GROWTH AND NUTRIENT DYNAMICS OF BEECH (FAGUS-SYLVATICA L) SEEDLINGS IN ACID SOILS

The relative uptake rates of N, P, K, S, Ca, Mg, Fe, Mn, Zn, Cu, and A l were estimated in beech seedlings pot cultured in the field in six a cid soils (treatments). The relative uptake rates were compared with t he relative growth rates. The relative uptake rates of N, K and Ca agr eed well with the growth rates of the seedlings irrespective of widely differing soil conditions (acid sand-clayey till, pH 4-6). The relati ve uptake rates of P, Fe, and Al differed from that predicted by the g rowth rate. The uptake rates of Fe and Al were highest at the lowest g rowth rates, and the P uptake rate was lower than the growth rate in t hese treatments. Thus the P availability probably limited growth in an eluvial (E) horizon of a podzol, and possibly in the illuvial (B) hor izon of a podzol and in an acid clayey till (Dystric Cambisol). Low P uptake was associated with a tendency towards higher relative root gro wth rates. In terms of the concept of steady state nutrition the high relative root growth rate in some treatments may be interpreted as an acclimation to low P supply. The P limitation seemed to be related to interactions among Fe, Al and organic compounds of the soil solution.