Fig. 2. Leachate Al (left panel) and Ca (right panel) concentrations. Data for both experiments are printed in one graph because the compost free treatments in first experiment (open symbols) can be assumed to represent the leachate conditions during the preleaching phase (360 mL) in the second experiment, during which no samples were taken. The first data point in the second experiment was taken after the preleaching, but before the surface application of compost, which is indicated by the vertical arrows. Means of two replicates for first experiment and three replicates for the second experiment.