INSTITUTE OF METEOROLOGY AND CLIMATE RESEARCH, ATMOSPHERIC ENVIRONMENTAL RESEARCH, IMK-IFU
DIVISION/Working Group… (change in master view)
Quantifying Greenhouse Gas Emissions
from Managed and Natural Soils
Klaus Butterbach-Bahl1,2, Björn Ole Sander3, David Pelster2, Eugenio Díaz-Pinés1
1: Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU)
2: International Livestock Research Institute (ILRI) , Nairobi , Kenya
3: International Rice Research Institute (IRRI) , Los Baños, Philippines

2
Motivation
Worldwide, agriculture is responsible for 47 and 84 % of anthropogenic
CH4 and N2O emissions, respectively (Smith et al 2007, IPCC WG III)
Smallholder farms are crucial in e.g. Sub-Saharan Africa
75 % of both agricultural and job production (Africa Development Bank 2010)
80 % of farms in SSA are smaller than 2 ha (FAO 2010)
Yields are low (ca. 1 Mg ha-1)
Evidence-based data of GHG emissions in smallholder farms is scarce
Source: Rosenstock et al. 2016. D.O.I. 10.1007/978-3-319-29794-1_1

3
Chamber methods for measuring GHG fluxes
in terrestrial ecosystems
Pros
+ Simple, no in-situ analyzers needed
+ Allow for treatment-plots experiments
+ Existence of protocols
Cons
- Change in the soil environmental conditions
- Spatial and temporal variability of fluxes
- Accuracy and reliability of measurements

4
Chamber
Placement
Terrain
Soil
Vegetation
Management
Logistics
•Depressions/ ridges/ slope
(deposition/ erosion, depth to
groundwater) / aspect
•Paths (bulk density)
•Stones/ terraces (management)
•Color (SOC/ flooding)
•Texture (water/ nutrient availab.)
•Compaction/Plough pan (bulk
density)
•Natural (vegetation layers/ patchiness,
species, coarse woody
materialnutrient/ water availability)
•Row crops (row/ interrownutrient/
water availability)
•Intercropping (nutrient/ water
availability)
•Irrigation/ flood water inlet/outlet
(soil processes)
•Fertilization (water/ nutrient
availab.)
•Compaction/Plough pan (bulk
density)
•Accessibility
•Change of soil properties along
access paths
•Interference with management

5
Gas
sampling
Monitor
Timing
& interval
Vials
Sampling
Storage
•Crop performance in/ outside
chamber
• Animal activity (e.g. ants, termites,
earthworms)
•Chamber seals/ maintainance
•Approx. at average daily soil-T (e.g.
morning 9-11)
•Minimize closure time (determine
minimum detectable flux) to
minimize chamber effects on soil
environmental conditions
•Flushing (min. 2x volume) or use
pre-evacuated vials
•Overpressurize
•Logical numbering
•Minimize disturbance at the plot
(plant cover/ soil compaction)
•Flush syringe
•Ensure headspace mixing
•Check seal tightness
•Determine max. storage time
•Use standards for comparison
•Store vials in boxes

6
Gas analysis
and data
processing
Responsibility
Measurement
instrument
Flux
calculation
Maintenance
Reporting
•Hierarchy of responsibility
(instrument maintenance/ analysis/
data storage/ reporting)
•Understand principles
•Optimize sensitivity in terms of
accuracy & precision
•Coefficient of variation for repeated
concentration measurements (e.g. N
=5) <1%
•Check relationship between
instrument signal and concentration
•Linear or non-linear (understand
advantages and disadvantages of
both)
•Calculate detection limits
•If slope of regression = 0 (check p-
value of slope)  flux = 0
•Stock spare parts
•Check & service instrument
regularly
•Clean environment
•Do flux calculations immediately
•Report back problems to sampling
team (e.g. numbering/ unusual
noise in concentration changes
across sampling interval
•Check logic of fluxes with
observations of auxilliary
measurements

7
Auxilliary
Measurements
& Reporting
Socio-
economy
Meteorology
Soil
properties
Soil hydrology
Crop/ plant
performance
•Precipitation
•Air temperature
•Photosynthetic active radiation
•Wind speed/ direction
•Relative humidity
•Evapotranspiration rates
•Soil-temperature/ moisture
(different layers down to 1m if
possible)
Multi-layer (0-10, 10-20, 20-50, 50-
100 cm)
•Texture/ SOC/ total N / inorganic
N/ bulk density/ pH
•Water saturated conductivity
•Microbial biomass C and N
•Litter type / depth / C and N
content (if applicable)
•Water infiltration / hydraulic
conductivity / water holding capacity
•Distance to groundwater
•Floodwater depth (e.g. rice paddies)
•Depth of drainage tiles
•Biomass development (monthly)
•Pests/ diseases/ weeds
•Development stages (e.g. tillering/
flowering)
•LAI
•Harvest index
•Yield / N content
Management
•Field operations (e.g. ploughing,
seeding, weeding, fertilization,
irrigation, harvesting, pesticide
applic.)
•Fertilizer types & amounts
•Crop type / rotation, variety and
planting density
•Residue management

8
Spatial and temporal variability of soil GHG fluxes
Source: Barton et al. 2015,
Scientific Reports,
D.O.I. 10.1038/srep15912
Source: Cowan et al. 2015,
Biogeosciences,
D.O.I. 10.5194/bg-12-1585-2015

9
Chamber 1
The gas pooling technique
Arias-Navarro et al. 2013, Soil Biol Biochem, D.O.I. 10.1016/j.soilbio.2013.08.011
Close
Mixing of the gas sample
Pressurize/ Expand
T0
Inject, flush &
overpressurize
glass vial
T0
T0
T1T2T3
T2 T1T3
Gas Chromatograph

10
Chamber-based methods are recommended in complex
landscapes such as smallholder agriculture.
Spatial and temporal variability remains a huge challenge
 adequate design and sampling frequency are crucial.
QA/QC is essential at all steps.
Chamber design and positioning
Gas sampling and analysis
Calculations and reporting
Conclusions
Voice: David Pelster, Klaus Butterbach-Bahl & Allison Kolar