C. Banik1, Willie G. Harris1, S. Balboa1, Larry Ellis2 and G. Wade Hurt3, (1)Soil and Water Science Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL (2)Box 110290, University of Florida, Gainesville, FL (3)University of Florida, Gainesville, FL
Depth and morphological expression of Bh horizons were studied with respect to iron (Fe), aluminum (Al) & carbon (C) concentrations along four transects encompassing transitions from poorly-drained Aquods to better drained soils. The Bh horizons of Aquods were well-expressed, but Bh horizons along the transition toward better –drained soils became shallower and less-well expressed, ultimately fading into the surface horizon. Organically-complexed and amorphous Fe and Al were extracted by pyrophosphate and ammonium oxalate, respectively, and measured by inductively coupled plasma spectrometry. Pyrophosphate-extractable C and total C were measured by flash combustion. Extractable Al in Bh horizons correlated positively with extractable- and total C as well as with measures of Bh expression and depth to upper boundary. However, extractable Fe correlated negatively with these variables. Weak Bh horizons of better-drained soils had higher Fe concentrations and Fe/Al ratios than did more strongly expressed Bh horizons of poorly-drained soils. Results suggest that pedogenic processes fostering Bh formation in Aquods are hindered by the presence of Fe in the grain coatings of better drained soils.