Influence of Soil Amendment on Iron Reduction in Paddy Field and Crop Improvement

Abstract

In the present investigation, laboratory incubation experiment and field trials were done to assess the effect of organic soil amendment including acetate, rice straw and charcoal at different levels on temporal changes of microbially reducible iron, evaluate plant root oxidase activity and crop performance in both simulated and field conditions. The contents of reduced iron in alluvial soil supplemented with acetate were in the range of 3.5 to 23 μmol g-1 soil as compared to the laterite soil. The addition of rice straw stimulated the process of iron reduction, as evident from the increased contents of reduced Fe(II) till 14 days of incubation. However, application of charcoal along with glucose showed inhibitory effect on Fe(II) production. Extensive field trial studies suggested that control plants and addition of charcoal at varying levels led to concomitant decreases in the iron reduction potential and α-naphthylamine oxidase activities. The crop performance was evaluated by grain yield of rice plants. Results clearly showed high yield content and harvest index when amended with 10 Mg ha-1 charcoal, highlighting that organic amendment significantly improve plant nutrient uptake and its availability by reducing sorption and leaching activity