Two year-old apple plants (Malus domestica cv. Red Chief Delicious) were grown in an acidic and limed soil, and fertilized with B (0, 1, 3 and 5 mg kg -1 soil). Fresh matter weight of plants was positively correlated with the applied B only in acidic soil. The number of nods, plant height, stem diameter, and shoot length were not particularly affected by either B additions or liming. The length of internodes of the plants grown in limed soil showed a positive correlation with the amount of added B, but the opposite effects were observed in the acidic soil. Boron and K concentration in leaves showed a positive correlation with added B in both soils. Leaf N and Fe concentrations were negatively affected by B additions in soils, while leaf Mn and Zn concentrations were also affected by added B and soil pH, reflecting thus their soil mobility. Chlorophyll content in leaves was reduced at high B treatments, only in plants grown in the acidic soil. Our results show that added B even in our high B-content acidic soil did not cause any detrimental effects on apple plants, and that liming seemed to buffer trace metal excesses, characteristic of any acidic soil.

In dry Mediterranean‐type climates boron (B) levels may naturally be high and even toxic to plants. Although liming of an acidic soil is expected to decrease B levels, it is not known what the effects would be in such areas of high‐B soils, especially in B‐sensitive crops such as apple trees. Thus, our aim was to study the behavior of added B in newly planted apple rootstocks in an acidic soil which was limed to pH 6.5 in an outdoor pot experiment. Added B increased significantly B extractability from soil, and B levels were lower in the limed compared to the acidic soils. Plant B concentrations also increased with added B but differences between limed and unlimed soils were not evident, because plant B did not seem to reflect changes in B behavior in soil. However, B uptake was significantly increased with added B, and was further increased with liming, contrary to what the soil extractions indicated, due to improved growth conditions. Our results show that although liming decreased soil B levels, at the same time it did not affect plant B concentration and accelerated the uptake of added B, indicating a possibility for increased soil‐to‐plant mobility of B.