Nutrient Relationships Between Soils and Needles of Loblolly Pine (Pinus taeda)

Abstract

Highly significant correlations were found between nutrients in the soil and needle content of 5‐year‐old loblolly pine for all seasons and needle age classes. Mineralized N was more highly correlated with percentage N in the needle than was total N. Available P by the Truog and Bray no. 2 methods was more closely related to percentage P in the needles than was total P. Percentage exchange capacity saturated with K accounted for more of the variability in percentage K in the needles than did either exchangeable K or acid‐extracted K. Exchangeable Ca and Mg were more closely related to percentages of these elements in the needles than was percentage saturation with these elements. Antagonism interactions were indicated between K and Ca or Mg but not between Ca and Mg. Needle samples of the previous year's first growth flush collected in late winter from the upper crown were best for relating nutrient content of needles to soil fertility.