This is a soil fertility test. It utilizes the DTPA micronutrient extraction method that estimates the amount of available zinc in a soil sample. Analyte concentrations are determined by atomic absorption spectrometry (AAS) or inductively coupled plasma atomic emission spectrometry (ICP-AES). The method has shown to be well correlated to crop response to zinc fertilizers. The method detection limit is approximately 0.1 mg/kg and is generally reproducible to ± 10%.