EFFECT OF ACIDITY ON GROWTH AND NUTRIENT COMPOSITION OF THE HIGHBUSH BLUEBERRY

Abstract

Two highbush blueberry cultivars (Blueray and seedling selection 50-6-9) were grown at various pH levels in water cultures. Within the pH range 3.5 to 6.0, growth of Blueray did not appear to be limited because of the direct effects of pH. At pH 2.5, however, growth was nonexistent and at pH 3.0 it was restricted. Growth of 50-6-9 was significantly greater at pH 4.0 and 5.0 than at pH 3.0 or 6.0. Plant roots became progressively darker with increasing pH above 4.0 to 4.5. In general, root nutrient levels, Ca excepted, were higher than foliar nutrient levels, although root and foliar Mg levels were not very different except at pH 3.0. Root Mn at pH 5.0 and 6.0 was 10 to 20 times greater than at pH 3.0 or 4.0.