uncovering the facts and fiction about conservation tillage systems

Uncovering the Facts and Uncovering the Facts and Fiction about Conservation Fiction about Conservation

Tillage SystemsTillage Systems

Wilson Faircloth and Diane RowlandWilson Faircloth and Diane RowlandUSDA-ARS, National Peanut Research USDA-ARS, National Peanut Research

Laboratory, Dawson, GALaboratory, Dawson, GA

National PeanutResearch

LaboratoryNational PeanutResearch

Laboratory

NPRL Mythbusters:NPRL Mythbusters: NPRL Mythbusters:NPRL Mythbusters:

Top 10 Myths About Top 10 Myths About Conservation TillageConservation Tillage

-OR--OR-

Why aren’t you using Why aren’t you using conservation tillage in conservation tillage in

your operation?your operation?

MytH #1: You save MytH #1: You save more water using more water using

conventional tillage conventional tillage

MytH #1: You save MytH #1: You save more water using more water using

conventional tillage conventional tillage

Absorbs rainfall impactAbsorbs rainfall impact

Cooler soil tempsCooler soil temps

Lower evaporative lossesLower evaporative losses

Greater soil water infiltrationGreater soil water infiltration

Increases plant available waterIncreases plant available water

Conservation TillageConservation Tillage

8” soil moisture in three tillage systems

0

20

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2006

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So

il w

ate

r p

ote

nti

al (

kP

a)

conventional tillage strip tillage no tillage

Cotton

peak flowering and boll fill

Strip till maintains moisture:•Better infiltration -or-•Deeper rooting (no roots at this shallow depth to pull water)


0

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/2/2

00

6

So

il w

ate

r p

ote

nti

al (k

Pa

)


Strip till remains moist


0

20

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00

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/2/2

00

6

So

il w

ate

r p

ote

nti

al (k

Pa

)


No till roots

-0.10

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.0417

918

218

518

819

119

419

720

020

320

620

921

221

521

822

122

422

723

023

323

623

924

224

524

825

125

4

Day of year

Soil Moisture DeficitsSoil Moisture DeficitsMore irrigation required in Conventional Tillage

Excess MoistureExcess Moisture

Irrigation RequiredIrrigation Required

Conventional TillageConventional Tillage

Strip TillageStrip Tillage

24 H

ou

r D

iffe

ren

ce i

n S

oil

Mo

istu

re

Soil Moisture Profile: Soil Moisture Profile: Before Before IrrigationIrrigation

Low WaterLow Water

20

40

60

80

10010% 20% 30% 40%

So

il D

ep

th (

cm

)

= VWC

Strip tillStrip till Conventional tillConventional till Conventional tillConventional tillStrip tillStrip tillHigh WaterHigh Water

Pea

nu

tP

ean

ut

0

1

2

3

4

5

68 73 78 83 88 93 98 103 108 113 118 123

Daily Water UseDaily Water Use24

Hou

r W

ater

Flo

w24

Hou

r W

ater

Flo

w

0

5

10

15

20

25

70 80 90 100 110

Days After Planting

Strip TillStrip Till

Conventional TillConventional Till

Co

tto

nC

ott

on



0

20

40

60

80

100

120

140

160

132 134 136 138 140 142 145 147 150 155 158 160 162

0

20

40

60

80

100

120

140

160Corn Water Use: Corn Water Use: Low Low

WaterWaterS

ap F

low

(g

/h)

Sap

Flo

w (

g/h

)

Day of YearDay of Year

STST

CTCT

0

20

40

60

80

100

120

140

160

132 134 136 138 140 142 145 147 150 155 158 160 162

0

20

40

60

80

100

120

140

160Corn Water Use: Corn Water Use: High High

WaterWaterS

ap F

low

(g

/h)

Sap

Flo

w (

g/h

)

Day of YearDay of Year

STST

CTCT

Water Use StrategiesWater Use Strategies

20

40

60

80

100

STST CTCT STST CTCT

Low Water:Low Water: Strip TillageStrip Tillage

Greater moisture stratification

Lower water contents at 60 cm depth (high root mass)

Greater root signalling → stomatal closure, lower water use

High Water:High Water: Strip TillageStrip Tillage

Moisture stratification lessened

Higher water contents at 60 cm depth (high root mass)

