Cadmium accumulation in soils from long-continued applications of superphosphate.

A simple, sensitive method developed for the analysis of geostandards was used to measure the accumulation of Cd in soils from superphosphate applied annually to grass‐land and arable soils for many years. Rates of application were equivalent to 33 kg P and 5 g Cd ha−1 yr−1 for 95 yr in three experiments in England and to 37 kg P and 20 g Cd ha−1 yr −1 for 30 yr in one experiment in New Zealand. Very little Cd accumulated in the surface horizons (0–22.5cm) of either of the arable soils from England; about one‐quarter of the applied Cd was detected in the sub‐soil (22.5–45.0 cm) of one experiment (Broadbalk) but none in the second (Barnfield). About one‐half of the applied Cd was retained in the 0–22.5 cm horizon of grassland soils from both England and New Zealand. The light (