What effect do brassicas have on mychorrhizal population of soils.

  Brassicas do not form a symbiotic relationship with mychorrhizal fungi so will they have any effect on the the population of mychorrhiza in the soil?  Will the spores die or just remain dormant until another mychorrhizal plant grows in that area?  Well there is lots of charcoal in the brassica bed because I used it in the planting holes of the sweet peas and runner beans last year and again when I planted out the brassicas this year.  The sweet peas and runner beans also got a pinch of mychorrhizal fungi spores.  So there must be mychorrhizal fungi in the brassicae bed soil at the moment.  This will probably be in the form of spores.  I would like to think that they are tucked away in the labyrinthine pores of the charcoal.  


Mychorrhiza  do not form an association with the brassicas but they might do with other plants around the brassicae bed.  The black currant bushes are the most prominent and I am hoping that these will act as a reservoir for VAMs; mychorrhizal fungi mycelium stretching out from the bushes to other plants around that area. Together with this, I have been weeding throughout the allotment and there are a number of weeds - particularly the grasses - that seem to have fungi growing over their roots.  Of course this is just conjecture but it is fascinating. 

Although there is an important point in trying to replicate the Terra preta recipe, I am going to continue along the lines of using comfrey.  My hypothesis is that the charcoal absorbs or adsorbs nutrients.     These can come from things found in the Amazon or from more local sources.  As far as I can see neither the charcoal or the plants seem to care where the nutrients are sourced.  The charcoal takes it up and the plants seem to access it and use it regardless.  I must also admit that other things go into the comfrey bins as well as comfrey.  The left over chicken manure and a little bit of blood fish and bone; sugar; quite a bit of nettles and sweet cicely; and whatever comes out of the worm bin.  They are all good sources of nutrient. 


I have written in the past about the more advanced countries sucking out the nutrients of third world countries by importing fruit and vegetables.  Maybe it is not only food miles we should be considering when importing food from other countries.   Local sources of nutrient might be better?

Then, when added to the soil,  the charcoal acts as a kind of buffer allowing nutrients to flow out when they are scarce and taking them in when they are in excess.

The charcoal is left in lumps in the marinading dustbins then when I need some I take it out and crush it.  If you do it like this it is easier to handle.  Crushing the charcoal means that it is easier to incorporate into the soil when adding it to the planting holes.  Last year I used some bigish lumps of charcoal but this keeps on being cast to the surface of the soil and will not mix in well.  I have started to collect up the larger pieces and crush them just to make them easier to mix with the soil.  I think that the mixing of charcoal with the soil is important and this will happen more readily if the charcoal pieces are relatively small.  

Then the charcoal acts as a kind of buffer allowing nutrients to flow out when they are scares and taking them in when they are in excess. I would also conjecture that the mychorrhizal fungi also aid in this buffering system in that they can access the nutrient locked up in the charcoal using single cell mycelium to penetrate the pores of the charcoal. 

There does seem to be a synergistic effect when comfrey and charcoal are mixed.  When marinaded together for some time they seem to have a much bigger effect on plants than they do on their own.  

The time that I leave the charcoal in the marinade bins depends upon when I need to use it.  I made some last autumn and did not need to use it until I started planting in the spring.  So I thought that the best place to leave it was in the bins.  It seems to have been a good decision because it certainly has had an effect on the vegetables in the allotment.  

Having said that, I have used the new batch only after about a month of marinading and there still seems to be a good effect. 

I have no objection to someone developing their own product to sell but I do object to them then justifying the product by plagiarizing other peoples research.  I am convinced that charcoal is a very important way of augmenting the soil but I cannot pretend that anything I have done is remotely scientific.  I would love to do proper scientific trials using differing conditions but I do not have the time or the facilities.    Also, when having such a remarkable results in the past,  it is very difficult not to use the charcoal on every occasion and this does not produce good comparisons - although I can compare with the vegetables on other allotments.  

This also suggests that I have a recipe for my charcoal mix.  However, it is more like my cooking.  Throw a lot of things in together and hope for the best.  

I  would hope that the charcoal will take up any nutrients that it comes into contact with and the buffering system will allow the right nutrient to be released when it becomes scarce in the soil.  So it does not matter where the nutrients come from or how much you put in the mix.  Whether the ancient South American peoples refined a formula or whether they just threw everything in the mix can only be conjecture at the moment.  I would suspect, from their very advanced horticultural skills, that they had a refined formula 


It could work with chemical fertilisers and I expect it would to some extent.  However,  I would suggest that it would not be any where as effective as using organic sources of nutrients.  This is because the vital and most important extra part of the formula are the micro organisms that are part of the mix as well.  


If you look at soils that have been augmented with artificial fertilisers for years they are bereft of any life whatsoever.  I don't think that artificial fertilisers and micro organisms are compatible.   Whether they are EMs or VAMs or other micro organisms or preferably all three, what matters is that there will be micro organisms and these will be added to the soil to make a living, breathing, balanced, growing medium that is sustainable over many years.  


This is what I am interested in now - whether there is a retained fertility or whether you have to keep adding inoculated charcoal.  I would suggest, from my results, the addition of further charcoal produces a cumulative effect.  The fact that plants do not need vast quantities of nutrients means that the charcoal could be a long lived source of sustenance.  It is regulating the availability of these nutrients and preventing their leeching away that is of great importance and charcoal seems to be eminently suitable for such undertakings.  

It is noticeable how much my soil has changed in the number of mini beasts it supports. I think that adding charcoal in this form changes a lot of things within the soil.  I would suggest that the increased micro organism population has produced an augmented food chain that has benefited more than just the plants on the allotment.  

Hey, what can I say, I am just an amateur gardener so take what I say with a big pinch of salt.