Zn, Mn, Fe, Cu.
This is a soil fertility test. The DTPA micronutrient extraction method is a non-equilibrium extraction for estimating the potential soil availability of zinc, copper, manganese, and iron. The extracts are analyzed by ICP-AES. The method has a detection limit of approximately 0.1 mg/kg for zinc, copper, manganese, and iron and is generally reproducible within 10% for copper and zinc and 15% for iron and manganese.