Trace elements in soils and plants: An overview

The movement of both essential and non-essential trace elements through agr icultural ecosystems and food chains is a complex phenomenon. Such elements as As, B, Cd, Cr, Cu, Hg, Ni, Pb, Se, U, V, and Zn, are generally present in soils in low concentrations but concentrations may be elevated because o f natural processes and human activities, such as fossil fuel combustion, m ining, smelting, sludge amendment to soil, fertilizer application, and agri cultural practices. Although a significant effort has been expended over th e past 40 years to evaluate and quantify the transfer of trace elements fro m soils to plants, more attention needs to be given to mechanisms within th e soil and plant systems, which influence their solubility, chemical specia tion, mobility, and uptake by and transport in plants. The prediction of mo vement of trace elements in the agricultural ecosystem must be partially ba sed on understanding the soil and plant processes governing chemical form a nd the uptake and behavior of trace elements within plants.