Download - 9 McElligott Biochar Biomass Conversion
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Kristin McElligott, Mark Coleman, and Debbie Page-Dumroese
THE EFFECTS OF BIOCHAR ON FOREST SOIL CHEMICAL
PROPERTIES AND TREE GROWTH
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Biochar Application in ForestryPresentation Overview
------------------------------
Context and Research Justification
Positive & Negative Aspects of Biochar
Research Results
Biochar/soil incubation study
Greenhouse Bioassay: Poplar growthresponse to biochar additions
Application and Feasibility
Potential Implications for LandManagers
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Context------------------------------
Remove forest biomass/residues
Forest health improvement, fuels reduction
Bioenergy production: portable fast pyrolysis units
Concerns associated with removals
Alter nutrient cycling, reduce SOC, site degradationover time?
Economics
Mollify concerns with biochar application? Return/retain site nutrients
Improve soil properties
Long-term C sequestration
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Forestry, Bioenergy, & Carbon------------------------------
Forestry: Source of biomass, need forfuels reduction
Bioenergy: Co-production of biofuels andbiochar via pyrolysis
Energy extraction without nutrient removals
Carbon: Biochar is 70-80% C, creates long-term soil carbon sinks
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Biochar Pros and Cons------------------------------
Carbon sequestrationpotential
Soil nutrient & water retention
Bioavailabilityplantproductivity
Soil fertility, microbial activity
Inhibit nutrient leaching
Reduce N2O and CH4emissions
Polycyclic aromatichydrocarbons (PAH)
Heavy metals
Priming
Raise pH? Reduce plant growth?
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Research Justification------------------------------
Environmental Implications: Demonstrate effects ofbiochar on forest soil properties and woody biomassgrowth
1. Biochar as a forest soil amendment:
Compare effects of biochar and application method onforest and agricultural soil chemical properties
2. Greenhouse bioassay:
Investigate if plant growth/biomass can be enhancedwith biochar
Uncertainties associated with regions/soils
Unique INW soils, volcanic ash inputs
Positive and negative results associated with biocharresearch
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Biochar Incubation Study------------------------------
Laboratory incubation study (Jan-Aug 2010)
Demonstrate biochar effects among various soils
Spodosol, Andisol, Mollisol
Demonstrate application methods
Top-dressing, Incorporation
One rate: 25 Mg ha-1
3 treatments x 3 soils x 6 replicates = 54 soil columns
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Soil Types------------------------------
Soil Classification Horizon Location
Forest Andisolmedial over loamy, mixed, frigid AlficUdivitrand
BwClearwater County,ID
Forest Spodosol sandy, mixed, frigid Aquic Haplorthod E Priest Lake, ID
AgriculturalMollisol
fine-silty, mixed, superactive, mesicPachic Ultic Haploxeroll
Ap Moscow, Idaho
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Biochar Incubation Study------------------------------
pH
OM (%)
Total C (%)
Total N (%) NH4-N (g g
-1)
NO3-N (g g-1)
Available K (g g-1)
Available P (g g-1)
Hypothesis: Biochar additions will enhancestandard soil chemical properties of all soils
CEC (cmol kg-1)
K (cmol kg-1)
Ca (cmol kg-1)
Mg (cmol kg-1
) Na (cmol kg-1)
Microbial Biomass
Leachate N analysis
Properties of interest:
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Measurements and data analysis------------------------------
Cores destructively sampled at 30 weeks
Soil chemical properties, leachate N, and microbial biomass
General linear model used to test for significant effects(=0.05)
Treatment type
Soil type
Interactions
LS Means & Tukeys post hoc procedure (SAS)
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Main Effects on Soil Properties------------------------------
OM increased by 7%
Mixed treatment increased CEC by 5% relative to the control
Available K increased in surface (13%) and mixed (27%) treatments
Control Surface Mixed
0
1
2
3
4
5
a bb
O
rganicMatter(%)
Control Surface Mixed
0
5
10
15
20
25
baba
CEC(cmolkg-1)
Control Surface Mixed
0
50
100
150
200
250
a
b c
A
vailableK(gg-1)
Biochar effects for all soil types combined. significant differences at P < 0.05.
