EFICIÊNCIA DE FERTILIZANTES FOSFATADOS ASSOCIADOS A ADITIVOS EM UM LATOSSOLO VERMELHO AMARELO ACRIFÉRRICO

Abstract

Phosphorus (P) availability in tropical soils is one of the main limiting factors for agricultural productivity, due to these soils’ high capacity to adsorb and immobilize the nutrient in forms that are scarcely available to plants. In this context, the present study aimed to evaluate the efficiency of phosphate fertilizers combined with additives on the dynamics of phosphorus fractions in an Acric Red-Yellow Latosol (LVAwf). The experiment was conducted in a greenhouse over 360 days, using two phosphorus sources (monoammonium phosphate – MAP and triple superphosphate – TSP) and two additives (KimcoatBioHP® and IFCoat), as well as a control treatment. Different soil phosphorus fractions (Pi-solution, labile Pi, non-labile Pi, occluded Pi, microbial Po, labile Po, among others) were analyzed at 30, 90, 180, 270, and 360 days after the experiment began. Results showed that MAP, especially when combined with the IFCoat additive, performed better in maintaining phosphorus in labile and available forms, reducing losses due to precipitation with iron (Fe) and aluminum (Al) during the first 90 days of incubation. However, after this period, additive efficiency progressively decreased, with a tendency for stabilization of the less available fractions. Additionally, the additives influenced microbial dynamics by increasing phosphorus in microbial biomass (Po-mic) and in labile organic fractions. TSP, on the other hand, showed lower responsiveness to additive use and a higher tendency to form more stable and less available phosphorus fractions.These findings highlight the importance of proper management of phosphate sources and additives to maximize fertilization efficiency, particularly in highly weathered soils such as LVAwf.