Growth and Nutrient Content of Red Spruce Seedlings in Soil Amended with Aluminum

Abstract

AbstractAluminum toxicity may be a factor linking acid deposition to forest decline. Acid precipitation may lower soil pH, which would raise the level of phytotoxic forms of Al in soil solution. A greenhouse study was conducted to examine the effects of soil Al on the growth and nutrient composition of red spruce (Picea rubens Sarg.). A Becket series forest soil (Typic Fragiorthod) was amended with AlCl3 to give a range of saturated paste extract Al concentrations from 37 to 537 µmol L−1 at harvest. Bare‐rooted seedlings were transplanted into pots and grown for 52 d. Biomass of needles, primary roots, and lateral roots were not significantly decreased by soil Al levels. The biomass of needles were negatively correlated with the concentration of Al in the needles. All seedlings were P‐deficient, which may account for the lack of response to soil Al levels. The concentration of Al in seedling needles increased significantly with increasing soil Al levels, but not in the primary or lateral roots. The concentration of Mn in seedling needles, primary roots, and lateral roots decreased with higher concentrations of Al in the soil. The concentrations of N, P, K, Ca, Mg, Fe, Zn, Cu, and B in the needles were not affected by soil Al. However, the Mg, Ca, and B concentrations in both primary and lateral roots were significantly lower with increasing levels of soil Al. Increasing soil Al levels resulted in lower nitrification rates in the soils. The addition of Al significantly reduced colonies of bacteria relative to the control soil. However, fungi/actinomycetes colonies were not significantly reduced by soil Al.