Vegetation

Gasifier Charcoal as a Substitute for Vermiculite in Container Growing Media
Tom Miles, August 22, 2009
P Pine Seedlings in 25% Biochar
Our second trial of biochar as a substitute for vermiculite in container media for growing tree seedling has proved successful. These tests are by a private nursery to determine if charcoal from a gasifier heating system can be used in container growing media.

Last year weathered charcoal was collected from forest fire burns, milled, and used as a direct substitute for vermiculite in up to 50% of the container mix. Some of those trees have been retained in containers for a second year and still look good. At that time the forest tree nursery concluded that the biochar could be used for up to 50% of the mix with some adjustments to plant nutrition.
http://terrapreta.bioenergylists.org/charcoalmedia

This year the nursery filled a larger sample with media containing 25% biochar from a gasifier.

During gasification the char is made as wood (mixed Pine and Douglas Fir from the California Coast range) is subjected to temperatures of 1000 C (1832 F) in an oxidizing atmosphere and 850C (1562 F) in a reducing environment. Tars are volatilized and combusted to carbon dioxide and water. Tars are completely consumed in the process. The CO2 reacts with the devolatilized charcoal to form a gas rich in carbon monoxide and hydrogen. The gas will be used in place of propane to heat greenhouses.

Water is condensed from the gas. The recovered water (condensate) could probably be used to supplement irrigation. It is clear to light lemon colored and has a faint odor. It has a pH of 7.1 and is highly saline with an electrical conductivity (EC) of 5.1 mS/cm. It will be analyzed for composition.

Less than 5% of the dry fuel is recovered from the gasifier as a charcoal residue. The charcoal residue is still being characterized. It is small in size and puffy with powdery fines that are like a confectioner’s sugar. Due to the conditions of carbonization it is likely that it has very low labile (volatile) carbon, high surface area, high CEC and high pH. (High pH does not appear to have affected nutrient availability in previous trials even up to 50% charcoal in the container mix.) It was tested at the nursery as biochar.

Ponderosa pine seedlings grown in 25% gasifier charcoal since June were identical in root development and plant growth as those grown in the vermiculite mix. Two of each are shown in the attached image.

Future trials will use biochar in media to grow other tree species.
Condensate from Wood Gas

Charcoal and Carbon Storage in Forest Soils of the Rocky Mountain West
The Wilderness Society, October 2007

"Charcoal produced during wildfire events represents an important form of long-term Carbon storage in forest ecosystems. Forest management practices, such as salvage logging or thinning without prescribed fire, may reduce soil charcoal content and, thus, long-term Carbon storage in mineral soils.

Conclusions

Charcoal represents an important component of the soil organic matter pool in temperate grasslands and forests. It contributes to the total water-holding capacity, ion exchange complex, and surface area of the soil environment.

Once deposited in soil, charcoal is highly stable, having mean residence times 30–100 times longer than that of woody materials and 5–12 times greater than humic materials. Contributions to this pool are dependent upon the occurrence of fire events in which biomass is partially consumed. The amounts of charcoal formed during a given forest-fire event is highly variable and dependent upon fire severity and fuel composition; however, a safe estimate would be 1 to 4 Mg charcoal as C . This stable form of C may be ultimately mixed into the mineral soil or it may be lost, either to biomass burning in a subsequent fire event or an erosion event.

Erosion represents a loss only from the immediate ecosystem, as it will ultimately be deposited in a lake or marine environment, where it may remain for millions of years.

The role of charcoal in the forest ecosystem is just now being explored. The long-term implications of fire exclusion and the elimination of charcoal deposition in forests are not well understood. Timber harvest without prescribed fire may be applied as a forest restoration tool; however, under these conditions, charcoal, as a passive C contribution to the soil system, will be eliminated and will lead to a modest, but long-term loss of C from the forest ecosystem.

