Building Soil Quality with No-Till, Crop Rotations & Cover Crops

Building Soil Quality with No-Till, Crop Rotations & Cover Crops

$$$$$$$$

D. Wayne ReevesJ. Phil Campbell Sr. Natural Resource Conservation Center

D. Wayne ReevesJ. Phil Campbell Sr. Natural Resource Conservation Center

“Soil degradation prevents the full

use of the soil resource to meet

human needs and impacts

ecosystem functions.”

“Soil degradation prevents the full

use of the soil resource to meet

human needs and impacts

ecosystem functions.”USDA-ARS Soil Resource Management National Program USDA-ARS Soil Resource Management National Program

“Agricultural mismanagement is the

most important causative factor of

soil degradation . . . . .”

“Agricultural mismanagement is the

most important causative factor of

soil degradation . . . . .”

Oldeman, 1994United Nations Environment Programme (UNEP), Global Assessment of Soil Degradtion (GlASOD)

Oldeman, 1994United Nations Environment Programme (UNEP), Global Assessment of Soil Degradtion (GlASOD)

“Perhaps the most dominant soil degradative processes are soil erosion and organic matter decline.”

“Perhaps the most dominant soil degradative processes are soil erosion and organic matter decline.” B.A. Stewart, R. Lal, and S.A. El-Swaify. Sustaining

the Resource Base of an Expanding World Agriculture.In: Soil Management for Sustainability. R. Lal and F.J. Pierce (eds.), 1991.

Soil Quality is the Converse of Degradation

Soil Quality is the Converse of Degradation

Environmental QualityEnvironmental Quality

Agricultural ProductivityAgricultural Productivity

Soil QualitySoil Quality

Health/HabitationHealth/Habitation

Soil c web

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

Total Organic C and N

Total Organic C and N

InfiltrationInfiltration

SoilSoilStrengthStrength

BulkBulkDensit

yDensity

WaterWater

contentcontent

retentionretention

capacitycapacity

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

SoilSoilRespirationRespiration

NN

Biomass CBiomass Cto TOC ratioto TOC ratio

RespirationRespirationto Biomass ratioto Biomass ratio

mineralizedmineralized CCCCAggregate Aggregate StabilityStability

Soil C is basis of Soil Quality/ProductivitySoil C is basis of Soil Quality/Productivity

Soil c web

SOM=SOC (x2)SOM=SOC (x2)SOM=SOC (x2)SOM=SOC (x2)

Soil C is the basis of Agricultural Sustainability . . . .Soil C is the basis of Agricultural Sustainability . . . .

Sandor and Eash, 1991Sandor and Eash, 1991

Evidence for Sustainability: SOM from ancient agricultural

sites

Evidence for Sustainability: SOM from ancient agricultural

sites

New Mexico1000-1150 ADNew Mexico

1000-1150 AD

Peru400 AD-present

Peru400 AD-present

continuous corncontinuous corn

diverse rotations, green & animal manures

diverse rotations, green & animal manures

Sandor and Eash, 1991Sandor and Eash, 1991

SO

M (

%)

SO

M (

%)

Evidence for Sustainability: SOM from ancient agricultural

sites

Evidence for Sustainability: SOM from ancient agricultural

sites

New Mexico1000-1150 ADNew Mexico

1000-1150 AD

00

44

33

22

11

Peru400 AD-present

Peru400 AD-present

Continuous CornContinuous Corn Rotation+Manures

Rotation+Manures

CultivatedCultivatedUncultivatedUncultivated

Conservation Tillage!Conservation Tillage!

How to increase soil C and improve soil quality?How to increase soil C and improve soil quality?

Compass loamy sand

Compass loamy sand

Dep

th (

cm)

Dep

th (

cm)

00

55

2020

1515

1010

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

No-TillNo-Till

ConventionalConventional

Tillage impact on SOM after 10 y on a sandy soilTillage impact on SOM after 10 y on a sandy soil

GA corn erosion pic Conservation tillage alone does Conservation tillage alone does notnot work !work !Conservation tillage alone does Conservation tillage alone does notnot work !work !

