Conservation Agriculture Carbon Offset Consultation

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Carbon balance and sequestration in no-till soils
under intensive cropping systems in tropical
agroecozones
João Carlos de Moraes Sá and Lucien Séguy
Conservation Agriculture Carbon Offset
Consultation
October 28 30, 2008 West Lafayette, Indiana, USA
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Cropping Systems and C-Sequestration Team
UEPG PR, Brazil Dr. João Carlos de Moraes Sá
(Coordinator)
CIRAD France Dr. Lucien Seguy (Coordinator)
and 12 researches located in Africa and
Asia Graduate Students - 07 Undergraduate
Students - 14 International Collaboration The
Ohio State University Dr. Rattan Lal
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Outline
Introduction
General overview soils characteristics and
No-till in the tropics
Concept of intensive cropping systems and comments
Methodology
General and specific objectives
Sites location and description
Description of cropping system and biomass input
Results
C input by biomass and conversion to SOC SOC
stock
C Sequestration rates by cropping system
Estimation and scenarios for C Sequestration
for Brazilian Cerrado and other tropical areas
Summary and conclusions
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General overview
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Main differences Tropical and Temperate soils
Oxisol
Mollisol
Variable charges deprotonation of surface
functional groups (pH dependent charge)
Permanent charges by isomorphic substitution
replacement of one atom by another of similar size
Type 11 Kaolinite, Iron and Aluminum oxides
Type 21 Montmorilonite, Vermiculite, Ilite
Good natural drainage
Moderate and poor natural drainage
Low natural fertility
High natural fertility
Low pH
Moderate to High pH
High exchangeable Al3
No exchangeable Al3
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Expansion of agricultural area in Brazil
RR
AP
AM
PA
MA
CE
RN
PB
PI
PE
AC
TO
AL
RO
SE
BA
MT
GO
MG
MS
SP
PR
SC
RS
Total cropped area 56 million ha
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Expansion of No-till area in Brazil (1972 2006)
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Methodology
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Experimental Sites
Laos
Thailand
Cameroon
Vietnam
Cambodia
Tropic of Cancer
Equator
Tropic of Capricorn
Brazil
Madagascar
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The concept of Intensive cropping system
The meaning of the intensive cropping system
comprise in to close the window between the
rainy season (wet summer) and the dry season (dry
winter) using cover crops and cash crops, to
maintain the soil surface permanent covered.
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The challenge in the tropics is to manage the
decomposition rate of the crop residues, and keep
the soil covered
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Crop residues decomposition (oats remaining
residues) during the corn development (Piraí do
Sul, 910 m ASL, 25 SL, 2003-04, Oxisol (62 of
clay)
Equador
Tropic of Capricorn
Piraí do Sul
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Crop residues decomposition (oats remaining
residues) during the corn development (Piraí do
Sul, 910 m ASL, 25 SL, 2003-04, Oxisol (62 of
clay)
10000
9106 kg ha-1 DM 4098 kg ha-1 C
8000
4210 kg ha-1 DM 1985 kg ha-1 C
6000
Dry biomass (kg/ha)
4000
y 9002 29.95x
2000
R2 0.98
29.95 kg day-1 of DM
0
0
50
100
150
200
Source Sá, et al, 2004
DAE of Corn
Flowering
Planting (05/10/03)
Physiological maturation
Harvest (14/03/04)
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Crop residues decopmposition (Brachiaria
decumbens) during the corn development (Rio
Verde, 880 m ASL, Latitude ? 16 S, 2003-04,
Oxisol (65 of clay)
Equador
Rio Verde
Tropic of Capricorn
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Crop residues (Brachiaria decumbens)
decomposition during the corn development Rio
Verde, 880 m ASL, Latitude ? 16 S, 2003-04,
Oxisol (65 of clay)
10000
8658 kg ha-1 DM ? 3896 kg ha-1 C
8000
6000
DM (kg/ha)
1910 kg ha-1 DM ? 860 kg ha-1 C
4000
2000
y 8980 58.26x
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R
0.96
58.26 kg day-1 of DM
0
Fonte Sá, et al, 2004
0
50
100
150
Source Sá, et al, 2004
DAE of Corn
Flowering
Planting (19/10/03)
Harvest (16/02/04)
Physiological Maturation
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Amount of crop residues to maintain the C
equilibrium in the soil
General Balance (- 3896) (- 754) - 4650 kg
C ha-1 ? 10.32 Mg ha-1 DM
Zero DM
- 1676 kg/ha MS ? - 754 Kg/ha C
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Results
Fonte Seguy Bouzinac, 2000
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Distribution of the decomposition products of the
crop residues in the SOM pools
CO2
0.736 ton 25 SL
Input of 1.0 ton of crop residues
Soil organic matter pools
0.044
0.06
0.16
Live organism
Humic Substances
No humic substances
Stable (0.22 ton)
Source Sá et al. 2001 2007
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SOC balance for 0- to 20-cm depth for
experimental sites
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Example of Soybean/Corn Brachiaria and Sorghum
Brachiaria rotation
Soil permanent covered
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Rainy season
Rainy season
Rainy season
Dry season
Dry season
Dry season
Example Campo Verde MT Oxisol, Red Dark
Latosol, Sand-Clay
Annual C input (Avg) 9.7 Mg ha-1 (21.6 Mg ha-1
of Crop Residues)
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Soybean harvest (3.5 to 4.0 tons of DM) February
Corn and Brachiaria planting - February
Corn harvest (7 tons of DM) June
10 to 20 days after harvest (root system gt 50 cm)
After harvest
Grazing June, July and August
Example of Soybean/Corn Brachiaria beef
cattle rotation
October
December ? 5.5 tons of Brachiaria DM
Soil permanent covered
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Distribution of C in the particle size fraction
in the profile under three crop rotations with
cotton as the main crop (Campo Verde-MT, Brazil,
16? SL)
10 - 20 cm, depth
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Cumulative C input x SOC sequestered
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In tropical areas the challenge with cropping
systems is to adjust cash crops and cover crops
that can be profitable and compensate the high
decomposition rates of the crop residues
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Scenario 1 Potential of C-sequestration based
in average rate
Average rate of C-Sequestration 0.5 Mg ha-1
yr-1 (Bernoux et al. 2006 Bayer et al., 2006
Cerri et al., 2007)
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Scenario 1
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Scenario 2
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Scenario 3
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Scenario 3
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Scenario 4
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Scenario 4
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Conclusions
In tropical areas the management of the soil
organic matter through adoption of intensive
cropping systems with high C input (more than 7.4
Mg C ha-1 yr-1 ), and based in the systemic
approach to close the window between wet and
dry season it is the main way to enhance SOC
sequestration and sustainability.
The challenge is to convince the farmers to
adopt these system in large scale.

• Four points to convince the farmers
• Reduction of costs
• Reduction of the risks with weather impact
  (Drought )
• Increase the yield of the main cash crop and the
  profitability of the whole system
• Making extra money with C-sequestration and
  giving a good contribution to the environment.