Soil physicochemical and biological properties in soybean areas under no-till Systems in the Brazilian Cerrado

No-till (NT) as a conservation practice aims to minimize soil disturbance and enhance soil sustainability. However, how NT practice affects soil physicochemical and biological properties in soybean areas remains unclear. This study selected 65 high-yielding soybean farms under a long-term NT system in the Brazilian Cerrado and collected soil samples at 0.0-0.10 m (L1), 0.10-0.20 m (L2) and 0.20-0.40 m (L3) depths. The effect of NT on soil properties and interactions with soybean productivities were assessed. Results showed that the average soybean yield of the study areas in the last three years was 4.13 Mg ha^-1, with 26 areas presenting yields over 4.20 Mg ha^-1. Most studied soil properties showed a depth stratification and were strongly concentrated in L1, except for S, Al³⁺ and aluminum saturation, which displayed lower surface and higher subsurface concentrations. Moreover, a high proportion of SOM is composed of light SOM fraction in areas of high soybean yield, with the average SOM values of 39.9, 27.8 and 19.6 g kg^-1 in L1, L2 and L3, respectively. Soils under long-term NT present moderate values of enzyme activity compared with the relatively low values under conventional tillage system, especially 94 % of the plots have moderate values of activity of arylsulfatase enzymes. The data presented support the conclusion that NT system can enhance soil fertility and biological quality in soybean cultivation. Our results suggest that it is necessary to adopt NT practice because it allows increasing soybean productivity in Brazil without the need to increase the sown area, in addition to increasing productivity associated with an improvement in the agroecosystem quality, thus moving toward a more sustainable agriculture.

Trace Elements in Beef Cattle: A Review of the Scientific Approach from One Health Perspective

The objective was to investigate the context, approach and research topics present in the papers that analysed trace elements in beef cattle to identify gaps and scientific perspectives for the sustainable management of trace elements in livestock. The main research groups came from the United States, Spain, Japan, Brazil, India and Slovakia, which represented 31% of the papers produced. Only 37% of studies addressed aspects that integrated animal, environmental and human health. The reviewed papers concerned 56 elements and 15 bovine tissues (Cu, Zn, Pb, liver, muscle and kidney highlighted). The main gaps were (1) lack of research in developing countries, (2) the need to understand the impact of different environmental issues and their relationship to the conditions in which animals are raised, and (3) the need to understand the role of many trace elements in animal nutrition and their relationship to environmental and human health. Finally, we highlight possible ways to expand knowledge and provide innovations for broad emerging issues, primarily through expanding collaborative research networks. In this context, we suggest the adoption of the One Health approach for planning further research on trace elements in livestock. Moreover, the One Health approach should also be considered for managers and politicians for a sustainable environmental care and food safety.

DIGESTIBILIDADE DA MATERIA SECA E PARÂMETROS DA FERMENTAÇÃO IN VITRO DE PLANTAS FORRAGEIRAS

Objetivou-se avaliar a digestibilidade da matéria seca (MS) e os parâmetros da fermentação in vitro de plantas forrageiras in natura e ensiladas no período da seca por meio da técnica de 24 horas de incubação. As plantas forrageiras avaliadas foram Brachiaria brizantha cv. Marandu; Brachiaria humidicola; Panicum maximum cv. Mombaça; Panicum maximum cv. Massai; silagem de milho (Zea mays); silagem de sorgo (Sorghum bicolor L. Moench); cana -de- açúcar (Saccharum officinarum L) picada in natura. Foi utilizado um delineamento experimental inteiramente casualizado (DIC), sendo consideradas como repetições de campo três baterias para a determinação da DIV da MS das forrageiras. A análise estatística das variáveis estudadas foi interpretada por meio de análise de variância e quando observada diferença aplicou-se o teste de Tukey a 5% de significância. Não houve (P>0,05) diferença significativa dentro dos gêneros das diferentes espécies forrageiras ou nos volumosos suplementares (silagem). Os valores da digestibilidade in vitro (DIV) da MS para os capins do gênero Brachiaria foram de 48,40% para o capim-marandu e 51,21% para capim-humidícola. Para o gênero Panicum os valores da DIV da MS foram de 46,70% e 40,49%, respectivamente, para o capim-mombaça e massai. Para os volumosos ensilados (silagem de milho e silagem de sorgo) e a capineira (cana-de-açúcar) observaram-se os valores de 63,22%, 54,00% e 59,76% da DIV da MS, respectivamente. Não houve (P>0,05) alteração nos valores de pH e na concentração do nitrogênio amoniacal durantes a fermentação in vitro das plantas forrageiras. Assim, conclui-se, que o valor da DIV da MS e os parâmetros da fermentação in vitro se mantem similar para os capins do mesmo gênero e forrageiras ensiladas no período da seca.