Attitude adjustment

Attitude Adjustment . . . Attitude Adjustment . . . Soil C and crop residuesSoil C and crop residues are the key to making are the key to making conservation tillage work. It’s not conservation tillage work. It’s not “the lack of “the lack of tillage”tillage” but the production & conservation of crop but the production & conservation of crop residues which offers the most benefit to residues which offers the most benefit to productivity.productivity.

Attitude Adjustment . . . Attitude Adjustment . . . Soil C and crop residuesSoil C and crop residues are the key to making are the key to making conservation tillage work. It’s not conservation tillage work. It’s not “the lack of “the lack of tillage”tillage” but the production & conservation of crop but the production & conservation of crop residues which offers the most benefit to residues which offers the most benefit to productivity.productivity.

USAUSA

(%)

Ad

opti

on

(%)

Ad

opti

on

00BrazilBrazil ArgentinaArgentina ParaguayParaguay

Derpsch, 2004Derpsch, 2004

2020

4040

6060

Brazilian Model . . .Brazilian Model . . .

HotHot

CoolCool DryDryWetWet

Need

for

Resi

du

eN

eed

for

Resi

du

e

Need for crop residues to sustain soil resource as affected by climate.Need for crop residues to sustain soil resource as affected by climate.

Conservation tillage – key component . . .

cover crops/residue

Conservation tillage – key component . . .

cover crops/residue

Effect of cover crop on SOM in no-till corn after 5 years . . .Effect of cover crop on SOM in no-till corn after 5 years . . .

Reeves and Wood, 1994Reeves and Wood, 1994

Dep

th (

cm)

Dep

th (

cm) 0-30-3

6-126-12

3-63-6

SOM (%)SOM (%)

0.50.5 1.51.5 2.52.5 3.53.5

clovercloverfallowfallow

Effect of tillage/rye cover crop on SOM after 5 yEffect of tillage/rye cover crop on SOM after 5 yD

ep

th (

cm)

Dep

th (

cm)

00

55

2020

1515

1010

2525Decatur silt loamDecatur silt loam

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

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

-Will Rogers, ca. -Will Rogers, ca. 19311931

-Will Rogers, ca. -Will Rogers, ca. 19311931

““Here is my Farm Relief Bill: Every time a Here is my Farm Relief Bill: Every time a Southerner plants nothing on his farm but Southerner plants nothing on his farm but cotton year after year, and the Northerner cotton year after year, and the Northerner

nothing but wheat or corn, why, take a nothing but wheat or corn, why, take a hammer and hit him twice right between the hammer and hit him twice right between the eyes. You may dent your hammer, but it will eyes. You may dent your hammer, but it will do more real good than all the bills you can do more real good than all the bills you can

pass in a year.”pass in a year.”

““Here is my Farm Relief Bill: Every time a Here is my Farm Relief Bill: Every time a Southerner plants nothing on his farm but Southerner plants nothing on his farm but cotton year after year, and the Northerner cotton year after year, and the Northerner

nothing but wheat or corn, why, take a nothing but wheat or corn, why, take a hammer and hit him twice right between the hammer and hit him twice right between the eyes. You may dent your hammer, but it will eyes. You may dent your hammer, but it will do more real good than all the bills you can do more real good than all the bills you can

pass in a year.”pass in a year.”