Lower root signalling → water use higher or equal to CTCT

0

50

100

150

200

Irrigation Level

bu/A *

Strip TillageStrip Tillage Conventional TillageConventional Tillage

Corn Yield 2006Corn Yield 2006

High WaterHigh Water Low WaterLow Water

Greater water-use Greater water-use efficiencyefficiency

Cotton yields2002-2006

0

200

400

600

800

1000

1200

1400

0 33 66 100

Irrigation amt (% of recommended)

Lin

t yie

ld (

lb/a

cre

)

conventional strip-tillage no-tillage

Peanut yields2002-2006

2000

2400

2800

3200

3600

4000

4400

0 33 66 100

Irrigation amount (% of recommended)

Nu

t y

ield

(lb

/ac

re)


Corn yields2003-2006

0

50

100

150

200

250

0 33 66 100

Irrigation amt (% of recommended)

Gra

in y

ield

(b

u/a

cre

)


MytH #2: nutrients MytH #2: nutrients are less available to are less available to

the crop in the crop in conservation tillage conservation tillage

MytH #2: nutrients MytH #2: nutrients are less available to are less available to

the crop in the crop in conservation tillage conservation tillage

Nitrogen & Potassium availability

0

50

100

150

200

250

300

350

400

450

conv notill striptill

Tillage

Nit

rate

N (

ug

/10c

m2 )

0

50

100

150

200

250

300

350

Po

tass

ium

(u

g/1

0cm

2 )

NO3--N mayNO3--N juneK mayK june

Calcium availability4” pegging zone

0

500

1000

1500

2000

2500

3000

0 33 66 100

Irrigation (% of recommended)

Cal

ciu

m (

ug

/10c

m2 )

conventional tillage no-till strip tillage

MytH #3: the cover MytH #3: the cover crop interferes with crop interferes with root growth of the root growth of the

cropcrop

MytH #3: the cover MytH #3: the cover crop interferes with crop interferes with root growth of the root growth of the

cropcrop

Root Dynamics: Root Dynamics: RhizotronsRhizotrons

Root Image Root Image AnalysisAnalysis

Root Length

Surface Area

Root Diameter

Volume

Number of Root Tips

Size Classification

020406080

100120

0.0 9.5 19.1 28.6 38.2 47.7 57.3 66.8 76.4 85.9

To

tal

Ro

ot

Len

gth

(cm

)

Soil Depth (cm)


Strip TillStrip TillCover Crop Rooting

Pattern

May 11May 11

4 4 inchesinches

12 12 inchesinches

20 20 inchesinches

27 27 inchesinches

33 33 inchesinches

Root Length - Root Length - PeanutsPeanuts

020406080

100120

0.0 11.5 21.0 30.5 40.1 49.6 59.2 68.7 78.3 87.8

To

tal

Ro

ot

Len

gth

(cm

)

Soil Depth (cm)



July 9July 9Large

concentration of roots at 30-55 cm

(12-22 in) depths in ST – follows cover

crop pattern

4 4 inchesinches

12 12 inchesinches

20 20 inchesinches

27 27 inchesinches

33 33 inchesinches

Root Length - Root Length - PeanutsPeanuts

MytH #4: the cover MytH #4: the cover crop interferes with crop interferes with peanut reproductionpeanut reproduction

MytH #4: the cover MytH #4: the cover crop interferes with crop interferes with peanut reproductionpeanut reproduction

0

100

200

300

400

500

600

06/07/2004 06/14/2004 06/21/2004 06/28/2004 07/05/2004 07/12/2004

0

100

200

300

400

500

600

700

06/08/2005 06/13/2005 06/17/2005 06/22/2005 06/27/2005 07/01/2005 07/06/2005

FloweringFloweringC

um

ula

tive

# F

low

ers


Date

20042004

20052005

4

5

6

7

8

9

10

11

12

6/11/2004 6/18/2004 6/25/2004 7/2/2004

Date

Day

s fr

om

Flo

wer

to P

egPeg Formation Peg Formation EfficiencyEfficiency


Tagged individual flowers in the field and Tagged individual flowers in the field and monitored until development of pegmonitored until development of peg

20042004

0

10

20

30

40

50

6/8/2005 6/15/2005 6/22/2005 6/29/2005 7/6/2005

Date

PeggingPegging

20052005


# P

egs

per

Pla

nt

010

203040

5060

6/1 7/1 8/1 9/1

Date

Pod Pod Number Number Strip Tillage, 2004Strip Tillage, 2004 Conventional Tillage, 2004Conventional Tillage, 2004

Strip Tillage, 2005Strip Tillage, 2005 Conventional Tillage, 2005Conventional Tillage, 2005

