Tillage and Cover Crops2012 LOUISIANA AGRICULTURAL TECHNOLOGY &

MANAGEMENT CONFERENCEParagon Casino Resort

Marksville, LAFebruary 15-17, 2012February 15-17, 2012

Kip Balkcom

Research Agronomist

USDA-ARS

National Soil Dynamics Laboratory

Auburn, AL

Total Organic C and N

Total Organic C and N

BulkBulk

SizeSizeDistributionDistribution

NH and NO , NH and NO , P, K, Ca, Al, P, K, Ca, Al,

CECCEC

NH and NO , NH and NO , P, K, Ca, Al, P, K, Ca, Al,

CECCEC

33334444

Microbial Biomass Microbial Biomass C and NC and N

Aggregate Aggregate StabilityStability

Soil C is the basis of Soil Quality/Productivity

from Doran et al., 1993from Doran et al., 1993

InfiltrationInfiltration

SoilSoilStrengthStrength

BulkBulkDensityDensity

WaterWater

contentcontent

retentionretention

capacitycapacity

C and NC and N

SoilSoilRespirationRespiration

NN

Biomass CBiomass Cto TOC ratioto TOC ratio

RespirationRespirationto Biomass ratioto Biomass ratio

mineralizedmineralized

How to increase soil C and improve soil quality?

Conservation Tillage with Cover Crops

Conservation System

Conventional Tillage Promotes Soil Erosion

Manage compaction . . .Manage compaction . . .

Non-inversion Tillage

Tillage and rye cover crop effects on SOM after 5 yTillage and rye cover crop effects on SOM after 5 y

00

22

44

SOM (%)SOM (%)00 11 22 33 44 55

88

66

44

1010Decatur silt loam

No-Till w/o coverNo-Till w/o cover

Conventional w/o coverConventional w/o cover

No-Till w/ coverNo-Till w/ cover

Fall Paratill w/ coverFall Paratill w/ cover

Effect of cropping/tillage system on soil C from an eroded Ultisol in Georgia.

0-15 mm0-15 mm15-30 mm15-30 mm30-80 mm 30-80 mm

3030

2525

2020

conversion to conventional till

soybean

conversion to conventional till

soybean

Grain sorghum no-till intocrimson clover

Grain sorghum no-till intocrimson clover

Bruce et al., 1995Bruce et al., 1995

30-80 mm 30-80 mm

55

1010

2020

1515

19841984 19861986 19881988 19901990Year Year

Depression (11%)Conventional: 2937 lb/AConservation: 3255 lb/A

Depression (11%)Conventional: 2937 lb/AConservation: 3255 lb/A

ConventionalConventionalConservationConservation

ConventionalConventional

ConservationConservation

ConventionalConventional

{{{{

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Field Scale ResearchField Scale Research

Conventional Conventional

Conservation Conservation

Eroded Slope (16%)Conventional: 2440 lb/AConservation: 2830 lb/A

Eroded Slope (16%)Conventional: 2440 lb/AConservation: 2830 lb/A

Plateau (14%)Conventional: 2651 lb/AConservation: 3032 lb/A

Plateau (14%)Conventional: 2651 lb/AConservation: 3032 lb/A

Conservation Conservation

Conservation Conservation Conventional Conventional

Conventional Conventional

}}}}

What is a Cover Crop?

• A crop whose main purpose is to benefit the soil and/or a subsequent crop in subsequent crop in one or more ways, but is not intended to be harvested for feed or sale.

