Effect of Moisture Regimes and Amendments on Iron Transformation in Acid Soils


                                An incubation experiment was conducted at Department of Soil Science and Agricultural Chemistry, Directorate of Natural Resources Management, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu during 2017-18, with an objective to study the iron transformation and changes in soil reaction in acid soils of Ambasamudram series (Aquic Haplustalf). There were two levels of FeSO>4 (0 and 50 kg ha-1), two sources of amendments viz., lime (as per requirement @ 22.5 t ha-1) and FYM @ 12.5 t ha-1, with three moisture regimes viz.,continuous submergence, alternate wetting and drying, and field capacity. The experiment was conducted for 60 days and the soil samples were drawn at 15, 30, 60 days after incubation, analyzed for pH, DTPA Fe, water soluble Fe and exchangeable Fe. Liming @ 22.5 t ha-1 was found to be effective for bringing the acidic pH to near neutral. Available iron and water soluble iron was noticed to be higher under submerged condition than compared to alternate wetting drying and field capacity moisture regimes. The recovery of Fe in various pools revealed that 25 to 33 percent of Fe entered into water soluble + exchangeable form at 60 days after incubation.

Key words : Acid Soil, Exchangeable iron, DTPA iron, Soil pH, Water soluble iron.