Is there any difference between distributions of cadmium in different soils with the same fertiliser history?

Abstract or Summary

Cadmium (Cd) is a potentially biotoxic metal that can be absorbed by soils and plants. The amount of Cd in NZ soils has previously increased following application of phosphate fertilisers. Cd concentration in three soil types: Te Kowhai, Horotiu and Bruntwood is being investigated. All three soils often occur in the same paddock, so have the same fertiliser history. However, these soils have contrasting drainage and mineralogical characteristics. Two paddocks with all three soils were sampled (depth of 60 cm) from a dairy farm near Hamilton and Cd concentration was determined. Initial results suggested that total Cd in the poorly drained Te Kowhai was higher than in Bruntwood/Horotiu. In some topsoils, Cd concentrations were greater than 1 mgkg-1, which according to Tiered Fertiliser Management System, would require fertiliser management by a “balanced programme” to ensure that Cd will not exceed an acceptable threshold (1.8 mgkg-1) in the next 50 years.