Energy and Agricultural Carbon
Utilization Symposium
10-11 June, 2004 University of Georgia Athens, GA
Impacts of intensive agriculture
on soil carbon, crop productivity
and climate
by change.
D.C. Reicosky
Agricultural
Research
Service
"SOILS LAB"
* MORRIS
USDA-ARS-MWA
North Central Soil
Conservation Research
Laboratory Morris, MN
USA
Pyrolysis of agricultural biomass is a part of carbon
linkage and cycling in agricultural ecosystems.
Charcoal
Terra Preta
soils
Char
Soil
conditioners
Agricultural
crop
residues
Biological
nutrient
cycling
Integrated
energy
byproducts
Wood chips and
byproducts
Forest wood
residues
Microenvironment
for microbes
Energy source
for microbes and
fungi
Ammonium
carbonation for
fertilizer
We have only
one
Earth!
Environment
Agricultural Biomass Carbon
Economy
Energy
Carbon is the key linkage of the 3 E’s
3 Pillars of Conservation Agriculture!
Conservation Agriculture
minimum
soil tillage
crop rotations/
cover crops
Continuous
residue cover
Soil Organic Carbon
True Conservation Agriculture
is
carbon management.
Conservation agriculture provides beneficial ecosystem
services:
1. Food and fiber and biofuels
2. Less erosion, less pollution, clean water, fresh air,
healthy soil, natural fertility, higher production, carbon
credits, beautiful landscape, sustainability etc., etc.
……
Soil carbon is a priceless key to the planet’s
health and our environmental quality.
Conservation Agriculture is carbon
management. Conservation Agriculture
is good for a lot of reasons. Climate
change is just one of those reasons.
Global Perspective
Greenhouse Effect and
Global Climate Change
The role of agricultural
tillage and soil carbon
LIST OF GASES THAT CAUSE “GREENHOUSE EFFECT”
GREEN HOUSE GAS
PERCENT OF
GREENHOUSE
EFFECT
Carbon Dioxide
CO2
50
Methane
CH4
19
Chloroflourocarbons
CFC
15
Nitrous Oxide
N2O
5
Other (O3,H2O,NOx,CO,etc.)
Source: Bouwman, 1990; USEPA Report, 1990
11
Midwest USA
Long Term Effects of Crop Rotations
Soil Organic Carbon (%)
4
Morrow Plots: Illinois
Corn-Oats-Hay Rotation
Corn-Oats (1885-1953, Corn-Soybeans (1954-Present)
Continuous Corn
3
2
Estimated
to 4 % in 1888
Wagner (1989)
1
Sanborn Field: Missouri
0
1870
Wheat, 6 Tons Manure/year
Corn, 6 Tons Manure/year
Continuous Wheat
Continuous Corn
1890
1910
1930
Year
1950
1970
1990
Possible explanations for soil carbon decline.
1. Intensive tillage - moldboard plow and disk harrow.
2. Changing from perennial species (60 to 90 % of
biomass below ground) to annual agronomic species
(15 to 20 % of biomass below ground).
3. Increased organic matter mineralization as a result
of increased use of inorganic nitrogen fertilizers. (Lit.
cit. Green et al., 1995, SSSAJ 59:453-459.)
No. 1 Environmental Enemy
in Production Agriculture
Intensive Tillage
Carbon Cycle in Agriculture
Ph
CO2
sis
Re
sp
ir
the
yn
ati
on
s
oto
Soil
Organic
Matter
Crop
Biomass
Decomposition
Soil organic matter is a mixture of
residual plant material in various
stages of decomposition and microbial biomass
and all their bi-products.
The “key” component is:
C
Soil carbon is linked to all
measures of soil quality.
Biological
Soil
Carbon
Physical
Chemical
Conservation Agriculture
Manage soil carbon!
“Delay Decay”
CO2
Green
plants
Carbon Cycle - a
“fantastic voyage”
Crop Residue/Stubble Decomposition Cycle as a temporal
continuum with carbon changing form and function as CO2
is released through microbial respiration.
