It is possible, if you know density of the soil (the mass of unit of soil volume in it's natural state). However, it is important to remember, that density of one soil changes with changes of humidity, compaction and other factors. The coarse soils (sands) are generally more dense (about 1,6g/cm3), the fine, but also silty soils have smaller density (more r less 1,3g/cm3 in dry state). Volcanic and organic soils have even smaller density (

It is possible, if you know density of the soil (the mass of unit of soil volume in it's natural state). However, it is important to remember, that density of one soil changes with changes of humidity, compaction and other factors. The coarse soils (sands) are generally more dense (about 1,6g/cm3), the fine, but also silty soils have smaller density (more r less 1,3g/cm3 in dry state). Volcanic and organic soils have even smaller density (

Yes,

Concentration [cmol/dm3 ] / soil relative bulk density =  Concentration [cmol/kg].

Each soil type has a standard average particle density (mass of soil per volume),  These can be  found easily in published materials. You can then use particle density to convert cmol/kg. So atleast you need to find out what type of soil it is (or where the it is from) and search for particle density. 

I agree with answer Barradas"Concentration [cmol/dm3 ] / soil relative bulk density = Concentration [cmol/kg].".  

If the bulk density is 1 g/cc  the value is the samei