Enhanced-efficiency phosphorus fertilizer: promising technology for carrot crop

ABSTRACT Several studies were carried out to evaluate polymer-coated mineral fertilizers; however, few studies, on the agronomic efficiency of these fertilizers in the field in carrot crop, are available. Thus, we aimed to evaluate the use of enhanced-efficiency phosphorus fertilizer coated with polymers in carrot (Daucus carota). The experiment was carried out in field, in Ipameri-GO. The experimental design was randomized blocks, arranged in an incomplete factorial design (5x2)+1, considering five phosphorus doses (150, 300, 450, 600 and 750 ha-1 kg P2O5), two P sources [conventional MAP (monoammonium phosphate) and polymer-coated MAP (Policote)] and one additional treatment (control, without P). The evaluated traits were plant height, root length, root diameter, total productivity, marketable root classes, agronomic efficiency of phosphate fertilization and P content in the roots. Data were submitted to analysis of variance and regression. Phosphate fertilization did not influence the P content in carrot roots, but increased plant height, root length and diameter and yield of carrot roots. Polymer-coated phosphate increased plant height, length, diameter and productivity of carrot roots, when compared to conventional fertilizer. Carrot productivity was, on average, 15.5% higher with polymer-coated P source (39.42 t ha-1) than with the conventional P source (34.11 t ha-1). Marketable roots were also improved with the use of polymer-coated phosphate fertilizer. Phosphate fertilizer coated with polymer increased the agronomic efficiency of phosphate fertilization in the carrot crop.