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Climate change and carbon sequestration in the Mediterranean basin:
Contributions of No-tillage systems
Dr. Rachid MRABET
http://rachidmrabet.googlepages.com
4th Mediterranean Meetings on No-tillage systems Setif, Algeria, May 3 -5 2010
Features of Mediterranean Basin
Myriad of atmospheric and climatic processes
Regional vs global influences
Mistral, Tramontane, Bora, Etesiens, Sirocco
A semi-closed basin
Sea-land interaction & contrasts
No More land for production: case of Morocco
7,4
7,6
7,8
8
8,2
8,4
8,6
8,8
9
9,2
9,4
1971
1982
1992
1993
1994
1995
1996
1997
1998
1999
2001
2003
Year
Ag
ricu
ltu
ral A
rea
(M
illio
ns H
a)
•The land available to produce this extra food is
shrinking because of urbanization and use of
agricultural land for other purposes.
Agriculture as driver of global warming
Carbon Dioxide is the most important GHG
Other GHG (Methane, Nitrous Oxide) more powerful
Still 77% of total GHG in CO2 equivalent is due to
CO2
Agricultural land use contributes 32% of all GHG:
24% of all CO2
61% of all CH4 and N2O
The major largest components are:
Deforestation: 18.3%
Nitrogen emissions from soils: 6%
Methane from livestock: 5%
Projected Impacts of Climate Change
Source: Stern Review
Pressures on Med-countries
•Mitigation of greenhouse gas emission
•Control of desertification & erosion
•Sustainable environment-friendly agricultural productions
•Reduction in reliance on fossil fuels
Air Temperature (°C): 2070-2099 vs. 1961-1990
using AORCM
Winter
Summer
(Somot et al., 2007)
•Increased
temperature
•Global warming
• frequency,
duration and
intensity of hot
periods “canicules”
9
Winter
Summer
(Somot et al., 2007)
Rainfall (mm/d): 2070-2099 vs. 1961-1990
using AORCM
Rainfall totals are likely
to decline between 4 and
27%.
Frequency of extreme
storm events
Drought is Morocco’s leading natural hazard
0
100
200
300
400
500
600
700
800
900
1000
mm
year
Total seasonal rainfall measured throughout Meknes
Agourai
Ain Jemaa
Sidi Slimane
609 mm
453 mm
Cereal yield trends
Focus on Water & Food, Africa & Asia
Impact of climate change on crop productivity for cereals and food legumes
Giannakopoulos et al., 2009
Wheat consumption
CHABANE, 2010
Algeria
Mediterranean basin is the hotest spot region
Living with drought and dealing with
climate change are unavoidable
Drought is expected to continue and get linked to desertification, the longer we wait,
the fewer our options!!!
Major Global Challenges with conventional agriculture
•Poor Energy Efficiency
•Poor Fertilizer Efficiency
•Poor Water Efficiency }
Its not difficult to fix, if we try
All guarantee poor carbon
balance
What is no-tillage?
B A C
NO-TILL SYSTEM
A = Absence of soil tillage: No Mechanical Soil Disturbance
B = Biodiversity: Crop Rotation / Cover Crops;
Integrating Livestock & Farming
C = Cover of the soil: Permanent Cover with Crop Residues
No-tillage is like a three legged stool
Pillars that Sustain the No-tillage System
Conservation agriculture motion
Argentina Brazil
USA Australia
Conservation Agriculture
Before….. Actually
C
O
N
S
E
R
V
A
T
I
O
N
A
G
R
I
C
U
L
T
U
R
E
Organisations
Partnerships Policies
Industries/Technologies
R&D Training
CA
Capacity Building
Financing
Knowledge Management
Environmental Impact of CA
Question!
Conservation agriculture has large environmental benefits,
but is it climate-friendly?
Emission Mechanisms
Inputs: (energy) Fuel, Machinery
Herbicides
Fertilisers
Outputs: (losses) Gaseous Carbon dioxide, nitrous oxide & methane
Nitrate in runoff and drainage
Carbon & Nitrate in eroded soil
}
}
Easily Quantified
For Known Systems.
Substantial
System Effects
Highly Variable,
Poorly Understood.
Very Large
System Effects,
Atmospheric Carbon as CO2
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.
Energy from
bio-fuels
CO2 CO2
Biological carbon cycle. Fossil carbon cycle.
