O objetivo desse artigo foi descrever as tecnologias aplicadas ao tratamento de dejetos animais e as suas vantagens ambientais e econômicas. O estudo envolve dados de dejetos de aves, bovinos e suínos dando ênfase à a duas tecnologias: biodigestores e a compostagem. Essas técnicas são utilizadas com o objetivo de mitigar a emissão de gases do efeito estufa (GEE) e a degradação do meio ambiente com um possível retorno financeiro por meio da venda de crédito de carbono no mercado internacional proporcionado pelo protocolo de Quioto.

The objective of this study was to evaluate the ability of diazotrophic bacteria isolated from Brachiaria brizantha rhizosphere to grow at different pH values and salt concentrations, to produce indoleacetic acid (IAA), and to solubilize phosphate. Both acidity and salinity tolerance tests were performed on modified solid FAM medium. Acidity resistance tests were performed at pH values of 4.0, 5.0, 6.0, and 7.0, while, salt resistance was evaluated at concentrations of 0.01, 5.02, 9.99, 14.96, 19.98, 24.95, 29.98, 34.94, 39.97, 44.94, and 49.96 gL-1 NaCl. For the IAA production assay, bacterial strains were cultivated in liquid DYGS medium both in the absence and presence of tryptophan (Trp). In addition, phosphorus solubilization assay was performed in GL liquid medium. All strains grew at every pH value tested, and a high diversity was observed after salt resistance, IAA production, and phosphate solubilization testing. Strains UNIFENAS 100-51, UNIFENAS 100-52, UNIFENAS 100-60, UNIFENAS 100-63, and UNIFENAS 100-65 were those with the best growth at the highest salt concentrations. Furthermore, in the presence of Trp, strains UNIFENAS 100-63 and UNIFENAS 100-69 were the ones with the highest IAA production. Strain UNIFENAS 100-52 showed the best response to the in vitro phosphate solubilization assay. Based on these results, it can be seen that studies related to the physiological and metabolic characteristics of diazotrophic bacterial strains are important to ensure greater success in the field.

A pecuária brasileira é de suma importância para a economia do país. As pastagens se destacam pelo seu baixo custo, e, quando em bom estado, atendem às necessidades nutricionais dos animais. Porém, as condições atuais dos pastos brasileiros têm sido questionadas quanto à ausência de manejo adequado e pela falta de rotatividade dos animais, resultando em um aumento nas taxas de degradação e nos índices de emissão de gases do efeito estufa (GEE). O objetivo deste trabalho foi abordar o uso de bactérias diazotróficas associativas como alternativa sustentável na produção animal e mitigação dos GEE. Os fertilizantes químicos, além do elevado potencial poluidor, são onerosos ao produtor, fazendo com que a prática não seja satisfatória ao pecuarista. Nesse contexto, o uso de bactérias diazotróficas torna-se uma alternativa viável devido aos seus benefícios para o sistema solo, planta e atmosfera, atuando como promotoras de crescimento vegetal (BPCV) através da solubilização e fixação de nutrientes, além da produção de hormônios de crescimento. O uso desses microrganismos traz benefícios ambientais, pois promove melhores condições para a pastagem, reduzindo a degradação e as emissões de GEE. Além disso, apresenta resultados satisfatórios quanto à produtividade de forragem, beneficiando economicamente o sistema e auxiliando na diminuição dos impactos gerados pela produção animal. Ponderando a constante busca por melhores condições de desenvolvimento e alternativas sustentáveis de produção, o uso de bactérias diazotróficas na pecuária tem se mostrado eficiente mesmo quando não se utiliza fertilizantes.

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<p>Coffee cultivation in Brazil is still predominantly in full sun. However, the shading technique has gained prominence to increase the sustainability and profitability of production. Coffee intercropping legumes, besides contributing to shading, act as green manure, improving soil characteristics. Thus, in this study the objective was evaluating the shading intercropping effect on the initial development of coffee trees. The experiment was carried out at Sítio Santa Felicidade, municipality of Campestre - Southern Minas Gerais. Four species of the Crotalaria genus were used and one control treatment without any intermediate species, totaling 5 treatments. The planting was carried out in 4 replicates per treatment, in a randomized block system (DBC), with 16 coffee plants per plot. The 10 central plants were used for evaluation. The variables analyzed were: seedling setting (%), plant height (cm), leaf area index (LAI), number of plagiotropic branch internodes and 50 cm from ground level (cm²), temperature (°C) and soil moisture (%). Data were statistically interpreted by variance analysis and comparisons of averages performed by the Scott-Knott test at 5% probability, using the statistical software SISVAR®. It was observed that, except seedling setting (%) wherein there was no statistical difference among treatments, the other parameters showed positive responses in intercropping with crotalaria when compared to the control, showing the beneficial effect of the use of this legume when intercropped with coffee tree. </p>

Wetland ecosystems represent about 20% of South America, and are classified according to the flood regime, which also influences on vegetation. Despite the value of ecosystem services provided by this environment, those areas are close to eradication in several parts of Brazil. These environments are extremely fragile. Flooded areas are subject to nitrogen losses (N) by leaching, becoming dependent on the N increases from biological nitrogen fixation (BNF). However, little is known about this process on wetlands. Understanding the adaptative strategies of these microorganisms and plants is essential for the maintenance and preservation of these ecosystems. The objective of this work is to present a literature review discussing aspects of floristic composition, biological nitrogen fixation, and morphophysiological adaptations that occur in the rhizobium-leguminous system in wetlands. For the bibliographic survey, articles and other academic works relevant to the topic were selected, in order to enrich the proposed discussion.

Eggshell is a nutrient-rich residue and can be used as a soil amendment and fertilizer. However, it has a slow release, making its use unfeasible, but microorganisms can accelerate the process of nutrient release. Based on this, the objective was to evaluate the solubilization of the eggshell in the culture medium and in the soil by bacterial strains. Two experiments were installed in a completely randomized design, which consisted of 13 treatments, 12 bacterial strains and a control experiment without inoculation. The first experiment was carried out in a 13 x 2 factorial scheme with minimal medium containing eggshell or CaCl2 with four replications. The media were incubated at 28 °C and after three and seven days the growth, the pH of the medium and the concentration of soluble Ca2+ were evaluated by flame atomic emission spectrometry. The second experiment was carried out in plastic flasks in which 175 g of soil and 0.75 g of eggshell were inserted. After incubation, the pH in CaCl2, the potential acidity (H + Al) and the concentration of K+, Ca2+ and Mg2+ were evaluated. In the final analysis, the bacterial strains did not change the pH and Ca2+ values ​​of the culture medium in the in vitro experiment. In the soil experiment, strains 100-40 and 100-5 showed the ability to solubilize eggshell calcium.