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Soil fertility has become an interconnected aspect of modern agriculture, incorporating factors such as nutrient availability from soil, and its revision has become necessary for ensuring sustainability. Therefore, to understand the solubility of nutrients from organomineral fertilizers pelleted with biosolids and sugarcane filter cake, and to evaluate the resulting chemical changes in soil from its use, an experiment was performed in a completely randomized design. The experiment was done with four replicates in a 3 × 5 +1 factorial scheme, using three fertilizer sources (mineral fertilizer, organomineral fertilizer pelletized with biosolids, and organomineral fertilizer pelletized with the filter cake); five doses (60%, 80%, 100%, 120%, and 140% of the recommended dose of fertilization for corn); and an additional control treatment (absence of fertilization). The formulation of the organomineral fertilizers was 5-17-10 with 10% total organic carbon. All fertilizer sources were packed in a microfiber cloth positioned 1 cm below the surface of the soil and incubated for 60 days. Subsequent evaluation of chemical attributes: pH H2O (1:2.5); pH SMP (Shoemaker-McLean-Pratt); and the content of exchangeable aluminum, phosphorus, potassium, calcium, magnesium, silica, and organic matter within the soil was done. Organomineral fertilizers pelleted with biosolids or filter cake do not acidify the soil, but they were found to reduce aluminum saturation and promote a slow release of nutrients, which allowed a more balanced base in the soil. This then ensured a better balance of nutrients, with greater cation exchange capacity, base sums, and base saturation. The use of these fertilizers can contribute to stabilizing the pH of the soil with fewer applications of acidity correctives

Coffee is a commodity important in economic and social terms. In order to obtain high yields and excellent quality products, more studies involving nutrient use efficiency and fertilizer sources need to be developed which offer new management options to producers, potentially providing more sustainable and better agricultural inputs and resources utilization. The aim of the study was to evaluate the application of biofertilizers (OM) in only leaf application and leaf and drip application, in growth, production and fruit quality of coffee cultivated under Savannah conditions (Araguari-MG), compared with conventional chemical coverage fertilization. The experiment was conducted with a randomized block design with three treatments and seven replications. The OM were used in leaf and leaf + drip applications, while the control treatment did not receive any OM application. The OM in leaf and in leaf + drip applications promote higher coffee tree height growth. The OM showed better results than control in 80.3 and 28.4%, in leaf application and leaf + drip application, respectively. However, further investigations need to be developed in order to find out the interference of organic constituents in plant physiology and nutrients dynamics.

This study determined the changes in soil nutrients, organic carbon, organic matter and heavy metals during the early development stages of maize fertilized with different sources and doses. Also, this study confirmed that the used biosolid in the formulation of organomineral fertilizer makes greater efficacy than the effects promoted by mineral or filter cake organomineral fertilizers already used in agricultural. The experiment was done in a greenhouse at the Federal University of de Uberlândia - Campus Umuarama. The experimental design was randomized block design, as a 2 x 5 + 2 factorial, containing two sources of organomineral fertilizer consisting of organic residues (biosolid and filter cake), five doses of organomineral fertilizer (60, 80, 100, 120 and 140% of P2O5 recommendation for maize crop), a positive control with mineral fertilization (100%) and a negative one with no fertilization with four replications. The soil pH and contents of phosphorus, potassium, calcium, magnesium base saturation, base sum, micronutrients, organic carbon, organic matter and heavy metals were determined subsequently after plant removal, 65 days after sowing. The organomineral fertilizers based on biosolid and filter cake yielded increases in phosphorus, boron and manganese in the soil, especially the biosolid source. Regardless of the fertilizer organic matter source, soil phosphorus increased linearly with increasing doses of the sources. Doses equal or below the recommendation for maize (100% P2O5) were less effective in supplying potassium. The organomineral sources did not add heavy metals to the soil. Fertilizers based on biosolid can supply nutrients, such as phosphorus, boron and manganese at high doses, replacing mineral fertilization, while maintaining and improving soil fertility with no contamination by heavy metals.

In the current world scenario of agriculture it is necessary to find technologies to reach high productivity that are effective in providing soil conditioning improvement for the plants. Thus, this study analyzed the efficacy of organomineral fertilizers formulated with different organic matter sources on growth factors of maize. The experiment was done in a greenhouse at Campus Umuarama, Federal University of 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 of P2O5 recommendation for the crop and two additional treatments: mineral fertilization (100% of P2O5 of the recommended dose) and a control (no fertilizer), with four replications. Plant height, stalk diameter, and chlorophyll a and b were determined at 35 days after sowing (DAS); plant height, stalk diameter, shoot and root fresh and dry matter were determined at 65 DAS. The organomineral 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 of the fertilizer sources. 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 can be a viable alternative for partial or total substitution of mineral fertilization, since similar or better results were found for maize growth characteristics.

Organomineral fertilizers have been used to meet plants’ nutritional needs and reduce producers’ reliance on mineral fertilizers. This study aimed to determine the effect of organic matter sources for organomineral fertilizers and traditional mineral fertilizers to the sorghum initial development. The experiment followed a randomized complete block design in a ‘4 x 3 + 2’ factorial arrangement, with four fertilizer doses (50, 75, 100 and 125%) of the recommended dose for sorghum crops (450 kg ha-1), three organic matter sources to compose the organomineral fertilizers (sewage sludge, filter cake, peat), a control (mineral fertilizer), and an untreated check (no fertilizers). Each experimental plot consisted of four plants divided into two pots. Plant height, stem diameter, chlorophyll a, chlorophyll b, and leaf area were performed at 30 and 60 days after seeding (DAS) when shoot dry mass was also measured. Organomineral fertilizers outperformed both control and untreated check plots for most variables at 30 DAS. Sorghum fertilized with organomineral fertilizers also showed positive results at 60 DAS, even with dose reductions. Considering the variables herein reported, organomineral fertilizers can replace mineral fertilizers in the development of sorghum, even with dose reductions. Key words: Biofertilizer, sewage sludge, filter cake, peat, plant nutrition.

Corn has great relevance for agribusiness as it is used in human and animal food, besides the energy matrix. The objective of this study was to assess the leaf content of macro and micronutrient, accumulation of primary macronutrients, production components and productivity with the application of pelleted organomineral fertilizer in different doses compared to mineral fertilization, in two soils of different textures in the corn crop. Two trials were conducted in the municipality of Uberlândia-MG-Brazil: one located near the highway BR 452 km 141, at the coordinate 18°55′26″S, 48°09′36″W, clay soil. The other at km 640 of BR 365, at coordinate 18°54′05″S, 48°25′20″W, sandy soil. A randomized block design with five replications was used, with five doses of organomineral fertilizer (40, 60, 80, 100 and 120% of the recommended dose of P2O5 for corn) and an additional with 100% of the recommendation of mineral P2O5, total of six treatments and 30 plots. The results showed that, with the exception of phosphorus leaf content, yield in the sandy texture and the number of grains per row in the clay texture, there was no difference between the doses of phosphate organomineral and did not differ from the mineral. Thus, phosphate organomineral is as efficient as mineral for phosphorus supply.