CO2
Stubble
residue
CO2
CO2
CO2
Organic matter --- humus
CO2
Basic
elements
Humic
fulvic
acids
Active pools ---- Passive pools ---- Recalcitrant pools
Agriculture has dug a “carbon hole” with intensive tillage.
Agriculture can now refill the “carbon hole” with less
intensive tillage.
Tillage-induced
Carbon Dioxide Loss
CO 2
CO 2
M = Mobile
R. = Research
G = Gas
E = Exchange
M = Machine
MR. GEM
Invisible effects of invisible forces!
Invisible effects of invisible forces!
Intensive tillage enhances biological
oxidation and decreases soil carbon
irrespective of residue management.
CO 2
$
$
$
$
Tillage very effectively
facilitates biochemical
degradation of organic matter.
Invisible forces of aerodynamics lifts
carbon dioxide out of tilled soil.
25 cm
MOLDBOARD
PLOW
BEFORE
AFTER
Tillage loosens the soil (i.e. changes soil air permeability) and enables rapid
soil gas exchange. Soil carbon dioxide is sucked and swirled into
turbulent eddies on into the atmosphere. Oxygen enters the large voids to
enhance microbial activity.
Tillage unlocks the potential microbial activity by creating more reactive
surface area for gas exchange on soil aggregates that are exposed to a
higher ambient oxygen concentration (21%). Tillage also breaks the
aggregates to expose "fresh" surfaces for enhanced gas exchange and
perhaps more carbon loss from the interior that may have a higher carbon
dioxide concentration.
Carbon is a “keystone” in nutrient cycling!
K
Mg
N
C
P
Ca
S
Zn Soil carbon is the
Mn
Cl “Keystone” for all soil Bo
physical, chemical and
biological processes
and properties.
Management platform
fertility, variety, irrigation, species, cover crop,
manure, rotations, tillage, soil type, erosion, timing,
Biological nutrient cycling requires carbon!
P
N
K
S
C
Ca
Bo
Zn
Mg
Mn
Cl
etc.
Nutrient Balance and Carbon Sequestration.
N
Net carbon sequestration
requires other nutrients.
P
K
S
7 – 10 units of C per unit of N
Zn
C
Ca
Mg
50 –60 units of C per unit of P
70 – 80 units of C per unit of S
Bo
Cl
Mn
etc.
Balanced fertilization is needed for both
crop uptake and carbon sequestration!
Rattan Lal, 27 Jan., 2000
Environmental Quality Triangle
Ai
r
ter
Wa
Q
Soil
Soil Quality is the foundation
of Environmental Quality.
Soil Carbon Sequestration
Environmental benefits are spokes
that emanate from the Carbon hub.
- increased water holding
capacity and use efficiency
- increased cation exchange
capacity
- reduced soil erosion
- improved water quality
- improved infiltration, less
runoff
- decreased soil
compaction
- improved soil tilth and
structure
- reduced air pollution
C
- reduced fertilizer inputs
- increased soil buffer capacity
- increased biological activity
- increased nutrient cycling
and storage
- increased diversity of
microflora
- increased adsorption of
pesticides
- gives soil aesthetic appeal
- increased capacity to handle
manure and other wastes
Carbon
- more wildlife
central hub of
environmental quality.
Atmospheric Carbon as CO2
Time Frame of Carbon Cycles
Fossil carbon cycle.
Cycle time is
millions of years
for fossil carbon.
Nonrenewable
Biological carbon cycle.
Cycle time is 1 10 years for
biological carbon.
Renewable
The major strength of biofuels is the potential to reduce
net carbon dioxide emissions to the atmosphere.
Fossil carbon cycle.
Biological carbon cycle.
Atmospheric Carbon as CO2
CO2
Energy from
fossil fuels
CO2
Energy from
bio-fuels
CO2
C
Plant biomass and
roots left on or in
the soil contribute
to Soil Carbon or
Soil Organic Matter
and all associated
environmental and
production
benefits.
