Pyrolysis

Step 3: Pyrolysis
Originally uploaded by paleorthid.

Charcoal holds a key to improved soil vitality. Reported effects are impressive. Level of response varies with the temperature the charcoal is produced at. Low temperature charcoal is better. The soil improvement process that charcoal initiates is poorly understood. I want to see this at work for myself.

Briquets are no good for my experimental use. They are made with a high-boron binder, and the temperatures that are used to produce them leave few wood gas condensates. At some point I'll find a supply or locate a collier. In the meantime I'm making my own, just to see what it takes.

I made a few small batches of low-temp charcoal with a retort fashioned from a cracker tin. It produced impressive volumes of smoke, so I got on a track of finding out how that smoke might be put to good use.

Thomas B. Reed, Biomass Energy Foundation president and CREST gasification list moderator, has been working on a better understanding of inverted downdraft gasification. He is passionate about improving the efficiency of cook stove fuel use in third world countries. Thus his perennial effort to perfect a household-size inverted downdraft gasifier. Of interest to soil scientists, some of his designs have the capacity to produce charcoal.

Tom Reed designs have inspired others. In 2003 Ray Garlington produced a simplified design. I modified Ray's design to be able to shut it down and hold the charcoal. I used it to boil a cup of water with only a small handful of cedar. It was 2 deg F outside but not a problem. I even produced a fair bit of charcoal. Photos of my run are posted on Flickr.

Update: Concise description of the process: "The wood is placed into the stove and ignited from the top. The top layer of wood burns, creating charcoal. The heat from the charcoal layer burning heats the wood below it, and ignites it. The gases (carbon dioxide and water) flow through the charcoal layer. Glowing hot carbon has a unique ability to strip oxygen molecules off of anything that it touches, so it converts the water into hydrogen, and the carbon dioxide into carbon monoxide. These two gases are flammable and they are ignited once mixed with air above the charcoal layer. The result is a flame that is much more controlled, and cleaner than that of raw wood burning." (Source)

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The Smell of Healthy Soil

Actinobacteria are a hyphae-producing soil bacteria that, in appearance and behavior, appear to have more in common with soil fungi. Like fungi, they decompose some of the more resistant forms of organic plant residues. Like fungi, they form branching filaments, which resemble the mycelia of fungi. Actinobacteria were originally classified as fungi under the older name Actinomycetes.

As bacteria, Actinobacteria have cell walls. They grow best in soil when conditions are damp and warm, playing an important role in decomposition of organic materials, such as cellulose and chitin. When the soil dries they produce spores. The wetness and force of rainfall kick these tiny spores up into the air. The moist air easily carries the spores to us so we breathe them in. These spores have a distinctive, earthy smell we often associate with rainfall. The smell comes from a compound, geosmin, which translates to "earth smell". The human nose is exquisitely sensitive to geosmin, able to detect it at concentrations down to 10 parts per trillion. Since the bacteria thrives in moist soil but releases the spores once the soil dries out, the smell is most acute after a rain that follows a dry spell, although you'll notice it to some degree after most rainstorms. Actinobacteria are important to healthy soil function, and are ubiquitous. Thus the smell of healthy soil is similar the world over.

Though they play an important role in soil quality, Actinobacteria are more commonly known for what it produces in the laboratory. Actinobacteria are unsurpassed in their ability to produce many compounds that have pharmaceutically useful properties. In 1940 Selman Waksman discovered that they made actinomycin, a discovery for which he was awarded a Nobel Prize. Hundreds of naturally occurring antibiotics have been discovered in these terrestrial microorganisms, especially from the genus Streptomyces.

Actinobacteria are also involved in nitrogen fixation; they convert atmospheric nitrogen into a form that can be used by plants.

Photo source: the earth smells good
Originally uploaded by kamalawalabear

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Triclosan, Triclocarban Concern

Triclosan and triclocarban are small organic molecules that give antimicrobial properties to personal-care products such as soap, deodorant and toothpaste as well as durable goods such as cutting boards, baby carriers and socks. The environmental persistence of these compounds is remarkable. More than a million pounds of these chemicals flow into the nation's sewers every year. Recently improved laboratory analysis demonstrates that 50 percent of triclosan and 76 percent of triclocarban remain unchanged by aerobic and anaerobic digestion in a typical wastewater facility, where most of it is retained in the solids fraction. We can assume that the same can be said of breakdown in the septic systems that 25% of us use in the USA. Most of these solids get spread on land to fertilize pasture, forest, biomass, fiber, feed and food crops.

Triclocarban has been determined by the FDA as having no verifiable benefit. Despite a lack of evidence that these compounds accomplish anything beneficial, usage rate is very high among consumers. Among the households I have surveyed, it approaches saturation.

It makes little sense to land apply recalcitrant compounds that needlessly get rid of soil microbes. Fomenting the growth of resistant strains of disease organisms is only one concern. Soil functional capacity is largely mediated by living processes. It is the height of folly to jeopardize those functions for a useless consumer item.

