Biochar in Conservation Agriculture

Improving Crop Yield and Storing Carbon

Gerard Cornelissen

Norwegian Geotechnical Institute (NGI) & Univ of Life Sciences (UMB), Norway

Victor Shitumbanuma, Elijah Phiri, Eugene Kana, UNZA, Zambia

Peter Aagaard, Jeremy Selby, Gibson Simusokwe, CFU, Zambia Odd E. Arnesen, Jan Erik Studsrød, Norad, Norway

Jan Mulder, Vegard Martinsen, Institute for Plant and Environment, UMB Magnus Sparrevik, Gijs Breedveld, NGI

Matthijs van Leur, Hans de Kruijf, Utrecht University, The Netherlands

What is biochar?

”Engineered” Charcoal:

• Product of airless combustion of organic waste (pyrolysis)

• Almost pure carbon (80-90%)

Open fire charcoal

Low carbon content

Not stable in soil

High ash content

Biochar

High carbon content

Stable in soil

Low ash content

Climate change mitigation

• Reduces other greenhouse gas emissions:

nitrous oxide (N2O), methane (CH4)

Soil fertility improvement

• Sponge for water (water holding capacity)

• Reverses soil acidification

• Sponge for nutrients (reduced nutrient leaching)

• Important: prolonged effects (one-time application)

Biochar is not only carbon storage...

Generating biochar: medium/large scale pyrolysis

Traditional Kiln, Mkushi, Zambia High-tech pyrolysis

Small-scale stoves (around US$30)

Top-lit up-draft Peko Pe stove

Advantages

• Biochar Soil Fertility

• Cleaner cooking

• Reduced fuel need

Other possibility:

• Medium-scale retort kiln:

• Energy generation (electricity, heat)

• Biochar generation

Mongu,

Zambia

Perspective C sequestration: maize husk in Zambia

- Zambia: 200 000 small-scale conservation farmers

- Make biochar of all their rice husks:

- 1.9 mill tons CO2 stored in biochar

- Enough to compensate whole Zambian carbon emissions

Biochar in Indonesia, Malaysia, Zambia, Nepal -

4 projects at Norwegian Geotechnical Institute and

University of Life Sciences

• Combination soil science, socio-economic science, implementation

– Norwegian Embassy / CFU – this project in Zambia, start Oct 2010

– Norwegian Research Council –

• ”NorGlobal”, ”FRIMUF”, Indonesia + Malaysia, 2011-2014

• ”Excellent Researcher Personal Stipend”, Zambia/Nepal/Indonesia, 2012-2017

Indonesia Malaysia Norway biochar consortium

Kaoma, Zambia

Biochar in Zambia: overview

• Pot trials, 5 soils, 2 biochars

• Field trials, 18 stations, maize biochar

• Biochars: corn cob biochar

• Small-scale farmers

• Crops: maize, groundnuts

Biochar and Conservation Farming: a happy couple!

• Conservation Tillage: planting basins, only 10-12% tilled

• Strongly reduces amount of biochar (and fertilizer) needed

Kaoma

Mkushi

UNZA farm

Shimabala

NRDC

Field Sites

Mongu

(2012)

GART

Chisamba

Pot trial University of Zambia (128 pots)

Control NPK Maize C Char C

+½NPK Maize C

+½NPK

1. 0.5% biochar + full fertilizer 43 g biomass

2. 2% biochar + 50% of fertilizer 34 g biomass

3. Only fertilizer 27 g biomass

4. Only 2% biochar 12 g biomass

5. Control 5 g biomass

Biochar application in conservation farming basins, Mongu

Biochar application in conservation farming basins, Mongu

Biochar + fertilizer in basins, Mongu

Look

Biochar

Works

in poor, sandy soil

at low nutrient status

and low water holding capacity

(Mongu and Kaoma April 2012:

Biochar strong positive effect for 8

out of 10 farmers) charcoal

4 t/ha maize char

4 t/ha

control

Kaoma, Western Zambia

Block trial, UNZA farm, close to Lusaka:

clear effect of 6 tons/ha biochar

maize char

6 t/ha

maize char

0 t/ha

NRDC: good soil

(not acidic, good nutrient and water holding capacity)

Control Charcoal 4 t/ha Maize Char 4 t/ha

No effect of biochar

-50

0

50

100

150

200

250

300

350

400

450

Kaoma Magoye UNZA Chisamba Mkushi Shimabala NRDC

CH

AN

GE

CO

MPA

RED

TO

CO

NTR

OL

(%

) CHARCOAL DUST 0.8 TON/HA

MAIZE CHAR 0.8 TON/HA

CHARCOAL DUST 4 TON/HA

MAIZE CHAR 4 TON/HA

Harvest relative to control plots

Sandy &

acidic soils

Acidic

soils Good

soils

Doublingof yield

Tripling of yield

Why is biochar so effective?

• Compensation of acidity

• Nutrient sponge (CEC doubled in poorest soils)

• Water sponge: could be most important effect

No effect in

field

Good

effect in

field New

station

2012

Soil/

char pH, no biochar pH, 5% biochar

Mkushi soil 4.9 6.8

Kaoma soil 5.4 7.0

UNZA soil 3.8 6.2

Charcoal dust biochar 8.8

Corn stover biochar 8.7

The farmer’s perspective: some rough numbers

Investment

Cost of biochar 4 tonn/ha US$ 200 once

– Kiln depreciation

– Maintenance

– Biomass transport

– Biomass cost

– Labour cost

Output

Increased yield around 1 tonn maize/ha US$ 200 per year

(Carbon quotes 4 tonn carbon US$ 80 once)

Life-cycle assessments of biochar in Zambia

Life cycle assessment can

address and combine these

effects to asses the overall

impact of biochar!

• Calculates negative and positive impacts over the whole life cycle

Total impact per kg corn harvest….

-100

100

200

300

400

500

600

700

800

CFU biocharTLUD

CFU biochar Improved kiln

CFU biochar traditional kiln

Conservation agriculture

Conventional farming

eco

po

ints

Remaining

Particulate matter formation

Climate change Ecosystems

Climate change Human Health

Low harvest per input

Particle emissions

Negative effect

Positive effect

Carbon sequestration

Mitigation

• Carbon storage: Biochar in CDM?

• Reduced need for deforestation in farming

• Reduced nitrous oxide emissions

Adaptation

• Drier climate in many parts of Africa: water sponge

Biochar and climate change

Challenges for biochar

Seems to good to be true, but…..

• Competition between biochar feedstock and food crops: use

only waste material

• Increased deforestation just for making biochar?

• Sufficient incentive for the extra work required?

• Kiln technology

Biochar kilns: another challenge

• Particle, methane, carbon monoxide emissions

• Emissions from traditional kilns offset the good effect of

carbon sequestration!

• Cleaner technology is needed for implementation

• Small scale: stoves (generate little biochar)

• Medium scale: retort kilns that lead back the gases (cost)

Conclusions

• Biochar is mitigation and adaptation

• Biochar regards carbon as a resource rather than a waste

• Local fertilization solution: spontaneous adoption by farmers?

• Traditional and directly applicable technique

”Wants to reduce climate gas

emissions with gnawed-off corn

cobs”

Leading

Norwegian

daily

newspaper