Effect of nano iron oxide application on iron availability in calcareous vertisols

Abstract

Incubation studies on dynamics of applied nano iron oxides in calcareous Vertisol was conducted for a period of 60 days at department of Soil Science and Agricultural Chemistry, University of Agricultural Sciences, Dharwad. The results revealed that, DTPA iron in soil decreased with advancement in period of incubation. Highest DTPA extractable iron (6.87, 5.97, 4.89 and 4.74 mg kg-1 at 15, 30, 45 and 60 DAI, respectively) and water soluble iron (1.59, 1.81, 1.92 and 1.72 mg kg-1 at 15, 30, 45 and 60 DAI, respectively) was recorded in the treatment receiving nano Fe2O3 @ 2.5 mg kg-1mixed with FYM. The water soluble iron increased in all the treatments up to 45 DAI and thereafter, decreased. The treatments which received iron oxide formulations chelated with FYM recorded higher DTPA extractable and water soluble iron than their respective unchelated ones at all the concentration levels. Between the sizes, the nanoparticles having the size < 50 nm were found better than the size range of particles between 50 - 100 nm in maintaining soil DTPA iron and water soluble iron status at all concentration ranges throughout the incubation period.