Fontes de matéria orgânica na composição de fertilizantes organominerais pelelizados na cultura do milho

Abstract

This study evaluated alternative sources of organic residues for the production of organomineral fertilizers for maize fertilization. A greenhouse experiment was done at Campus Umuarama of Universidade Federal de Uberlândia, MG, in a randomized block design, as a 2 x 5 + 2 factorial, containing two sources of organic matter (biosolid and filter cake), five doses (60, 80, 100, 120 and 140% of 120 kg ha-1 of P2O5 recommendation for maize crop), and two additional treatments (mineral fertilization - 100% de P2O5, and a control with no fertilization), with four replications. Soil pH and contents of phosphorus, potassium, calcium, magnesium base saturation, base sum, micronutrients, organic carbon, organic matter and heavy metals were determined at 65 days after sowing (DAS). Also, plant height, stalk diameter, and chlorophyll A and B were determined at 35 DAS; plant height, stalk diameter, shoot and root fresh and dry matter were determined at 65 DAS. The organomineral fertilizers performed similarly to the chemical fertilization for most of the chemical variables, except for phosphorus, boron and manganese contents, which presented increases in soil contents with the use of sources with organic material. The doses 100 and 80% were less effective in supplying potassium. The use of organomineral sources resulted in the absence of heavy metals in the soil. Sources with biosolid and filter cake yielded greater height and diameter at 35 DAS than those of mineral fertilization. Regardless of the fertilizer organic matter source, stalk diameter at 35 DAS presented linear increase with increasing doses. The use of fertilizer based on biosolid resulted in greater shoot fresh matter than the filter cake source, regardless of dose applied. In general, greater results were obtained for root fresh and dry matter at the greater fertilizer doses in comparison with the mineral fertilization. Organomineral fertilizers formulated with biosolid demonstrated potential for use for complete or partial supply of nutrients, replacing mineral fertilization, since similar or better results were found for soil chemical properties and maize growth characteristics.