This document summarizes research on amending soils with biochar or charcoal. It finds that charcoal amendment can increase seed germination, plant growth, and crop yields. Specifically, it leads to enhanced soil structure and nutrients, increased water retention, and reduced greenhouse gas emissions. Studies showed increased aggregate stability and carbon sequestration in soils mixed with 10-50% charcoal. Respiration rates were similar for aggregates with up to 90% charcoal. Finer-textured conventional tilled soils allowed better charcoal penetration than other soils. Overall, the research demonstrates the agricultural and environmental benefits of charcoal-amended soils.

1. “Biochar-Infused” Soil Aggregates
Photo by Dr. Saran Melissa K. Erickson
Paul Sohi, UKBRC
Michigan State University

2. Carbon-Poor Soil vs. Native Carbon-Rich Soil
Nutrient-Poor Oxisol Amended
Oxisol Into Terra Preta
Photo courtesy of Bruno Glaser, 2000

3. Background: Charcoal Amended Soils Around
the World
Orissa,
India
Hokkaido,
Japan
Uganda,
Africa
Photos by Dr. N. Sai Bhaskar Reddy

4. Why Amend Soil with Charcoal?
-Increased seed germination (~30% enhancement)
-Increased plant growth (~24% greater shoot height)
-Greater crop yields
Norman (1979)
ZechUNCCD.pdf, published by Dr. Bruno Glaser

5. Advantages of Bio-char in Soil
Enhances Soil Biologically, Chemically and Physically
1. Prevents leaching of nutrients out of soil
2. Increases available nutrients for plant growth
3. Increases water retention
4. Reduces the amount of fertilizer required
5. Decreases N2O, CH4 and other greenhouse gas
emissions from the soil

6. Advantages of Bio-char Amendment - Continued
Animal Feed
1. Provides additional minerals
2. Helps maintain a healthy digestive system
3. Reduces animal methane production
4. Reduces odor and ammonia emissions from manure slurry

7. Advantages of Natural Charcoal Amendment
Researchers at Iowa State investigating using charcoal and bio-
oil to produce a charcoal/anhydrous ammonia fertilizer.
They expect three significant results from their studies:
1. Farmers producing their own renewable energy to
manufacture fertilizer for their fields.
2. Farming that improves soils because the added charcoal to
promote soil organisms.
3. The charcoal sequestering carbon in the soil, thus reducing
the amount of greenhouse gases in the atmosphere. It is
estimated a 640-acre farm could retain the equivalent of
1,800 tons of carbon dioxide in the soil. That's the annual
emissions created by about 340 cars.

8. Types of Charcoal and Soil Analyzed
Research Approaches:
1. Charcoal: SAFFE, B.C. 550°C (500 grams), Lots 11 and 12
2. Soil texture: Wooster silt loam (fine-loamy, well-drained,
mesic Typic Fragiudalf).
3. Soil aggregates were sampled at depths of 0 to 5 cm from
fields subjected to conventional till (CT), no till (NT), and
native forest (NF) ecosystems of a Wooster silt loam using
the following aggregate sizes:
NF (Native Forest): 1.0 – 5cm, > 9.5mm
NT (No Till): 0 – 5cm, > 9.5mm
CT (Conventional Till): 0 – 5cm, > 9.5mm

9. Wooster Soils Amended with Charcoal
(wet/dry cycle-formed, 30% Charcoal shown)
1. Added mixtures of ground soil and
30% charcoal by weight.
2. Filled sample cups with mixture and
added six ml of water to 57mm
aluminum dish.
3. Hydrated sample mixtures with water
for 48 hours.
4. Removed water from samples and air
dried for 24 hours.
5. Repeated steps two through four nine
more times, for a total of ten cycles.
6. Inspected aggregate for structural
Creation of aggregates from NF,
integrity. NT and CT treatments mixed with
30% charcoal.

10. Wooster Soils Amended with Charcoal
(Molded, Conventional Till Soil as shown)
1. Added mixtures of powdered
soil and 0%, 10%, 30%, 50%,
90%, and 100% charcoal by
weight.
2. Added distilled water to create
a slurry.
3. Filled molds with slurry from
each percent sample through
holes in the top.
4. Dried in 60ο oven for 48 hours.
5. Removed from molds and
stored in petri dish till used. Molded synthetic aggregates from CT
treatments mixed with 0%, 10%, 30%,
50%, 90%, and 100% charcoal using a
rubber candy mold.

11. Soil aggregate Stability by Two methods
Display of soil aggregates
containing 30% charcoal;
constructed after 10
wetting/drying cycles.
Synthetic aggregates
constructed by wetting and
drying cycles (right) and
molded samples (left).

