Many thanks for the primer on moisture. I am one among many who would very much appreciate similar treatments of other issues related to characterizing chars.
I have had very considerable success convincing small farmers in the developing world (Asia and recently in Africa) to convert crop waste to biochar and to use the char as a soil amendment.
In practice, the char seems to work well. Recently, however, a spate of articles have cast doubt on the efficacy of "low rent" chars. This has led many potential funders to ask for proof in the form of "scientific" data. Needless to say, farmers cannot provide this; I am hoping that we can.
Your guidance much appreciated, since lab fees are beyond our budget and unthinkable to our farmers.