How Does Farmland
Sequester Carbon?
Ron Follett
Agriculture Research
Service/USDA
Topics
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What is carbon sequestration?
How does it occur?
Where in the soil does it occur?
The Virginia Experience
How much can occur?
Maintaining important soil properties?
Carbon sequestration strategies.
Summary.
„
Carbon sequestration
refers to the long-term
storage of carbon in the
terrestrial biosphere,
underground, or the
oceans so that buildup of
carbon dioxide (the
principal greenhouse
gas) concentration in the
atmosphere will reduce
or slow. In some cases,
this is accomplished by
maintaining or
enhancing natural
processes; in other
cases, novel techniques
are developed to dispose
of carbon.
„
*US Dept. of Energy
Climate
energy
Soils
CO2
product
Soil organic matter
Management
Left to right:
1.Narrow-leaf 4o’clock
2. Prairie false
bonnet
1
Depth
m
3. Blue Grama
4. Globemallow
1
5. Psoralea tenuiflora
6. Sideranthus
2
7. Buffalo grass.
8. Ragweed
9. Skeleton weed
3
2
3
5
8
6
4
7
9
Topics
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What is carbon sequestration?
How does it occur?
Where in the soil does it occur?
The Virginia Experience
How much can occur?
Maintaining important soil properties?
Carbon sequestration strategies.
Summary.
Kevin Swanson’s & neighbor’s:
Farms near Overton, NE
0
Cropped sites
Soil Profile Depth (cm)
-20
Native sites
-40
-60
-80
Mass of SOC with depth across 30 - paired US sites
-100
5000
10000
15000
20000
25000
30000
Soil Organic Carbon (kg ha-1)
35000
4000
Topics
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What is carbon sequestration?
How does it occur?
Where in the soil does it occur?
The Virginia Experience
How much can occur?
Maintaining important soil properties?
Carbon sequestration strategies.
Summary.
Richmond
Hurricane Floyd (1999)
• 500 year storm event
• 457 mm (18 in) rainfall in < 24 hours
Observations about Continuous Never-till by Farmers:
• No Gully formation (on 7 to 9 % slopes)
• Concentrated water flow minimal
• Minimum sediment movement to streams
Farmer originated research on wheat-corn
rotations under no-till, near Richmond, VA:
The issues:
Soil erosion
Water Runoff
Nutrients
Headsmut in wheat
Colonial Soil & Water Conservation District
Quinton, Virginia
Innovative
Cropping
System
Improving Water Quality
One Acre At A Time
Renwood Farm, VA – Data by cropping
system – 7.5% slope, 5 year storm event.
Runoff
Treatment
Sediment
M3 ha-1
N
P
Kg ha-1
Plow+fert
4550
3560
10
4
No-till+litter
1080
34
0.60
0.42
No-till
1410
21
0.55
0.30
No-till (subsoil)+fert
1075
6
0.53
0.29
No-till+fert
960
18
0.52
0.28
Ave reduction by no-till
(%)
74.9
98.2
94.7
92.0
DAYCENT Historical Simulations
35000
Historical SOC - Tilled Sites no sludge
30000
Altavista
Kempsville/Emporia
Bojac
kgC ha
-1
25000
20000
15000
10000
5000
1750
native
Vegetation
1800
1850
1900
cotton cropping
1950
2000
Corn/soy
cropping
DAYCENT Model Projections
50,000
Kempsville/Emporia - SOC
45,000
kgC ha
-1
40,000
35,000
conventional till
conservation till
never till
observed conservation till
observed never till
30,000
25,000
20,000
15,000
1989
2004
2040
Topics
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What is carbon sequestration?
How does it occur?
Where in the soil does it occur?
The Virginia Experience
How much can occur?
Maintaining important soil properties?
Carbon sequestration strategies.
Summary.
On-Farm Research
Lessons being learned:
Changes in SOM over time under a complete notill system in Central Illinois. (From Kinsella, 2002)
4
3.5
% SOM
3
2.5
2
1.5
1
0.5
0
1974
1987
1990
1997
2000
No-till wheat & barley
Gordon Gallup Farm;
near Rarie, Idaho
1985 (begin no-till) Organic matter = 1.25%
2000 (cont. no-till) Organic matter = 2.6 to 3.25%
Topics
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What is carbon sequestration?
How does it occur?
Where in the soil does it occur?
The Virginia Experience
How much can occur?
Maintaining important soil properties?
Carbon sequestration strategies.
Summary.
Large-plot Research: Farmers
Controlled Tram Line (Bill Richard’s Farm, in OH)
Small-plot Research: Scientists
16
T im e in
M in u te s
14
12
10
8
6
4
2
0
Native
No-till
Conv-till
Time for 1 inch of water to infiltrate into the
soil, South Central Ohio.
Seconds
Single ring infiltration for 1 inch of
water in seconds (Idaho: May, 2003).
1800
1600
1400
1200
1000
800
600
400
200
0
Native
CRP
Infiltration
No-till
Conv-Till
On-Farm Research Lessons
Practices that sequester soil carbon, also:
• Decrease soil sediment losses
• Decrease farm chemical losses
• Decrease atmospheric particulates
• Decrease farm fuel requirements
• Decrease the impacts of dry years
• Require less drawbar horsepower
• May decrease fertilizer requirements
• Increase net profitability to farmers
Topics
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What is carbon sequestration?
How does it occur?
Where in the soil does it occur?
The Virginia Experience
How much can occur?
Maintaining important soil properties?
Carbon sequestration strategies.
Summary.
Soil C trajectories
agriculture
Shape?
Slope?
Soil carbon
Amount?
Characteristics?
Amount?
Influences?
Rate?
Initial
cultivation
Effect on:
Amount?
Stability?
Duration?
Location?
Types?
Reasons?
Agricultural production?
Energy consumption?
Agronomic decisions?
Management
change
Soil Organic Carbon Sequestration
Strategies for Cropland
• Conservation Tillage & Residue Management
• Cover Crops & Elimination of Fallow
• Crop Rotations
• Precision Farming & Integrated Nutrient Mgmt
• Conservation and Wetland Reserve Programs
(CRP/WRP)
• Water Conservation and Improved Irrigation Mgmt
• Soil Applications of Manures & Organic Wastes
Topics
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What is carbon sequestration?
How does it occur?
Where in the soil does it occur?
The Virginia Experience
How much can occur?
Maintaining important soil properties?
Carbon sequestration strategies.
Summary
Soil Organic
Carbon is Linked
to:
•Food Security
• Agricultural
Sustainability
• Improving
Degraded Soils
• Improving Nutrient
Use Efficiency
• Poverty Reduction
A Role for Agriculture
• Agriculture can be part of the solution
for environmental issues
• Agriculture can help mitigate the
greenhouse effect
• Enhanced soil, water, and air quality
and agricultural sustainability
result from increased soil carbon
sequestration
Thank you for your Attention
Questions ?