DTPA‐extractable iron soil test correlation with hybrid grain sorghum production on gypsum affected soils

Abstract

Abstract Two studies on a complex of Holloman soils (fine‐loamy, gypsic, thermic, shallow Typic Torriorthents) and Reeves soils (fine‐loamy, gypsic, thermic Typic Gypsiorthids) were conducted to correlate DTPA‐extractable Fe with grain sorghum stover or grain yield. Study #1 included sampling successive plots along two transects across areas of variable Fe chlorosis expression. Study #2 included sampling paired sites (normal vs. chlorotic) in three fields. Fe analysis was conducted on air‐dry soil samples in Study #1 and both air‐dry and field‐moist soil samples in Study #2. Soil test Fe (air‐dry soils) was significantly correlated with grain yield but not stover yield in Study #1 (r=0.589** and 0.114, respectively). In Study #2, air‐dry soil test Fe was significantly correlated with grain and stover yield (r=0.618* and 0.594*, respectively) but moist soil test Fe was significantly correlated with only stover yield (r=0.606*). Air‐dry and moist soil test Fe showed no correlation.