Amelioration of sodic soil with silicon and gypsum

A pot culture experiment was conducted in order to check the effect of silicon (Si) and gypsum in the amelioration of sodic soil. The Si sources used were rice hull ash (RHA), diatomite (DE) and calcium silicate. Gypsum was applied based on the gypsum requirement of the soil. Combined application of Si and gypsum proved to be effective in lowering the pH and ESP of soil than the sole application of Si. Application of RHA@250 kg Si ha-1 with 100 % gypsum significantly lowered the pH of soil (7.91) at harvest of rice. The reduction in ESP occurred with the application of DE @ 250 kg Si ha-1 + gypsum @ 100 % GR was statistically significant over the rest of the combinations at both the sampling periods. Regardless of the dosage, the combination of Si as DE and RHA performed well with gypsum than CaSiO3 with gypsum which might be due to the difference in reactivity of these silica materials with gypsum and with soil.