Crop RotationCrop Rotation

No legume/no N (1, 6) Winter legumes (2,3, 8) 120 lbs. N/acre/yr (13)

Cotton every year

Cotton-corn rotation Winter legume (4,7)

Winter legume + 120 lbs. N/acre/yr (5,9)

3-year rotation

Cotton (legumes)-Corn (small grain for grain)soybean (10,11,12)

Old Rotation ExperimentOld Rotation Experiment

250250250250

100100100100

0000

Yie

ld In

crease

(%

)Yie

ld In

crease

(%

)Yie

ld In

crease

(%

)Yie

ld In

crease

(%

)

200200200200

50505050

CotCotCotCotCot(Leg) Cot(Leg) Cot(Leg) Cot(Leg)

Cot/Corn (Leg)Cot/Corn (Leg)Cot/Corn (Leg)Cot/Corn (Leg)Cot/Corn (Leg+134 kg Cot/Corn (Leg+134 kg N/ha/yr)N/ha/yr)Cot/Corn (Leg+134 kg Cot/Corn (Leg+134 kg N/ha/yr)N/ha/yr)

150150150150

1986-19951986-19951986-19951986-1995

““Old Rotation” cotton yield increase from Old Rotation” cotton yield increase from first ten years (1896-1905) first ten years (1896-1905)

““Old Rotation” cotton yield increase from Old Rotation” cotton yield increase from first ten years (1896-1905) first ten years (1896-1905)

1996-20051996-20051996-20051996-2005

400400400400

200200200200

Yie

ld In

crease

(%

)Yie

ld In

crease

(%

)Yie

ld In

crease

(%

)Yie

ld In

crease

(%

)

600600600600

300300300300

500500500500 1986-19951986-19951986-19951986-1995

Corn/Cot (Leg)Corn/Cot (Leg)Corn/Cot (Leg)Corn/Cot (Leg)

Cot/Corn (Leg +134 kg Cot/Corn (Leg +134 kg N/ha/yr)N/ha/yr)Cot/Corn (Leg +134 kg Cot/Corn (Leg +134 kg N/ha/yr)N/ha/yr)Cot/Corn/Wht-Soy (Leg +60 kg N/ha on wheat)Cot/Corn/Wht-Soy (Leg +60 kg N/ha on wheat)Cot/Corn/Wht-Soy (Leg +60 kg N/ha on wheat)Cot/Corn/Wht-Soy (Leg +60 kg N/ha on wheat)

1996-20051996-20051996-20051996-2005

““Old Rotation” corn yield increase from Old Rotation” corn yield increase from first ten years (1896-1905) first ten years (1896-1905)

““Old Rotation” corn yield increase from Old Rotation” corn yield increase from first ten years (1896-1905) first ten years (1896-1905)

Conservation Tillage-constraints…Cooler, Wetter Soils

Conservation Tillage-constraints…Cooler, Wetter Soils

MAY 1

65 oF @ 8:00 a.m.

Manage constraints . . .Manage constraints . . .

50 DD60’s

50 DD60’s

MAY

50 -55 oF @ 8:00 a.m.

Manage constraints . . .Manage constraints . . .

2800 GDD

2800 GDD

Conservation Tillage-constraints…Poor Seed-Soil Contact

Conservation Tillage-constraints…Poor Seed-Soil Contact

Conservation Tillage-constraints…Soil Compaction/Crusting

Conservation Tillage-constraints…Soil Compaction/Crusting

Manage compaction . . .Manage compaction . . .

Manage residue . . . Manage residue . . .

Manage compaction . . .Manage compaction . . .Non-Inversion TillageNon-Inversion Tillage

Timing Non-inversion TillageTiming Non-inversion Tillage

Conservation tillage – key components . . .

Manage soil compaction

Conservation tillage – key components . . .

Manage soil compaction

Cover Crops/ ResidueCover Crops/ ResidueCover Crops/ ResidueCover Crops/ Residue

Conservation tillage – key components . . .

Manage soil compaction

Conservation tillage – key components . . .

Manage soil compaction

No Cover Crop or Rotation !No Cover Crop or Rotation !

Conventional TillageConventional Tillage

No-Till w/o Cover CropNo-Till w/o Cover Crop

No-Till with Cover CropNo-Till with Cover Crop

No-Till with Cover Crop and Fall ParatillingNo-Till with Cover Crop and Fall Paratilling

Agricultural ProductivityAgricultural Productivity

Health/HabitationHealth/Habitation

Environmental QualityEnvironmental Quality

Soil QualitySoil Quality

Tillage negates cropping system effects!