Nonrenewable
Renewable
Conservation Agriculture
(Direct Seeding or No-Till farming)
CO2
CO2
Agriculture’s role in
the carbon cycle.
O2
CO2
Credit : 1998
Jim Kinsella,
respiration
O2
O2
photosynthesis
CO2
combustion
O2
CO2
Renewable energy resources
wind
solar
hydroelectric
Constantly replenished with environmental
benefits obvious because no CO2 emitted
in the generation and no CO2 taken up, not
part of the fossil or biologic carbon cycle.
biofuels
biological feedstocks
cellulosic biomass, ethanol
Constantly replenished
with environmental
benefits that CO2 emitted
in combustion is recycled
into biomass through
photosynthesis as part of
the biological carbon
cycle, thus no net increase
in CO2 emissions.
feed grains, ethanol, methanol
crop and vegetable oils, sunflower, soybean
starch and sugar waste streams
wood and logging residues, hybrid poplar
energy crops-annual and perennial,switch grass
municipal and industrial waste, sewage sludge
methane from manure production
turkey manure
The major strength of renewable fuels is the potential to
reduce net carbon dioxide emissions to the atmosphere.
Atmospheric carbon
management is a two-way
street: carbon in and carbon
out of the system.
Renewable fuels or biofuels combustion emits carbon
dioxide like fossil fuels, however, renewable fuels
“close the carbon cycle” by reusing carbon dioxide
through photosynthesis to form new plant biomass.
Fossil fuels combustion emits carbon dioxide from a
very old carbon sources that do not “close the carbon
cycle” by reusing carbon dioxide in a reasonable time
to form new biomass.
Benefits of the Biobased
Economy
Economic
– Reduce cost, better control of product properties
– New product & market opportunities
– Improved balance of trade & energy independence
Environmental
– Pollution prevention, reduced emissions of GHG
and toxics
– ‘Green’ fuels, chemicals & materials
– Reusable & recyclable products
Social
– Rural economic diversification & growth
– Developing countries can access the biobased
economy
– Improvements in human/environmental health &
quality of life
Switch grassSwitchgrass
keeps the carbon out of the air and in the soil!
Environmental benefits of switch grass as a bio-fuel.
-- decreased soil erosion
-- decreased water pollution and sedimentation
-- decreased greenhouse gas emissions
-- increased wildlife habitat
-- carbon sequestration (tradable carbon credits)
-- low chemical inputs (fertilizer, herbicides)
-- perennial grass
Tolbert, V. 1998. Environmental effects of biomass crop production. What
do we know? What do we need to know? Guest Editor. Biomass and
Bioenergy 14(4):301-414.
ECOSS Fertilizer Schematic
Enriched Carbon Organic Slow release Sequestering Fertilizer
Carbon capture
through
photosynthesis
Hydrogen
for fuel
cells
Agricultural
and Forestry
Crop Biomass
Controlled
slow release
N fertilizer
Carbon management through pyrolysis
N2
N fertilizer
without use
of fossil fuel
Semi-permanent
soil C sequestration
via char bi-product
Increased
agricultural
productivity
Improved
Environmental
Quality
Decreased CO2 and
N2O emissions, less
denitrification
Conservation Agriculture is
Carbon Management!
Economic prosperity
Environmental protection
Social Responsibility
Direct seeding is a new technology
that provides food and fiber and
helps protect the environment.
Carbon in the soil is
like money in the bank!
$ principle
< ----- > soil organic matter
$ interest
< ----- > crop stover (residue)
$ withdrawal
< ----- > intensive tillage
$ re-invest interest < ----- > conservation tillage
and surface residue
Now with possible
carbon credits, it’s
real money$$$
“Piggy Bank”
“Soil Bank”
Estimates of global carbon
sequestration markets
The U.S. Agriculture Department estimates that
the U.S. carbon sequestration market could swell
to $5
billion per year by 2035.
