How apple responds to boron excess in acidic and limed soil

Abstract

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.