# P

ods

per

Pla

nt

0

500

1000

1500

2000

2500

3000

3500

4000

4500

Peanut Peanut YieldYieldStrip TillageStrip Tillage Conventional TillageConventional Tillage

20032003 20042004 20052005

Yie

ld (

lbs

/ A

cre)

0

24

68

10

1214

1618

20

6/20

/200

6

6/27

/200

6

7/4/

2006

7/11

/200

6

7/18

/200

6

7/25

/200

6

8/1/

2006

Sample Date

Mea

n #

Flo

wer

s/P

lan

t2006 2006 FlowersFlowersStrip TillageStrip Tillage Conventional TillageConventional TillageNo TillNo Till

0

5

10

15

20

25

30

35

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/200

6

6/27

/200

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2006

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/200

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7/18

/200

6

7/25

/200

6

8/1/

2006

Sample Date

Mea

n #

Peg

s/P

lan

t2006 Pegs2006 Pegs

Strip TillageStrip Tillage Conventional TillageConventional TillageNo TillNo Till

0

2

4

6

8

10

12

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16

18

6/20

/200

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/200

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7/4/

2006

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/200

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7/18

/200

6

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/200

6

8/1/

2006

Sample Date

Mea

n #

Po

ds/

Pla

nt

2006 Pods2006 Pods


MytH #5: aflatoxin is MytH #5: aflatoxin is increased in increased in

conservation tillage conservation tillage peanutspeanuts

MytH #5: aflatoxin is MytH #5: aflatoxin is increased in increased in

conservation tillage conservation tillage peanutspeanuts

0

200

400

600

800

1000

1200

1400

1600

Tillage

Tota

l Afla

toxi

n (p

pb)

Aflatoxin ContaminationAflatoxin Contamination


MytH #6: TSWV is MytH #6: TSWV is increased in increased in

conservation tillageconservation tillage

MytH #6: TSWV is MytH #6: TSWV is increased in increased in


0

10

20

30

40

50

60

60 120

Sampling Date (DAP)

TS

WV

Per

cen

t In

fect

ion

Conventional

Strip

Tillage Tillage Effect: Viral Effect: Viral InfectionInfection

0

10

20

30

40

50

60

70

80

90

Cultivar

TS

WV

Perc

en

t In

fecti

on


Tillage Effect X Tillage Effect X CultivarCultivar

GA-02CGA-02C AP3AP3 GGGG GA-02CGA-02C AP3AP3 GGGG

Percent Percent STST TSWV reduction:TSWV reduction:

GA-02C GA-02C 41%41%

AP3 AP3 62%62%

GGGG 45%45%

0

10

20

30

40

50

60

70

80

90

TS

WV

Per

cen

t In

fect

ion

ControlControlThimetThimetThimet+ProlineThimet+ProlineTemikTemik

Cultivar X Cultivar X InsecticideInsecticide

Cultivar

Compared to control…Compared to control…

GA-02CGA-02C AP3AP3 GGGG

2000

2200

2400

2600

2800

3000

3200

3400

3600

3800

0 10 20 30 40 50 60 70

2000

2200

2400

2600

2800

3000

3200

3400

0 10 20 30 40 50 60

1600

1800

2000

2200

2400

2600

2800

3000

3200

3400

0 20 40 60 80 100

GA-02CGA-02C

AP-3AP-3

Georgia Georgia GreenGreen

Yie

ld (

lbs/

Ac)

Yie

ld (

lbs/

Ac)

ThimetThimet

TemikTemik

ControlControl

Yield vs. Yield vs. InfectioInfectionn

Percent TSWV Infection

0

10

20

30

40

50

60

70

80

Insecticide Treatment

TS

WV

Pe

rce

nt

Infe

cti

on

ControlControlThimetThimetThimet+ProlineThimet+ProlineTemikTemik

Strip TillageStrip TillageConventional TillageConventional Tillage

Tillage X Tillage X InsecticideInsecticide


ControlControl 60%60%

ProlineProline 64%64%

TemikTemik 25%25%

ThimetThimet 48%48%


ControlControl 60%60%

ProlineProline 64%64%

TemikTemik 25%25%

ThimetThimet 48%48%

0

500

1000

1500

2000

2500

3000

3500

Conventional Strip-till No-till

Yie

ld (

lbs

/ac

re)

62

63

64

65

66

67

68

69

70

71

72

Gra

de

(%

tsm

k)

YieldGrade

2005 peanut yield + grade

Conservation systems:

