Effects of row spacing and intercrop on maize grain yield and forage production of palisade grass

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Método não destrutivo de estimativa da área foliar de plantas daninhas de ambiente aquático: tanner-grass e capim-fino

The continuous inputs from agriculture areas and human or industrial sewer have been provided a widely demographic explosion of tropical tanner-grass and para grasss plants in the rivers and water reservoirs of Brazil. Considering the importance of these noxious weeds there is a vast necessity of basic studies on aspects related to reproduction, growing, development, nutritional requirements, responses to control systems and others. In most studies, leaf area knowledge is crucial and it is one of the most difficult characteristics to be measured because it usually requires expensive equipments or it uses a destructive technique. The objective of this work was to develop equations for leaf blade dimensional parameters to allow determination of the leaf area of African tanner-grass (Brachiaria subquadripara (Trin.) Hitchc) and para grass (Brachiaria mutica (Forsk.) Stapf.). Correlations between real leaf area and dimensional parameters of leaf blade such as length along the main vein (L) and maximum width (W) perpendicular to the main axis were studied. Only the linear equations allowed a good leaf area estimate. It is suggested to opt for a simple linear equation involving respective products of length times maximum width considering linear coefficient equal to zero. Thus, B. subquadripara (SS) and B. mutica (SM) non destructive leaf blade area estimates may be performed by the following formulas: SS = 0.7719 (L x W) and SM = 0.7479 (L x W), with coefficients of determination (R(2)) of 0.9594 and 0.9408, respectively.

Recovery of Trichostrongylus colubriformis infective larvae from three grass species contaminated in the autumn

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Vertical migration of Haemonchus contortus third stage larvae on Brachiaria decumbens grass

The present study aimed at evaluating the vertical migration of Haemonchus contortus third stage larvae (1-3) on Brachiaria decumbens grass, as well as at verifying whether larval numbers on pasture varies over the day due to climatic conditions. Feces containing H. contortus L3 were deposited on the soil in the middle of herbage which was initially 30 cm high. Seven days later, samples of different herbage strata (0-10, 10-20 and >20 cm), remaining feces and a layer of approximately 1 cm soil were collected. Tests were carried out in four periods: September 2006, December 2006, March 2007, and June 2007. Samples were collected at sunrise, mid-day, sunset, and mid-night. The humidity and temperature conditions observed in different months influenced larval migration from the feces to the grass. In September, December and March, it rained after fecal deposition on pasture, which favored migration of larvae from the feces to the herbage. Conversely, in June 2007, when there was no rainfall after fecal deposition and temperatures were lower, L3 were mainly recovered from feces. As regards the vertical migration of larvae, the numbers of H. contortus L3 in the forage strata remained relatively constant over the day. This indicates there is not a determined period in which sheep on pasture are at higher risk of infection. Finally, in all collection periods a considerable amount of third stage larvae was observed on the herbage top, which is the first plant part consumed by sheep. (C) 2008 Elsevier B.V. All rights reserved.

Reproductive morphology of the early-divergent grass Streptochaeta and its bearing on the homologies of the grass spikelet

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Microsporogenesis is simultaneous in the early-divergent grass Streptochaeta, but successive in the closest grass relative, Ecdeiocolea

Simultaneous microsporogenesis is described for the first time in a grass, Streptochaeta spicata Schrad., a tropical Brazilian species that belongs in the early-divergent subfamily Anomochlooideae. Microsporogenesis is successive in all other Poaceae examined so far, and most other members of the order Poales, to which grasses belong. The only other reports of simultaneous microsporogenesis in Poales are in Rapateaceae and some members of the cyperid clade (Juncaceae, Cyperaceae, Prionium and Thurnia). Among the graminids, Ecdeiocolea (the putative closest relative to Poaceae) is successive, as are Joinvillea, Flagellaria and all other Poaceae, indicating that the simultaneous condition is autapomorphic in Streptochaeta, though Anomochloa has yet to be examined. Anther wall development in Streptochaeta is of the reduced type, as also in another early-divergent grass Pharus, though most other Poales, including most grasses, have the monocot type. In Streptochaeta, as in Pharus, the endothecium lacks thickenings, unlike other grasses that have a persistent endothecium with thickenings. The centrifixed anthers and nonplumose stigmas of Streptochaeta suggest entomophily.

