Effect of temperature on nutrient availability in sludge amended soil

Abstract

Temperature is one of the important factors in availability of nutrients. Three type of soils i.e. alluvial red and black soil were used, sludges were mixed with soils at the rates of 0, 25 and 50 g sludge kg-1 soil (dry weights. The sludge amended soil was thermally treated at 50°C, 100°C and 200°C and availability of macro and micro nutrients were analysed. Nitrogen availability increased with the increase in temperature, because due to higher temperature mineralisation of nitrogen increased. Phosphorus availability also increased because high temperature decomposition of organo-phosphorus was increased that ultimately increased availability of phosphorus. But potassium availability was not significantly increased with increase in temperature. Because potassium is mostly bounded with the mineral lattice, so at 200°C temperature no change was possible in lattice structure and it was only element that 100% present in mineral form. Organic matter/carbon content was decreased significantly with increase in temperature; because of exhaustion of organic carbon occurs as carbon di-oxide. Micronutrients like iron (Fe), manganese (Mn), zinc(Zn) and copper(Cu) availability was increased with increase in temperature due to high organic compound or cheleted compounds become decomposed and released and increased their availability in soil significantly.