Comparison of sulfurous acid generator and alternate amendments to improve the quality of saline-sodic water for sustainable rice yields

The prolonged irrigation with marginal quality water can cause secondary salinization of soils, which necessitates for better understanding of water management alternatives. Relative performance of sulfuric acid and gypsum is still controversial to counter sodium hazards in soil/water system. As an alternative, sulfurous acid generators (SAG) are also being marketed. But up-till-now, there is not even a single field study published in scientific journals about their efficiency and economical viability for the treatment of saline-sodic water. Therefore, a field study was carried out to compare the effectiveness of SAG and alternate amendments applied on an equivalent basis to grow rice crop. SAG treatment of saline-sodic tube well water decreased only residual sodium carbonate (RSC) from 5.4 to 3.6 mmol(c) l(-1), and had no beneficial effect on its sodium adsorption ratio (SAR) or electrical conductivity (EC). All the treatments kept soil EC and SAR around their respective threshold levels. For paddy yield, SAG, sulfuric acid, and gypsum treatments depicted nonsignificant differences. SAG and sulfuric acid treatments of water were about six times expensive than that of gypsum. It was concluded that soil-applied gypsum, to counter sodic hazards of irrigation water, is economical to sustain irrigated rice in dry regions.