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Interactions------------------------------
C increased for all soils - magnitude varies by soil
Surface and mixed treatment decreased NH4 (63%, 42%) in the Andisol only
pH increased by 8% in the Spodosol
K increased in the Andisol (16%, 21%) and Mollisol (19% mixed trt)
Andisol Spodosol Mollisol0.0
0.5
1.0
1.5
b
a
b a
a
aa
a
ab
K(cmol/kg)
Andisol Spodosol Mollisol0
20
40
60 a
a
a
b
a
ab
a
aN-Ammonia(ug/g)
Andisol Spodosol Mollisol3
4
5
6
a
a
b
a
ab
a
a
a
a
pH
Andisol Spodosol Mollisol0
2
4
6
8
10Control
Top
Mix
b
a
a
bc cd
ef
f
ededCarbo
n%
treatment*soil interactions
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Leachate------------------------------
Biochar reduces NH4 (38%, 99%) and NO3 (56%, 94%) in theMollisol
Andisol Spodosol Mollisol0
20
40
60
80 a
b
c
a aa
aaa
Control
Surface
Mixed
Le
achateNH4mgL-1
Andisol Spodosol Mollisol0
200
400
600
800
1000a
b
caa aaaaLe
achateNO3mgL-1
Leachate N response to biochar treatments
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Test Value
pH 6.8
CEC (cmol kg-1) 30
OM (%) 9
Total C (%) 62
Total N (%) 0.18
K (cmol kg-1) 1.6
Ca (cmol kg-1) 2.2
Mg (cmol kg-1) 0.35
Na (cmol kg-1) 0.17
NH4+ (g/g) 3.3
NO3+NO2 (g/g) < 1.6
Available K (g/g) 710
Available P (g/g) 17
Nutrient Value: direct or indirect effects of biochar?
Indirect = nutrient retention, change in physical properties, soilinteractions
Dynamotive CQuest Biochar------------------------------
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Results Summary------------------------------
Mixed biochar treatments alter exchange sites and increases CEC ofall three soils
Both biochar treatments resulted in significant increases in C andOM among all soil types
K significantly increased in both the Andisol and Mollisol withbiochar additions, but was unchanged in the Spodosol
NH4-N significantly decreased with biochar treatments in theAndisol only
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Discussion Points------------------------------
Application method matters: pH, CEC, and available K
Incorporation may accelerate organo-mineral relationships
Increases in C, OM and available K direct input from biochar
Magnitude of difference varies - Differences in starting colloid properties(OM, C, Clay)
Short lived benefits?
Decreases in NH4
Losses due to leaching, nitrification, volatilization, or immobilization ?
Dilution effect, N-depleted amendment
pH increase in Spodosol only
Result of starting pH of soil (3.8) and biochar (6.8)
Improved nutrient retention
Relevant in fertilized systems
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Biochar is effective at significantly enhancing soil C, OM, K, CEC,
and pH on a short timescale
Improved soil quality and site productivity over time, maybe
Concerns with NH4 reductions in INW soils
Can we expect these results in the field?
Depends on rate, biochar, application method, and plant & microbialinteractions, time
Soil amelioration tool and can
increase the recalcitrant soil carbon pool, long-term carbonsequestration
Repeatable?
Likely, using same char source
Different char, different results?
