[tluds] Weight vs Volume RE: Biochar Friday before ETHOS meeting.. #tlud #ethos

Tom Miles



Thanks for the information. Biochar is often about half the weight of compost or manure so 15% would be 7% by weight. Recommendations for co-composting (biochar+organics) are often 10-20% by volume or 5%-10% by weight. We have used up to 25% biochar by volume in soil-less media for growing seedlings.


In the Malawi case the 50:50 biochar-manure blend is likely placed into the soil with the seed so a small amount is probably placed in the soil in proximity to the seed. That is similar to techniques others have used where biochar is placed in a planting hole with seed and other amendments. If it is 50% by volume it should be about 25% by weight.   


The composition of the char is also important. Biochars from crop straws and ag residues typically have higher ash content and therefore carry nutrients such as potassium and may have a higher liming effect. They are also slightly lower in carbon.  


Coconut shell biochar has beneficial attributes which is why it is often activated and exported. Most of the organic based activated carbons sold in the US are from imported coconut shell. One biochar producer uses coconut shell biochar as a base for their formulated products.


What blends have others used?  With what crops and in what soils?




From: <> On Behalf Of abraham abyslo
Sent: Sunday, January 19, 2020 8:54 AM
Cc:; Paul Anderson <psanders@...>
Subject: Re: [tluds] Weight vs Volume RE: Biochar Friday before ETHOS meeting..


From our work on planting coconut seedling here in Nigeria,we have this ratio that consistently works:15/20/20/45 of biochar,compost,top soil and sand grains respectively.


Biochar from coconut shell is best in giving highest  yield after charring.


On Sun, Jan 19, 2020, 14:45 Paul S Anderson <psanders@...> wrote:



I am a believer in biochar benefits.   We all need to help develop the proofs of what we are preaching.  


Question:   For the Ghana / Malawi report (by WarmHeart, right?), is the 50:50 by volume or by weight?   I suspect that it is by volume.


And what would that proportion be if expressed the second way?        50:50 by volume becomes what by weight?    Or the other way around?      Weight is weight and does not change, but volume also subject to particle size, soft vs hard wood vs agro-refuse.     


Do we (as a community) have reasonable answers about this variation in the mixing formulae? 




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From: <> On Behalf Of Tom Miles via Groups.Io
Sent: Saturday, January 18, 2020 11:12 PM
Subject: Re: Biochar Friday before ETHOS meeting.......RE: [Biochar] [tluds] ETHOS and low-cost TLUDs


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Thanks for leading the biochar discussion at ETHOS, Paul. As you discuss biochar production in TLUDs you might remember that it doesn't take that much biochar when combined with manure and used strategically to make a big difference. You have probably seen the reports, video and pictures from Ghana and Malawi where 70 kg of a 50:50 blend of biochar and manure, which a smallholder can make for practically nothing, performs better than 25 kg of synthetic fertilizer that requires cash.