Elephant grass silage inoculated with cellulolytic fungi isolated from rumen

ABSTRACT The objective was to evaluate the inoculation with Aspergillus terreus and/or Trichoderma longibrachiatum on fermentation, chemical and microbiological composition of elephant grass ‘Cameroon’ silage (Cenchrus purpureus). Treatments were A. terreus at 105 colony forming units (CFU)/g (AT15), T. longibrachiatum at 105 CFU/g (TL20), a mixture of both at 105 CFU/g (MIX), and a control group without inoculation (CONTR). The design was completely randomized with seven replicates. The MIX silage was most stable, while CONTR, AT15, and TL20, had lower dry matter losses. There was no effect of inoculation in the chemical composition of silages. Only MIX silage (4.40) had pH above the minimum of 4.2 for humid grass silage and above the control (4.05). Bacteria from Diplococcus genus was identified at the opening of TL20 and CONTR silages. After air exposure, the population of rods, Lactobacillus, and total lactic acid bacteria was higher in theTL20 and MIX. The inclusion of a T. longibrachiatum and A. terreus mixture increases dry mater loss and silage pH. T. longibrachiatum was more efficient in maintaining populations of total lactic acid bacteria after opening; therefore, this strain has potential as an additive for elephant grass ‘Cameroon’ silage

Repeatability of agronomic traits in Panicum maximum (Jacq.) hybrids

When evaluating plants, in particular perennial species, it is common to obtain repeated measures of a given trait from the same individual to evaluate the traits’ repeatability in successive harvests. The degree of correlation among these measures defines the coefficient of repeatability, which has been widely utilized in the study of forage traits of interest for breeding. The objective of the present study was to evaluate the repeatability of agronomic traits in Panicum maximum hybrids. Hybrids from three progenies totaling 320 hybrids were evaluated in an incomplete- block design, with consideration of production and morpho-agronomic traits. Of the production traits, total dry matter and leaf dry matter showed the highest repeatability and varied from 0.540 to 0.769, whereas stem dry matter had lower coefficients (0.265-0.632). Among the morpho-agronomic traits, plant height and incidence of Bipolaris maydis had higher coefficients (0.118-0.460). The repeatability values of the agronomic traits were low-to-moderate, and six evaluations were sufficient to provide accuracy in the selection of hybrids regarding total dry matter, leaf dry matter, plant height, and incidence of B. maydis, whereas the other traits require more repeated measures to increase reliability in the prediction of their response

Productive and physiological characteristics of elephant grass under nitrogen fertilization

The objective of this study was to evaluate forage production in shoot and root, the in vitro activity of nitrate reductase and the content of photosynthetic pigments in plants of Pennisetum purpureum cv. Cameroon subjected to nitrogen fertilizer doses. The experiment was conducted in a greenhouse in a completely randomized design with four treatments (no nitrogen, 50, 100 and 150 Kg·ha-1 of nitrogen) and four replicates. The soil was fertilized according to the analysis of fertility. Plants were harvested 60 days after planting and evaluated for dry matter yield and in vitro activity of nitrate reductase in leaf blades and roots and pigment contents. Nitrogen fertilization increased biomass production of shoots and roots of P. purpureum, as well as nitrate reductase, in both leaf blades as the root activity. As they increased the nitrogen, we observed a higher accumulation of leaves. We also observed increased activity of nitrate reductase in the blades in relation to the roots of elephant grass, and the enzyme activity increased as they increased nitrogen fertilization. The crude protein content and the content of photosynthetic pigments linearly and positively responded to nitrogen fertilization. Nitrogen fertilization increases the production of dry matter in elephant grass plants. The activity of the enzyme nitrate reductase is more pronounced in the leaves than in roots, regardless of the nitrogen levels and the application of this nutrient induces the enzyme activity and the synthesis of photosynthetic pigments.A produção de forragem foi estudada avaliando-se a parte aérea e o sistema radicular, a atividade in vitro da enzima nitrato redutase e o conteúdo de pigmentos fotossintéticos em plantas de Pennisetum purpureum cv. Cameroon submetidas a doses de nitrogênio. O experimento foi conduzido em casa de vegetação em delineamento inteiramente casualizado com quatro tratamentos (ausência de adubação nitrogenada, 50, 100 e 150 Kg·ha-1 de N) e quatro repetições. O solo foi adubado de acordo com a análise de fertilidade. As plantas foram cortadas 60 dias após o plantio e avaliadas quanto à produção de massa seca, atividade in vitro da enzima nitrato redutase e conteúdo de pigmentos fotossintéticos. A adubação nitrogenada promoveu maior produção de biomassa da parte aérea e do sistema radicular de P. purpureum, bem como na atividade da nitrato redutase em lâminas foliares e raízes. À medida que se elevou as doses de nitrogênio, observou-se maior acúmulo de folhas. Observou-se também maior atividade da nitrato redutase em lâminas foliares quando comparado ao sistema radicular, sendo a atividade da enzima incrementada à medida que se aumentou a adubação nitrogenada. O teor de proteína bruta e o conteúdo de pigmentos fotossintéticos responderam linear e positivamente à adubação nitrogenada. A adubação nitrogenada aumenta a produção de massa seca em plantas de capim-elefante cv. cameroon. A atividade da enzima nitrato redutase é mais pronunciada nas folhas do que nas raízes, independentemente da dose de nitrogênio, e a aplicação desse nutriente induz a atividade da enzima, bem como a síntese de pigmentos fotossintéticos