CO2
C Energy from
fossil fuels
Renewable Nonrenewable
60% reduction in fuel
20% reduction in fertilizer/pesticides
50% reduction in machinery
no burning
Conservation Agriculture mitigating climate change
Franzluebbers (2005) Soil Tillage Res. 83:120-147
Nitrogen Fertilization (kg . ha
-1 . yr
-1)
0 100 200 300
Changein
SoilOrganicCarbon
(Mg . ha
-1 . yr
-1)
0.0
0.4
0.8
1.2
1.6
Conventional Tillage
Nitrogen Fertilization (kg . ha
-1 . yr
-1)
0 100 200 300
Changein
SoilOrganicCarbon
(Mg . ha
-1 . yr
-1)
0.0
0.4
0.8
1.2
1.6
Conventional Tillage
No Tillage
Soil Carbon Sequestration
Nitrogen fertilization effect
Nitrous Oxide Emission
Interaction of tillage with soil type
Rochette (2008) Soil Till. Res. 101:97-100
Soil Aeration
N2O
Emission
(kg N .
ha-1
)
0
1
2
3
4
5
6
7
8
Good Medium
Conventional tillage
No tillage
Poor
p = 0.06
45 site-years of data reviewed
Brazil, Canada, France, Japan,
New Zealand, United Kingdom, USA
C
Crop biomass is a critical component of
the biological carbon cycle!
Soil carbon is an important link between sustainability and
productivity within agricultural ecosystems.
Soil Surface
Carbon comes into crop
biomass and system
through photosynthesis.
Carbon goes out of
the soil system
mainly through
respiration.
- 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
- 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
- more wildlife Carbon central hub of environmental
quality.
C
Environmental benefits are spokes that
emanate from the Carbon hub of the
“Environmental Sustainability wheel.”
Soil Carbon Sequestration
Soil organic carbon can be sequestered with adoption of conservation
agricultural practices
Enhanced soil fertility and soil quality
Mitigation of greenhouse gas emissions
Soil erosion reduction is most notable
Long-term changes are most scientifically defensible
Soil C vs Time
Carbon in Med-Soils
Country Soil order Horizon (cm)
Years NT CT References
France Alfisol 0-5 4 21.5 17.3 Monnier et al. (1976) Alfisol 0-5 33 22.6 11.0 Oorts (2006) & Oorts et al. (2007b)
Syria Inceptisol 0-10 10 17.5 11.0 Ryan (1998) Tunisia Isohumic
Fersialitic 0-20 0-20
4 4
27.5 22.4
24.1 15.5
Ben Moussa-Machraoui et al. (2010)
Morocco Calcixeroll 0-5 5 17.3 16.6 Mrabet (2008a) Calcixeroll 0-2.5 11 28.9 23.5 Mrabet et al. (2001)
Italy Cambisol 0-40 3 7.5 7.5 Borin et al. (1997)
Entisol 0-10 - 20.1 14.3 Basso et al. (2002)
Portugal Cambisol 0-20 3 14.82 12.94 Basch et al. (2008) Vertisol 0-10 - 25.3 19.1 Carvalho & Basch (1995)
Spain Xerocrept 0-5 18 22.5 15 Álvaro-Fuentes et al. (2008) Xerofluvent 0-5 15 18.81 8.8 Álvaro-Fuentes et al. (2008)
Calciorthid 0-5 16 13.7 8.7 Álvaro-Fuentes et al. (2008) Calcisol 0-5 7 12.55 10.17 Fernandez-Ugalde et al. (2009) Haploxeralf 0-5 14 11 7 Hernanz et al. (2002)
Haploxeralf 0-10 8 11.6 8.8 Medeiros et al. (1996) Xerofluvent 0-5 3 17.2 15.7 López-Garrido et al. (2009)
Temporal SOC dynamics from 2010 to 2100 for the different management scenarios
Alavaro-Funentes and Paustian, 2010
Re-building soil organic matter
Ogle et al., 2005
No-Till: CO2 emission!
Reicosky and Lindstrom, 1993
Reicosky
y = 0,0792x + 9,7647
R2 = 0,9698
0
30
60
90
120
150
180
0 250 500 750 1000 1250 1500 1750 2000
Severity of disturbance (cm2)
CE
R (
g C
O2 m
-2)
MP
SS
RM
MK
NT L128
Cumulative Carbon Dioxide Loss after 24 hours
Alvaro-Fuentes et al., 2007
No-Till: CO2 emission!
