COVER CROPS: ARE THEY IMPORTANT?

Tim  Reinbott

100+ Years of Tillage

The Evils of Tilling-Whether It Is a Plow or a Field Cultivator

Loss of Organic Matter Soil structure Soil microbial

biomass Release of CO2

Soil Erosion

Why Till? Weed Control

Tilled VS No-Till-We have lost nearly 1 ft of top soil

LONG TERM NO-TILL TILLED IN A CORN/SOYBEAN/WHEAT ROTATION

Soil Erosion-Even With No-Tillage

CO2 Levels Over Time

Greenhouse Gases in Agriculture-N2O or Nitrous Oxide-300 X More

Potent Than CO2

U.S. Nitrous Oxide Emissions

Image created by EPA

Agriculture is the main source of nitrous oxide in the U.S., due in large part to nitrogen-based fertilizers, but residue breakdown also contributes

Nitrous Oxide-N20 Contributed by Agriculture

Anerobic Conditions wet

Nitrogen Fertilization 1.5% of all N is lost

as N20

Animal Manures/Compost

N from Cover Crops?

Organic Matter

This is what separates us (Missouri) from Central Iowa, Illinois, Minnesota, Indiana, etc

In these areas climatic conditions favor the accumulation of Organic Matter Slower breakdown,

long history of deep rooted native perennial plants

What Does Organic Matter Do?

Nutrient Cycling Nutrient Holding Capacity Pool of Nutrients Food for soil organisms

Water Dynamics Improves water infiltration Improves water holding

capacity Structure

Reduces crusting, compaction, erosion

Encourages root development

Loss of Organic Matter and Loss of Soil Structure

SOM & RootsSOM is NOT just from crop residues!

12

Cover Crops in Winter-Something Green and Growing Year Around

And Feed The Soil Life.

Micro Organisms: In One Teaspoon of A Healthy Soil

Bacteria-100 million-1 Billion!

Fungal Filaments-Several Yards

Protoza-Several Thousand

Nematodes-10-20

Need To Feed The Soil Year Around-1200 lbs/acre of Soil Microbes

Microorganisms

The Decay Zone

CAN COVER CROPS BE THE ANSWER?

Legumes

Nodules-Symbiotic Relationship Between the Plant and the Bacteria. Atmospheric Nitrogen is Fixed by the Bacteria For Use by the Plant.

Important to Inoculate

Each Species of Legume has a Different Species of Bacteria

You must match them together.

How Do You Know A Nodule Is Fixing Nitrogen?

Hairy Vetch, Queen or Beast?

A lot of biomass-2-3 tons/acre

Winter Hardy High Nitrogen Fixation-

100 plus lbs/acre Wide window of

planting August-mid October March Hard Seed, late

maturing Problem When Wheat

is in the Rotation

Hairy Vetch-in Mid MO

Early May Late May

Timing of Hairy Vetch Harvest and Corn Yield

Adapted from Gallagher, Penn State

2007 Hairy Vetch Corn Yield-0 NTime lbs/acre %N N lbs/acreEarly (May 4) 1,400 3.82 55 113Middle (May 15) 4,300 4.43 190 132Late (May 31) 6,600 4.15 274 140

2008Early (May 1) 3,204 2.49 80 92Middle (May 14) 4,005 2.92 117 121Late (May 29) 4,361 4.55 197 79

Austrian Winter Pea

Large Biomass High N fixation-80-

120 lbs/acre Plant fall or early

spring Not as winter hardy

Seedling Disease problems

Austrian Winter Pea at Maturity

Crimson Clover

Plant August-September

Early spring maturity

Not as much biomass as Hairy Vetch or Peas

Can reseed themselves

Crimson Clover

NON LEGUMES

Buckwheat

Very Short Growing season-60 days

Some Weed Control-Allelopathy

Inexpensive Seed-much like wheat or rye

Attract Beneficial Insects

Many uses for Vegetable production

Nutrient Cycling

Cereal Rye

Inexpensive Seed Rye is very winter

hardy Rye tremendous

dry matter Suppress weeds

Allelopathy or Blocking Light

Good to mix with legumes

Oats

Spring or Winter Spring planted in

the fall will winter kill

Quick Growth in the Fall

Great Companion Crop

Triticale

Cross between wheat and cereal rye

Hardiness of cereal rye

Good forage potential

Does not have the allelopathic potential as cereal rye

Annual Ryegrass-DO NOT USE!

Plant in Fall Overwinter-most of

the time Deep Roots-5-6 ft Scavenge Nitrogen Dense matt controls

weeds Can become a

weed! Herbicide

resistance problem

Radish-Forage or Oil Seed

Late Summer Planted

Sequester Nitrogen

Loosen Soil

Weed Control?

Forage or Diakon Radish

FallSpring

Radish-Small Roots Go Down Deep!

Summer Cover Crops

Following Wheat Summer Annual

Legumes Sunn Hemp Sesbania Cowpea

Cowpea

Summer Legumes

Sesbania Sunn Hemp

ECONOMICS-COST OF SEED

Brief

Seed Costs

Hairy Vetch-$2.0/lb or $40-60/acre Austrian Winter Pea-$0.73/lb or $29-

44/acre Crimson Clover-$1.2/lb or $24/acre Radish-$4 lb or $32/acre Cereal Rye-$0.23 or $14-21/acre Annual Rye-$0.80 or $16/acre Sunn Hemp-$2.5/lb or $50-75/acre Sesbania-$2.4/lb or $48/acre

Cost of Nitrogen per PoundAmmonium Nitrate is $0.60/lb

Hairy Vetch-$40@ 100 lb N/acre=$0.40/lb

Austrian Winter Pea-$29@80 lb N/acre=$0.36/lb

Crimson Clover-$24@75 lb N/acre=$0.32/lb

Sunn Hemp-$50@80 lb N/acre=$0.62/lb

Sesbania-$48@80 N/acre=$0.60/lb

Polycultures

Micro Organisms: In One Teaspoon of A Healthy Soil

Bacteria-100 million-1 Billion!

