Temperature correction factor for DTPA-extractable Zn

DTPA (diethylene triamine penta-acetic acid) is one of the common extractant used for the determination of available micronutrients (i.e. zinc) in soil. Laboratory temperatures vary from 15 to 35 oC during winter and summer, and may adversely affect the reproducibility of extractable zinc. By studying the effect of temperature of extractant on the DTPA-zinc, the resulting equation (Y=0.005+0.038x) giving correction factor Y can be successfully used by soil testing laboratories to convert the DTPA-zinc at any temperature (x) to a standard temperature of 25oC.