Akbolat et al., 2009
No-Till: CO2 emission!
Oorts et al., 2007
No-Till: CO2 emission!
Runoff projections with respect to climate change scenarios
Runoff reduction !
Jordán et al., 2010
Soil loss reductions!
Fleskens & Stroosnijder (2008) Portugal & Italie
Sediment loss reductions!
0 40 80 120
0
100
200
300
400
500
0 40 80 120
0
100
200
300
400
500
Y = X
0 40 80 120Sediments. Cover, g m-2
0
100
200
300
400
500
Se
dim
en
ts. T
illa
ge
, g
m-2
Y = 2X
In 80,3% of cases the relation
between N/C has been greater to 2
In 92,4% of cases the relation between N/C has been greater to 1
0 20 40 60 80 100Cover, %
0
20
40
60
80
100
Se
dim
en
t co
nce
ntr
atio
n, g
L-1
Tillage
Plant cover
Espejo-Pérez et al. 2006
Water capture & movement in soils with No-Tillage systems
.1Improved water entry in place of water runoff
.2Reduced water evaporation
.3Channels and macropore in
place of crust and slacking for improved water distribution
and movement in soil profile
.4Water storage for seasonal availability and use by crops
Ruan et al., 2001
NT vs CT for Cereals in Med-Basin
Yield variability vs climate!
yield CT = 0,0033 Rainfall + 1,4116
R2 = 0,1823
yield NT = 0,0028 Rainfall + 2,01
R2 = 0,1457
0
0,5
1
1,5
2
2,5
3
3,5
4
150 200 250 300 350 400 450 500
Rainfall (mm)
Gra
in Y
ield
(M
g/h
a)
No-tillage
Conventional Tillage
Mrabet, 2010
Yield Variability vs climate!
De Vita et al., 2007
Drought Management!
Water evaporation suppression or
water management with crop residues!
0
10
20
30
40
50
60
Cu
mu
lati
ve
so
il e
va
po
ra
tio
n (
mm
)
0 100 200 300 400 500
Cumulative potential evaporation (mm)
OD SW DP CH RT NT-0 NT-80
Mrabet, 1997
Seasonal Carry over of soil water to crop critical stages
Water
gain
No-till Residue Cover Suppression of Soil Water Evaporation
0
10
20
30
40
50
60
Cu
mu
lati
ve
So
il E
va
po
rati
on
(m
m)
0 100 200 300 400 500 Cumulative Potential Evaporation (mm)
0 50 60 80 100
No-till Residue Cover Percent
Mrabet (1997)
Water Conservation: securing water against drought
0
5
10
15
20
25
30
35
40
45
0 50 60 80 100
Residue cover under no-tillage
Tim
e t
o w
ilti
ng
po
int
(days)
0
5
10
15
20
25
30
35
40
Disk plow Stubble
Mulch
Chisel Rotary
tiller
Off-set
disk
No-tillage
w ith 60%
cover
Tillage System
Tim
e t
o w
ilti
ng
po
int
(days)
Keeping the soil moist longer as residue cover increase!
Halting evaporation process in semi-arid areas!
Mrabet, 1997
Precipitation storage efficiency
•Low and highly variable rainfall are major sources of risk for
farms of drylands!
•Precipitation storage efficiency increases as tillage intensity is
reduced during the summer fallow period.
•The increased soil water storage is a result of both maintained
crop residues at the surface and no-turing and mixing of the soil
moisture.
Conservation agriculture: mitigating climate change through
Drought
management
High reduction
in CO2
emission
High
environmental
resilience
Carbon
sequestration
Lets finish this talk with these important statements!
.1The fact is no one has ever advanced a scientific reason for plowing (Edward H.
Faulkner, 1943).
.2No-tillage systems are means for capturing the synergy between climate change
adaptation and mitigation and prevention of desertification (Virdin, 2001).
Transforming research efforts and development (farmers) achievement s on policy issues
Think Thank
To get all elites and leaders in research, development and education with international organisations and NGOs for the same objectives.
Lobbying
Transform weakness on strenghts to convince policy and industries.
« Climate change is a shared responsability and the future is no longer as it used to be »
Merci
“You’ve got to be very careful
if you don’t know where you’re going,
because you might not get there.”