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Here is a post I made elsewhere at ICmag about making pyrolyzed rice hulls.
HTH
Making and using carbonized (as pyrolyzed) rice hulls:
Pyrolyzing is much preferred method to make bio-char. Traditionally Terra Preta was house hold wastes, food wastes, night soil, etc. One can make them at home! They are the ultimate biochar (terra pretta) IMO, easy to make, easy to find/buy, great soil/media amendment and environmentally sound too!
Here is how to make pyrolyzed bio-char on a DIY basis with a "retrot stove":
By Folke Günther
http://www.holon.se/folke/carbon/simplechar/simplechar.shtml
Folke Günther's Biochar blog:
http://folkegunther.blogspot.com/
See this study abstract about PRH (pyrolyzed rich hulls):
Pyrolyzed rich hulls are as good/better than amendments like pumic, Axis, Turface, etc. Pyroylzed rice hulls have high C:N ratio its wise to pre-soak the pyrolyzed rich hulls (or most any high carbon bio-char) in a solution of water and hydrolyzed fish (to lower C:N and C
ratio) and humic acid (to increase CEC of PRH).
Kämpf, A.N. and Jung, M. 1991.
THE USE OF CARBONIZED RICE HULLS AS AN HORTICULTURAL SUBSTRATE. Acta Hort. (ISHS) 294:271-284
http://www.actahort.org/books/294/294_29.htm
P.S., That paper on CRH uses a term "micropore", I define what that means below:
"Micropores" are pores between media particles and pores comprising media particles which are the size of < 10-0.2 microns, the water tension is 30-1,500 kPa. This is termed "buffer water" (BW) and can be used by plants but it's harder for roots to use BW than AW (see below). Protozoa prefer micropore sized pores to graze and feed upon bacteria; protozoa prefer about 9.7-2 micron pore sizes. Bacteria tends to prefer pores from 2-0.75 microns, those pores are termed "protection pores" because protozoa can't eat bacteria colonizing in pores less than 2 microns.
"Mesopores" hold water plants can use water (i.e. "available water"; AW) from pore size of 416-10 microns and water pressure of 1-30 kPa. Plants and soil food webs can use the water held in these pores.
"Ultramicopores" are smaller than 0.2 microns and are considered to hold "unavailable water" (UW) which roots, bacteria, microfauna (protozoa) and mesofauna (nematodes) can not use; only microfungi (microbes which are fungi) can use water in pores < 0.2 micron AFAIK. Ultramicropores have a water tension of greater than 1,500 kPa (1.5 MPa) which is also known as the "Persistent Wilting Point" of plants. In one good study on arid/desert soils fungi are dominant in soil food web even with water tension as high as 6,000-8,000 kPa!!! (Wow!)
HTH, sorry to get so technical but these are important issues to understand when building an ideal soilless media for roots AND soil food web.
More references:
1. Simone E. Kolb, Kevin J. Fermanich and Mathew E. Dornbush. 2009
HTH
Making and using carbonized (as pyrolyzed) rice hulls:
Pyrolyzing is much preferred method to make bio-char. Traditionally Terra Preta was house hold wastes, food wastes, night soil, etc. One can make them at home! They are the ultimate biochar (terra pretta) IMO, easy to make, easy to find/buy, great soil/media amendment and environmentally sound too!
Here is how to make pyrolyzed bio-char on a DIY basis with a "retrot stove":
By Folke Günther
http://www.holon.se/folke/carbon/simplechar/simplechar.shtml
Folke Günther's Biochar blog:
http://folkegunther.blogspot.com/
See this study abstract about PRH (pyrolyzed rich hulls):
Pyrolyzed rich hulls are as good/better than amendments like pumic, Axis, Turface, etc. Pyroylzed rice hulls have high C:N ratio its wise to pre-soak the pyrolyzed rich hulls (or most any high carbon bio-char) in a solution of water and hydrolyzed fish (to lower C:N and C
ratio) and humic acid (to increase CEC of PRH).Kämpf, A.N. and Jung, M. 1991.
