Involving bacteria to Inorganic Substance Changes in an Acid Sulfate Soil (Rangsit Soil Series)

Abstract

A study of the group of bacteria that played a role in changing inorganic substances in an acid sulfate soil (Rangsit soil serie) was carried out using the denatured gradient gel electrophoresis (DGGE) technique and the relationship between bacterial community and changed inorganic substances was examined using canonical correspondence analysis (CCA). Soil basic properties were analyzed and the soil was incubated under submerged condition in laboratory. This Rangsit soil had clayey texture and was extremely acid soil (pH 4.3). Result revealed that nitrate content decreased rapidly from the redox potential of +200 mV and entirely disappeared at 0 mV. Soluble manganese content in the soil increased from the redox potential of +200 mV and reached the maximum (14 mg/kg) at -150 mV. The amount of iron in soil solution clearly increased from the redox potential of +150 mV while sulfate tended to slowly increase from the beginning. It can be divided into, in accordance with the relationship between the group of bacteria and changed inorganic substances in the soil, four groups as follow; 1) the group dominant in the unchanged state of organic substances, 2) the group thriving in the condition both with or without oxygen that can reduce nitrate, iron and manganese, 3) the group dominating in the redox potential ranging between +150 - -250 mV of which the reduction of nitrate, iron, manganese and sulfate took place, especially in the cases of iron, manganese and sulfate, and 4) the group found only during the reduction of iron, manganese and sulfate.