Date post: | 16-Jan-2016 |
Category: |
Documents |
Upload: | noel-houston |
View: | 213 times |
Download: | 0 times |
Conservation Agriculture Carbon Offset ConsultationOctober 28 – 30, 2008
West Lafayette, Indiana, USA
Carbon balance and sequestration in no-till soils under intensive cropping systems
in tropical agroecozones
João Carlos de Moraes Sáand
Lucien Séguy
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
Outline
General overview: soils characteristics and No-till in the tropics
Concept of intensive cropping systems and comments
General and specific objectives
Methodology
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
Introduction
General overview
(10.1%) (17.9%) (7.5%) (8.1%)
Main differences – Tropical and Temperate soils
Variable charges – deprotonation of surface functional groups (pH dependent charge)
Permanent charges by isomorphic substitution – replacement of one atom by another of similar size
Low natural fertility High natural fertility
Low pH Moderate to High pH
High exchangeable Al3+ No exchangeable Al3+
Good natural drainage Moderate and poor natural drainage
Type 1:1 – Kaolinite, Iron and Aluminum oxides
Type 2:1 – Montmorilonite, Vermiculite, Ilite
Oxisol Mollisol
AM
AC
RR
PA
AP
RO
MT
MS
RS
SC
PR
SP
GO
MG
BA
TO
MA
PI
CERN
PBPE
SEAL
Expansion of agricultural area in Brazil
Total cropped area56 million ha
0.23
10 years
0.023 million ha yr-1 0.112 million ha yr-1
1.75
mill
ion
ha y
r-1
10 year
s
18.84
10 years
1.35
4.87 times 15.62 times
Expansion of No-till area in Brazil (1972 – 2006)M
illio
ns o
f ha
year
25.50
Methodology
Brazil Madagascar
Cambodia
Tropic of Cancer
Equator
Tropic of Capricorn
Vietnam
LaosThailand
Cameroon
Experimental Sites
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.
The concept of Intensive cropping systemThe concept of Intensive cropping system
“The challenge in the tropics is to manage the decomposition rate of the crop residues, and keep the soil covered”
Crop residues decomposition (oats + remaining residues) during the corn development (Piraí do Sul, 910 m ASL, 25 °SL, 2003-04, Oxisol (62% of clay)
MTRO
PA MA
PI
GOBA
MG
SP
PR
SC
RS
RJMS
AM
RRAPEquador
Tropic of Capricorn
Piraí do Sul
Sour
ce: S
á, e
t al,
2004
y = 9002 – 29.95x
R2 = 0.98***
0
2000
4000
6000
8000
10000
0 50 100 150 200
DAE of Corn
Dry
bio
mas
s (k
g/ha
)
29.95 kg day-1 of DM
Planting (05/10/03)
Flowering Physiological maturation
Harvest (14/03/04)
Crop residues decomposition (oats + remaining residues) during the corn development (Piraí do Sul, 910 m ASL, 25 °SL, 2003-04, Oxisol (62% of clay)
9106 kg ha-1 DM = 4098 kg ha-1 C
4210 kg ha-1 DM = 1985 kg ha-1 C
MTRO
PA MA
PI
GOBA
MG
SP
PR
SC
RS
RJMS
AM
RRAPEquador
Tropic of Capricorn
Rio Verde
Crop residues decopmposition (Brachiaria decumbens) during the corn
development (Rio Verde, 880 m ASL, Latitude 16° S, 2003-04, Oxisol (65% of clay)
Planting (19/10/03)
Flowering Harvest (16/02/04)
Crop residues (Brachiaria decumbens) decomposition during the corn development
Rio Verde, 880 m ASL, Latitude 16° S, 2003-04, Oxisol (65% of clay)
10000
DAE of Corn
Font
e: S
á, e
t al,
2004
y = 8980 – 58.26x
R 2 = 0.96
0
2000
4000
6000
8000
0 50 100 150
DM
(kg/
ha)
58.26 kg day-1 of DM
Sour
ce: S
á, e
t al,
2004
Physiological Maturation
8658 kg ha-1 DM 3896 kg ha-1 C
1910 kg ha-1 DM 860 kg ha-1 C
-2000
0
2000
4000
6000
8000
10000
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190
Days after Corn planting
Dry
mat
ter
loss
(kg
/ha)
8658 kg ha-1 DM 3896 kg ha-1 C
- 1676 kg/ha MS - 754 Kg/ha
C
Amount of crop residues to maintain the C equilibrium in the soil
Zero DM
General Balance = (- 3896) + (- 754) = - 4650 kg C ha-1 10.32 Mg ha-1 DM
1st yr 2nd yr 3th yr
SO N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A
