The formative element 'od' stands for

The formative element ‘od’ stands for Spodosol.
Spodosol is denoted by ‘od’.
Mollisol is denoted by ‘all’.
Aridisol is denoted by ‘id’.
Oxisols are denoted by 'ox'
Spodosol is one of the 12 soil orders in the US soil taxonomy. These are ashy gray, acidic soils with a strongly leached surface layer. Their suitability for cultivation is limited to acid-tolerant crops and orchards, provided with sufficient lime and fertilizer.