Organic Matters for the Formulation of Organomineral Fertilizers Pelletized in the Development of Sorghum.

Organomineral fertilizers have being used to meet the nutritional needs of plants, reduce dependence on mineral fertilizers and optimize the use of nutrients by plants. The study aimed to determine the effect of organic matters in the composition of organomineral fertilizers and compare them to traditional mineral fertilizers in the initial development of sorghum. The research was conducted in greenhouse at Federal University of Uberlandia, in Uberlandia, Minas Gerais, Brazil. It was used sorghum seeds simple hybrid 1G100 in Oxisol. The experimental design was a complete randomized block in a factorial 4 x 3 + 2; the factors consisted of four fertilization levels (50, 75, 100 and 125% of 450 kg ha-1), three sources of organic matter for the production of organomineral fertilizers (sewage sludge, filter cake and peat), control (100% mineral fertilizer) and witness (without fertilizer). The plot consisted of two pots with two plants each. The evaluations were performed at 30 and 60 days after sowing. Plant height, stem diameter, chlorophyll A, chlorophyll B and leaf area were evaluated. Only the stem diameter was not affected at 30 days by the presence of fertilizers, the other variables showed higher means than the control and witness when used organomineral fertilizers. In the analysis at 60 days, sorghum fertilized with organomineral fertilizer, even at the recommended lower doses, averaged similar to the control. Stem diameter and dry mass of shoots showed the greater means when the highest levels of organomineral fertilizers were used. The use of organomineral fertilizers can replace mineral fertilizer even with dose reduction in the initial development of sorghum. Financial support: FAPEMIG