Above- and Below-ground Biomass and Soil Organic Carbon Inventories of Willow Biomass Crops Across a 19-year Chronosequence

Transcription

1 Above- and Below-ground Biomass and Soil Organic Carbon Inventories of Willow Biomass Crops Across a 19-year Chronosequence Renato S. Pacaldo 1, Timothy A. Volk 1, Lawrence P. Abrahamson 1, and Russell D. Briggs 1 1 Department of Forest and Natural Resource Management, SUNY College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, NY 13210

2 Overview Introduction Methods site selection and lay-out of sampling plots belowground biomass aboveground biomass soil organic carbon Results and Discussion biomass accumulation pattern across a 19-yr chronosequence on below- and above-ground biomass above- and below-ground biomass ratio soil organic carbon Conclusion

3 Introduction Previous Life Cycle Analysis (LCA) (Heller et al. 2003): Willow biomass crops: low carbon fuel source 3.7 Mg CO 2eqv ha -1 emissions over 7 rotations 499 Mg CO 2eqv ha -1 accumulated in above ground woody biomass over 22 years

4 In willow production system Most data focused on aboveground biomass Aboveground stool biomass No data available Stems (stool) biomass Belowground biomass (belowground stool) (coarse roots) (fine roots) Very limited data available Heller et al. (2003) LCA s used shoot-root (S:R) ratio of 1.75, derived from Matthews (2001) and Volk (2002), to estimate belowground biomass. Shoot biomass: 13.6 odt ha -1 yr -1 from 3 rd rotation data

5 Objectives Inventory on above- and below-ground biomass and soil organic matter (SOM) across a 5-, 12-, 14-, and 19- year old willow (SV1 - Salix dasyclados) chronosequence. Variables measured Biomass: leaves, stems, and aboveground stool fine root, coarse root, and belowground stool total aboveground and total belowground SOM in 15 cm increments to 45 cm soil depth Determine shoot-root (S:R) ratio

6 Importance Information on belowground biomass is essential in the determination of GHG balances and C dynamics Inform the ongoing debate: high /low carbon fuel source? Or carbon neutral? Or carbon sink?

7 Study Sites 3 sites at Tully and 1 site at Lafayette, NY Planted 1997 Planted 1995 Planted 1990 Planted 2004

8 Study Sites 6 plots/ site Site characteristics for both sites Soils Tully: gravelly silt loam, well-drained; shallow bedrock and fragipan Lafayette: gravelly silt-loam; well-drained to moderately poorly drained; shallow bedrock and fragipan Topography Tully: 0 % slope (flat) Lafayette: 0-5 % slope (slightly rolling terrain Climate: Both sites have mean annual precipitation of 960 mm; mean annual temperature 8 C

9 5 m Sampling Procedure Taking samples for stem biomass x x x x4 m x x x x

10 Sampling Procedure Leaf biomass, above- and below-ground stools biomasses aboveground stool x x x x x x x x x x x x x x x x x x x x Take representative plant within sampling plot Cut the stool Harvest leaves and stems belowground stool

11 same age across the four willow fields because we cut them at the same time age: 6, 13, 15, and 20 years old across four willow fields

12 2 ft 2 ft Fine roots Sampling Procedure 2 ft x x 5 x ft x x x x x x x x x x x x x x x x x x x x x 3.5 ft sampling pit x x x x x x

13 Fine roots Sampling depth: 45 cm in 15 cm interval composite soil samples for fine root biomass hand pick the fine roots and oven-dry at 65 C for 15 days

14 2 ft Sampling Procedure Coarse roots (> 2 mm diameter) x x x x x x x x x x 3.5 ft x x x x x x x x x x x x x x

15 5 m Sampling Procedure Soil organic matter (SOM) in 15cm increments x x x x4 m x x x x soil sample x x for total SOM xdetermination x by loss x xon ignition (LOI) measure coarse fragment volume 2 mm sieve

16 Results and Discussion Salix dasyclados relative distribution of fine roots, coarse roots, and belowground stool across a 19-year chronosequence 18 Biomass Production (odt ha -1 ) Belowground Stool Fine Roots Coarse Roots Age of Willow Crop (year)

17 Salix dasyclados relative biomass distribution of foliage, stem,and aboveground stool. Stem biomass includes a two-year growth accumulation. 50 Biomass Production (odt ha -1 ) Stem Aboveground Stool Foliage Age of Willow Crop (year)

18 Total Biomass Production (odt ha -1 ) Salix dasyclados total above- and belowground biomass productions. Stem biomass includes a two-year growth accumulation Total Aboveground Total Belowground Age of Willow Biomass Crop (year)

19 Below- and above- ground biomass ratio Age (yr) Total Belowground Biomass (kg/plant) Total Aboveground Biomass (kg/plant) Above:Belowgrou nd Ratio (R:S Ratio) a 1.43 b 0.95 ( 0.14) b b 2.00 b 0.72 ( 0.10) c a 2.71 a 1.18 ( 0.10) ab a 2.77 a 1.23 ( 0.18) a P values n=24 < < Consistent with other studies on SR ratio: 1.40 (Volk, 2002) for young Salix dasyclados (SV1) clone

20 Different ratios between stems and belowground biomass across the four willow ages Age (yr) Stem: aboveground stool + total belowground Stem:total belowground Stem+foliage :total belowground a 0.54 a 0.69 a b 0.34 b 0.43 b a 0.70 a 0.83 a a 0.70 a 0.86 a

21 total amount of SOC (Mg ha -1 ) Salix dasyclados Soil Organic Carbon (SOC) Mg ha Mg ha Control Age of Willow Crop (Year)

22 Previous reports 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).

23 Aboveground Stool Stand Age Above- and Belowground Stool Biomass (Mg ha -1 ) CO 2 Eq. Sequestration (Mg ha -1 ) ( 0.74) ( 1.47) ( 1.34) Belowground Stool ( 1.91) 38.48

24 Adjustment of previous life cycle analysis. Emissions LCA results from Heller et al. (2003) CO 2 (Mg CO 2 ha -1 ) Other GHG (Mg CO 2 eq ha -1 ) Diesel fuel Agr Inputs N 2 O from N fertilizer N 2 O from foliage C Sequestration Total (Mg CO 2 eq ha -1 ) Below ground Soil C 0 0 Net Total Harvested Biomass Current Study CO 2 (Mg CO 2 eq ha -1 )

25 Conclusions Total belowground biomass: No statistically significant differences were detected among 12-, 14-, and 19- year old stands Biomass increases from 5 to12 years; stabilize onward with slight variations. Biomass production: 11 to 22 Mg ha -1 for 12- and 19- year old stands, respectively. Total aboveground biomass: No statistically significant differences were detected between stands: 14- and 19- yr old and 5- and 12-yr old Biomass production: 10 to 21 Mg ha -1 yr -1 for 5- and 19- year old stands.

26 total above:belowground (S:R) ratio increases with age. S:R ratio of 0.53 could be used to predict belowground biomass for mature willow crop using the harvested shoots (stem) biomass data Steady state SOC across a19-year chronosequence. Our data suggest that SRC willow is not only a source of renewable energy, but also a carbon sequestration production system

27 Acknowledgment This 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 for their help and support 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 And above all to our Almighty God!

28 Thank You!