it is not that the soil has been depleted, this is a fact, most of our soils in californina are dead zones. it is as in any marketing opportunity a lot more credit is given to a product than it is capable of sustaining. i have read numerous articles on biochar, some by creditible sources many not.
any compound mixed in with the soil should be blended into the soil in moderation.

before i accept info i want to see blind studies, and true comparitive analysis. there is a logical path to most information. i'm not interested in the placibo effect.

no part of the world needs to have it's soils replenished more then the united states. being the bread basket of the world our water supply has been drastically reduced and the soil has been biologically depleted of naturally occuring nutrients. i am behind any way that the soil can be revitalized. unfortunately i believe it would take many years of intense work to bring back just part of the soil. to produce biochar; how many forest will have to be cut done to meet the market demand? our forest are already over cut. much of which goes to other countries.

the question i was responding too was why couldn't it be used in place of expanded clay.