Manure and peat based iron-organo complexes - II. Transport in soils

Iron transport in soils amended with Fe-enriched farmyard manure (FYM), poultry manure (PM) and Huleh Valley peat (Peat) was studied in saturated soil columns under constant water flow rate. The Fe concentration in the effluent varied with the type of the organic material, water soluble fraction (WSF) concentrations and the susceptibility of the WSF to chemical and microbial degradation. Incubation of soils treated with the enriched organic materials significantly enhanced the levels of leachable Fe complexes in the case of the FYM and PM treatments which were easily subjected to biodegradation, whereas incubation of a soil with Fe-enriched peat resulted in minor effects. Under a simulated drip irrigation regime (5 irrigation cycles during 104 days), DTPA extractable Fe concentration increased to a depth of 45 cm and to a horizontal distance of 30 cm from a point source of Fe enriched organic matter. The Fe movement in the soil was attributed to mass-flow of water-soluble complexes which are partially present in the original organic material and partially formed by degradation processes.