The state of knowledge of cadmium in New Zealand agricultural systems: 2021

Cadmium (Cd) has accumulated in New Zealand agricultural systems, predominantly from the application of phosphorus (P) fertiliser to soils. Elevated Cd concentrations in soils are an important issue due to their potential adverse effects on food quality, soil health, land use flexibility, and the environment. This paper reports on our current knowledge of Cd in New Zealand agricultural systems, summarising published and unpublished research that has been undertaken over the last 30 years to better understand, improve, and manage the potential adverse effects of Cd in agricultural soils. We found the research has been wide ranging, investigating factors such as Cd uptake in plants and animals, the rate of Cd inputs, transformation and losses from soils, Cd bioavailability, the development of animal uptake and Cd mass-balance models, as well as identifying and testing strategies and remediation options to manage Cd accumulation in agricultural systems. This research is then placed alongside the policy and regulatory context for managing Cd in agricultural systems in New Zealand, including national Cd management strategies. Finally, key knowledge gaps are presented, along with some potential Cd research directions for the future.