Tillage negates cropping system effects!

Effect of cropping/tillage systemon SOC (0-15 cm) from an eroded UltisolEffect of cropping/tillage systemon SOC (0-15 cm) from an eroded Ultisol

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

Soil

Carb

on

(g

kg

–1)

Soil

Carb

on (

g k

g –1

)

55

1010

3030

2525

2020

1515

19841984 19861986 19881988 19901990

Year Year

conversion to conventional till soybean

conversion to conventional till soybean

Grain sorghum no-till intocrimson cloverGrain sorghum no-till intocrimson clover

No-tillageNo-tillage Conventional tillageConventional tillage

Top 2-cm of soil after 6 y of corn-soybean with clover cover cropTop 2-cm of soil after 6 y of corn-soybean with clover cover crop

Water is key picsWater is THETHE key!Water is THETHE key!

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Surface soil effects pic Residues/Soil C: Surface soil effects are most critical

Residues/Soil C: Surface soil effects are most critical

Rainfall sim pic lead-in

Rainfall Simulation Study . . . Rainfall Simulation Study . . .

Tillage Systems 12 yr old Tillage Systems 12 yr old

+/- residue removed+/- residue removed

Rain

fall

(%)

Rain

fall

(%)

100100

8080

00

6060

4040

2020

No Till w/ residue

No Till w/ residue

No Till w/o residue

No Till w/o residue

ConventionalTillage

ConventionalTillage

Tillage and residue effects on infiltration of a Coastal Plain Soil (50-mm rain event)Tillage and residue effects on infiltration of a Coastal Plain Soil (50-mm rain event)

3 days3 days

11 days11 days

6 days6 days

Conservation Tillage Systems are Site-Specific. . . ..

Conservation Tillage Systems are Site-Specific. . . ..

Limestone Valleys – Clay SoilsLimestone Valleys – Clay Soils

Coastal Plain – Sandy SoilsCoastal Plain – Sandy Soils

Conservation Tillage Systems are Site-Specific. . . ..

Conservation Tillage Systems are Site-Specific. . . ..

The Future: Site Specific Soil Management

The Future: Site Specific Soil Management

GPS Guidance SystemGPS Guidance System

Electrical Conductivity MapElectrical Conductivity Map

-85.8995-85.8995 -85.899-85.899 -85.8985-85.8985 -85.898-85.898 -85.8975-85.8975 -85.897-85.897 -85.8965-85.8965 -85.896-85.896 -85.8955-85.8955

32.424532.4245

22 44 55..55 77 88..55

32.424032.4240

32.423532.4235

32.423032.4230

32.422532.4225

32.422032.4220

32.421532.4215

No-tillage improves degraded soils andreduces spatial and temporal yield variablilityNo-tillage improves degraded soils andreduces spatial and temporal yield variablility

Conservation Tillage

Conservation Tillage

Conventional TillageConventional Tillage

(+16%)(+16%)

(+11%)(+11%)

Conclusions…Conclusions…

Soil degradation is the problem . . .Soil degradation is the problem . . .

Conservation tillage by itself cannot solve the problem of soil degradation . . .

Conservation tillage by itself cannot solve the problem of soil degradation . . .

Conclusions…Conclusions…

Conclusions…Conclusions…

Soil degradation is the problem . . . Soil degradation is the problem . . .

Residue production and conservation is the solutionResidue production and conservation is the solution

Conclusions…Conclusions…

Soil degradation is the problem . . . .Soil degradation is the problem . . . .Residue

production . . . . Residue

production . . . . Conservation tillage and cropping intensity are

the means to the solution

Conservation tillage and cropping intensity are

the means to the solution

“It is not the stronger of the

species that survives, nor the

most intelligent, but the one most

responsive to change.”

“It is not the stronger of the

species that survives, nor the

most intelligent, but the one most

responsive to change.”

Charles DarwinCharles Darwin