Inoculated charcoal Terra preta soil

The judges for the allotment competition came back to see my allotment again today.  I think that they were interested in the sweet peas but did not really look at anything else.

They were asking what was put on the soil to augment it and I said horse muck, inoculated charcoal, comfrey liquid and mychorrhizal fungi.  They could not believe that such a productive allotment could be sustained with so little input of fertiliser.

Most soils will have ample nutrients for plant growth without a great deal of augmentation, although whether these nutrients are readily available to the plant is another question.  Making the nutrients available is the work of the mychorrhizal fungi.

Nitrogen input into the soil comes from the legumes growing on the allotment.  The allotment is producing a remarkable amount of produce now and the plants are growing particularly big.  Is this due to the charcoal experiment?

Inoculated charcoal has been used throughout the allotment during the planting season.  It certainly seems to have helped the vegetables grow well.  Ordinary lump charcoal for barbecues was used.  It was put into a dust bin and comfrey liquid poured over the top of it.  The charcoal marinaded in the comfrey liquid for several months during the winter. In the spring the charcoal was crushed with a bull hammer and put into the planting holes of the vegetables.  The hypothesis is that the charcoal adsorbs and absorbs nutrient from the comfrey liquid so that it becomes saturated with it.

When it is added to the soil it acts as a type of buffer; releasing nutrient when there is a lack of them but absorbing or adsorbing them when there is a surplus.

Another suggestion is that mychorrhizal fungi can find nutrients in the charcoal and transport them to the plant easily.  So they are added to the planting hole as well.
Now it has been said before that there is plenty of mychorrhizal fungi in the soil all ready.  However, I think that we destroy these symbiotic relationships when we disturb the ground for digging and cropping.  Therefore adding them to the allotment will only help the plants to grow.