Foliar mass and nutrition of Abies concolor Christmas Trees following application of organic and inorganic fertilizer

Fertilization in Christmas tree production is common to increase tree growth and quality, with many recommendations focusing on N as a primary amendment. However, other nutrients may limit growth, or N application may induce deficiency of other nutrients. We applied fertilizer as either ammonium nitrate (AN) or chicken manure compost (CMC) to concolor fir (Abies concolor [Gord. and Glend.] Lindl.) at eight sites across central New York in 2003 and measured foliar mass and macronutrient response (N, P, K, Ca, and Mg) to assess the potential for an inducible nutrient deficiency or nutrient limitation other than N. Foliage mass, N concentration, and N content increased following both fertilizer treatments, indicating that N limits growth at these sites. Macronutrient (P, K, Mg, Ca) concentrations were reduced following AN application because of nutrient dilution following increased growth. Compared with published sufficiency nutrient concentrations, concentrations of P and K were diluted to levels considered limiting to growth. In contrast, there was no reduction in macronutrient concentrations for P, Ca, and Mg in the CMC application, indicating the potential for this amendment to maintain balanced tree nutrition with increased growth. Foliar K content was increased in the CMC treatment, and needle mass (as the primary growth response variable), was correlated with foliar K concentration (r² = 0.71, P < 0.01). The results indicate a strong possibility of K limitation in concolor fir across a variety of site conditions. With few exceptions, there were no apparent relationships between soil nutrient pools and foliar nutrition, demonstrating the limitation of soil tests as a guide to nutrient amendments.