Evaluation of various sources of magnesium fertiliser for correction of acute magnesium deficiency in oil palm.

All fertilisers evaluated greatly improved the visual appearance of Mg deficient palms. A significant decline in the number of fronds displaying new symptoms occurs as early as four to six months after treatment (MAT). By 16 MAT, majority of treated palms exhibit only light symptoms of Mg deficiency. Statistically, no significant differences were recorded between the various fertiliser types in raising leaf Mg levels and reducing the severity and emergence of new Mg deficiency symptoms. However, when based on palm vegetative growth improvement, kieserite still elicited the best responses and exhibited a higher relative agronomic efficiency (RAE) over the other five Mg fertilisers.