Rainy season Dry Season Rainy season Dry Season Rainy season Dry Season
Scv1 Soybean Soybean SoybeanFallow Fallow Fallow
Scv2 Soybean SoybeanAfrican Millet African milletAfrican Millet Soybean
Scv3 Soybean Soybean SoybeanE.coracana + Crt E.coracana + Crt E.coracana + Crt
Scv4 Soybean Soybean SoybeanSorghum + Brachiaria Corn + Brachiaria Sorghum + BrachiariaC. V
erde
, Luc
as d
o RV
, MT
1710 mm 1710 mm 1710 mm171 mm 171 mm 171 mm
Sow
ing
Har
vest
Cover crop(Brachiaria)
Sow
ing
Har
vest
Sow
ing
Har
vest
Sow
ing
Har
vest
Sow
ing
Cover crop(Brachiaria)
Har
vest
Har
vest
Sow
ing
Cover crop(Brachiaria)
Fonte: Seguy & Bouzinac, 2000
Results
Input of 1.0 ton of crop residues
0.736 ton
25° SL
Soil organic matter pool’s
Live organism
0.044
Stable (0.22 ton)
Humic Substances
No humic substances
0.06
0.16
COCO22
Source: Sá et al. 2001; 2007
Distribution of the decomposition products of the crop residues in the SOM pools
Cerrado Sinop-MT
0.863 14° SL Cerrado
(PvLt) 0.847 16° SL
Site Cropping SOC Measured C input SOCSystem/Till. t1 t2
Cumulative Annual Sequestration rates
------------------------ Mg ha-1 --------------------- Mg ha-1 yr-1
CV CT-S 18.12 17.04 2.29 1.15 -0.54MT-S/Mlt 23.66 20.41 7.62 3.81 -1.63NT-S/Els+Crt 28.47 32.05 18.78 9.39 1.79NT-S/Sgh+Brq 30.66 35.03 19.38 9.69 2.18
LRV CT-S 48.30 43.70 4.87 0.97 -0.93NT-S/Els+Crt 55.80 65.10 37.12 7.42 1.86NT-S/Sgh+Brq 58.30 68.80 39.54 7.91 2.10
Snp CT-S 48.68 43.70 3.67 0.92 -1.25NT-S/Els+Crt 40.30 47.20 40.12 10.03 1.73NT-S/Tifton 43.02 53.40 51.26 12.82 2.60
Adrom. Fallow 47.37 41.40 1.08 0.12 -0.66Madag. NT-M/S 47.37 56.38 16.05 1.78 1.00
NT-M+SD 47.37 52.69 25.08 2.79 0.59NT-S/GB+KK 47.37 56.81 35.50 3.94 1.05
SOC balance for 0- to 20-cm depth for experimental sites
Soybean harvest (3.5 to 4.0 tons of DM) – February
Corn and Brachiaria planting - February
Corn harvest (6 to 7 tons of DM) – June
After harvest10 to 20 days after harvest(root system > 50 cm)
October – Before soybean planting 11-12 tons of Brachiaria DM
Example of Soybean/Corn + Brachiaria and Sorghum + Brachiaria rotation
November – 12 days after soybean planting
November 9.5 tons of Brachiaria DM
December 7.0 tons of Brachiaria DM
Soil permanent covered
Soybean
Corn
+ Brachiari
a
Brach. Cover crop
Soybean Sorghum
+ Brachiaria
Sorgh. +
Brach. Regro
w
Soybean Corn
+
Brachiaria
Afr
ican
M
ille
t SoybeanSorghum +
Brachiaria
Brach. Cover crop
Sorghum +
Brachiaria
Soybean Corn
+ Brachiari
a
Brach. Cover crop
Soybean
Example: Campo Verde– MT
Oxisol, Red Dark Latosol, Sand-Clay
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)
S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S
Dry season Dry seasonDry season
Rainy season Rainy season Rainy season
Soybean harvest (3.5 to 4.0 tons of DM) – February
Corn and Brachiaria planting - February
Corn harvest (7 tons of DM) – June
After harvest10 to 20 days after harvest(root system > 50 cm)
Example of Soybean/Corn + Brachiaria + beef cattle rotation
Grazing June, July and August
October December 5.5 tons of Brachiaria DM
Soil permanent covered
October/November (Regrow)
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)
Cumulative C input x SOC sequestered
“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”
Scenario 1 – Potential of C-sequestration based in average rate
12.75 MT
Average rate of C-Sequestration0.5 Mg ha-1 yr-1
(Bernoux et al. 2006; Bayer et al., 2006; Cerri et al., 2007)
Scenario 1
3.29 MTCerrado
9.63 MTSouthern
Scenario 2
20.55 MT
Scenario 2
9.74 MTCerrado
10.79 MTSouthern
Scenario 3
24.73 MT
Scenario 3
13.94 MTCerrado
10.79 MTSouthern
Scenario 4
32.13 MT
Scenario 4
16.94 MTCerrado
15.79 MTSouthern
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.
Conclusions
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.