The effects of apple dwarfing rootstocks on leaf nutrient element composition in stoolbed production

The nutritional status of 22 apple (Malus domestica Borkh.) dwarfing rootstocks, with varied degrees of dwarfing, was evaluated during stoolbed production in 1983 and 1984. Rootstock effects were observed for all leaf nutrient elements studied except Cu. Except for EMLA 27, leaf N levels were generally highest in dwarfing EMLA and Polish series and lowest on vigorous MAC and EMLA rootstocks. Relatively few significant differences were found in leaf P and K content among rootstocks. Foliar Ca and Mg concentrations were generally highest on Polish and Budagovski rootstocks and lowest on EMLA 111. Leaf B levels on vigorous and semi‐dwarfing EMLA rootstocks and Fe levels in MAC, Polish, and Budagovski series were considerably higher than on other rootstocks. Although significant differences were found in leaf Mn and Zn among rootstocks, no specific effect for rootstock vigor was observed for either element. Positive correlations between leaf Ca and Mg occurred in 17 rootstocks while negative correlations between N and Fe were observed in 21 rootstocks.