RED MAPLE (ACER RUBRUM) IMPARTS STRUCTURAL CHANGES TO SOIL CLAY MINERALS NOT OBSERVED IN SOILS WITH LOBLOLLY PINE (PINUS TAEDA)

Potassium (K⁺) is a macronutrient essential for plant growth which is derived from mineralogical sources. Well-established deep rooting profiles govern the nutrient cycling of K⁺, yet past research in the Calhoun Critical Zone Observatory (CCZO) has demonstrated that rooting profiles are not reestablished for over eighty years following land use change. This research investigates consequences for K⁺ cycling dynamics after changes in land use by comparing the effects of the hardwood Acer rubrum on soil exchangeable potassium (EK) and clay mineralogy against the effects of the pine Pinus taeda.

Both species were grown in substrates collected from the CCZO and surrounding areas for 90 days. At the end of this period, soil EK was measured by atomic absorption spectrophotometry and mineral structures were investigated using X-ray diffractometry. The two species had similar effects on EK, but A. rubrum imparted structural changes to the clay minerals which were not observed after the growth of P. taeda. These findings underscore the possibility that tree species may differ in their K⁺ uptake strategies, contributing to changing nutrient cycling dynamics over periods of changing land use as different tree species dominate the landscape.