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From: "Stan Slaughter stan@... [biochar]" <biochar@...>
Date: November 15, 2019 at 7:03:14 AM PST
Subject: [biochar] Radioactive wood ash
I’ve heard that trees old enough to have “Breathed” 1950’s air have marginally radioactive ash. What do we know about that?
Stan Slaughter, M.A., Biology
US Composting Council Educator of the Year, 2000
Education and Garden Specialist-
Missouri Organic Recycling
There are lots of examples of soil restoration or improvement with biomass boiler ash. There are some great aerial photos of farms in the US that were improved with boiler ash. I have a client that bought a “desert” patch where they dispose of all their bottom ash and flyash. It is now farmed in triticale (wheat/rye) for them. Several wood boiler owners lease ash amended land to farmers. A survey in 1992 estimated that about 90% of the biomass ash in the US was land applied. Today that number has probably dropped to about 40%. Many of the independent biomass producers are owned by companies that don’t want the liability of anything happening due to the use of their ash, especially if it might contain heavy metals from urban wood waste, so the ash and flyash goes to landfills. Biomass plants that control their raw materials tend to land apply their ash when they can.
In most cases the carbon content of bottom ash and flyash should be very low. If it isn’t people like me haven’t been doing their job. We have looked at the cost of pulling out carbon enriched flyash in several boilers. It is often easier in older boilers. Most modern boiler are so close coupled that it is expensive to extract just the carbon rich flyash. So it becomes an expensive carbon for brokers who might size it for biochar uses.
An African soil scientist I work told me that the carbon content of African soils is so low that you could add shoe leather and improve growth. That is certainly the case of most soil surveys that I have seen.. The combination of biochar and manure that WarmHeart has been using seems to make substantial improvements at a low cost.
I have been around the block many times on this one. I understand perfectly, but cannot apply. Where I work (1) no one knows anything about their soil and (2) there is no choice about biochars - feedstock is whatever crop waste is at hand, temperature, residence time, quenching and what not are all a function of the available technology, which is limited to TLUD, trough or trench, and water. Bottom line: in the developing world, or at least where most people live in the developing world, the issue is really finding ways to teach farmers to produce good enough char from the waste they would otherwise burn.
My interest in the HCBA was not notional, however. As biomass power plants slowly catch on, especially in rural areas, the question arises what to do with the ash. In most instances it is either made into briquettes or landfilled. To learn that it can be used and the base of a reasonable good soil amendment is therefore a fine thing.
It has been said many times “All Biochars are different”. Since there are many different uses for biochar, this fundamentally means that there is a need for many different biochars.
The fundamental question should be: “What kind of biochar should I use to get maximum benefit from its use in my specific soil?”
Such an approach requires two important steps:
1: What soil deficiencies does my soil have that can be improved upon through the use of biochar? (This requires an appropriate soil analysis.)
2: What specific biochar can I get that best meets the specific needs of my soil? (This requires an appropriate biochar analysis.)
If my soil is suffering from heavy metal contamination, then it might very well be that an “Activated Carbon Biochar” (high temperature, probably graphitic) would be the best selection. However, in other soils, a low temperature biochar might be best.
One cannot get “optimal results” unless one uses the “optimal biochar..”
OK. I am always happy to see money for removal (although the cost of qualification has always excluded my farmers to date).
But I think that I am going to have to stick with lower temp stuff, because if the graphite form doesn't also serve a solid agricultural purpose, I don't know how I can justify pushing my farmers to spend time with it. This is what really interested me about the idea of using HCBA (that I have always assumed was high temp) with organic material to get a growth kick.
Both. Graphite is a very stable modification of carbon and therefore a possible storage of carbondioxide. (Getting carbon credits) The participation in soil ecology is limited. Therefore in the "Terra preta" economy lower temperature is preferred.
It is funny to see, that some prefer quite uncontrolled systems (flame cap), with little known reactions and temperatures.
Roland (The Chemist), AgroKarbo.Info (Germany)
---In biochar@..., <d.michael.shafer@...> wrote :
I have always been warned - that when heated to 1,000 C or thereabouts, the carbon rings that define char fuse into graphite and graphic is useless in the soil. True? Not true?
Posted by: Stan Slaughter <stan@...>
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Your message went to the group and you are a member in good standing so you shouldn’t have been rejected. Please send me the rejection message offline at tmiles@...
Biochar@groups.io <Biochar@groups.io> On Behalf Of
Friday, November 15, 2019 8:23 AMTo:
Biochar@groups.io; Tom Miles <tmiles@...>Subject:
Re: [Biochar] Radioactive wood ash
I did try to reply. My message was rejected. Advice?
Please reply to Biochar@groups.io This is our new host. The transfer from Yahoo is complete.
If you search for "radioactive" on the Groups site https://groups.io/g/Biochar/topics you will find 27 messages containing radioactive. The archives go back to June 2008. Radioactivity was detected in fireplace ash in the Northeast .several years ago but it didn't become a major issue.
The new web interface will take some learning but there are more useful functions hashtags. Search is better All archives, files and photos have been transferred.