Fertilising with Biochar

amancalledgeorge

Morning all,

Have been looking into biochar for a while and as usual with such heavily marketed innovations it was useful to find some actual research backing the benefits of using it in a temperate climate. Considering getting some biochar fertiliser to use next year, have any of you tried using it and what were the results you've had? 

Hostafan1

Sorry George, I've neither used it nor heard of it. 

punkdoc

I have seen some of the evidence, and it does sound promising. However, I think it is too expensive for me to consider, and I have read that some companies are just selling charcoal, but calling it Biochar.

amancalledgeorge

punkdoc said:

I have read that some companies are just selling charcoal, but calling it Biochar.

Oh of course...like with any new introduction the opportunists will flock to money grab. There seem to be a few trustworthy suppliers like Carbon Gold. But yes it's much more expensive than the pelleted Q4 I'm currently using. But I suppose the fact that the carbonised wood remains in the soil long term is a unique trait of that type of fertiliser. Until it gets more mainstream presumably the prices will remain as high. 

WillDB

There's some data here. https://www.carboncommentary.com/blog/2013/02/10/how-much-proof-do-we-need-that-biochar-can-double-food-production-on-some-tropical-soils

//The most important finding is that biochar works best at heavy dosage (about 6 tonnes/acre or 15t/ha) and when supplemented by sanitised urine.//

So you need very large quantities, and you still need to add plant nutrients (biochar doesn't contain nutrients itself it just holds on to them). I think buying expensive containers of the stuff from Amazon etc is unlikely to give a good return on investment. Making the stuff yourself could be viable though?

//Putting six tonnes of biochar into an acre of soil is not a trivial task. It needs three units of raw material going into the kiln to make one unit of biochar. To get optimum dosages of biochar, the farmer therefore needs to process eighteen tonnes of agricultural wastes or wood. This is the average yearly production of several hectares of land. Opponents have focused on the risk that the increasingly clear yield advances offered by biochar might encourage rapid deforestation as farmers cut down trees to obtain raw materials.//

By the way when I clicked on the link in the article it took me to a vibrator website   

amancalledgeorge

Goodness me @WillDB the link works as expected on my end Yes making it at home makes sense for anyone not in an urban situation...I was thinking of using fertiliser based on biochar so it has the nutrients but hopefully helps with retention. I suppose may try a small batch and see how we get on. 

Allotment Boy

I have seen it in the Organic gardening catalogue but never tried it. I find seaweed meal, and Rockdust or Remin (both crushed volcanic rock) ideal for the long term fertilisation of permanent crops such as fruit trees asparagus etc  not cheap but not nearly as expensive as biochar. I guess it depends on your soil conditions and what you are trying to achieve.

BobTheGardener

I have a tub of 'carbon gold' which was on special offer when I bought a lot of other stuff.  Unfortunately, I forgot all about it this year so nothing to report yet but I do intend to do a comparative test on sweet pepper plants in pots next year.

Decades ago, I remember seeing a documentary about highly fertile 'black soil' somewhere in (I think) South America which was thought to contain charcoal added by the inhabitants centuries ago.  Perhaps further research led to these products?

scullion

we did a test a few years back, using bought potting compost as the base compost. three big boxes, one with added biochar, one with biochar and urine and  one with nothing added as a control, growing lettuces.
 the lettuces were all harvested at the same time and their leaf and root growth measured. the conclusion from the results were that there was no significant difference and if there was a minuscule difference it was in favour of the control. so we never bothered using it again.
my partner says there is some data that biochar/terra prater is more effective in equatorial areas but that it has not been found to make a significant change in our climate - otherwise people would be using it as a matter of course!

amancalledgeorge

Your partner is right @scullion that's why the research has been focusing on proving any increase in fertility in temperate regions. But then even if the research so far indicates there's an improvement it is a whole different question if the effect is replicable in home gardening scenarios.

Make sure you remember it next year @BobTheGardener 😉

Allotment Boy

I did not see it all but on Country file they were talking about giving cattle small amounts of Biochar to help stop them belching out so much methane! Early trials look promising,  and it makes the manure better too!