The influence of surface incorporated lime on subsurface soil acidity

Abstract

The aim of this study was to establish whether surface incorporated liming materials could reduce subsurface acidity. Three sites on the southwest slopes of New South Wales, between Wagga and Albury, were sampled at 2 cm depth increments to 16 cm, 5 years after the liming materials were applied. Limestone and dolomite had been applied at 0,2 and 8 tlha in 3 replicates. At 2 t/ha the effect of the liming materials on pH was largely confined to the depth of incorporation. At 8 t/ha substantial pH increases occurred to 6 cm or more below the depth of incorporation. In general, the movement of Mg>Ca> HCo3 (pH), and was consistent with the soil's ability to hold those cations and to neutralize alkalinity respectively. Agriculturally realistic liming rates are not likely to ameliorate subsurface soil acidity on the south-west slopes of New South Wales.