The World Bank has estimated that greenhouse gas
trading will be a $10
billion market by 2005.
The investment bank Rothschild Bank Australia said it
was estimated that the global carbon trading market
could be worth up to $150
billion by 2012.
Deutsche Bank has pegged the global emissions
market at about $100 billion by 2010, about half
the size of the U.S. wholesale electricity market.
Carbon Trading Markets
Chicago Climate Exchangesm
25 Leaders from Energy, Industrial, Farm and Forest
Sectors to Design New Chicago Climate Exchangesm
As proposed, the Exchange could:
1. demonstrate that greenhouse gas trading can
achieve real reductions in emissions across
different business sectors;
2. help discover the price of reducing greenhouse
gases;
3. develop the standard frameworks for monitoring
emissions, determining offsets and conducting
trades needed for a successful market.
Web site: www.chicagoclimateX.com
Web site: www.carbonexchange.com
IGF Insurance Company is the fifth-largest crop
insurance company in the industry that
specializes in agribusiness risk management.
Web site: www.igfinsurance.com/services/
Web site: www.ieta.org/
World Bank's Prototype Carbon Fund
Web site: www.prototypecarbonfund.org/
Suppliers of Carbon Emission Reduction CreditsTM
Web site: www.carbonquest.com
Global Environmental Quality
depends on soil quality.
Carbon inputs
Tillage intensity
C
a
r
b
o
n
C
a
r
b
o
n
Sustainable agriculture
Climate
Vegetation
Topography
Parent material
Soil organic carbon
Age
3 Pillars of Conservation Agriculture!
Conservation Agriculture
minimum
soil tillage
crop rotations/
cover crops
Continuous
residue cover
Soil Organic Carbon
Many environmental benefits point to carbon!
Soil Erosion
Redistribution of soil within
the landscape by:
wind
water
tillage
Rolling terrain with Eroded Landscape
Accumulated
Soil
A horizon
B (AC) horizon
C horizon
Original
Surface
}
A
B
C
Credit: Michelle Erb and David Lobb
CO 2
CO 2
Incorporating
crop residues
with intensive
tillage maximizes
residue-soil
contact and is
the fastest way to
convert soil
organic matter to
a “puff” of carbon
dioxide.
Carbon in the soil is the cradle
of environmental quality!
Global Environmental Quality
5 hours after tillage
24 hours after tillage
160
159.7
-2
Cum. CO2 Loss (g CO2 m )
80
60
59.8
120
40
80
66.2
31.7
20
40
26.7
11.5
19.4
4.7
0
3.4
1.4
MP SS MK YK RM NT
15.4
7.2
0
MP SS MK YK RM NT
Tillage Type
Strip Tillage #1
3 June 1997 Swan Lake
Cumulative Carbon Dioxide Loss after 24 hours
CER (g CO2 m-2)
180
MP
150
s
s
lo
120
90
60
30
RM
NT
n
o
b
r
a
c
SS
g y = 0.0792x + 9.7647
n
i
s
2
a
e
R
= 0.9698
r
MK nc
I
L128
0
0
250
500
750 1000 1250 1500 1750 2000
Cross Sectional Area Loosened Soil (cm2)
Nature’s Interdependent Tri-Cycles:
Water, Carbon, Nitrogen,
Tillage disrupts the natural cycles!
H2O
C
N
Tillage
Layer
Properties and Processes
Physical
Chemical
Biological
Cumulative Et Values
Strip Tillage #2 7/16/97
18.3
Evaporation (mm)
20
MP = 5.23 times more
evap. than NT in 24 h.
15
9.7
8
10
5
5 Hours
24 Hours
2.8
6.8
4.1
2.5
2.2
2.1
1.4
3.5
0.7
0
Plow
Mole Knife
Subsoil
Residue Management
Yetter Knife
Not Tilled
Tillage Method