9 mcelligott biochar biomass conversion

7/31/2019 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(%)


0

5

10

15

20

25

baba

CEC(cmolkg-1)


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)


4

5

6

a

a

b

a

ab

a

a

a

a

pH


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


20

40

60

80 a

b

c

a aa

aaa

Control

Surface

Mixed

Le

achateNH4mgL-1


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.

9 mcelligott biochar biomass conversion

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