Conversely, restoration harvests that incorporate prescribed fire will more effectively emulate natural fire events and deposit charcoal across the activity unit. The importance of charcoal in soils and its contribution to long-term C storage requires greater consideration during ecological assessment, C modeling, and in forest management.

This report appeared in Frontiers in Ecology and the Environment, a publication of the Ecological Society of America. The report was authored by Tom DeLuca and Greg Aplet of The Wilderness Society."

Report-CharcoalAndCarbonStorageInForestSoils.pdf

See: Wilderness Society wilderness.org

Biochar Trial Photos

Empty Planting Trays on Rack	Fine Wet Processed Charcoal Settling in Flask	Bamboo Feedstock	Softwood Chip Feedstock
Charcoal Production in Woodgas Stoves	Charcoal Grades	Char Measurement
Amended Pots Prior to Mixing	Pots Mixed and Seeds Sown	Growth After 9 Days	Wheat and Peas Seperated to Avoid Shading

Some design features below:
Exploring interaction effects of feedstock type, soil, char application
rate, crop species, char size, fertilization, and mycorrhizal fungi.
No repetition (n=1), this loses the ability to assign a statistical
significance level to results, but allows more interactions (96 unique
combinations, 96 pots) to be tried given limited resources.

Charcoal produced in WoodGas stoves.
Char yield 12-18% (char mass/air dry biomass mass) (ie not adjusted to conventional dry weight yield unit, yet).
Fine Char - Blended and sieved to 230 mesh (<63 micron).
Coarse Char - Blended and sieved to between ~24 mesh - 8 mesh.
Fertilizer - 4-4-4 NPK Organic (bone meal, feather meal...)
Potting Soil - Potting Mix
Sandy Soil - Mixture of Horticultural Sand and Sandy Loam from Central Valley

Pots arranged in random spatial order (to randomize light/watering variation). Trays rotated to limit effects of light/watering variation.
Automatic drip emitter watering. Pots grown in enclosed cage outdoors.

Blocks - ( 8 pots/block)
    Fertilizer {Yes,No}
    Plant {Wheat, Pea}
    Soil {Sandy, Potting}

Blocks - (12 blocks * 8 pots/block = 96 pots)
    B1 -    Char (0 g)
    B2 -    Char (1 g, Pine, Fine)
    B3 -    Char (1 g, Pine, Coarse)
    B4 -    Char (1 g, Bamboo, Fine)
    B5 -    Char (1 g, Bamboo, Coarse)
    B6 -    Char (5 g, Pine, Fine)
    B7 -    Char (5 g, Pine, Coarse)
    B8 -    Char (5 g, Bamboo, Fine)
    B9 -    Char (5 g, Bamboo, Coarse)
    B10 -   Char (0 g) + Mycorrhizae
    B11 -   Char (5 g, Pine, Coarse) + Mycorrhizae
    B12 -   Char (10 g, Pine, Coarse)
 

Bear Kaufmann. Initially posted April 7, 2008. Updated August 5, 2008.

Images showing trial preparation and radish germination
(Select image to enlarge in Gallery.)

Materials/Methods

Char was Lazzari Brand mesquite BBQ char (due to availability), crushed and screened to 1/8".
No nutrients were added to the char itself or to the soil.
Soil was FoxFarm OceanForest Potting Soil.
Sand used was horticultural sand.
No mycorrhizal fungi were added.
Mixtures range from 0-100% sand, soil, and char in ~16% increments by volume. 90 pots total. 28 combinations with 3 pots each + 6 additional pots at 33%/33%/33% composition. Pots were placed randomly within the tray. Tray was rotated 180° occasionally.
Plants were watered daily by a drip irrigation system.
Plants were removed from pots ~1 month after first watering. Soil was rinsed from roots and roots were patted dry with a towel. Wet weight of roots+shoots was measured (Acculab VI-3mg, 0.001 g precision).

