This International Standard specifies a method for the extraction of trace elements in soil samples using a buffered diethylenetriaminepentaacetic acid (DTPA) solution. This method mainly applies to the estimation of the availability of copper, iron, manganese and zinc to plants which grow in the soils. It is preferably applicable to soils having a pH greater than 6. Potentially toxic elements such as cadmium, chromium, nickel and lead can also be determined in the extracts. In soils containing large amounts of one or more of these elements, the efficiency of the extraction of any of these elements can be lessened by exceeding the complexation capacity of DTPA. This International Standard does not specify the methods of measurement of the trace elements in the extracts.