US-EPA, which has oversight on land application of biosolids, is studying the situation. More work is needed, but everyone writing on this issue seems to get it: this is not an arrangement that we want to sustain.

Sources: (1), (2), (3), (4), (5), (6)

Update: The American Medical Association took an official stance against adding antimicrobials to consumer products in 2000 and has repeatedly urged the Food and Drug Administration (FDA) to better regulate these chemicals. (Source)


Photo: hand sanitizer
Originally uploaded by chewywong.

Technorati Tags: soil science biosolids microbiology health

Soil Science has Changed

For Carol, over at the Garden Bloggers Book Club, who comments on a previous post:

...be interesting in knowing how soil science has changed in the last 25+ years. I took an introductory class in soil science in 1978 or 79. And I don't recall much discussion about what was living in the soil. Has that become more of an emphasis?

The short answer to that is, yes.

Let's take a bit of a look back to those times. I took my soils classes mostly in 1974 through 1976 at UC Davis. One was a soil microbiology class, and it covered many of the soil-food-web fundamentals that Jeff Lowenfels expands on in "Teaming with Microbes", but it touched only briefly on species interdependence. Ecology was a fairly new field at the time, and much that we know now as soil ecology was just a glimmer in our eyes.

I took an introductory level ecology class in 1973. My recollection was this was only the second year an ecology class was available at UC Davis.

The emphasis in soil microbiology, at the time, was on the metabolic processes the soil biology contributes to nutrient cycling: respiration, immobilization, symbiotic nitrogen fixation, nitrification, ammonification. Carbon:nitrogen ratios of disked in residue were a big deal due to microbial immobilization. There was a strong emphasis on bacteria, and I don't recall anything said about mycorrhizal fungi.

I remember a deep respect for the living component of soil among my pedologic-oriented instructors: "Dirt is soil without life" was drilled into us countless times whenever we slipped up and used the term "dirt" when we should have used "soil".

My edaphic-oriented instructors were not as soil biology oriented. But this was before "soil health" and "soil quality" movements in agricultural soil science became established. It was also before the interest in wetland soil process, bioremediation, protecting groundwater, and understanding why septic systems fail, combined to drive dramatic changes in edaphology.

Edaphology is the study of soil (edaphic) effects. Until about 25 years ago, it mostly synonymous with agricultural soil science as distinguished from pedology, the study of soil in its natural setting. Edaphology now encompasses the new field of environmental soil science, with its more formal emphasis on interdependent living processes in soil.

Soil science has gone through dramatic changes in the last 25+ years.

Picture Source: The Divine Soil
Originally uploaded by Room With A View.

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Technical Difficulties

January visited a host of computer problems on our household. This culminated with an early dawn motherboard meltdown Wednesday. It was a six-year old machine, so I was pushing my luck. I was hoping to limp it along until Vista was better established.

If the machine had gone out the week before, I would have replaced it with another XP machine. No XP machines were available this week. I bought an HP Pavilion a1730n, 2.4 GHz Athlon 64 X2 with 2 GB of RAM, GeForce 6150 video card w/ 128 MB RAM and one 320 GB SATA HD. There is a 5 inch bay available for another drive. It has a 300 watt power supply. It was off the shelf.

I stripped my old machine. It was a fast machine in its day, made right when DDR RAM came out. It had 2 roastingly hot Athlon processors and a high end graphics card. It had a nasty habit late in life of eating 400+ watt power supplies until I shelled out for a lovely Antec ps. It was noisy, hot and an energy hog. I had grown quite attached to it.

Rosemary got the 2 GB sticks of RAM, which made her quite happy. The 2 and 4 year old WD harddrives turned out to be fine also, but it took me awhile to figure out how to access them. A major problem (I thought) was that there is not a single SATA HD external enclosure in stock within driving distance, and I spent hours pursuing what turned out to be misleading and incorrect information. Finally my tech guy got back in and set me up to transfer files. It was an easy solution. I already had the cables and I should have figured this out myself.

My fears that Vista will make my life miserable are fading fast. Although I have yet to do any billable time on the beast, Vista is looking good. My open source programs appear to be Vista worthy with one exception. Working are OpenOffice.org 2.1, GIMP 2.2, ghostscript 8.54, and my ghostscriptviewer, GSView 4.8. These are all running perkier than I have ever experienced, especially GIMP, the graphics program I rely on for marking up maps.

An open source application not working is my PDFCreator 0.9, which I use heavily for creating pdf invoice and map files to email to clients. The good news is that ghostscript, which PDFCreator relies upon, does not seem to be the problem. A fix can't be too far off.

I haven't loaded all my programs and data yet, but no matter how bad it gets, it looks to be clearer sailing and better winds than we had in January.

Tech Tags: vista