This group of soils is similar to soil group No.13 but they contain appreciable amount of pyrite. Under anaerobic environment, soil reaction is very alkaline but under aerobic condition soil reaction is very strong acidic to extremely acid due to oxidation of pyrite. Soils in this group are Bang Pakong (Bpg) and Ta Kua Tung (Tkt) series.

                This group of soils are not suitable for any agricultural production. In some places they are applied to be salt pan and aqua culture. It was recommended to grow mangrove forest or to be aqua culture areas. To do aqua culture, waste water treatment is recommended. The mangrove area should be reserved to be buffer of wind and wave and marine resources.