Monoammonium phosphate coated with polymers and magnesium for coffee plants

Abstract

The coating of phosphate fertilizer granules with polymers and magnesium (Mg) is a technology that can improve phosphorus (P) use efficiency and mitigate problems of low Mg supply in coffee crops. The objective of this work was to evaluate the growth and nutrition characteristics of coffee seedlings and the agronomic efficiency (AE) of monoammonium phosphate (MAP) coated with anionic polymers and Mg in comparison with other phosphate fertilizer technologies. The experiment was carried out in a greenhouse in 20 L pots. Two five-month-old coffee seedlings were transplanted into each pot. The experimental design was completely randomized with three replicates. The following treatments, applied at a dose corresponding to 20 g pot-1 of P2O5, were carried out: MAP; MAP coated with anionic polymers (Policote Phós®); MAP coated with anionic polymers+Mg (Policote Phós_Mg®); Top-Phós®; and Agrocote®. A control (without P) was prepared. Plant height; leaf area; dry mass of leaves, stems, and roots; total dry mass; shoot/root ratio; specific leaf weight; P and Mg content in plants and their availability in the soil after cultivation and efficiency indicesof the phosphate fertilization treatment were evaluated. The recovery of applied P and the agronomic efficiency of phosphate fertilizers was found to increase in the following order: MAP = Top-Phós® = Agrocote®<MAP+Policote Phós® = MAP+Policote Phós_Mg®. The coating of the MAP+Policote Phós_Mg® granules increased growth, the content and accumulation of P and Mg in coffee seedlings, the availability of these nutrients in the soil after cultivation and the agronomic efficiency of phosphate fertilization.