Published online by Cambridge University Press: 03 October 2008
Soil analysis on samples taken from apple orchards in Khorasan and quince orchards in Esfahan, suggested that at a sampling depth of 20–45 cm., the critical soil concentration of calcium carbonate at which chlorosis might appear seems to be 14–15 per cent for apple and 39–40 per cent for quince. The incidence of lime-induced chlorosis was accompanied by lowered leaf Ca/K ratios. The application of various iron chelates to chlorotic trees not only benefited yield of apples but also exercised a residual effect in succeeding seasons.