Comparison of slag-based gypsum with commercial gypsum as a nutrient source on soil properties, nutrient uptake and yield of rice (Oryza sativa L.) under aerobic and wetland conditions

Slag-based gypsum (SBG) is produced from LD slag (Linz-Donawitz slag) which is a byproduct of the steel industry. As the constituents of SBG are almost similar to the commercial gypsum (CG), two field experiments on acidic and alkaline soil under aerobic and wetland conditions were conducted to know their performance on rice. The treatments included recommended dose of fertilizer (RDF) as control, 300, 450, 600 and 750 kg ha(-1) of SBG and CG along with RDF. Application of 750 kg SBG ha(-1) recorded higher grain (6.15 and 9.22 t ha(-1), respectively) and straw yield (10.80 and 12.71 t ha(-1), respectively) in acidic and alkaline soils. The application of 750 kg SBG ha(-1) increased the pH of acidic soil from 4.56 to 5.00 and from 9.04 to 9.37 in alkaline soil. Available nutrients in the post-harvest soil increased with the increase in the application rates of SBG and CG in soil. There was an increase in total uptake of the nutrients by the rice crop with an increase in application rates of SBG and CG. Application of a graded levels of SBG recorded higher grain and straw yield, nutrient uptake and nutrient availability in comparison to CG.