Correcting Magnesium Deficiency of Limes Grown on Calcareous Soils with Magnesium Nitrate1

Marcotted 'Persian' (Tahiti*) lime trees with severe magnesium deficiency were sprayed with magnesium nitrate at 3 concentrations (1.75, 3.50, and 5.25 pounds of MgO/100 gallons of water). Three applications were made between March and September, 1967. Most of the magne sium deficiency symptoms disappeared after 2 sprays. The trees were completely green after the third spray, regardless of the rates used. The control trees remained chlorotic. Treated trees remained green for about 18 months after the last spray when some magnesium deficiency symptoms began to appear on trees sprayed with the low rate (1.75 pounds MgO/100 gallons of water). The practical aspects of magnesium nitrate spray for control of magnesium deficiency are discussed with respect to rates and frequency of application, compatibility with other compounds, and effects of rainfall or sprinkler irrigation within a few days after application.