We investigated the growth and mineral nutrition of Scots pine (Pinus sylvestris L.) seedlings under a shift from an acidic to a calcareous soil chemical environment using a Chernozemic (Typic Boroll) soil. The study consisted of a greenhouse experiment to evaluate the response of Scots pine to changes in soil chemistry, specifically, increasing soil pH, soluble ions, and CaCO3. As the soil pH increased from 5.5–6.2, seedling weight and height decreased 15 and 37%, respectively. Further growth decreases were related to soil EC and soluble Ca levels in excess of 2 dS·m-1 and 11–19 meq·L-1, respectively. In addition, “active” CaCO3 and NO3-N were also factors in conifer growth. Plant analysis indicated that increasing cation uptake, especially Ca, was associated with organic anion accumulation and a decrease in P uptake. The decrease in seedling weight was also related (r2 = 0.90) to organic anion accumulation. The Ca to P ratio in the seedlings increased from 2.6 to 9.9 as the soil pH increased from 5.5 to 7.9, respectively. Expressing nutrient content in proportions relative to N indicated an imbalance of Ca and K to P as soil acidity decreased. Mean proportions of nutrient content (N:P:K:Ca:Mg) were 100:5:48:14:7 and 100:3:61:33:7 at a soil pH of 5.5 and 7.9, respectively. Scots pine on high base-saturated Chenozemic soils, with neutral pH and acceptable EC and soluble Ca levels, will show a slight but significant reduction in growth rate compared with acidic soil conditions.
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