Conservation Agriculture Carbon Offset Consultation October 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 Sá and 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 fertilityHigh natural fertility Low pHModerate to High pH High exchangeable Al 3+ No exchangeable Al 3+ Good natural drainageModerate 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 CE RN PB PE SE AL Expansion of agricultural area in Brazil Cerrado Region New cropland area in the last 10 years Higest concentration of soybean Total cropped area 56 million ha

years million ha yr million ha yr million ha yr years years times times Expansion of No-till area in Brazil (1972 – 2006) Millions of ha year 25.50

Methodology

BrazilMadagascar Cambodia Tropic of Cancer Equator Tropic of Capricorn Vietnam Laos Thailand 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 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, , Oxisol (62% of clay) MT RO PA MA PI GO BA MG SP PR SC RS RJ MS AM RR AP Equador Tropic of Capricorn Piraí do Sul

Source: Sá, et al, 2004 y = 9002 – 29.95x R 2 = 0.98*** DAE of Corn Dry biomass (kg/ha) 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, , Oxisol (62% of clay) 9106 kg ha -1 DM = 4098 kg ha -1 C 4210 kg ha -1 DM = 1985 kg ha -1 C

MT RO PA MA PI GO BA MG SP PR SC RS RJ MS AM RR AP Equador Tropic of Capricorn Rio Verde Crop residues decopmposition (Brachiaria decumbens) during the corn development (Rio Verde, 880 m ASL, Latitude  16° S, , 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, , Oxisol (65% of clay) DAE of Corn Fonte: Sá, et al, 2004 y = 8980 – 58.26x R 2 = DM (kg/ha) kg day -1 of DM Source: Sá, et al, 2004 Physiological Maturation 8658 kg ha -1 DM  3896 kg ha -1 C 1910 kg ha -1 DM  860 kg ha -1 C

8658 kg ha -1 DM  3896 kg ha -1 C kg/ha MS  Kg/ha C Amount of crop residues to maintain the C equilibrium in the soil Zero DM General Balance = (- 3896) + (- 754) = kg C ha -1  Mg ha -1 DM

1 st yr2 nd yr3 th yr SONDJFMAMJJASONDJFMAMJJASONDJFMAMJJA Rainy seasonDry SeasonRainy seasonDry SeasonRainy seasonDry Season Scv 1 Soybean Fallow Scv 2 Soybean African MilletAfrican milletAfrican MilletSoybean Scv 3 Soybean E.coracana + Crt Scv 4 Soybean Sorghum + Brachiaria Corn + BrachiariaSorghum + Brachiaria C. Verde, Lucas do RV, MT 1710 mm 171 mm SowingHarvest Cover crop (Brachiaria) Sowing Harvest Sowing HarvestSowing HarvestSowing Cover crop (Brachiaria) Harvest Sowing Cover crop (Brachiaria)

Fonte: Seguy & Bouzinac, 2000 Results

Input of 1.0 ton of crop residues ton 25° SL Soil organic matter pool’s Live organism Stable (0.22 ton) Humic Substances No humic substances CO 2 Source: Sá et al. 2001; 2007 Distribution of the decomposition products of the crop residues in the SOM pools Cerrado Sinop-MT ° SL Cerrado (PvLt) ° SL

SiteCroppingSOC MeasuredC inputSOC System/Till. t1t1 t2t2 CumulativeAnnualSequestration rates Mg ha Mg ha -1 yr -1 CVCT-S MT-S/Mlt NT-S/Els+Crt NT-S/Sgh+Brq LRVCT-S NT-S/Els+Crt NT-S/Sgh+Brq SnpCT-S NT-S/Els+Crt NT-S/Tifton Adrom.Fallow Madag.NT-M/S NT-M+SD NT-S/GB+KK 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 harvest 10 to 20 days after harvest (root system > 50 cm) October – Before soybean planting  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 + Brachiaria Brach. Cover crop SoybeanSorghum + Brachiaria Sorgh. + Brach. Regrow Soybean Corn + Brachiaria African Millet SoybeanSorghum + Brachiaria Brach. Cover crop Sorghum + Brachiaria SoybeanCorn + Brachiaria 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) SONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS Dry 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 harvest 10 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)

cm, depth 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 MT Average rate of C-Sequestration 0.5 Mg ha -1 yr -1 (Bernoux et al. 2006; Bayer et al., 2006; Cerri et al., 2007)

Scenario MT Cerrado 9.63 MT Southern

Scenario MT

Scenario MT Cerrado MT Southern

Scenario MT

Scenario MT Cerrado MT Southern

Scenario MT

Scenario MT Cerrado MT Southern

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.