Courtesy: Harry Schomberg, USDA-ARS

High Residue Cover Crop

Why use Cover Crops?• Erosion control

• Soil and water quality improvement

• Increased water infiltration infiltration

• Minimize nutrient loss

Soil organic carbon

Soil organic carbon

Tennessee Valley-Clay SoilsTennessee Valley-Clay SoilsNo-Till w/o Cover CropNo-Till w/o Cover Crop

Tennessee Valley-Clay SoilsTennessee Valley-Clay SoilsNo-Till with Cover CropNo-Till with Cover Crop

3000

3500

4000

4500

5000

PD 2

PD 1

Planting Date - Clover Biomass

0

500

1000

1500

2000

2500

3000

EVS2004 EVS2005 TVS2004 TVS2005 JAY2005

PD 3

PD 4

PD 5

Courtesy: Andrew Price

Winter Cover Crop Biomass and Weed Suppression

800

1200

Wee

d bi

omas

s (k

g/ha

)

0 2000 4000 6000 8000 10000

0

400

800

Rye biomass (kg/ha)

Wee

d bi

omas

s (k

g/ha

)

Cover crop planting date affects rye biomass and pigweed density

6000

8000

10000

Rye

Biom

ass

(kg/

ha)

600000

80000010000001200000

Pigw

eed

Den

sity

(p

lant

s/ha

)

0

2000

4000

PD1 PD2 PD3 WF CT

Treatment

Rye

Biom

ass

(kg/

ha)

0

200000400000600000

Pigw

eed

Den

sity

(p

lant

s/ha

)

Cover Crop Fertilization

90 lb N ac-1 0 lb N ac-1

N Fertilizer Effects on Rye Cover Crop Biomass Production

Rye

biom

ass,

kg

ha-1

8000

10000

12000

14000200320042005

WGS Headland, ALNitrogen rate, kg ha-1

0 34 67 101

Rye

biom

ass,

kg

ha

0

2000

4000

6000

8000

Rainfall Simulation Study . . .

*No Deep Tillage*No Deep Tillage100100

8080

6060

Tillage and residue effects on infiltration of a Coastal Plain Soil (2-inch rain event)

Tillage and residue effects on infiltration of a Coastal Plain Soil (2-inch rain event)

11 days11 days

00

60

4040

2020

No Till w/ residue

No Till w/ residue

No Till w/o residue

No Till w/o residue

ConventionalTillage

ConventionalTillage

3 days3 days

Soil Water Conservation

Plot 141Plot 141 Plot 142Plot 142

Timing Termination

MAY 1

Bio

mas

s, lb

ac-1

8000

10000

12000200420052006200720082009

Biomass Production Time of Termination

Bio

mas

s, lb

ac

0

2000

4000

6000

RyebeforeCorn

WheatbeforeCotton

RyebeforeCotton

WheatbeforeCorn

Methods of Termination

Physical methods• Incorporation

• Mowing

• Mechanical Rolling

Roller Variations

Roller Variations

Roller Variations

Roller Variations

Rollers/crimpers developed at the NSDLTwo-Stage

roller/crimperU.S. Patent pending

(Kornecki)

Smooth roller with crimping bar

U.S. Patent pending(Kornecki, et al.)

Roller for elevated beds:U.S. Patent allowed

(Kornecki)

One row – two furrows

Two rows – three furrows

Less vibration transferred to tractor, adjustable crimping force, a unique crimping bar design to accommodate for uneven soil surface

Compact design, with adjustable crimping force. Drum with crimping bars isolated to minimize vibration. Intended for small vegetable farm operation: Designed both for field

and vegetable crops

Ripper Modification

Planter Attachments

Summary• Plant covers in a timely fashion.

• Consider additional N fertilizer for small grain cover crops, especially if residual N is low.

• Terminate covers ~ 3 weeks ahead of • Terminate covers ~ 3 weeks ahead of anticipated planting date to allow soil moisture recharge and reduce problems with equipment operation.

• Take advantage of equipment modifications to facilitate tillage and/or planter operations in heavy residue.

Tillage and Cover Crop Resources• Managing Cover Crops Profitably, 3rd ed. Sustainable

Agriculture Network. www.sare.org/publications/covercrops/covercrops.pdf

• UC SAREP Cover Crop Resource Page www.sarep.ucdavis.edu/ccrop/

• National Sustainable Agriculture Information Service (ATTRA) www.attra.org

• Schomberg, H.H., and K.S. Balkcom. Cover crops [Online]. Available at: www.soilquality.org/practices/cover crops.html

www.ars.usda.gov/msa/auburn/nsdl