Tolerância do Tifton 85 ao glyphosate em diferentes épocas de aplicação

O Tifton 85 é uma forrageira de alto valor nutritivo, recomendada para pastejo, fenação e silagem, podendo ser considerada uma espécie daninha, principalmente em áreas de cultivos agrícolas e produção de sementes de outras forrageiras, devido a sua fácil propagação e seu rápido desenvolvimento. Este experimento foi proposto com o objetivo de avaliar a tolerância de plantas de Tifton 85 a doses crescentes de glyphosate em duas épocas diferentes. O experimento foi conduzido em vasos de polietileno com capacidade de 10 L, em delineamento experimental de blocos casualizados, no esquema fatorial 2 x 8, sendo duas épocas de aplicação (inverno e verão) e oito doses de glyphosate (0, 270, 540, 1.080, 2.160, 3.240, 4.320 e 5.400 g ha-1), com quatro repetições. Para cada época de aplicação, o controle das plantas de Tifton 85 foi feito aos 15, 30 e 60 DAA (dias após aplicação). Obteve-se controle superior a 90% de Tifton 85 a partir de 2.636,72 g ha-1 de glyphosate em aplicação realizada no inverno e de 3.607,03 g ha-1 em aplicação no verão. Os resultados evidenciaram a alta tolerância do Tifton 85 ao glyphosate e o maior controle das plantas expostas a esse herbicida em épocas mais frias do ano (inverno), quando em comparação com as plantas expostas ao herbicida no verão.Tifton 85 is a type of forage of high nutritive value, recommended for grazing or hay and silage production. It can be considered a weed, mainly in agricultural and forage seed production areas, probably due to its easy propagation and fast development. Thus, this experiment aimed to evaluate Tifton 85 tolerance to increasing levels of glyphosate during two different seasons. The experiment was arranged in a completely randomized block design with four replications in a 2 x 8 factorial arrangement, and pulverization in two seasons (winter and summer) and eight glyphosate levels (0; 270; 540; 1,080; 2,160; 3,240; 4,320; and 5,400 g ha-1). The experiment was carried out in polyethylene pots with 10L capacity. For each season, control of the Tifton 85 plants was performed at 15, 30 and 60 DAA (days after application). Around 90% of Tifton 85 plant control was observed with 2,636.72 g ha-1 of glyphosate in the winter and 3,607.03 g ha-1 of glyphosate in the summer. The results obtained showed that Tifton 85 is highly tolerant to glyphosate and control is more efficient in the winter than in the summer

Grazing management strategies for Xaraés grass (Brachiaria brizantha cv. Xaraés)

