Adding legumes to sugarcane silage is a strategy used to improve silage quality and reduce losses. This study's objective was to evaluate the chemical composition and fermentation profile of silages sugarcane and pigeon pea. A completely randomized design was used, with five treatments and four replications. The treatments consisted of sugarcane silage with increasing pigeon pea proportions (0, 25, 50, 75 and 100%). The forages were ensiled in experimental microsilos that remained closed for 60 days. Their chemical compositions were evaluated by determining the pH value and dry matter, crude protein, neutral detergent fiber, acid detergent fiber, hemicellulose, cellulose and lignin content. Fermentation profiles were evaluated by determining the effluent, gas, and total dry matter losses and dry matter recovery of the silage. Including pigeon pea in sugarcane silage decreases the hemicellulose content and increases the crude protein, acid detergent fiber and lignin content. Fermentation losses are reduced by adding pigeon pea to sugarcane silage with reduced effluent and gas losses and increased dry matter.
KEYWORDS
Bioindicators Invasive plants Microbial respiration rate Metabolic quotient
PALAVRAS-CHAVE Bioindicadores Plantas invasoras Taxa de respiração microbiana Quociente metabólico
ABSTRACT:The objective of this study was to evaluate the impact of different glyphosate-based herbicide formulations on microbial activity of soils from Carajás National Forest. We tested three formulations of glyphosate, i.e., Roundup Original , Roundup Ultra and Roundup WG that were applied in five doses: 0; 240; 480; 720 and 1440 g of active ingredient in acid equivalent ha -1 , with four replications. Herbicides were sprayed on pots containing 500 g of soil derived from the 0-10 cm layer of the study site. We determined the carbon from microbial biomass (C-MB), microbial respiration rate (MR) and metabolic quotient (qCO 2 ) at one and 28 days after herbicide application. No treatment affected the C-MB and MR at one and 28 days of incubation. There was no difference for qCO 2 at any dose of Roundup Ultra and WG formulations at one and 28 days of incubation. However, the qCO 2 was inhibited by the Roundup Original at one day post treatment. This parameter was normalized at 28 days after herbicide application. The data indicate that no one of the treatments tested cause significant impact on soil microorganisms of the Carajás National Forest, suggesting that herbicide-based invasive weed control could be used.
RESUMO: Objetivou-se com este estudo avaliar o impacto de diferentes formulações de herbicidas à base de glyphosate na atividade microbiana de solo da Floresta Nacional de Carajás. Foram testadas três formulações comerciais de glyphosate (Roundup Original
The present research had the objective to use the factor analysis in the evaluation of the competitive capacity of three native species from the Carajás National Forest in competition with different plant densities of the Urochloa brizantha grass. The experiment was conducted in a greenhouse and consisted in planting pots with the native species Bauhinia longipedicellata, Mimosa acutistipula and Solanum crinitum in competition with the exotic grass Urochloa brizantha. The exotic grass was established at densities ranging from 1 to 5 plants per pot, composing a 3 × 5 factorial arrangement with four replications that were delineated completely at random. Data were submitted to factor analysis for further analysis of variance and Tukey’s test at a 0.05 level of significance with the extracted factors. The effects of U. brizantha densities were evaluated by regression analysis. Out of the four extracted factors, three could be interpreted and were defined as vegetative growth index, infestation density index and physiological quality index. The Solanum crinitum species was slightly greater than the others in terms of vegetative growth rate and physiological quality. Generally speaking, native species maintain their vegetative growth in competitive conditions with up to two Urochloa brizantha plants; above that, the vegetative growth index tends to zero, while the infestation density index becomes positive.
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