Relationships between Douglas fir seedling growth and levels of some soil and tissue nutrients

Growth of Douglas fir seedlings was increased by application of calcium superphosphate to a nursery soil containing 56 ppm available P. Under nursery conditions of nutrient supply growth was seriously limited when tissue P concentration of one-year old seedling was near 0.18% or lower. At higher tissue P concentrations growth was apparently dependent on tissue K concentration. Increase of soil Mg level above 1.5 m.e.q./100 g. soil depressed growth. Under greenhouse conditions 61% of seedling variation in dry weight was accounted for by considering concentration of 6 tissue nutrients but under nursery conditions only 41% of variation was accounted for by 5 tissue nutrients.