+583 lbs yield**

+5.5% tsmk**

MytH #7: it’s more MytH #7: it’s more expensive to use expensive to use


MytH #7: it’s more MytH #7: it’s more expensive to use expensive to use


($37.47)

$47.55

$54.54

($60.00)

($40.00)

($20.00)

$0.00

$20.00

$40.00

$60.00


Re

turn

s (

$/a

cre

)Average net return

4-year summary

How we calculated this value:

•Detailed records of all inputs

•Budgets specific for every input

•4 years * 3 crops/year * 3 replications

($150.00)

($100.00)

($50.00)

$0.00

$50.00

$100.00

$150.00

$200.00

Re

turn

($

/ac

re)

0 33 66 100

Irrigation level

conventional till strip till no-till

Average net return4-year summary

MytH #8: MytH #8: Conservation tillage Conservation tillage promotes digging promotes digging losses in peanutlosses in peanut

MytH #8: MytH #8: Conservation tillage Conservation tillage promotes digging promotes digging losses in peanutlosses in peanut

Peanut digging loss

0

200

400

600

800

1000

1200

0 33 66 100

Irrigation level (% of recommended)

Dig

gin

g lo

ss (

lb/a

cre)

conv strip notill

Dry soil

Moist soil

MytH #9: peanut MytH #9: peanut maturity is slower in maturity is slower in conservation tillageconservation tillage

MytH #9: peanut MytH #9: peanut maturity is slower in maturity is slower in conservation tillageconservation tillage

Peanut maturity by tillageDawson, GA 2005

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

White Yellow 1 Yellow 2 Orange Brown Black

Pe

rce

nt

of

tota

l po

ds

No till Conventional tillage Strip tillage

Peanut grades are a good indicator of maturity

62

63

64

65

66

67

68

69

70

71

72


Gra

de

(% ts

mk)

+ 5 %

Indicates more uniform pod set

The Big Gamble: when to The Big Gamble: when to dig dig Current Method (Williams and Drexler, 1981):Current Method (Williams and Drexler, 1981):

Class according to mesocarp color and predict days to diggingClass according to mesocarp color and predict days to digging

Developed Maturity Indices to Predict Grade and Yield

Degree Day Degree Day Predictions Predictions

Degree Day Method:Degree Day Method:

(ATmax + ATmin)(ATmax + ATmin) - 13.3 - 13.3

22

0.0

0.2

0.4

0.6

0.8

1.0

1200 1300 1400 1500 1600 1700 1800 1900

Cumulative Degree Days

Ma

turi

ty In

de

x

Best Predictor of Yield and Grade:

#Black Pods#Black Pods + #Brown #Brown PodsPods Total Pods Placed on Total Pods Placed on

BoardBoard

= Maturity Index= Maturity Index+ Cumulative

Water Received 92% accuracy

+ Cumulative Water Received 92% accuracy

Nutrient predictor Nutrient predictor modelmodel

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 1 2 3 4 5 6 7 8

Harvest = MaturityHarvest = Maturity

Lea

f N

utr

ien

t In

dex

Lea

f N

utr

ien

t In

dex

RR22 = 0.96 = 0.96

Leaf nutrient analysis Leaf nutrient analysis at 100, 130, listed max at 100, 130, listed max

maturity for variety maturity for variety DAPDAP

MytH #10: MytH #10: conservation tillage conservation tillage is not essential to is not essential to

long-term long-term sustainabilitysustainability

MytH #10: MytH #10: conservation tillage conservation tillage is not essential to is not essential to

long-term long-term sustainabilitysustainability

On-farm fuel production with On-farm fuel production with peanutspeanuts

• Low-cost of production– Varieties that

respond well to heavy disease pressure

• High oil output per acre

• Carbon recycling in soil

• Using less to get MORE!

What if you could…..What if you could…..

• Grow 100 acres of peanuts and generate Grow 100 acres of peanuts and generate enough fuel for 1,000 acresenough fuel for 1,000 acres

• Increase soil organic matter and carbon Increase soil organic matter and carbon content (and get paid for it!!)content (and get paid for it!!)

• Make the same or better cropsMake the same or better crops

• Decrease irrigation withdrawalsDecrease irrigation withdrawals

ALL AT THE SAME TIMEALL AT THE SAME TIME

uncovering the facts and fiction about conservation tillage systems

Documents

diane rowlandusdaars

shallow depth

boll fillstrip

deeper rooting

better infiltration