 0 200

100 0 20

010

0 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 20

010

0 0 200

100 0 20

010

0 0 200

100 0 20

010

0 0 200

100 0 20

010

0 0 200

100 0 20

010

0 0 200

100 0 20

010

0 0 200

100

0 200

1000 20

010

0 0 200

1000 20

010

0 0 200

1000 20

010

0 0 200

1000 20

010

0 0 200

1000 20

010

0 0 200

1000 20

010

0 0 200

1000 20

010

0 0 200

1000 20

010

0 0 200

1000 20

010

0 0 200

1000 20

010

0 0 200

1000 20

010

0 0 200

1000 20

010

0 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

To

ns o

f co

mp

ost to

su

pp

ly 1

50 lb

s o

f N/a

cre

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 peas\covercrop soys/SWW beets Wheat Sugar Beets RR Soy seed Wheat

50 Myers West peas\covercrop soys/SWW beets Soy RR Corn Wheat soy

50 Myer East peas\covercrop 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 Aug July Nov Oct Sept

A B C

June 30th : manure ? Seeding.. Uneven

density

Quebec plots - Yield (bu/ac) in 2010

Field

seed

ing

rate

# of r

epet

ition

rye

gras

s

raiti

ng*

Yie

ld (b

u/ac

)

mois

ture

at h

arve

s

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 Aug July Nov Oct Sept

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 – Seeding Rate

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 Corn 12 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

Tillage

Tillage

Water Infiltration (seconds to drain 2.5 cm)

Cover Crops in the Spring

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

Other options – strip till

Multi mix – late fall stand

Organic Dairy - pasture

Interseeding in Corn

Companion planting

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?

So let’s talk about…

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!

So let’s talk about…

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

More oilseed radish

So let’s talk about…

Austrian Winter Peas/Peas

• Large seed

• Inconsistent winter survival

• N cycling?

So let’s talk about…

Austrian Winter Peas/Peas

• Do not seed late

So let’s talk about…

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