Download "Sequestering C in Soil"

R. Lal
Carbon Management and Sequestration Center
The Ohio State University
Columbus, OH 43210 USA
C-MASC 04-09
Biofuel offset?
Biota
620 Gt
MRT = 6Yr
1.6 + 0.8 Gt/yr
Deforestation
Atmosphere
120 + 2.0 Gt/yr (photosynth)
800 Gt
Plant respiration
60 + 1.6 Gt/yr
+4 Gt/yr
MRT = 5Yr 60 Gt/yr
Fossil fuel
Combustion & Cement manufacture
92.3 Gt/yr
90 Gt/yr
Soils
2,500 Gt (i) SOC - 1,550 Gt
(ii) SIC - 950 Gt
8 Gt/yr
0.6+0.2 Gt/yr
(Burial)
Fossil Fuels
4,130 Gt
(i) Coal: 3,510 Gt
(ii) Oil: 230 Gt
(iii) Gas: 140 Gt
(iv) Other: 250 Gt
Ocean
38,400 Gt + 2.3 Gt/yr
(i)  Surface layer: 670 Gt
(ii)  Deep layer: 36,730 Gt
(iii)  Total organic: 1,000 Gt
MRT = 25Yr
Lal, 2004
Mean Residence Time (MRT) = 400Yr
Organic C Pool (Pg C to 1-m depth)
Ecosystem
Total in world soils
Cropland soils
Range
Mean
% of
Total
Flux
(Pg C/yr)
1395-2011
1580
100
60
128-168
152
9.6
3
57%
Grassland/Savannas
279-559
425
26.9
26
Plantations
-
90
5.7
5
Forests
-
704
44.5
17
C-MASC 04-09
Farmers have custody of more environment
than does any other group.
. . . . Paarlberg (1980)
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There are numerous advantages:
1.  It is a familiar property,
2.  It involves direct measurement,
3.  It can be measured in 4 dimensions (length,
width, depth, time),
4.  It lends itself to repeated measurements over
the same site,
C-MASC 04-09
5. It is linked to ecosystem performance and
services,
6. It is a key driver of soil formation,
7. It is important to soil fertility,
8. It has memory,
9. It has well defined properties,
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10. It can be used in synergism with other
indicators,
11. Its uncertainty can be quantified,
12. Its pathways across the landscape can be
followed,
13. It is an important archive of paleoenvironmental conditions.
C-MASC 04-09
Innovative
Technology II
100
Subsistence
farming, none or
low off-farm input
soil degradation
New
equilibrium
80
Innovative
Technology I
Adoption of
RMPs
Maximum
Potential
Rate
ΔY
60
Attainable
Potential
ΔX
Accelerated erosion
40
20
0
20
40
60
80
100
120
140
160
Time (Yrs)
C-MASC
02-09
C-MASC 04-09
Lal, 2004
Historic Loss from Terrestrial Biosphere =
456 Gt with 4 Gt of C emission = 1 ppm of CO2
The Potential Sink of Terrestrial Biospheres = 114 ppm
Assuming that up to 50% can be resequestered = 45 – 55 ppm
Cropland Soils: 1 Gt/yr
Rangeland Soils: 1 Gt/yr
Restoration of Degraded/Desertified: 1 Gt/yr
Drawdown: 50 ppm of CO2 over 50 years
C-MASC 04/09
Soil Carbon Sequestration
Avoiding Emissions
Controlling
Erosion
Reducing CBased Input
Sequestering Carbon
Improving Energy
Efficiency
• Biofuels
Mulching
Creating Negative
C Emissions
Cover
cropping
Soil
Amendments
• Biochar
• Manure
• Zeolites
Creating Positive
Nutrient Budget
Biofertilizers
Chemical
Fertilizers
C-MASC 04/09
C Sequestration = C input > C output
C Depletion
= C input < C output
C output
C input
= Erosion, Decomposition,
leaching, Harvest
= Residues, Mulch, Compost,
Amendment, Deposition
C-MASC 04-09
C-MASC 04-09
1.  Physical: Aggregation, Illuviation
2.  Chemical: Humification, OrganoMineral complexation
3.  Biological: Recalcitration of SOM
C-MASC 04-09
According to hierarchical model, 3 different
classes of SOM are:
•  Persistent Pool: > 250 µm macro-aggregates
•  Transient Pool: 53-250 µm micro-aggregation
•  Temporary Pool: <52 µm silt and clay contents
Lal, 2004
C-MASC 04-09
Clay Crystals Forming
Clay Domain
Soil Organic Matter
Quartz
Quartz
Pore
Space
Carboxylated Polymer
SOIL ORGANIC MATTER AND AGGREGATION (Emerson, 1959)
15
1.4 x 10 g/yr
decomposition
and emission to
the atmosphere
15
1500 x 10 C
in world soil
15
3.99 x 10 g/yr
stored within the
terrestrial ecosystem
15
5.7 x 10 g/yr C
displaced due to erosion
15
Lal, 2003
0.57 x 10 g/yr
transported to
the ocean
World……
1.1 Pg C/y
USA……..
15 Tg C/y
Brazil……
60 Tg C/y
India……..
4.8 - 7.2 Tg C/y
Iceland…..
0.01-0.02 Tg C/y
(60-250 Tg C/1000 yr)
C-MASC 04-09
1.  Dynamic replacement of SOC at eroding sites and
decrease in decomposition at depositional sites.
