Determinação de micronutrientes e macronutrientes secundários em fertilizantes organominerais e mineral misto

Abstract

Fertilizers are products provided with nutrients, of organic origin or not, and their function is to replace one or more nutrients for plants. They are of fundamental importance for agriculture, since, in cases where the soil does not have the necessary nutrients, the plants have their development and healthy growth directly affected. In this work, three samples of fertilizers sold in Fortaleza (CE) were analyzed, two of them classified as organo-mineral fertilizers and one as mixed mineral fertilizer. The analyses were performed using optical emission spectrometry with inductively coupled plasma (ICP-OES) for the determination and quantification of the elements calcium and magnesium, classified as secondary macronutrients, and of the elements boron, copper, iron, manganese, molybdenum, nickel and zinc, classified as micronutrients. The results obtained were compared with the values set out in Normative Instruction No 61, of July 8, 2020 and Normative Instruction No 39, of August 8, 2018, which refer to organic and mineral fertilizers, respectively. Sample A (organomineral) presented the nickel content lower than the minimum value established by the legislation, however, the other nutrients showed satisfactory results. Sample B (organo-mineral) generated results below the minimum limits for iron, magnesium, and nickel. Sample C showed only nickel as an element with unsatisfactory concentration. However, a more detailed investigation for these specific elements that presented values outside the standard would be necessary, such as a new analysis of the samples, as well as an analysis of products from different lots or the use of another technique to compare results. In general, the samples presented results that meet the parameters of the current legislation for most of the elements analyzed.