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Soil carbon sequestration under Miscanthus x giganteus
A large scale survey
Jesko Zimmermann
Jens DauberMichael B. Jones
Miscanthus
Miscanthus x giganteus
• Ligno-cellulosic or „second generation“ bioenergy crop
• Rhizomatous perennial grass with a C4 photosynthesis
pathway
• Originates in Asia (tropics and subtropics)
• Remarkable adaptability to cool temperate climates
• Introduction subsidised in Ireland
Soil carbon sequestration potential due to physiological features and management practices
Picture: Jens Dauber
Research questions
Research on carbon sequestration mainly on
experimental fields, however differences can be
expected in commercial plots
This study is focused on commercial large-scale
Miscanthus fields in south east Ireland, looking at:
• Soil carbon sequestration
• Initial soil carbon loss
• What is influencing the processes?
Picture: Susannah Cass
Regional-scale study
Sampling
Nested sampling design
A number of soil cores taken at three subplots in a Miscanthus field and an adjacent control site representing the former land-use
Cores divided into three depth and bulked over the sub plot.
Additional cores taken for bulk density
Materials & Methods
Analyses
The bulked samples were processed in the lab and following measurements were taken:
Total organic carbon
13C/12C stable isotope ratio to determine the Miscanthus-derived carbon (13C natural abundance method)
Soil bulk density, particle size distribution, and pH
Materials & Methods
-10.00 0.00 10.00 20.00 30.00 40.00
Control
Miscanthus
Control
Miscanthus
Control
Miscanthus
10
20
30
SOC [Mg ha-1]
Dep
th [
cm]
C3-derived carbon
C4-derived carbon
-10.00 0.00 10.00 20.00 30.00 40.00
Control
Miscanthus
Control
Miscanthus
Control
Miscanthus
10
20
30
SOC [Mg ha-1]
Dep
th [
cm]
After Zimmermann et al., (2012) Global Change Biology Bioenergy, Vol. 4, Issue 4.
Tillage Grassland
Field-scale study
Picture: Susannah Cass
MG14 TCD_2_1
Average patch area 4.357 m2 3.710 m2
Standard deviation 8.702 25.245
No. Patches 901 1243
Sum of patch area 0.393 ha 0.461 ha
Overall field size 4.390 ha 3.982 ha
Share of field 8.95 % 11.58 %
Zimmermann et al. (in prep.)
Farm Area [m2] SD Radius [m] SD
MT3 8.672 6.287 1.519 0.691
MT5 8.151 4.111 1.570 0.372
MT6 10.595 6.028 1.772 0.496
MG11 18.185 14.109 2.233 0.923
MG18 4.329 1.965 1.146 0.264
MG20 10.488 6.335 1.751 0.537
-50 -40 -30 -20 -10 0
MT6
MT5
MT3
MG20
MG18
MG11
Difference to area of a non-patch field [%]
Farm
High
Medium
Low
Zimmermann et al. (in prep.)
Miscanthus-derived carbon [Mg ha-1]
-0.50 0.50 1.50 2.50
10
20
30
High density
Open patch
-0.50 0.50 1.50 2.50
10
20
30
Tillage Grassland
Zimmermann et al. (in prep.)
Farm scale
-40 -30 -20 -10 0
MG11
MG18
MG20
MT3
MT5
MT6_1
MT6_2
Difference in Miscanthus-derived carbon to a no-patch field [%]
High
Mean
Low
Conclusions
Measurable soil carbon sequestration even 2 to 3 years after planting Miscanthus
No significant loss of soil organic carbon due to plantation
High variability between farms
Crop patchiness has significant impact on yield and soil carbon sequestration
Acknowledgements
David BourkeKees-Jan van Groenigen
Susannah CassKate Harte
Bas BootsKatie WennigCatherine FontanaZeno WongMaximilian von SternburgErin Jo TiedekenSarah Kimberley
The Simbiosys Team
The land-owners for their kind permission to work on their lands
The EPA for funding the project
