Temporal changes in some soil chemical properties at four depths following the surface application of lime

The effect of a surface application of lime (5000 kg/ha initially then 2500 kg/ha 1 year later) on soil properties in four soil layers was measured over 15 years on a yellow-grey earth (Duric Palic soil). The maximum increase in soil pH occurred about 2 years after lime was initially applied in the 0-50 mm soil layer, after 5 years at 50-100 mm, after about 12 years at 100-150 mm, and was still increasing at 150-200 mm. The average rate at which soil pH increased until a maximum difference occurred was 0.57, 0.15, 0.04, and 0.009 pH units/year in the 0-50, 50-100, 100-150, and 150-200 mm soil layer, respectively. The average rates of soil re-acidification (rate of decrease after reaching a maximum) were 0.075 and 0.02 pH units/year in the 0-50 and 50-100 mm layer, respectively. For exchangeable calcium (Ca), the average rate of decrease after reaching a maximum was 0.82 and 0.17 cmol(+) Ca/kg per year in the 0-50 and 50-100 mm soil layer, respectively. At this rate of decrease, lime should increase soil pH in the 0-50 mm layer until about 17 years after application. Lime significantly decreased exchangeable magnesium (Mg) for only 5 years, with the maximum decrease between 0 and 100 mm occurring about 3 years after lime was applied. Below 100 mm, exchangeable Mg was about 0.2 cmol(+)/kg lower in the lime treatment from 5 years after lime was applied. Lime decreased Olsen P at an average rate of 0.53 and 0.27 mu g/ml per year in the 0-50 and 50-100 mm layer, respectively up to 6 years after lime was applied. This decrease was partly attributable to higher plant phosphorus (P) uptake in the lime treatment.