Biochar is charcoal used as a soil amendment for both carbon sequestration and soil health benefits. Biochar is a stable solid, rich in carbon, and can endure in soil for thousands of years
The junction between the carbon layer and the mineral layer is the rhizosphere where a vastly-spread root-fungal network exists. This junction is the interaction between the mineral soil and carbon layer where the roots of trees suck the nutrition in mineral form and convert into life form for the consumption of mammals ,birds and insects.
but these days most farmlands have leached out the top soil and only the mineral soil lies on the top. now since the microbes and their metabolites do not exist is the farmlands ,a lot of Chemical fertilizer nutrition from synthetic sources is being used.
Biochar is very porous which acts a housing for soil microbes and also it is very beneficial for chemical farmers as well because it could prevent leaching of the fertilizers and thus decrease the input-need by increasing the nutrient-availability.