Nutritional Problems of Pinus taeda L. (Loblolly Pine) Growing on Pocosin Soil

Apart from drainage considerations, the main factors militating against good growth on most pocosin soils are a deficiency of available P and a high exchange acidity of the soil. Liming and fertilization with P both increased the height growth of loblolly pine. Combination applications of lime and P produced the greatest height increases. The results of chemical analyses of foliage and soil explain the large differences in growth of loblolly pine on treated and control plots. Significant linear correlations were found between the height of loblolly pine and available P in the soil and between tree height and the content of P in loblolly pine and Lyonia foliage. Critical values were established for P in the soil, loblolly pine needles, and Lyonia foliage as guides for P fertilization. The critical level of P in Lyonia foliage establishes predictor values of growth equal to those produced by the critical levels of P in loblolly pine needles, thus providing an indicator species in the absence of the pine.