Above- and Below-ground Biomass and Soil
Organic Carbon Inventories of Willow Biomass
Crops Across a 19-year Chronosequence
Renato S. Pacaldo*, Timothy A. Volk, Lawrence P. Abrahamson, and
Russell D. Briggs
Department of Forest and Natural Resource Management, SUNY College of
Environmental Science and Forestry,
1 Forestry Drive, Syracuse, NY 13210
8TH BIENNIAL SRWC OPERATIONS WORKING GROUP CONFERENCE
SHORT ROTATION WOODY CROPS IN A RENEWABLE ENERGY FUTURE:
CHALLENGES AND OPPORTUNITIES
OverviewOverview
IntroductionIntroduction
MethodsMethods
site selection and laysite selection and lay--out of sampling plotsout of sampling plots
belowground biomassbelowground biomass
aboveground biomassaboveground biomass
soil organic carbonsoil organic carbon
Results and DiscussionResults and Discussion
biomass accumulation pattern across a 19biomass accumulation pattern across a 19--yr yr chronosequencechronosequence
on belowon below-- and aboveand above--ground biomassground biomass
aboveabove-- and belowand below--ground biomass ratioground biomass ratio
soil organic carbonsoil organic carbon
ConclusionConclusion
IntroductionIntroduction
Short Rotation Willow Biomass Crops:Short Rotation Willow Biomass Crops:
Carbon Neutral (Carbon Neutral (KeoleianKeoleian and Volk, 2005)and Volk, 2005)
OROR
Low Carbon Fuel?Low Carbon Fuel?
IntroductionIntroduction
Previous Life Cycle Analysis (LCA) (Heller et al. 2003):Previous Life Cycle Analysis (LCA) (Heller et al. 2003):
Willow biomass crops: low carbon fuel source
3.7 Mg CO2eqv ha-1 emissions over the 22 year lifespan
499 Mg CO2eqv ha-1 accumulated in above ground woody biomass
over 22 years
IntroductionIntroductionMost studies focused on aboveground biomass
production
Limited data available on below ground biomass
Previous LCA estimate assumed belowground
biomass accumulation occurred over 3 rotations based
on harvested yield and shoot:root ratio of 1.75.
Why Important?
Belowground biomass is essential for determining
GHG balances and C allocation dynamics
IntroductionIntroduction
On soil organic carbon (SOC)
Ulzen-Appiah (2002) reported no measurable
changes in soil C in willow coppice systems
production for 12 years.
SOC in hybrid poplar declined at early stage
(Hansen, 1993) and then increased after 5
years (Grigal and Berguson, 1998; Coleman et.
al., 2004).
Same pattern across a 19-yr chronosequence?
ObjectivesObjectivesTo inventory aboveTo inventory above-- and belowand below--ground biomass and soil ground biomass and soil
organic matter (SOM) across a 5organic matter (SOM) across a 5--, 12, 12--, 14, 14--, and 19, and 19-- year year
old willow (SV1 old willow (SV1 -- Salix Salix dasycladosdasyclados) ) chronosequencechronosequence. .
Variables measuredVariables measured
Biomass:Biomass:
leaves, stems, and aboveground stoolleaves, stems, and aboveground stool
fine root, coarse root, and belowground stoolfine root, coarse root, and belowground stool
total aboveground and total belowgroundtotal aboveground and total belowground
RootRoot--shoot ratioshoot ratio
SOM in 15 cm increments to 45 cm soil depth SOM in 15 cm increments to 45 cm soil depth
HH00: there is no significant difference in above: there is no significant difference in above-- and and
belowbelow-- ground biomass and soil organic carbon by age.ground biomass and soil organic carbon by age.
Planted
1995
Planted
1990
Planted
2004
Study Sites
3 sites at Tully and 1 site at Lafayette, NY
Planted
1997
6 plots/ site
Site characteristics
Tully:
Soil: gravelly silt loam, well-drained
High Meadows, Lafayette Road
Soil: gravelly silt loam, well-drained to somewhat
poorly drained
shallow bedrock and fragipan in some locations
MAP ≈ 960 mm
MAT ≈ 8 C
Study Sites
SpeciesSpecies
Salix Salix dasycladosdasyclados (SV1)(SV1)
5-year old willow crop 19-year old willow crop
During inventory period, the stems had been
growing for two years since the last cutting
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4 m
5 m
Sampling ProcedureSampling Procedure
Taking samples for stem biomass
Leaf biomass, above- and below-ground stools biomasses
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Sampling ProcedureSampling Procedure
Take representative
plant within sampling
plot
Cut the
stool
Harvest leaves and stems
aboveground
stool
belowground
stool
Fine roots
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2 ft
2 ft
5 ft
3.5 ft
2 ft
sampling pit
Sampling ProcedureSampling Procedure
composite soil samples
for fine root biomass
hand pick the fine roots and
oven-dry at 65 C for 15 days
Fine roots
Sampling depth: 45 cm in 15
cm interval
Coarse roots (> 2 mm diameter)
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3.5 ft
2 ft
Sampling ProcedureSampling Procedure
Soil organic matter (SOM) in 15cm increments
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4 m
5 m
soil sample for total
SOM determination
by loss on ignition
(LOI)
measure coarse
fragment volume2 mm sieve
Sampling ProcedureSampling Procedure
Statistical AnalysisStatistical Analysis
ANOVA to find out significant difference of ANOVA to find out significant difference of
biomass and SOC by age classesbiomass and SOC by age classes
if the results are significantly different, if the results are significantly different,
treatment means are compared by Least treatment means are compared by Least
Significant Difference (LSD) test.Significant Difference (LSD) test.
