This presentation was presented during the 1 Parallel session on Theme 3.2, Managing SOC in: Grasslands and livestock production systems, of the Global Symposium on Soil Organic Carbon that took place in Rome 21-23 March 2017. The presentation was made by Mr. Juan Antonio Comerma, from IDECYT – Venezuela, in FAO Hq, Rome

1. :
Rosa Mary Hernández-Hernández1,
Dimas Acevedo2, Lina Sarmiento2
1Universidad Simón Rodríguez, Miranda, Venezuela.
rodama33@yahoo.com.mx
2Universidad de Los Andes, Mérida, Venezuela.
dimas@ula.ve y lsarmien@ula.ve
Carbon Sequestration Potential in
the Savannas Ecosystems of
Venezuela
Rome, March 2017

2. The flatlands occupy
28% (25MM ha) of
Venezuela.
They are dominated by
ecosystems of savannas
with different
landscapes, soils, and
vegetation, mostly
adapted to acid soils,
low fertility and
subjected to frequent
fires

3. J F M A M J J A S O N D0
50
100
150
200
0
10
20
30
40
PRECIPITATION(mm)
TEMPERATURE(ªC)
MONTHS
 They are dominated
by grasses that
growth in dystrophic
soils.
 Well drained soils are
predominant, but
there are also
extensive areas with
poor drainage during
the rainy season.
 All soils are subjected
to a dry season (4 to
6 months) and
recurrent anthropic
fires during this
season.

4. EAST CENTRAL WEST
Types of Savannas in Venezuela

5. Site Guarico
Central
Flatlands
Venezuela (2)
Arauca
Eastern
Lowlands
Colombia (4)
Monagas
Elevated
Plateaus
Venezuela (3)
Soil type Ultisol
Alfisols
Dystrudepts Kandiustult
pH 5.1 5.13 4.9
SOC (%) 1.3 1.6 0.46
CEC (cmol/kg) 4.6 8.02 1.9
Al saturation (%) 25.1 96.01 --
P (ppm) -- 23.30 2
K (cmol/kg) 0.4 0.12 Traces
Ca (cmol/kg) 1.4 0.07 0.3
Mg (cmol/kg) 0.9 0.13 0.2
Bulk density (0-20cm)
(Mg.m-3)
1.46 1.27 1.55
(1) Rao, 1998; (2) Hernández and López, 2002; (3) Comerma and Chirinos, 1976; (4) IGAC, 2003 )
Tomado de Rondón et al. (2006)

6. Main land uses and
management
The main management practice in
the Llanos has been the burning
of native grasses. But In recent
decades it has being intensified i
through the introduction of exotic
grasses such as Brachiarias,
Panicum and Digitaria among
others. Also crop species such as
sorghum, maize, beans, rice ,
Forest plantations of pinus ,
eucalyptus and teak are now
also important

7. 1.- To compile the results published about of C (%) at
depths from 0 to 30 cm and its bulk density.
2.- To estimate the storage and potential sequestration of
C in the soil, derived from the changes in land use in this
ecoregion.

8. Review of bibliography of
 areas of the main types of landscapes, their
ecosystems, and the land use types
 the soil C content (%),
 bulk density of the first 30 cm of soil,
 distribution of the principal suborders of soils
Then
 For each paper we calculated the stock of C for 0-
30 cm (C % x bulk density x ha)
 Then, calculated the accumulation of C for each
landscape unit using the average of C stock, the
extent of the ecosystem and the type of land use.

9. Landscapes Regions C stocks (MgC.ha-1) C (%)
Recent alluvial plains
Deciduous forests West 77.0 ± 19.4 5.0 ± 1.3
Hyperseasonal savannas ( lowlands) 45.2 ± 17.3 3.2 ± 1.4
Semiseasonal savannas (lowlands) 61.5 ± 12.0 5.2 ± 1.1
Alluvial Plains from the Pleistocene
Hyperseasonal savannas ( lowlands) West 39.0 ± 8.5 2.6 ± 0.6
Seasonal savannas 33.5 ± 6.4 2.2 ± 0.5
Seasonal savannas East 42 0.9
Seasonal savannas Central 46 2.9
Eolic Plains
Poorly drained savannas West 65 ± 7.1 4.2 ± 0.3
Well drained savannas 22 ± 4.2 1.4 ± 0.2
Elevated Plateaus
Seasonal savannas West 24 ± 9.9 1.6 ± 0.7
Seasonal savannas East 17.7 ± 7.5 0.8 ± 0.5
Seasonal savannas Central 51.3 ± 22.5 3.5 ± 1.6
Rolling hills
Seasonal savannas Central 31 3.3

10. Estimated C stocks for the main land use systems in the Venezuelan
savannas
Area
Estimated Carbon stocks (0-
30 cm depth)
Landscape position/land use (Mha) MgC.ha-1
Remaining natural systems
Elevated plateaus 5.04 35.66
Well drained lowlands 4.81 43.16
Poorly drained low plains 5.45 59.41
Rolling hills 1.66 40.00
Gallery and deciduous forest 1.52 75.00
Subtotal 18.48
Modified systems
Introduced pastures 5.00 78.00
Annual crops, conventional tillage 0.83 38.10
Annual crops, reduced tillage 0.17 43.20
Tree plantations 0.80 27.00
Urban, water bodies etc. 0.90
Subtotal 7.70
Total 26.18
Published in (Rondon et al. 2006)

11. 5 Tg C
8 Tg C
2 Mha
Annual crops
under
conventional
tillage
148 Tg C
5 Mha 1 8 Mg/ha
1.02 Pg C
(Rondón et al 2006)
Minimun
tillage
Agroforestry
If we stop
the burning
of the
savannas
Introduced
pasture
If all the
savannas are
covered with
introduced
pastures
If we increase the
area of introduced
pastures
Change to minimun tillage
If all the planted areas
goes to minimun tillage

12. I. Tropical savannas play key roles in biogeochemical cycles.
II. The alluvial and the eolic plains have the largest capacity of
carbon sequestration, due to their extent and to their C
content in the upper 30 cm of their soils. Data indicate that
this capacity increases toward the western llanos, related to
an increase in rainfall .
III. Savanna soils have a large potential to sequester up to 1.02
Pg of C, assuming that all the native land could be converted
into well managed and sustainable pastures.
IV. There are currently available technologies to allow
sustainable agriculture, livestock and forestry in the region.
Most of these technologies also sequester atmospheric
carbon in the biomass or in the soils.
V. The use of sustainable agriculture will result in more organic
matter being sequestered into the soils of the Llanos. This
will have important benefits for the global environment
through reductions in the net fluxes of greenhouse gases but
also to the health status of the soils of the region
VI. More and better data is required