DTPA as an extractant of available soil iron

Abstract

Experiments were conducted to evaluate DTPA as an extractant of available soil Fe and to establish interpretive guides. A critical level of 6 ppm DTPA‐extractable soil Fe correctly predicted Fe deficiency of field grown plants at 11 of 13 locations. In a greenhouse experiment increased yields of sorghum from treatments that increased soil Fe availability were correctly predicted on 13 of 14 soils by a critical level of 5 ppm.