Effects of Nursery Fertility and Density on Seedling Characteristics, Yield, and Field Performance of Loblolly Pine (Pinus taeda L.)

Abstract The effects of nursery fertility and density were studied over a 3‐year period using a 3 × 4 factorial arrangement of fertility and density. The fertility levels employed were 75 + 22 + 62, 150 + 44 + 124, and 300 + 88 + 249 pounds of N + P + K, respectively. The densities were 15, 30, 45, and 60 seedlings per square foot. Generally, increasing fertility increased the concentrations of N, P, and K and had no effect on Ca and Mg in the foliage. No such effects of density were noted. The total nutrient content of the foliage and the plant size increased with increasing fertility and decreasing density. Fertility and density interacted to control yield of plantable seedlings. At a density of 15 seedlings per square foot, the yield over the range of fertilities used varied from 94 to 92%, while at a density of 60 seedlings per square foot the yield was increased from 34 to 81%. The effects of nursery treatment on field performance on two site extremes were strongly related to field height growth, but not to survival. Total height at the completion of three field growing seasons increased with increasing fertility and decreasing density. Field height growth is related to such seedling characteristics as size and nitrogen content at lifting.