Nitrate leaching and adsorption in a krasnozem from Redland Bay, QLD. II. Soil factors influencing adsorption

Abstract

Laboratory determinations of nitrate adsorption from a 0.005M potassium nitrate solution indicated that exclusion occurred in soil from 0-20 cm and that adsorption increased through the subsoil from 0.16 m-equiv./100 g at 45-90 cm to 0.45 m-equiv./100 g between 360 and 600 cm. These profile changes appeared to be related to decreases in organic matter and pH and increases in kaolinite content. Correlation studies showed a strong relation (r = 0.87) between nitrate adsorption and relative net charge as measured by ÄpH (pHKCl pHH2O) and a negative relation (r = -0.67) with pHH2O. Correlations with sesquioxide fractions were variable and mostly negative.