THE USE OF CARBONIZED RICE HULLS AS AN HORTICULTURAL SUBSTRATE. Acta Hort. (ISHS) 294:271-284
http://www.actahort.org/books/294/294_29.htm
P.S., That paper on CRH uses a term "micropore", I define what that means below:
"Micropores" are pores between media particles and pores comprising media particles which are the size of < 10-0.2 microns, the water tension is 30-1,500 kPa. This is termed "buffer water" (BW) and can be used by plants but it's harder for roots to use BW than AW (see below). Protozoa prefer micropore sized pores to graze and feed upon bacteria; protozoa prefer about 9.7-2 micron pore sizes. Bacteria tends to prefer pores from 2-0.75 microns, those pores are termed "protection pores" because protozoa can't eat bacteria colonizing in pores less than 2 microns.
"Mesopores" hold water plants can use water (i.e. "available water"; AW) from pore size of 416-10 microns and water pressure of 1-30 kPa. Plants and soil food webs can use the water held in these pores.
"Ultramicopores" are smaller than 0.2 microns and are considered to hold "unavailable water" (UW) which roots, bacteria, microfauna (protozoa) and mesofauna (nematodes) can not use; only microfungi (microbes which are fungi) can use water in pores < 0.2 micron AFAIK. Ultramicropores have a water tension of greater than 1,500 kPa (1.5 MPa) which is also known as the "Persistent Wilting Point" of plants. In one good study on arid/desert soils fungi are dominant in soil food web even with water tension as high as 6,000-8,000 kPa!!! (Wow!)
HTH, sorry to get so technical but these are important issues to understand when building an ideal soilless media for roots AND soil food web.
More references:
1. Simone E. Kolb, Kevin J. Fermanich and Mathew E. Dornbush. 2009
Effect of Charcoal Quantity on Microbial Biomass and Activity in Temperate Soils. Soil Sci Soc Am J.2009; 73: 1173-1181 http://soil.scijournals.org/cgi/content/abstract/73/4/1173
2. Warnock, D.D., Lehmann, J., Kuyper, T.W. and Rillig, M.C. 2007.Mycorrhizal responses to biochar in soil – concepts and mechanisms. Plant and Soil 300, 9-20.
3. Nichols, K. 2002.
Glomalin: Hiding Place for a Third of the World's Stored Soil Carbon. Agricultural Research: 50(9): 4-7
4. Nichols, K.A. 2008.Indirect Contributions of AM Fungi and Soil Aggregation to Plant Growth and Protection. IN: Siddiqui, Z.A., Akhtar, M.S., Futai, K. (eds.) Mycorrhizae: Sustainable Agriculture and Forestry. Spinger Science. pp. 177-194.
5. Nichols, K.A. 2008.Microbial engineering to enhance your bottom line. Meeting Proceedings for the 12th Annual No-Till on the Plains Winter Workshop, Salina, KS, Jan. 29-30. pp. 138-139.
6. Liang, B. , Lehmann, J., Solomon, D., Kinyangi, J., Grossman, J., O'Neill, B., Skjemstad, J.O., Thies, J., Luizão, F.J., Petersen, J. and Neves, E.G. 2006.
Black carbon increases cation exchange capacity in soils. Soil Science Society of America Journal 70: 1719-1730
7. Steiner, C., Teixeira, W. G., Lehmann J., Nehls, T., Vasconcelos de Macêdo, J. L.V., Blum, W. E. H. and Zech, W. 2007.Long term effects of manure, charcoal and mineral fertilization on crop production and fertility on a highly weathered Central Amazonian upland soil. Plant and Soil. 291, 275-290.
8. Steiner, Christoph, K.C. Das, M. Garcia, B Forster, and Wolfgang Zech, 2007.Charcoal and smoke extract stimulate the soil microbial community in a highly weathered Xanthic Ferralsol. Pedobiologia In press.
9. Woods, William I., Newton P. S. Falcão, and Wenceslau G. Teixeira. 2006.Biochar Trials aim to enrich soil for smallholders. Nature 443:144.
10. Woolf, Dominic, 2008Biochar as a Soil Amendment - A review of the Environmental Implications. Swansea University.
11. Yaman, S, 2004.Pyrolysis of biomass to produce fuels and chemical feedstocks. Energy Conversion and Management 45, 651-671.
. That way i get powder, coarse stones and the occasional larger piece which makes a good home to the micros. For thi price i rather just buy it since rice hulls would cost the same or more to convert..
