Soil and Foliar Guidelines for Phosphorus Fertilization of Loblolly Pine

Abstract

Several established studies of phosphorus fertilization in 3-year-old plantations of loblolly pine were measured for tree height and sampled for soil tests and needle analysis in order to relate soil and needle content to response to fertilization. Soil tests with the extractant adopted by the North Carolina Soil Testing Laboratories and percentage of P in needles were useful for prediction of tree response to P fertilization in the southeastern Coastal Plain but not in the Piedmont. Needle content of 0.10 percent P and values of the above-namedextractant of 3 p.p.m. were critical levels above which tree height at age 3 was not increased by P fertilization and below which P fertilization usually increased tree growth. The data indicated that N influenced growth and limited response to P fertilization on some sites.

Citation

Wells, Carol G.; Crutchfield, D.M.; Berenyi, N.M.; Davey, C.B. 1973. Soil and Foliar Guidelines for Phosphorus Fertilization of Loblolly Pine. Res. Pap. SE-110. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 17 p.