Key Functions of Biochar in Soil -...

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Key Functions of Biochar in Soil Biochar: can it replace Soil Organic Matter? Kor Zwart Biochar Climate saving soils Final Conference, Groningen 10-12-2013

Transcript of Key Functions of Biochar in Soil -...

Page 1: Key Functions of Biochar in Soil - ENKIarchive.northsearegion.eu/...KorZwart-Keyfunctionsofbiocharinsoil.pdf · Key Functions of Biochar in Soil Biochar: can it replace Soil Organic

Key Functions of Biochar in Soil

Biochar: can it replace Soil Organic Matter?

Kor Zwart

Biochar Climate saving soils Final Conference, Groningen 10-12-2013

Page 2: Key Functions of Biochar in Soil - ENKIarchive.northsearegion.eu/...KorZwart-Keyfunctionsofbiocharinsoil.pdf · Key Functions of Biochar in Soil Biochar: can it replace Soil Organic

Some basic Algebra

If X = a

AND Y = a

THEN X = Y

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SOM and BIOCHAR - Algebra

Biochar = organic carbon

SOM = organic carbon

Biochar = SOM ?

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SOIL ORGANIC MATTER

Role of SOM Biology

Source of energy

Source of carbon, nutrients Resilience soil-plant

system

Physics

Soil structure Water retention

Thermal properties

Chemistry

CEC Buffer capacity Complexation

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SOM types in SOIL types

CLAY

Soluble

Particulate

Humus

Inert

SAND

CEC

Soil

structure

Energy for

biological

processes

Provision

of

Nutrients

Soil

Temperature

0%

20%

40%

60%

80%

100%

Cla

y co

nte

nt

After: http://grdc.com.au/uploads/documents/cso000291.pdf

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SOIL ORGANIC MATTER

Role of SOM Biology

Source of energy Source of carbon,

nutrients Resilience soil-plant

system

Physics

Soil structure Water retention Thermal properties

Chemistry

CEC Buffer capacity Complexation

After Baldock and Skjemstad, 1999

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http://www.treepower.org/biochar/main.html

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Reed and McLaughlin North American Biochar 2009

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Pyrolysis conditions

Keiluweit et al, (2010) Environ. Sci. Technol.

Activated C: 1500-2500 m2/g

Page 10: Key Functions of Biochar in Soil - ENKIarchive.northsearegion.eu/...KorZwart-Keyfunctionsofbiocharinsoil.pdf · Key Functions of Biochar in Soil Biochar: can it replace Soil Organic

Spokas (2010) Carbon Management (2010) 1(2)

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Biochar Carbon & Energy for micro-

organisms ?

Thermodynamically: No problem

Enzymatically: ??, especially at low O:C ratio’s

CO2 evolution:

Low

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Biochar Humic acid Clay

Biochar Refuge for micro-organisms ?

Sohi et al (2009) faculty.yc.edu/ycfaculty/ags105/week08/soil_colloids/soil_colloids_print.html

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Hydrophobic interaction bacteria and sand

in a Fluidized bed reactor

Mussati et al, 2005

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Relation SOM-plant available water

(pF 2-4.2)

SOM %

Plant available

water mm

2 50

4 66

5 70

6 75

8 81

10 86

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Biochar and WHC ?

Streubel et al, 2011, JSSSA, 75:1402-1413

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Biochar and Water retention ?

Plant available

water

Gravity

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Water retention Interreg Biochar Project

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Pore size distribution

K. Sun et al. / Bioresource Technology 102 (2011) 5757–5763

pF 4.2: 200 nm

SMITH AND FLETCHER UNIVERSITY OF STRATHCLYDE

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Water infiltration Interreg Biochar Project

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Water infiltration Interreg Biochar Project

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CEC reclaimed peat soils

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CEC reclaimed peat soils

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NH4+ Ca++ K+

NO3- NO3

-

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Humic Acid structure

Hatcher et al 1994

C:O Fulvic acids: 1

Humic acids : 0.55

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CEC

(cmol/kg)

1000

750

500

400

300

200

100

80

60

30

20

15

10

5

1

0

fine sandy loams

loams and silt loams

clay loams

clays

smectite

vermiculite

humic acids

sands

fine sandy loams

loams and silt loams

clay loams

clays

smectite

vermiculite

humic acids

fulvic acids

sands

compost-carbon

1000

750

500

400

300

200

100

80

60

30

20

15

10

5

1

0

fine sandy loams

loams and silt loams

clay loams

clays

smectite

vermiculite

humic acids

fulvic acids

sands

biochars

compost-carbon

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Modification of Biochar

Activation (?)

Adsorption of SOM

Biological modification (?)

Chemical modification, strong acids, bases, oxidation

● Functional groups CEC

● Functional groups AEC (NR4+)

Page 27: Key Functions of Biochar in Soil - ENKIarchive.northsearegion.eu/...KorZwart-Keyfunctionsofbiocharinsoil.pdf · Key Functions of Biochar in Soil Biochar: can it replace Soil Organic

SOM and BIOCHAR - Algebra

Biochar = organic carbon

SOM = organic carbon

Biochar = SOM

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Conclusions

Biochar can be used to sequester short cyclic C in the soil

Fresh biochar is rather different from SOM

It seems rather unlikely that (fresh) biochar can completely replace SOM

Modification of biochar to improve its functionality is needed and possible

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