Improvement of waste water quality to increase planting index in acid sulphate soil of Central Kalimantan

This study aimed to determine the water return effect through the application of formulas from isolates of the bacterium Thiobacillus ferroxidan in increasing the crop index in acid sulphate soil. This research was carried out during two planting seasons in the tidal swampland based on hydrological units and overflow types with crop production in MT 1 and MT 2. This study used the split plot design with main plots the water management system, namely: (1) control with an open water system (leaching); (2) inoculant formulas with closed systems (no leaching); (3) without formula with a closed system (no leaching). Subplots were types of organic materials, namely: (1) control; (2) multi organic compost; (3) farmer patterns; (4) rice husk biochar + multi organic compost. The results showed that application of Thiobacillus ferroxidan in waste channels in acid sulphate soil effectively improved wastewater quality by increasing the pH value of wastewater by 13.09%. The returning water through the application of formulas from isolates of ferroxidan in sewage can increase the crop index to IP ≥200 in acid sulphate soil and rice yields of 20.94% dry grain in the first planting season and yield of corn shelled by 34.57% in the second season.