Long‐term Response to Phosphorus Fertilization on Selected Southeastern Coastal Plain Soils

Significant response in height, diameter, basal area, and volume growth to phosphorus (P) fertilization at time of planting lasted 17 to 20 years on a variety of sites in northern and western Florida. Ground rock phosphate and the more soluble ordinary superphosphate were equally effective P sources. Comparing the residual fertilizer P in the soil to a long‐term response of slash pine ( Pinus elliottii Engelm. var elliottii) helped explain lack of differences in effectiveness of P sources. The largest long‐term slash pine responses were apparent on a poorly drained Ultisol and Inceptisol while the Spodosols were more variable in their response. There were no P responses on well‐to‐excessively‐drained Entisols.