|Author: ||F.J. Peryea|
|Keywords: ||arsenic, cadmium, cobalt, copper, lead, zinc, fertilizer|
Tree fruit mineral nutritionists traditionally have focused on the effects of nutrient management on tree vigor and fruiting performance.
Increasing knowledge about the potentially deleterious effects of heavy metals on environmental and human health has prompted closer examination of the presence and behavior of such elements in agricultural ecosystems.
Heavy metals occur in many fertilizers and in some pesticides, purposefully included as micronutritional or biocidal components, present as naturally occurring contaminants, or introduced when waste materials are used to formulate fertilizer products.
Heavy metals may be of particular concern in tree fruit production because of the importance of foliar sprays, which deposit fertilizer and pesticide residues directly onto fruit.
Furthermore, many orchards have histories of receiving high application rates of heavy metal-containing fertilizers and pesticides.
Current issues concerning heavy metals and nutrient management include natural Cd and As enrichment in P fertilizers, anthropogenic heavy metal contamination of Zn fertilizers, Cu and As contamination of soil resulting from historical pesticide application, and effects of P fertilizer on soil As solubility and phytoavailability.
Disparate viewpoints regarding the significance of heavy metal contamination have resulted in varying regulatory approaches towards safeguarding human and environment health.
Heavy metal concentrations in tree fruits are very low even when grown on contaminated soils.
In contrast, the heavy metal contents of some orchard soils may be high enough to cause adverse effects in people, plants and the environment.
Depending on land use, some type of remediation may be required in such soils.
Avoiding future contamination of currently uncontaminated orchard soils will require modifying nutrient management practices to minimize importation of heavy metals.
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