Análise de variabilidade e concentração de fósforo em amostras de fertilizantes fosfatados

Abstract

Usually plants are able to produce their own food by removing from the soil all the nutrients they need to develop properly, with the need for human fertilization. According to Brazilian legislation, manufacturers of phosphate fertilizers are obliged to adapt in terms of the composition of total phosphorus, water soluble phosphorus, phosphorus soluble in citric acid 2% and phosphorus soluble in CNA + water. The objective of this study was to verify the variability and concentration of phosphorus in phosphate fertilizer samples. The experiment was carried out at the Araguaia Multiuser Research Center (CPMUA) of UFMT/CUA, in Barra do Garças-MT. Seven samples of commercial phosphate fertilizers (two simple superphosphate, one triple superphosphate, two monoamonic phosphate and two Hiphós) and one standard ANDA sample were analyzed. Five replications of all fertilizers were performed for each determination of total phosphorus, water soluble phosphorus, phosphorus soluble in 2% citric acid and soluble phosphorus in CNA + water, using the spectrophotometric method of molybdovanadophosphoric acid, according to the Manual of Official Analytical Methods for Fertilizers and Correctives (BRASIL, 2017). Analyzing the results obtained, it was observed that the concentrations of each fertilizer were within the minimum guarantee limit and with values close to that established by the manufacturer. Regarding variability, it was observed that the methodologies that contained heating/agitation showed higher standard deviation and variance.