[tinyallotment]

Hi All

I am always looking for ideas to improve my soil especially if I can do so for free. I have a good supply of offcuts of wood and was thinking about building a biochar processor as my next project.

Do any of you guys use biochar on your allotments and if so what are your thoughts.

BioChar is just charcoal that is used as a  soil amendment. It is reported to increase yields, reduce the need for irrigation and fertiliser, and reduce soil borne diseases.

It is very simple and cheap to make in small batches at home and is carbon negative so sequesters carbon and locks it up in a stable condition in the soil

Sounds too good to be true?

I don't know but it will be fun finding out

paul

[Nobbie]

Basically it's just charcoal? Sounds like it's of use on acid oils, but I'd check what the offcuts have been treated with before using on the soil. Might contain chemical preservatives. I suppose you get the same effect from having a bonfire and then spreading out the ash and charcoal left at the end, only minus the ash. That does seem to open up the soil so might be worth a go on a test patch. Let us know how you get on.

[JayG]

The backers of the global Biochar project see it as a win-win solution to global warming - excess carbon dioxide in the atmosphere is absorbed by plants, the plants are then turned into charcoal which is buried, which improves soil fertility, and by virtue of elemental carbon's relative lack of biodegradability, locks the carbon into the soil.

As a bonus, the charcoal producing process produces gases which can be used as fuels, although clearly that only applies when done on a large scale.

A quick Gurgle will reveal that it's not quite as simple as that, although there doesn't seem to be much evidence that adding charcoal to soil is likely to cause any actual harm, but as Nobbie suggests if you are making your own make sure the wood isn't contaminated with preservatives or old lead paint.

Lots of Biochar websites needless to say - it would be interesting to see the results of a side-by-side test to see if you can replicate their results:
http://www.biochar.info/biochar.biochar-overview.cfml

You can even volunteer to join in a British experiment to find out what difference it makes in your own garden or allotment:
http://www.bigbiocharexperiment.co.uk/

[Kevin67]

About four years ago, I had several bonfires in a pit that I knew I was going to plant young trees in. I also planted equally young trees in another area that did not have a bonfire pit. The bonfire pit trees have done massively better.

Although not strictly Bio-Char, I did some reading about burnt soil and burnt ash within the soil and how it is beneficial. I need to plant some more trees and now will not plant them without a bonfire pit first.

I have thought about doing a similar thing for the soil I will use for veg beds.

[mumofstig]

Could it just be that the trees benefitted from the fires killing any diseases in the soil, before planting 

John's thoughts on Biochar are here
http://www.allotment-garden.org/compost-fertiliser/biochar.php

[Kevin67]

Could be - that thought was never mentioned but that the fire created extra carbon which was apparently beneficial.

Yours is a brilliant thought, actually.

[kirpi]

John's thoughts on Biochar are here
http://www.allotment-garden.org/compost-fertiliser/biochar.php

I keep reading on here about this John fellow - who is he and why is he so revered? Serious question because I know he is John Harrison, but apart from that ...

[mumofstig]

He's the site owner - Simples 

[Madame Cholet]

He's the site owner - Simples 

[solway cropper]

Like all quick fixes biochar should be taken with a huge dose of salt. If your soil is devoid of nutrients it may well make a significant difference, but then so will cow muck, seaweed and a host of other things. As for using it  to negate the impact of climate change....dream on.

[beesrus]

Like all quick fixes biochar should be taken with a huge dose of salt. If your soil is devoid of nutrients it may well make a significant difference, but then so will cow muck, seaweed and a host of other things. As for using it  to negate the impact of climate change....dream on.

Well said Solway, somebody had to say it. Some interests out there have no shame whatsoever in positioning an idea in the marketplace of commerce, life and the universe. I wonder what the next wheeze will be.

[tinyallotment]

Like all quick fixes biochar should be taken with a huge dose of salt. If your soil is devoid of nutrients it may well make a significant difference, but then so will cow muck, seaweed and a host of other things. As for using it  to negate the impact of climate change....dream on.

I am not for or against Biochar at the moment as I am still looking into it but I don't think it is in any way a quick fix. It can take several seasons to start to have a positive effect and once it does it carries on having an effect for 1000s of years.

We are constantly being told by 'experts' that we should be reducing our carbon footprint and the government delights in separating us from our hard earned cash in the name of green taxes. Biochar does sequester CO2 from the atmosphere without giving the government a penny.

From what I can see, Biochar doesn't actually add that much to the soil. What it does is hold onto the water and nutrients that are in the soil and reduces the amount that leeches away. This also reduces the amount of pollution finding it's way into water courses.

paul

[al78]

I participated in a biochar experiment this year which involved marking out two 1 sq m areas of ground, adding biochar to one and sowing carrots and beetroot and measuring size/weight of crop. My findings were that the beetroot grew more vigorously, grew larger on average and cropped better in the treated plot but the carrots did significantly better in the non-biochar plot. This suggests that biochar can have mixed results depending on the crop.

It would be interesting to know why it helps beetroot but hinders carrots, and would be good to try it again next year with different crops. If there is a physical explanation for my result it may be possible to predict in advance which crops will benefit from biochar.

[Welsh Merf]

Last year we had a wood-stove fitted in the house, and over last winter I collected all the ash into a large plastic drum (when it was cold, of course!). All the wood we burned was untreated raw timber direct from the tree itself. This year, as I was digging over the beds for winter, I tipped the whole drum onto one bed and mixed it in, to see if it makes any difference when compared with the other bed's crop next year.

I have absolutely no idea what the outcome will be, or whether I've done the right thing in the first place. But let's just call it an experiment, and I'm sure lessons will be learned from it.

[beesrus]

Over the years, I have always had the odd plot bonfire with woody waste that hasn't composted fast enough, from corn stalks to hedging stumps. Most gets totally burnt, some turns to charcoal over 24 hours. The site of the fire and it's remants get spread over a wide area. I assume it does the plot some good.... and most growers have done it for centuries. What I have never noticed is 20kg of 5,5,5 feriliser based on fire remnants costing me £39.99. That's the going price for biochar fertilisers. Organic chicken pellets with a similar NPK from just up the road, that doesn't contain 90% of a hitherto waste material shipped from halfway around the world, costs about £7 for that 20kg pro rata. That's the reality, but I guess chicken manure doesn't have the sexy PR. Green is the brand of the moment. It doesn't have to be green, it just needs to sold as green. I no longer despair, I just smile