Content: C/Charcoal = 98% http://en.wikipedia.org/wiki/Charcoal
Conversion: hectare = 10,000 m2 (100 m x 100 m)
Conversion: Mg = kg x 10+3
Density: Charcoal = 205 kg m-3 http://www.simetric.co.uk/si_materials.htm
Void volume: Charcoal, loose = 50% (estimated)
Density: Water = 1000 kg m-3 http://www.simetric.co.uk/si_materials.htm
Target application: 50 MgC ha-1 (Lehman, 2007) from http://www.orgprints.org/13268/01/Biochar_as_a_soil_amendment_-_a_review.pdf based on http://terrapreta.bioenergylists.org/lehmannfrontiers07
50 MgC ha-1 = 5 kgC m-2 or 1 lb ft-2
5 kg m-2 /1000 kg m-3= .005 m or 5 mm if water
5/.205 = 24.39 mm if C
24.39/.98 = 24.89 mm if solid charcoal
24.89/.5 = 49.78 mm if loose charcoal
= 5 cm or 2 inches