univariateunivariate procedure procedure –– for testing normal data for testing normal data
distributiondistribution
Leven’s test Leven’s test –– for testing homogeneity of for testing homogeneity of
variancevariance
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
5-yr old 12-yr old 14-yr old 19-yr old
Mg
ha
-1
Salix dasyclados belowground biomass
Belowground Stool
Coarse Roots
Fine Roots
Results and DiscussionResults and Discussion
Salix dasyclados stem & leaf biomass
(annual yield)
0
5
10
15
20
25
5-yr old 12-yr old 14-yr old 19-yr old
Mg
ha
-1yr-
1
leaf biomass
stem biomass
17.6
7.2
2.63.3
Salix dasyclados aboveground stool
biomass (total yield)
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
5-yr old 12-yr old 14-yr old 19-yr old
Mg
ha
-1
4.8
10.2
Salix dasyclados above- and below- ground
biomass (total yield at time of inventory)
0
10
20
30
40
50
60
5-yr old 12-yr old 14-yr old 19-yr old
Mg
ha-1
belowground biomass
aboveground biomass
22 Mg ha-1
13 Mg ha-1
48 Mg ha-1
21 Mg ha-1
Below- and above- ground biomass ratio
Age (yr) Total Belowground
Biomass(kg/plant)
Total Aboveground
Biomass(kg/plant)
Below:Above-
ground Ratio
(R:S Ratio)
19 2.33a (0.37) 4.24a (0.24) 1:1.82
14 2.39a (0.10) 4.39a (0.49) 1:1.83
12 2.88a (0.28) 2.93b (1.06) 1:1.02
5 1.48b (0.11) 2.16 b (0.46) 1:1.46
P values
n=24
<0.0001 <0.0001
Consistent with other studies on SR ratio:
1.75 (Heller et al 2003)
1.40 (Volk, 2002) – for young Salix
dasyclados (SV1) clone
The higher SR ratio (i.e 1.8) in Tully compared to Lafayette
site (1.0) could be attributed to the differences in site quality
Tully Study Sites (Age 5, 14, 19) Lafayette Study Site (Age: 12)
Age Bulk density in
30-45 cm depth
(g/cm3)
5 1.3 -1.6
12 1.5 - 1.7
14 1.3 - 1.4
19 1.0 - 1.2
In poor site, about
60% of NPP is used
to develop short-live
roots (Reyes et al.,
1981)
Salix dasyclados Soil Organic Carbon (SOC)
100
120
140
160
180
200
0-yr old 5-yr old 12-yr old 14-yr old 19-yr old
Mg
ha
-1
182 Mg ha-1
175 Mg ha-1
Age
5-yr old 14-yr old 19-yr old 12-yr old
SO
C (
Mg
ha-1
)
0
20
40
60
80
100
120
0-15 cm
15-30 cm
30-45 cm
Salix dasyclados Soil Organic Carbon (SOC) by Depth
SOC in this study is consistent with some
previous reports:
No detectable changes in microbial biomass
carbon (labile carbon) in SRWC across a 12-yr
chronosequence (Ulzen-Appiah, 2002)
SOC declined at early stage (Hansen, 1993)
and then increased after 5 years (Grigal and
Berguson, 1998; Coleman et. al., 2004).
SOC in SRWC poplar ranged from 20 to more
than 160 Mg ha-1 (Coleman et al., 2004).
LCA Results from Heller et al. (2003)
CO2
(Mg CO2
ha-1)
Other GHG
(Mg CO2
eq ha-1)
Total
(Mg CO2
eq ha-1)
Emissions
Diesel fuel 3.1 0.1 3.2
Agr Inputs 2.9 0.4 3.4
N2O from N fertilizer 3.9 3.9
N2O from foliage 7.3 7.2
C Sequestration
Below ground -14.1 -14.1
Soil C 0 0
Net Total -8.0 11.7 3.7
Harvested Biomass -499.2 -499.2
3.2
7.2
3.4
3.9
Current Study
CO2
(Mg CO2 eq
ha-1)
-38.5
0
-20.8
Estimates of GHGs gas flows per hectare of willow plantation,
accumulated over 7 rotations
ConclusionsConclusionsThere is significant difference in total belowground biomass There is significant difference in total belowground biomass
across a 19across a 19--year year chronosequencechronosequence
increases until about age 12, and stabilize onward with slight increases until about age 12, and stabilize onward with slight
variations. variations.
No significant difference in belowground stool biomass between No significant difference in belowground stool biomass between
ages 5ages 5-- and 12and 12-- year old and between ages 14year old and between ages 14-- and 19and 19--year old year old
SRWC plantation.SRWC plantation.
Aboveground biomass is significantly different across the Aboveground biomass is significantly different across the
chronosequencechronosequence and increases with age. and increases with age.
No significant difference in SOC across a19No significant difference in SOC across a19--year year
chronosequencechronosequence . .
Limitation of this study: site quality confounded the effects of Limitation of this study: site quality confounded the effects of
age as shown in Lafayette site. Variation of site quality is one of age as shown in Lafayette site. Variation of site quality is one of
the major sources of error in the major sources of error in chronosequencechronosequence studies (studies (YanaiYanai et et
al., 2000).al., 2000).
AcknowledgmentThis study was carried out with the funding support
from USDA Rural Development through Timothy A.
Volk and Lawrence P. Abrahamson.
We wish to thank the following people for their help during the
data collection
Project Staff:
Rebecca Allmond, Eric Fabio, Philip Castellano, and Ken Burns
Student Assistants:
Jacob Bakowski, Tyler Harvey, Gabe Kellman, Jason Maurer,
Ryan Newby, and Devin Mc Bride
Thank You!