Responses of Quercus alba L. seedlings to fertilization with nitrogen and phosphorus

Effects of fertilization with diammonium phosphate on growth and foliar N and P concentrations of 1-0 Quercus alba seedlings were evaluated one year after planting and fertilization. Soil P tests were made by three methods: dilute acid extractable P (Mehlich), acid flouride extractable P (Bray no. 1), and total P by perchloric acid digestion. Correlation analyses were performed on seedling growth, foliar P content, and soil P tests.

Confounding factors, including site variation, seedling stress resulting from planting, and an equilibration period of only one growing season, suggest that first-year results are inconclusive. Site factors were the most common source of variation for growth and soil P measurements.

Dilute acid extractable P was significantly correlated with height growth. Correlations of first-year responses may be obscured by factors discussed.