Before revision: Four or five parameters are evaluated: A: Soil depth and texture; B: Soil permeability; C: Soil chemical characteristics; D: Drainage, Surface runoff; E: Climate (only if it is not homogeneous, if so than it should not be included in the formula); The index is calculated from the multiplication of these parameters, that is: Sindex = A x B x C x D x E The disadvantage of this method is that if we have a value of zero in any category, than the result will be zero and won't be suitable for using.
After revision: Four or five parameters are evaluated: A: Soil depth and texture; B: Soil permeability; C: Soil chemical characteristics; D: Drainage, Surface runoff; E: Climate (only if it is not homogeneous, if so then it should not be included in the formula); The index is calculated from the multiplication of these parameters, that is: Sindex = A x B x C x D x E The disadvantage of this method is that if we have a value of zero in any category, than the result will be zero and won't be suitable for using.