Figure 1. Box Plots Showing Effect of Composition Across Three Transects

Figure 2. Pictures of Radishes at Important Compositions

Results

Plant growth was stunted even for the best preforming plants, likely due to the small pot size. Leaf color varied across different compositions.
A mixture of 33% charcoal and 67% soil had the best growth (176% of pure soil). Aside from mixtures around this level (Figure 1b), high levels of charcoal showed a generally negative effect on plant growth (Figure 1c).

Discussion

The positive interaction effects of charcoal and soil (Figure 1a,1b) are interesting. Assuming charcoal itself provides no integral nutrients to the soil (eg. nitrogen), increasing amounts of charcoal reduce nutrients available from the soil mixture. The effects at 33% char/67% soil, however, show beneficial effects. This could be explained by increased mineralization rates caused by the charcoal causing soil nutrients to be more available to plants. Beyond 33%, the Cation Exchange Capacity of the charcoal may have held the nutrients produced by mineralization, making them less plant available. Since the charcoal was not amended/soaked in a nutrient bearing solution it likely had a low Base Saturation leading to adsorption of nutrients as they became available. Other potential explanations for increased growth along the soil/char transect include alterations to pH or limiting nutrients (eg potassium(?)) provided by the charcoal. The speculative mineralization/CECi model could also explain the effects seen along the sand/char transect. Here, since the sand lacks organic materials and bound nutrients for soil microorganisms to make plant available, the increasing unsaturated CEC may have made any nutrients less plant available.

Author: Bear Kaufmann bear at ursine-design.com

Gardening with Biochar FAQ (Wiki)
Philip Small, May 21, 2008

Welcome to a Gardening with Biochar FAQ!
... a work in progress...

When gardeners add biochar to garden soil, we are, in effect attempting to follow in the footsteps of the originators of Terra Preta. Because we don't know exactly how that process worked, nor how we can best adapt it outside its area of origin, we are left to discover much of this by experimenting with our own gardens and comparing observations within our own communities.

See:

Gardening with Biochar FAQ (Wiki)

Soil Analysis: Interpreting a Soil Test for lawns
John R. Street, Maurice E. Watson, William E. Pound, Ohio State University Extension Fact Sheet, HYG-4028

Factsheet. This publication will help you interpret the recommendations provided by The Ohio State University's soil testing laboratory. The facility is termed the Research Extension Analytical Lab (R.E.A.L.) and is an important facility for testing lawn soils.

The Effect of Charcoal from Recycled Japanese Cedar Waste on the Elimination of Organic Matter in
Agricultural Land Drainage
Laboratory of Water Environment Conservation, Department of
Hydraulic Engineering, National Institute for Rural Engineering, Japan,

Partially burned material a boon to plants: Sandy (Oregon) resident sees biochar as a way to fertilize and capture carbon
By Garth Guibord, The Gresham Outlook, Mar 30, 2007

When most people see a pile of sticks and wood, all they see is sticks and wood. Sandy resident Paul Elmore, 39, sees possibilities. He sees biochar – burned organic material that can be used to make plants grow.

Contributions of Pinus Ponderosa Charcoal to Soil Chemical and Physical Properties
Christopher M. Briggs in Briggs, Breiner, Graham Pinus Ponderosa Charcoal 9 May 2005

Abstract
Charcoal results from the incomplete burning of plant material and is found in most
soil surface horizons, but little is known about its effects on soil properties. The objectives of this
study were (1) to determine the chemical and physical properties of ponderosa pine charcoal

Indonesia: Survey on the Effect of Charcoal to Tree Growth and Charcoal Production in West Kalimantan (1.3 mb pdf)
Carbon Fixing Forest Management project
Demonstration Study on Carbon Fixing Forest Management in Indonesia
Cooperation Project between Forestry Research and Development Agency (FORDA), Ministry of Forestry, Indonesia, Japan International Cooperation Agency (JICA)
Collaboration with Yayasan Dian Tama December 2005

FOREWORD