Some effects of varied magnesium nutrition on the growth and composition of olive plants (cultivar ‘chondrolia chalkidikis’)

Olive plants (Olea europaea cultivar ‘Chondrolia Chalkidikis’) were grown in perlite: sand (1 : 1) cultures irrigated with nutrient solutions widely varying in magnesium (Mg) levels. When calcium (Ca) concentration in solution was 4 mM, maximum fresh weight (Fw) was produced with 0.4–2 mM Mg. Above 2 mM Mg in solution, fresh weight yield declined. The ratio of $\text{Ca}\text{Mg}$ in solution for optimum vegetative growth of olive trees was 2.Ca concentration of leaves and roots fell consistently with increasing Mg concentration in solution from 0.005 to 20 mM. When the concentration of Ca was 0.5 mM, an increase of Mg in solution from 3 to 20 mM did not further reduce Ca content of tissue. Mg concentration of leaves and roots increased, but not in proportion to the increase of Mg in the nutrient solution. An increase of Mg in solution from 2 to 10 mM was followed by a proportional increase of manganese (Mn) content of leaves. Above 10 mM Mg, a plateau in Mn concentration was reached.The zinc (Zn) content of leaves and roots was increased when Mg in solution increased up to 0.2 mM, then was reduced in the range 0.2–2 mM Mg and remained constant between 2 and 20 mM Mg. Other elements like copper (Cu) and iron (Fe) were not affected by increasing Mg concentration in solution.