2.  Deep burial of carbon.
3.  The magnitude of the sink range from 0.1-1 Pg/y
(Van Oost et al., 2007; Stallard, 1998; Smith et al., 2001).
C-MASC 04-09
C-MASC 4-09
A 10% substitution of petrol and diesel fuel
is estimated to require:
•  43% of the current cropland area (USA)
•  38% of the current cropland area (EU)
Which means forests and grasslands would
need to be cleared to enable production of
energy crops.
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1000-3500 L/L
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(Glasod, 1994)
Process
Area (106 ha)
% Total Land Area
Water Erosion
1094
8.4
Wind Erosion
549
4.2
Chemical Degradation
239
1.8
Physical Degradation
83
0.6
1965
15.0
Total
Total Earth’s Land Area = 13,069 Mha
C-MASC 04-09
Parameter
Value
Area degraded (106 ha)
3506
% of land area
23.5
Total NPP loss (Tg C/y)
955
Total Population affected (billion)
% Total Population
1.54
23.9
C-MASC 04-09
Region
Total Land
Used Land
Available Land
---------------Gha------------------Sub-Saharan Africa
1.05
0.157
0.893
South/Central America
0.98
0.147
0.833
Asia an Pacific
0.74
0.474
0.266
North America
0.43
0.232
0.158
Europe
0.32
0.202
0.118
North America
0.28
0.179
0.101
North Africa/Near East
0.04
0.04
0
World
3.82
1.452
2.368
Tropical Regions
= 1.99 Gha
Temperate Regions = 0.38 Gha
C sequestration through reclamation of salt affected soils in northern India
(Recalculated from Garg, 1998; Lal et al., 1998).
Sub-catchment
Carbon sequestration rate (Mg C ha-1y-1)
Low
High
Bingham River
3.8
5.2
Collie River Central East/James Well
3.8
5.2
Collie River East
3.3
4.4
Collie River South Branch
4.6
6.0
Harris river
8.5
11.5
Wellington Reservoir/
Collie River Central
6.6
9.0
SOC Concentration
0
10
Plow Till
No-Till
20
30
40
50
60
70
80
90
100
C-MASC 04-09
Parameter
Kg CE/ha
Conventional Till
No Till
1. Input
803
786
2. Output
6431
6688
-60
0
4. C Sequestration
-500
500
5. Net C output
5871
7188
7·3
9·1
3. Soil erosion
6. C Output : Input
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(Derpsh, 2007)
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Wet
High
Medium
Medium
Low
Moisture
Dry
Cool
Temperature
Hot
Technology
Temperate
Humid
Sub-Humid
Tropics
Arid
Humid
Sub-Humid
No-Till
Cover
Cropping
Manuring
Biochar
Agroforestry
Irrigation
INM
Improved
Pasture
C-MASC 04-09
Highlands
Arid
Humid
Sub-Humid
Arid
Clay
Technology
Poorly Drained
Well Drained
Silt
Erodible
Non-Erodible
No-Till
Cover
Cropping
Manuring
Biochar
Agroforestr
y
Irrigation
INM
Improved
Pasture
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Sandy Loam
Erodible
Droughty
Depends on many factors:
1. Baseline or reference point.
2. Clay content and type.
3. Antecedent SOC pool.
4. Residue management.
5. Internal drainage.
6. Soil wetness.
C-MASC 04-09
Zero Emission
Negative Emission
1. Reduces the rate of CO2 increase in 1.  Removes CO2 from the
the atmosphere
atmosphere
2. High cost
2. Cost effectiveness
3. MMV essential
3. Dangerous leakage cannot occur
4. Ancillary benefits (EOR, CBM)
4. Ecosystem services
5. Reduces energy efficiency by 15%
5. Essential to food security
C-MASC 04-09
Strategy
GHG Abatement (Euro/t CO2 E)
Tillage and Residue Management
- 50
Waste Recycling
- 15
Degraded Land Restoration
10
Second Generation Biofuels
5
Pastureland Afforestation
10
Degraded Forest Restoration
12
Agriculture Conversion
25
Biomass Co-firing Power Plant
30
Coal C Capture & Sequestration
45
Gas Plant Capture & Sequestration
60
C-MASC 04-09
Soil Organic Matter and
Food Security
Maintaining soil organic matter above the threshold (1.1%
SOC in the root zone) is critical to sustaining soil quality
because of the following:
– 
– 
– 
– 
– 
– 
– 
– 
– 
Improving soil structure
Controlling erosion
Increasing soil water holding capacity
Increasing nutrient reserves in soil
Improving use efficiency of input
Enhancing soil biotic activity
Strengthening nutrient recycling
Increasing crop yield
Improving nutritional quality of food
SUGGESTIONS FOR POLICY
MAKERS (SHORT-TERM 30 YRS)
If the objective to mitigate CO2 and global warming policy
makers may be better advised to focus on the following:
(i)  Increase the efficiency of fossil fuel use,
(ii)  Conserve the existing forest and savannahs,
(iii)  Restore natural forests and grasslands or croplands
that is not needed,
(iv) Restore soil C pool, and
(v) Trade C credits.
C-MASC 04-09
SUGGESTIONS FOR POLICY
MAKERS (LONG-TERM >50 YRS)
Non-C Fuel Technology
(H2)
C-MASC 04-09