Fungal Filaments-Several Yards

Protoza-Several Thousand

Nematodes-10-20

Polyculture Seeding Rate

Divide monoculture seeding by number of species:

Ex) Hairy Vetch-30 lb/acre, Cereal Rye-90 lb/acre, Austrian Winter Pea-60 lb/acre in monoculture

When mixed: Hairy Vetch-10 lb/acre, Cereal Rye 30 lb/acre, and Austrian Winter Pea-20 lb/acre

Polyculture Before Harvest

Cover Crops Between MelonsCompetition Reducing Weeds

Sorghum x Sudan In Between Rows of Tomatoes-Can Help Control Weeds

Sorghum X Sudan Can Be Mowed Back and It Will Regrow. Returning Biomass

(Shoot and Root) To The Soil

ESTABLISHMENT OF COVER CROPS

Interseeding

Seeds Must Have Rain and Be Covered

Establishment-Drilled After Soybean or Corn

Alternative: Corn And Soybean Planter

Cover Crops in 15 inch rows

GET CREATIVE WITH PLANTING

Alternating 15 inch Rows With Cereal Rye and Winter Legumes

Cover Crops on 15 inch rows

In the Spring

PLANTING INTO THE COVER CROP

Plowing Under Cover Crops?

Desiccation of the Cover CropRoller Crimper

Flail Chopper or Mower

To Roll or Flail Chop

DAY OF DESICCATION 5 DAYS LATER

Flailed Rolled Rolled Flailed

What If The Cover Crop Is Still Alive?

PLANT PERPENDICULAR TO THE WAY IT WAS ROLLED

SEED TO SOIL CONTACT CAN BE A CHALLENGE

No-Till With Cover Crops After Crop Emergence

Can Cover Crops Help Control Weeds

After Tillage Radish-No Winter AnnualsCover Crop on the Left Has NoMarestail (left)

A Thick Mulch

Getting Good Seed To Soil Contact

No-Till Planters

Modification of the Planter: Taking Off The Coulter and Changing The Closing

Wheel

Planting Into Rolled Cover Crops With Different Closing Wheels

Planting Soybeans Into Standing Crop in Mid May

Corn Population Rolled First vs. Planting Into Standing

27,427

25,606

2013 Corn Yield After Cover Crops

Corn Yield 2013 Cover Crops Overseeded into Soybean September 2012 Corn Treatment Yield Bu/acre Control 175 Hairy Vetch 199 Crimson Clover 165 Radish 174 Cereal Rye 175 Hairy Vetch+Rye 187 Crimson Clv. +Rye 181 Radish + Rye 173 Rye+Radish+HV+CC 174

Reinbott, 2013

Not As Much Yield Advantage As It Looked

2013 Soybean Yield After Cover Crops

Soybean Yield 2013 Cover Crops Overseeded into Corn Sept. 2012 Treatment Yield Bu/acre Control 29 Hairy Vetch 24 Crimson Clover 28 Radish 27 Cereal Rye 36 Hairy Vetch+Rye 28 Crimson Clv. +Rye 33 Radish + Rye 29 Rye+Radish+HV+CC 27

Reinbott, 2013

WHY ARE WE GETTING THIS INCREASE IN

YIELD?

The N Effect From Legumes: But There Is More To Cover Crops Than

Just Nitrogen

N Release over Time From Cover Crops in North Carolina

2 4 8 12 160

10

20

30

40

50

60

70

80

90

100

Rye

Crimson Clover

Hairy Vetch

From Wagger, 1989. Agronomy Journal

lbs/

acr

e

Weeks

WHAT OTHER BENEFITS DO RYE, RYEGRASS, AND TILLAGE RADISH HAVE?

Nutrient Scavenge, Loosen Soil, Weed Control

Tillage Radish Root dug out-32”Courtesy of Steve Groff-Pennsylvania

TillageRadish®

field

Openfield

Soil compactiondecreased by >40%

Ohio State UniversityCourtesy of Steve Groff

Loosen Soil-Increase root growth and water infiltration?

Less Compaction Equals More Root Density Deeper Following Radish and Rye

Gruver, et al, 2012

Soybean Roots Follow Cover Crop Root Channels

Williams and Weil, 2004

NUTRIENT SEQUESTRATION AND WATER RELATIONS

Increase in Soil Test P Around Tillage Radish Roots by 2X

1.25 inch

2 inches

White and Weil, 2011

Radish and Rye Capture Nitrate-N in the Soil Profile

From Steve Groff

Cover Crop

No Cover Crop

Cover Crops Reduce Water Runoff or Increase Water Infiltration

Conventionally Tilled

Cover Crop Residue Allows Water to Soak Into the Soil

Water From Tilled (left), No-Till (middle) and No-Till With Cover Crop (right)

Tilled No-Tilled No-Till Cover Crop

Cover Crops Can Attract Beneficial Insects Including Pollinators

Cover Crops Attract Butterflies, Bee (including Bumble Bees and other Native Bees), beneficial beetles, lacewings, etc.

QUESTIONS?