The objective of this study was to evaluate the effects of two intermittent grazing strategies, with 24 fixed resting days and 95% light interception in Xaraés grass. For evaluation of productive, structural and nutritive characteristics, we used a completely randomized design with repeated measures in the time, with four grazing cycles and two grazing strategies. For consumption by the animals, we used a completely randomized design, in a 2 x 3 factorial, with two grazing strategies and three days of occupation. There was no effect for the variables: availability, structure and chemical composition of forage, except for light interception and crude protein, in which treatment with LI showed the highest value of light interception and lower content of CP. There was effect for dry matter intake between the days of occupation, and the highest values found on the first day and the lowest on the third day of occupation. Thus, taking into account practicality of adoption, good soil and climatic conditions, grazing management with intensification of fixed days shows great potential for pasture use.Objetivou-se com este estudo, avaliar os efeitos de duas estratégias de pastejo intermitente, com 24 dias fixos de descanso e com 95% de interceptação luminosa em capim-xaraés. Para a avaliação das características produtivas, estruturais e bromatológicas foi utilizado o delineamento inteiramente casualizado com medidas repetidas no tempo, com quatro ciclos de pastejo e duas estratégias de pastejo. Para o consumo dos animais foi utilizado o delineamento inteiramente casualizado em arranjo fatorial 2 x 3, sendo duas estratégias de pastejo e três dias de ocupação, e para a taxa de lotação utilizou-se o arranjo 2 x 4 (duas estratégias e quatro ciclos de pastejo). Não houve efeito para as variáveis: disponibilidade, estrutura e composição bromatológica da forragem, com exceção para interceptação luminosa e proteína bruta, onde o tratamento com IL obteve maior valor de interceptação luminosa (2,73% superior que o DF) e menor teor de PB (1,08% inferior ao tratamento DF). Para o consumo de matéria seca houve efeito (

HERBICIDE SELECTIVITY TO SIGNAL GRASS AND CONGO GRASS

<div><p>ABSTRACT This study was conducted in order to evaluate the selectivity of signal grass and congo grass, submitted to post-emergence herbicide application. The experiment was conducted under greenhouse conditions, in Diamantina, Minas Gerais state, and it was arranged in a randomized block design, with five replications. Treatments were set in factor scheme (8 x 2) + 2. Eight herbicides (nicosulfuron; clomazone; glyphosate; fluazifop-p-butyl + fomesafen; lactofen; fomesafen; fluazifop-p-butyl and mesotrione) were applied in doses recommended by the manufacturer on two fodder species: Brachiaria decumbens cv. Basilisk (signal grass) and Brachiaria ruziziensis (congo grass); in addition, there were two control samples without herbicide application, for a total of 18 treatments. The evaluated herbicides showed less intoxication on signal grass when compared to congo grass. Nicosulfuron and glyphosate promoted higher intoxication on both species when compared to the other herbicides. Glyphosate, fluazifop-p-butyl + fomesafen, fluazifop-p-butyl, mesotrione and nicosulfuron affected the ratio variable / maximum fluorescence (Fv/Fm) in both species, indicating an effect provided by these herbicides on the electron transport chain. Results demonstrated that signal grass and congo grass have higher susceptibility to glyphosate, fluazifop-p-butyl + fomesafen, fluazifop-p-butyl, mesotrione and nicosulfuron. congo grass shows higher susceptibility to the studied herbicides when compared to signal grass.</p></div

Forage yield and nutritive value of Tanzania grass under nitrogen supplies and plant densities

The objective of this experiment was to evaluate the nitrogen and plant density influence on the yield, forage dissection and nutritive value of Tanzania grass (Panicum maximum Jacq.). The design was of completely randomized blocks with three replications in a factorial arrangement with four nitrogen levels (0, 80, 160 or 320 kg/ha N) and three plant densities (9, 25 or 49 plants/m²). The plots were cut at 25 cm from soil level when the canopy reached 95% of light interception. The total dry matter forage yield and dry matter forage yield per harvest increased linearly with the nitrogen fertilization. The leaf and stem yield had the same response. The senesced forage yield was quadratically influenced by the nitrogen. The stems ratio in the morphologic composition was high in the high nitrogen levels and in the low plant densities. The leaf:stem ratio showed high values in this trial, but it was increased in plots without nitrogen and high plant density. The pre-grazing height was reduced with the increase in plant density. The nutritive value was favored by the nitrogen fertilization, which increased the crude protein level and reduced neutral detergent fiber and lignin. These factors increased the leaf and stem in vitro digestibility of organic matter. Nitrogen fertilization increases the forage yield of Tanzania grass under rotational grazing. After the establishment, plant density has little influence on the Tanzania grass yield and its forage dissection. The harvest with 95% light interception improves the structure and nutritive value of Tanzania grass pastures