HEIGHT GROWTH, NEEDLE MASS AND NEEDLE NUTRIENT CONCENTRATIONS OF N, P, K, CA, MG AND CU IN A 6-YEAR-OLD BLACK-SPRUCE PEATLAND-PLANTATION INNEWFOUNDLAND, CANADA

Height growth, needle mass and needle concentrations of N, P, K, Ca, M g, and Cu were determined for black spruce (Picea mariana (Mill.) B.S. P.) 2 years, 4 years and 6 years after planting on an ombrotrophic dom ed bog. Experimental treatments included four ditch spacings (3 m, 5 m , 7 m and lj m), two surface preparation treatments (tilled, untilled) , and 2 fertilization treatments (PK, unfertilized), contained within five blocks. The most effective treatment for early growth of black sp ruce was a 3-m and/or 5-m ditch spacing that had been tilled and ferti lized with PK, The effects of tilling alone on growth and nutrient upt ake were minimal. However, in many instances, growth was increased by the combined effects of tilling and PK fertilization or tilling and dr ainage. Fertilization with PK significantly increased needle concentra tions of P and K as well as N. Because concentrations of K were above ''optimum'' levels, et-en within the unfertilized treatments, uptake w as accounted for by luxury consumption, thereby precluding the need fo r K fertilization. Thus, improved height growth and needle mass in the PK-fertilized treatments can be attributed to addition of P, and the subsequent increase in N uptake. Needle concentrations of Mg were slig htly increased by PK-fertilization treatments in 1987. However, over t he 6-year period, concentrations of Ca, Cu. and Mg, were generally not affected by treatments.