# Presentation: 470676

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

## “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

## “Agricultural mismanagement is the most important causative factor of soil degradation . . . . .”

- Oldeman, 1994
- United 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

- Environmental Quality

- Health/Habitation

## Soil c web

*from Doran et al., 1993*

*from Doran et al., 1993*

*Total *
*Organic C and N*

*Infiltration*

*Soil*

*Strength*

*Bulk*

*Density*

*Size*

*Distribution*

***N***

*mineralized*

*C*

_*Soil C *_ is basis of Soil Quality/Productivity

## Soil c web

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

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

## Evidence for Sustainability:  

- Evidence for Sustainability:
- 	SOM from ancient agricultural sites

- New Mexico
- 1000-1150 AD

- Peru
- 400 AD-present

*continuous corn*

*diverse rotations, green &                                                                     **	**animal manures*

## SOM (%)

*Sandor and Eash, 1991*

- Evidence for Sustainability:
- 	SOM from ancient agricultural sites

- New Mexico
- 1000-1150 AD

- 0

- 4

- 3

- 2

- 1

- Peru
- 400 AD-present

*Continuous Corn*

*Rotation+Manures*

*Cultivated*

*Uncultivated*

## Conservation Tillage!

## Depth (cm)

- 0

- 5

- 20

- 15

- 10

- SOM (%)

- 0

- 1

- 2

- 3

- 4

- 5

- No-Till

- Conventional

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

## GA corn erosion pic

*Conservation tillage alone does *_*not*_* work !*

## Attitude adjustment

*Attitude adjustment*

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

## Brazilian Model . . .

- USA

- (%) Adoption

*0*

- Brazil

- Argentina

- Paraguay

*Derpsch, 2004*

*20*

*40*

*60*

## Slide 15

## “The virgin fertility of our soils and the vast amount of unskilled labor have been more of a curse than a blessing to agriculture.  This exhaustive system for cultivation, the destruction of forest, the rapid and almost constant decomposition of organic matter, have  made our agricultural problem one requiring more brains than that of the North, East or West.”

- “The virgin fertility of our soils and the vast amount of unskilled labor have been more of a curse than a blessing to agriculture.  This exhaustive system for cultivation, the destruction of forest, *the rapid and almost constant decomposition of organic matter, have  made our agricultural problem one requiring more brains than that of the North, East or West.*”

- George Washington Carver
*The Need of Scientific Agriculture in the South*

## Conservation tillage – key component . . .

- 	cover crops/residue

## Effect of cover crop on SOM in 

- no-till corn after 5 years . . .

- Reeves and Wood, 1994

- Depth (cm)

- 0-3

- 6-12

- 3-6

- SOM (%)

- 0.5

- 1.5

- 2.5

- 3.5

- clover

- fallow

## Depth (cm)

- Effect of tillage/rye cover crop on SOM after 5 y

- 0

- 5

- 20

- 15

- 10

- 25

*Decatur silt loam*

- SOM (%)

- 0

- 1

- 2

- 3

- 4

- 5

- No-Till w/o cover

- Conventional w/o cover

- No-Till w/ cover

- Fall Paratill w/ cover

## “Here is my Farm Relief Bill:  Every time a Southerner plants nothing on his farm but cotton year after year, and the Northerner nothing but wheat or corn, why, take a hammer and hit him twice right between the eyes.  You may dent your hammer, but it will do more real good than all the bills you can pass in a year.”

- -Will Rogers, ca. 1931

*“**Here is my Farm Relief Bill:  Every time a Southerner plants nothing on his farm but cotton year after year, and the Northerner nothing but wheat or corn, why, take a hammer and hit him twice right between the eyes.  You may dent your hammer, but it will do more real good than all the bills you can pass in a year.”*

## Old Rotation Experiment

**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” cotton yield increase from 

- 250

- 100

- 0

- Yield Increase (%)

- 200

- 50

*Cot*

*Cot(Leg) *

*Cot/Corn (Leg)*

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

- 150

- 1986-1995

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

## “Old Rotation” corn yield increase from 

- 400

- 200

- Yield Increase (%)

- 600

- 300

- 500

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

## Conservation Tillage-constraints...

- 	*Cooler, Wetter Soils*

## MAY 1

*MAY 1*

- 65 *o*F @ 8:00 a.m.

_*Manage constraints*_* . . .*

- 50 DD60’s

## MAY 

*MAY *

- 50 -55 *o*F @ 8:00 a.m.

_*Manage constraints*_* . . .*

- 2800 GDD

## Conservation Tillage-constraints...

- 	*Poor Seed-Soil Contact*

## Conservation Tillage-constraints...

- 	*Soil Compaction/Crusting*

## Manage compaction . . .

## Manage residue . . . 

- Manage residue . . .

## Manage compaction . . .

- Non-Inversion Tillage

## Timing Non-inversion Tillage

## No-tillage resists compactionby equipment

*No-tillage resists compaction**by equipment*

## Conservation tillage – key components . . .

- 	*Manage soil compaction*

- Cover Crops/ Residue

## Conservation tillage – key components . . .

- 	*Manage soil compaction*

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

## Conventional Tillage

## No-Till w/o Cover Crop

## No-Till with Cover Crop

## No-Till with Cover Crop and Fall Paratilling

- No-Till with Cover Crop and Fall Paratilling

## Soil Quality

- Agricultural Productivity

- Health/Habitation

- Environmental Quality

*Soil Quality*

## Effect of cropping/tillage system

- on SOC (0-15 cm) from an eroded Ultisol

*Bruce et al., 1995*

- Soil Carbon (g kg –1)

- 5

- 10

- 30

- 25

- 20

- 15

- 1984

- 1986

- 1988

- 1990

- Year

- conversion to
- conventional till
- soybean

*Grain sorghum no-till into*
*crimson clover*

## Top 2-cm of soil after 6 y of 

- No-tillage

- Conventional  tillage

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

## Water is key pics

- Water is ***THE***** **key*!*

## Surface soil effects pic

## Rainfall sim pic lead-in

- Rainfall Simulation Study . . .

*Tillage Systems 12 yr old *

*+/- residue removed*

## Rainfall (%)

- 100

- 80

- 0

- 60

- 40

- 20

- No Till
- w/ residue

- No Till
- w/o residue

- Conventional
- Tillage

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

*3 days*

*11 days*

*6 days*

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

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

## The Future: Site Specific Soil Management	

*GPS Guidance System*

## Electrical Conductivity Map

- -85.8995

- -85.899

- -85.8985

- -85.898

- -85.8975

- -85.897

- -85.8965

- -85.896

- -85.8955

- 32.4245

- 32.4240

- 32.4235

- 32.4230

- 32.4225

- 32.4220

- 32.4215

## No-tillage improves degraded soils andreduces spatial and temporal yield variablility

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

- Conservation Tillage

- Conventional Tillage

- (+16%)

- (+11%)

## Conclusions...

- Soil degradation is the problem . . .

## Conclusions...

## Conclusions...

- Soil degradation is the problem . . .

## Conclusions...

- Soil degradation is the problem . . . .

- Residue production . . . .

## “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 Darwin