No abstract

Biological nitrogen fixation in soybean is enhanced when seed is treated with cobalt (Co) and molybdenum (Mo) prior to planting. In this study, our objective was to verify if Co and Mo application during the reproductive phase of the crop increases seed Co and Mo concentration without adverse effects on seed quality. Two experiments were conducted. First, we investigated foliar and soil Co and Mo application under greenhouse conditions. Next, we validated the results obtained in the first study. The treatments for both experiments consisted of Co doses combined with Mo, and a control without Co and Mo application. The foliar application was more efficient in producing enriched Co and Mo seed; meanwhile, as Co doses increased so did Co and Mo concentrations in the seed. There were no adverse effects on nutrition, development, quality, and yield of parent plants and seed when these micronutrients were applied. The seed showed higher germination, vigor, and uniformity for the development of soybean seedlings. We concluded that the application of 20 g ha−1 Co and 800 g ha−1 Mo via foliar application at the reproductive stage of soybean increased germination rate and achieved the best growth and vigor index of enriched seed.

A presença de arsênio no lodo de esgoto pode limitar a utilização agrícola desse resíduo, pois esse elemento químico apresenta elevada periculosidade aos seres vivos, podendo entrar na cadeia alimentar e acumular-se ao longo dessa. Diante do exposto, a pesquisa teve como objetivo avaliar o potencial de fitoextração de As pelo capim elefante, cultivado em lodo de esgoto puro. Visando o desenvolvimento de uma tecnologia de baixa custo para retirada de As do lodo de esgoto. O experimento foi realizado em casa de vegetação do ICA/UFMG durante 150 dias, em delineamento blocos casualizados. Os tratamento corresponderam a 5 períodos do cultivo de P. purpureum em parcelas de lodo de esgoto (30; 60; 90; 120 e 150 dias a partir do plantio de estacas) e 2 testemunhas (parcelas de lodo não cultivado e plantio da gramínea em solo). O As foi detectado em concentrações de 0,41 e 0,37 mg kg-1 no lodo de esgoto e solo, respectivamente. O P. purpureum  foi capaz de absorver  e translocar quantidades consideráveis de As, média de 0,35  mg kg-1,  variando de acordo com os períodos de cultivo. No final do período experimental, houve decréscimo de 27,03% na concentração de As no lodo quando comparado aos valores iniciais.

No abstract

Carrot plants do not develop well in clayey soils. In its turn, the charcoal fine (CF), which is a residue composed of porous particles, has the potential to be mixed in the soil to reduce its density. However, there is no evidence that the application of CF improves carrot production in clayey soil. Thus, an experiment in pots was designed, consisting of 16 treatments composed of the combination of 5 sizes of CF particles (1-2 mm, 2-4 mm, 4-8 mm, 8-16 mm, 16-32 mm) with 3 volumetric rates of CF (25%, 50% and 75%, plus a control (soil alone), aiming to verify which situation promotes the better plant growth and production. It was observed that mixing CF into the soil decreases substrate density and increases substrate water retention. The results of this research also revealed that the highest yield (fresh and dry weight) of carrots was achieved with CF mixed with the soil at a rate of 50%, using a CF particle size of 2-4 mm. The greatest length and diameter of carrots were obtained with a dose of CF of around 45%. CF-containing substrates delayed initial plant growth up to 45 DAE, but increased plant development after 75 DAE and improved plant performance and carrot yield measured at the harvest time (90 DAE).