ESTIMATION OF REFERENCE SOIL ORGANIC CARBON (SOC) FOR MINERAL SOILS OF COLOMBIA
Neira M. Fredy H.1, Turriago Juan D., Berrio Viviana
Introduction
Colombia is located in the equatorial – tropical latitude with differences in altitude
Climate and edafo– diversity due to its climate, geology, relief, soil materials…
Estimating SOC reference is a challenge due to lack of data
Objectives
To estimate Soil Organic Carbon (SOC) for mineral soils using IPCC methodology as reference
Future uses: - Estimate emissions under land cover changes- Validate IPCC methodology for national scale
Methodology
1 Soil MapUSDA Taxonomy
2 Climate zonesCaldas Lang
IPCC Soil System
IPCC climate zones
IPCC SOC ref. values
SOC ref
1. Homologation of soil map (USDA to IPCC)
Date
1. Organic soils
1Histosols? 2. Sandy soils
2> 70% A &< 8% Ar?
3. Wet lands3
Aquic ?
yes
No yes
No
yes
4. Volcanic soils
4Andisols?
No
yes
5. Spodic soils5
Spodosols?
No
yes
7. High Activity Clays
(HAC)
6-7Oll, ert;
No
yes6. Low Activity Clays (LAC)
NS. No Soil
Start0
ME, AFR, MR
yes
No
No
Homologation steps- Typic Haplofibrist Organic (O)
- Typic Melanudands Volcanic (V)- Typic Quartzipsamment Sandy (S)- Oxic Dystrudepts LAC - Typic haplustoll HAC
Weigh: 50% T. Haplustoll (HAC), 30% T. Haplofibrist (O), 20% T. Haplohemist (O) Organic (50%)/HAC 50%
Database with % of each soil type per unit
1. Homologation of soil map (USDA to IPCC)
Tropical wet
Elevation > 800m
TMA> 12°C
Warm temperate moist
MAP> 1000
Yes
No
YesYes
Warm temperate dry
NoMAT > 1,5
No
Cool temperate moist
PMA: PET> 1
Yes
Yes
Cool temperate dry
Tropical Montano
StartMAT > 18°C
Yes
No
No
MAP > 4000 mm
Yes
Tropical moistMAP > 2000 –
4000 mm
Tropical dry
Nival
No
Yes
No
2. Climate homologation (Caldas Lang – IPCC)
MAT = Mean Annual Temperature
MAP = Mean Annual Precipitation
Date
RESULT 1. Homologation of soil map (USDA to IPCC)
IPCC Soil Area (ha) %Organics 579.511 0,51
Sandy soils 7.276.236 6,39Wetland soils 14.131.937 12,41
Volcanic 8.324.948 7,31Spodic soils 8.159 0,01Law Activity
Clays 76.013.824 66,73
High Activity Clays 4.323.411 3,8
Others 3.261.473 2,86
Direct IPCC Homologation. Adjusted IPCC Homologation
CLIMA (IPCC)Polar dry
Cool temperate moist
Warm temperate dry
Warm temperate moistTropical montanoTropical dryTropical moistTropical wet
Date
Default reference Soil Orgnic C Stocks (SOC ref)for mineral soils (tonnes C ha-1 in 0-30 cm depth)
Date
Default reference Soil Orgnic C Stocks (SOC ref)for Wetland Mineral Soils (in 0-30 cm depth)
Date
Results: Reference Soil Organic Carbon (SOCr) for mineral soil
5.957,71 Gigaton C
Cold humid climate soils from the Andes stock more Organic C than warm, or tropical soils from Caribe, amazonas and Orinoco Regions.
Discussions: Soil Homologation
Wetland soils: plenty of soil types have “aquic” conditions and flooding time vary per year from 1 to more than 6 months.“Recommended to consider specifications for wetland soils”
LAC vs HAC soils: - Great part of mineral soils are neither LAC or HAC. Thus over/under- estimation of SOC.• Recommended to create an intermediate class
IPCC considers low precipitation differences between tropical wet and Tropical moist (1000 mm) when precipitation vary up to 14000 mm (wide range)IPCC does not considers a tropical arid class, (Guajira = Caribe).Climate zoning must be estimated using effective precipitation, specially in mountain regions where runoff occurs commonly
Climate considerations
Date
Use of Reference Soil Organic Carbon (SOCr)Next steps:
Validate with local data
Compare with land cover to estimate Soil Organic Carbon loss
Determine local factors of C stock and C loss
Thankyou very much
Muchas Gracias