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Fig. 4. Temporal pattern of molar phosphate (PV):arsenate (AsV) ratio in the soil solution of the root compartment with increasing amounts of goethite application to the artificial substrate (G-0 = 0 g kg–1; G-1 = 1 g kg–1; G-4 = 4 g kg–1). In treatment G-4, the ratio could only be calculated for 3 and 10 d after planting; thereafter, PV concentrations were close to zero. The bars, representing SD, refer to the variation between the five suction cups positioned in the root compartment.