12. Farming that Improves the Environment
Robert C. Brown, Iowa State’s Bergles Professor in Thermal Science is
also studying charcoal amendment of soils with the aim of implementing
farming practices that actually improve the environment through
responsible, sustainable soil amendment techniques. In his words:
“The conventional goal of good land stewardship is to minimize soil
degradation and the amount of carbon released from the soil.”
“This new approach to agriculture has the goal of actually improving
soils.”
Source: http://www.buyactivatedcharcoal.om/natural_fertilizer
“In other words, producing and applying bio-char to soil would not only
dramatically improve the soil and increase crop production, but also
could provide a novel approach to establishing a significant, long-term
sink for atmospheric carbon dioxide”
Johannes Lehman, in “Muck and Mystery: Bio-Char” website

13. Current Studies of Charcoal Effectiveness
as an Organic Fertilizer
Growth and Harvest of Soybeans
Areas not using Areas using Areas Using
Fertilizer nor Charcoal for Chemical
ITEM
Charcoal Compost fertilizer
No. of leaves 64 139 71
Avg. Leaf Length cm 5.76 7.68 6.04
Avg. of Leaf Width cm 3.25 4.08 3.26
Germination Rate (%) 80 90 85
Root Length cm 22 24 25.5
Stem Length cm 14.66 17.19 18.23
Stem Diameter cm 1.2 1.35 1.33
No. of Seeds 26 89 37
Weight of 100 Seeds g 28.1 44.25 33.85
Utilization Experiment of Charcoal Tested in Indonesia
Data Provided by the Japanese Forestry Agency

14. Carbon Respiration Sample Preparation Method
1. Convert vacuum tube into micro-
respirometer. Place glass wool in
the bottom, then the aggregate, and
seal with the top with septum.
2. Add 12% distilled water to each vial
being analyzed, using a syringe.
3. Equilibrate water within soil
aggregate sample.
4. Flush respirometer with CO2 free air.
5. Maintain constant temperature
during CO2 analysis of sample. Micro-respirometer chamber
with soil aggregate.

15. Carbon Respiration Sample Evaluation Method
1. Using a 1 ml syringe, pull the plunger past the 0.5 ml mark, then push
fully forward. Repeat this process at least two more times, to ensure
the syringe is completely evacuated.
2. Insert needle through rubber septum of respirometer containing
aggregate sample. Gently pull the plunger back past the 1.0 ml mark,
then push forward to extract exactly 1.0 ml of gas in sample tube.
3. In a slow, smooth motion, inject the full 1.0 ml sample into the injection
port of the Infrared Gas Analyzer (IRGA).
4. The IRGA results are correlated to CO2 gas standards with accuracies
of 1 microgram (µg). Repeat steps 1 through 3 for each sample to be
evaluated.

16. Carbon Respiration Sample Evaluation Method
5. After completing the test run, flush each sample tube with dry CO 2 free
compressed air.
6. Incubate samples at 23 C for the time determined in the sampling
schedule. Repeat steps 1 through 5 at each sample interval.
Sample flushing manifold IRGA Setup

17. Carbon Dioxide Respiration Results

18. Carbon Dioxide Respiration Results, Continued

19. Carbon Dioxide Respiration Results, Continued

20. Aggregate Stability Conclusions
The Wooster Silt Loam soil from the Conventional Tillage (CT) areas
sampled exhibited a finer soil aggregate structure, compared to the
compaction seen in Native Forest (NF) and No-Till (NT) soil samples.
The finer CT soil structure allowed for greater penetration of the
introduced charcoal into the soil matrix than was observed with the NF
and NT soils.
The charcoal added to the soil matrix increased aggregate stability and
improved erosion resistance.

21. CO2 Respiration Conclusions
For 10% to 90% charcoal/soil aggregates, no significant variation in CO 2
respiration was observed for the first 24 hours of respiration data
collection, regardless of charcoal content or aggregate formation method.
For 10%, 30% and 50% charcoal/soil aggregates, molded sample CO 2
respiration after 48 hours exceeded that of the wet/dry cycle-formed
aggregates.
For pure charcoal aggregates in the same time frame, and 90%
charcoal/soil aggregates after 144 hours, wet/dry cycle-formed CO 2
respiration rate exceeded that of the molded samples.
It was observed that molded aggregates exhibited a more compact
nature, while wet/dry cycle-formed aggregates were looser and more
porous at all charcoal concentrations.

22. Acknowledgements
The researcher is very grateful for the cooperation and interest of Dr. Alvin Smucker
and the Soil Biophysics Laboratory, who supported and guided this study.
This research was supported and funded by Michigan State University College of
Agriculture and Natural Resources Undergraduate Research program.
The researcher wishes to thank her committee; Professor Alvin Smucker, Professor
Karen Renner, and Professor Sasha Kravchenko, and also her colleague and peer,
Hyen Chun, for their many hours of review and suggestions to the report and
presentation.

23. References
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