CLIFF Workshop 2017
GHG Quantification Approaches
Bandhu Raj Baral
Ph D Scholar (Soil Science), Agriculture and Forestry University,
Rampur, Chitwan, Nepal

Outlines
1. Introduction and background
2. Research objectives and hypothesis
3. Methodology of research
4. Results
5. Conclusion
6. Future work and application

Introduction- GHG in agricultural system
IPCC (2007)

Projections for 2030 and 2050 - Agriculture
Source: FAO: World Agriculture towards 2030/2050

Objectives
• To learn techniques how to take sample to quantifying for GHG
emission from agricultural system fertilized and unfertilized soil
Ph D Research objective
• Enhancing nitrogen use efficiency in rice and rice based system
in Mid western terai region of Nepal
• N Fertilizer type, methods and rice varieties can minimize N
losses i.e application of Urea briquatte in deep placement can
reduce N loses through available directly NH4 at reduced root zone.
Therefore N losses through nitrification, denitrification, emission
through fluxes and leaching is reduced.
•Use of decision support tools minimize N loss and support getting
high net returns
Ph D Research hypothesis

•Close Chamber method (transparent,
opaque, static, dynamic)
•Eddy covariance
•Relaxed eddy covariance method
•Flux-gradient method
•Energy balance method
•Models, tools and calculators (Cool Farm
Tool, CCAFS Mitigation option Tools)
GHG emission measurement/estimation
methods

Research site details
Host Organization: CIMMYT, India
Host Scientist: Dr. Tek Sapkota
Research location site: ICAR-CSSRI farm land,
Karnal, Haryana
Geo coordinates: Latitude 29.685700N
Longitude 76.99050S
Crop: wheat
Av. Annual rainfal:669 mm
Agroecology: Warm semi arid subtropics
Soil texture: Medium
Soil pH: 6.4-8.2
Soil OM: 0.41 -0.7%
Soil Bulk density:1.5 g/cm3
CEC : 20.12-22.86 C mole/kg

Methods of close chamber design & installation

Methodology: Chamber installation

Gas sample taking and prepared for gas chromatography

Results and learning outcome
Advantages:
• Can measure very small flux
• relatively inexpensive to build and use
• Simple operating principle
• can be adapted to a wide range of field conditions
Limitations:
• Can not account for spatio-temporal variability
• Perturbation
• Influenced by temperature, pressure and moisture fluctuation
inside the chamber
Advantages and disadvantages of Chamber method of GHG flux
sampling
•Unfortunately, N2O measurement was not possible due to Gas
Chromatography did not well functioned at that time in Karnal, India and in
Nepal not available but we learnt many important techniques of sampling
and principle behind it and tried some of the techniques and principle in my
Ph D research

Emission measurement approach used in PhD
research
• Close chamber approach used in my research to
measure NH3 emission
• Periodic flux measured after N fertilizer application
• When NH3 is passed through the acid trapping solution,
it neutralizes some of the acid. Adequate acid
stoichiometric capacity of the trap system is thus critical
to ensure all the NH3 in the sample air is absorbed
without complete acid neutralization. For example,
when sulfuric acid solution is used in the trap,
stoichiometrically one mole of the acid can completely
trap two moles of ammonia as shown in Eq. H2SO4
+2NH3⇒(NH4 )2SO4

M & M : Experiment 1
Experimental set up
• Experiment type: Field trial
• Design: Factorial stripplot
RCBD
• Replication: Three
• Plot size: 3.6m x 4m (14.4 m2 )
• Spacing : 20 x 20 cm
• Beginning of experiment:
June,2017
• Location: Khajura, Banke,
Nepal
Treatments
Factor A
Variety
1) Hybrid rice Arize-6444
2) Improved variety Radha-4
3) Drought tolerant (Sukkha 4)
Factor B
Fertilizer application method
1. 0 kg N/ha
2. Broadcast-granular urea (78 kg N/ha)
3. Deep placement-granular urea (78 kg
N/ha )
4. Deep placement-urea Briquatte (78 kg
N/ha)
5. Broadcast-granular urea (100 kg N/ha)
Note: After rice to see the residual
effect of fertilizer wheat crop with
75% RDF will be applied except
control plot
Exp. 1: Evaluation of different N fertilizer application methods for N use
efficiency in rice and succeeding wheat

M & M Experiment 2
Experimental set up similar to experiment 1
Treatment
1) Control (0 kg N/ha)
2) Complete Optical sensor guided based on NDVI
3) Complete Chlorophyll meter (SPAD) guided
4) Complete Leaf Color Chart (LCC) guided
5) 25 kg/ha basal N rest OS guided
6) 25 kg/ha basal N rest SPAD guided
7) 25 kg/ha basal N rest LCC guided
8) Recommended practice fixed dose 100 kg N/ha in
3 split dose ½ as Basal, ¼ at tilleringand ¼ at
panicle initiationstage
9) Urea deep placement (78 kg N/ha)
Exp. 2: Test, evaluate and identify the most effective decision support tools for site
specific in-seasonnitrogen management in rice and wheat under rainfed condition

Close Chamber method flux trapping applied picture

Results: Effect of fertilizer application and rice
varieties on NH3 flux
0
1
2
3
4
5
6
7
Control BC 78 kg N/ha DP 78 kgN/ha Briquatte DP 78
kgN/ha
BC 100kg N/ha
NH3 fluzkg/ha/18hr
Hybrid Arize 6444 Radha-4 Sukkha dhan 3

Results : Effect of fertilizer application on NH3 flux
0
1
2
3
4
5
6
Control BC 78 kg N/ha DP 78 kgN/ha Briquatte 78 kg
N/ha
BC 100 kg N/ha
NH3Fluxkg/ha/18hr

Result: Relationship of pH and NH3 flux
0
1
2
3
4
5
6
7
8
9
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45
Soil pH
NH3 Flux

Conclusion
• N2O measurement was not possible due to Gas
Chromatography did not well functioned at that
time in Karnal, India and in Nepal not available.
• Sampling through the chamber method was very
low cost techniques and feasible for sampling
• Chamber techniques can be applied for other GHG
measurement
• It is possible to integrate an ammonia acid trap in
an insitu-GHG emission monitoring system
• GHG farm tools/calculator and model are also
applicable for farm based GHG flux estimation

Future work
• Sampling through chamber techniques can be
applied in future further work
• Further research necessary for any low cost
techniques alternative to measure N2O flux
measurement
• It is possible to integrate an ammonia acid
trap in an insitu-GHG emission monitoring
system in future
• Farm and region based modeling tools for
calculation of GHG will be practical in future.

Thank you
for
your attention