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.