Vicente de Paula Freitas

Potencial forrageiro de novos clones de capim-elefante

The objective of this experiment was to evaluate the forage potential of new selected clones of elephantgrass. The evaluation was conducted at the Dairy Cattle Research Centre - EMBRAPA, Coronel Pacheco, Minas Gerais, for two consecutive years. Twenty selected clones obtained by the elephantgrass breeding program were evaluated, and two traditional cultivars Cameroon and Taiwan A -146 were used as control. The experimental procedure was a randomized block design with four replicates. The fertilization for both establishment and maintenance was applied according to the soil chemical analysis and elephant grass nutritional requirements. Significant differences among the clones were observed regarding to forage production potential, leaf:stem ratio, and aerial and basal tillering. The majority of the evaluated new clones were superior to the traditional cultivars Cameroon and Taiwan A-146 with relation to dry matter production during the dry and rainy periods. Crude protein content in the forage did not differ among the new clones and the control cultivars (Cameroon and Taiwan A-146), during both dry and rainy seasons. The clone F 27-01, released as elephant grass cultivar Pioneiro, was superior for the most evaluated agronomic traits.

Efeitos do Sombreamento na Composição Mineral de Gramíneas Forrageiras Tropicais

The influence of three levels of artificial shade (0, 30 e 60%) on mineral composition of six forage grasses (Andropogon gayanus, Brachiaria brizantha, B. decumbens, Melinis minutiflora, Panicum maximum and Setaria sphacelata) was studied. The predominant soil in the region was classified as red-yellow latosol of medium texture and the assay was conducted according to randomized block design, with split plots, in four replicates; the plots corresponded to the shading levels and the split plots corresponded to the forage species. Shading affected the mineral composition of grasses and there was a tendency of increasing the concentration of P, K, Ca and Mg.

Efeito do manejo pós-plantio no estabelecimento de pastagem de capim-elefante

A good establishment is an important condition to obtain adequate levels of productivity in elephantgrass pastures. However, besides the adoption of good agronomic practices at planting, it is necessary to assure that the post-planting management is correct, to favor the future productivity and persistence of the pasture. Aiming at obtaining a good initial density of elephant-grass in the pastures, various post-planting management systems were studied. The following treatments were compared: grazing three months after planting, followed by cutting at 20 cm height from ground level (P20-3), at 40 cm (P40-3) and at 80 cm (P80-3); cutting three months after planting, at 20 cm from ground level (C20-3) and cutting four months after planting at 20 cm from ground level (C20-4). The experiment was undertaken in Coronel Pacheco, MG, in a red-yellow latosol. Experimental design was randomized blocks with four replications, and plots measured 8 x 10 meters. Forage availability, number of plants per hectare and percentage soil cover did not differ among treatments. The cutting at 20 cm height from ground level, three months after planting did not contribute to increase plant density or forage dry matter yield. Basal tillering was not affected by treatments. It was concluded that elephant-grass pastures can be grazed three months after planting, without reducing its productivity thereafter.

Autoclave-assisted acidic extraction of water-soluble carbohydrates in forage grasses

Abstract Methods for extracting water‐soluble carbohydrates (WSC) in plants are often time‐consuming and limited to few samples per run. Aiming at resolving such restraints, the utilization of an autoclave in replacement of the traditional reflux‐based protocol was studied in completely randomized design experiments with five replicates. WSC contents were determined in stocks of 11 standards and samples of 14 grass species, following autoclave‐ or reflux‐assisted hydrolyzation. Results revealed that both methods were equally effective in recovering most standards, and plant WSC levels were similar or only narrowly lower with autoclave. Autoclave was operationally advantageous, allowing for 15‐min concurrent processing of 90 samples against a 150‐min extraction of 4 samples with reflux, and energy savings of more than 87% on a per sample basis. It is concluded that the utilization of autoclave for acidic WSC extraction is feasible and even preferable compared with reflux for the studied standards and grasses.