Application------------------------------
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Tree Growth Response------------------------------
Investigate effects of biochar on woody biomass
Greenhouse bioassay:
Investigate if soil nutrient supply, uptake,and plant growth can be increased withbiochar additions
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Research Justification------------------------------
Current Biochar Research
Agricultural Soil
Crop-growth response
Highly degraded soils
Tropical and Arid Regions
Research Gaps
Forest Soils
Tree growth response
Temperate regions
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Greenhouse Bioassay------------------------------
Biochar and Sand Rates 0%, 25%, 50%
Sand = inert amendment and control
With/without fertilizer
8 weeks, 2 harvests, 10 reps
100 total cuttings
Effects on different soil types? Coarse- and fine-textured Andisol
Expected an increase Poplar growth with biocharadditions
Ashy-pumiceous, glassy Xeric Vitricryands
medial over loamy, mixed, frigid Alfic Udivitrand
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Measurement and Analysis------------------------------
Harvest = separating the plant intoleaves, stems, cutting and roots
Drying, weighing, grinding
Leaf C & N
General linear model used to testfor significant effects (=0.05)
treatment type (control, biochar,sand)
rate (0, 25, 50%)
fertilizer (yes, no)
biomass, and leaf N properties
LS Means, Tukeys post hoc (SAS)
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Results Overview------------------------------
Soil type is significant
Best growth in FA
No Biochar effect
Total, above- and below-groundbiomass (p>0.05)
both soils
Fertilizer effect
Total Biomass FA & CA
Above-ground biomass FA
Negative sand response in CA only
Total and above-ground biomass
No fertilizer effect
Biochar Sand
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Biochar has no significant effect on Total Biomass
Sand amendments significantly reduce Total Biomass
Coarse Andisol
0
2
4
6
8
10a a
a
Control 25% Char 50% Char
TotalBiomass(g)
0
2
4
6
8
10
b
a
b
Control 25% Sand 50% Sand
TotalBiomass(g)
Results------------------------------
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0
2
4
6
a
b
abab
ab
ab
Control 25% Char 50% Char
A
bove-groundBiomass(g)
0
2
4
6
ab a ab
b
abab
No Fert
Fert
Control 25% Sand 50% Sand
A
bove-groundBiomass(g)
Results------------------------------
No response with biochar or sand
Biochar + Fert has greatest positive response Physical properties of char
Potential negative growth response at high rates
Fertilizer additions could avoid negative effects
Fine Andisol
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Results------------------------------
Biochar: no significant differences among rates Follows trend of sand amendment
Sand: decreased growth for CA and not FA
Harvest 2 char*soiltype
0
1
2
3
4
5a
ab
c
bcabc
ab
Control 25%Char 50%Char
Above-groundBiomass(g)
Harvest 2 sand*soiltype
0
1
2
3
4
5
a ab
c
a
bc
ab
Coarse Andisol
Fine Andisol
Control 25%Sand 50%Sand
Above-groundBiomass(g)
Soil Comparison
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Biochar significantly reduces leaf N
Control 25% Char 50% Char0.0
0.5
1.0
1.5
2.0
2.5
a
b b
Leaf
%N
Control 25% Sand 50% Sand0.0
0.5
1.0
1.5
2.0
2.5
a
abb
Leaf
%N
Results------------------------------
Leaf N
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Application in forestryWhy not?
No biochar effect, but potential for negativeconsequences
Decreased leaf N
Short- or long-term effects on productivity?
Soil texture effects response
Biochar application rate is important
Bioassay Summary------------------------------
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Predicted: Slight effect of biochar on forest soilproperties
Mostly positive enhancements in nutrient status
Direct and indirect
Application method
Do these soil alterations effect forest productivity
Probably not - depends on biochar rate
Alterations over time
Short vs. Long-term Effects
Implications------------------------------
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Reduce reliance on fossil fuels Promote rural development
Improve economics & finance forest managementactivities?
Reduce wildfire risk
Eliminate in-woods burning of biomass
Sequester C
Conserve or improve site nutrients
Enhance forest productivity
Bioenergy & Biochar Co-production Potential------------------------------
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University of Idaho
Sustainability Center
Acknowledgements------------------------------
We thank the Moscow Forestry Sciences Lab and the UI Center forForest Nursery and Seedling Research for work space, the IFTNC forassistance, Dynamotive Energy Systems for biochar donations, USDA
FS and UI Sustainability Center for funding.