Low base saturation, low cation exchange capacity, and a plinthic compaction zone characterize the northern Florida ultisols. High annual rainfall adds to the potential leaching of nutrients, particularly N, K, and S from the A horizon. The plinthic layer may be located 6 to 14 inches below the surface and is comprised primarily of Fe oxides that may be able to fix some K and S but it is not known how much it contributes to forage nutrition. Additionally, the plinthic layer may be impermeable to root penetration by many crops while allowing for water and mineral movement, i.e., K and S leaching. The North Florida Research and Education Center researchers are studying bahiagrass in sod rotations, in part, as a means to break through the hardpan layer, thereby extracting nutrients deeper in the soil profile and making these deeper soils and nutrients accessible to succeeding crops.