Use of sugarcane bagasse and grass hydrolysates as carbon sources for xylanase production by Bacillus circulans D1 in submerged fermentation

The use of sugarcane bagasse and grass as low cost raw material for xylanase production by Bacillus circulans D1 in submerged fermentation was investigated. The microorganism was cultivated in a mineral medium containing hydrolysate of bagasse or grass as carbon source. High production of enzyme was obtained during growth in media with bagasse hydrolysates (8.4 U/mL) and in media with grass hydrolysates (7.5 U/mL). Xylanase production in media with hydrolysates was very close to that obtained in xylan containing media (7.0 U/ mL) and this fact confirm the feasibility of using this agro-industrial byproducts by B. circulans D1 as an alternative to save costs on the enzyme production process. (c) 2005 Elsevier Ltd. All rights reserved.

Grass-dominated stream sites exhibit low fish species diversity and dominance by guppies: an assessment of two tropical pasture river basins

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Indirect method for quantifying the content of photosynthetic pigments in genotypes of dwarf elephant grass

O objetivo deste ensaio foi determinar equações que indiretamente associem os valores obtidos no medidor de clorofila SPAD-502 aos teores de clorofila e carotenóides de genótipos de capim-elefante anão. Folhas de genótipos de capim-elefante anão foram utilizadas e, depois de coletadas, foram transportadas em caixas de isopor, protegidas da luz, até o laboratório de Fisiologia Vegetal da UENF. Posteriormente, os discos foliares de área conhecida foram extraídos. Com o auxílio do medidor portátil de clorofila (MPC) SPAD-502, foi obtida a média de 5 leituras/disco foliar e utilizaram-se 6 discos para cada intervalo, distribuídos de acordo com a seguinte escala de valores do MPC: 0-10; 10-20; 20-30; 30-40; 40-50; 50-60. O medidor de clorofila SPAD-502 possibilitou uma rápida e eficaz estimativa do conteúdo de clorofila total, clorofila-a e clorofila-b em genótipos de capim-elefante anão.

Daily intake of lactating crossbred cows grazing elephant grass rotationally

O objetivo deste trabalho foi o de estimar o consumo total e o diário de matéria seca do pasto, de vacas mestiças Holandês - Zebu, em piquetes de capim-elefante (Pennisetum purpureum Schum.). Três grupos de 24 vacas foram usados em piquetes (4,5 vacas/ha), pastejados por três dias e submetidos a diferentes períodos de descanso durante dois anos. Os tratamentos consistiram de descansos de 30 dias sem concentrado e 30, 37,5 e 45 dias com a suplementação de 2 kg de concentrado (20,6% de proteína bruta). de julho a outubro, as vacas receberam, como suplementação, cana-de-açúcar mais 1% de uréia. O consumo total de matéria seca foi estimado a partir da digestibilidade in vitro da matéria seca da extrusa e da produção fecal obtida com óxido crômico. Independentemente do tratamento, o consumo total foi 2,7; 2,9 e 2.9±0,03%, e o consumo de matéria seca do pasto foi de 1,9; 2,1 e 2,1±0,03% do peso vivo (p<0,05), respectivamente, no primeiro, segundo e terceiro dia de ocupação do piquete. Somente no verão, o consumo do pasto foi semelhante nos três dias de pastejo. A mistura cana-de-açúcar e uréia substituiu o pasto, principalmente no primeiro dia de pastejo, ocasião em que o consumo do pasto era mais baixo.

Nitrate reductase activity in leaves and stems of tanner grass (Brachiaria radicans Napper)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemical treatment of post-harvest Marandu grass seed residues with different moisture contents

Objetivou-se avaliar o efeito do tratamento químico com ureia (3 ou 5% na MS) e amônia anidra (3% na MS) no feno de resíduo pós-colheita de sementes de Brachiaria brizantha, cv. Marandu, contendo diferentes teores de umidade (15, 25 ou 30%). O delineamento experimental foi em blocos ao acaso com oito tratamentos e quatro repetições (camadas de fardos dentro das pilhas). O feno tratado com 3% de amônia anidra com 15% de umidade ocasionou redução de 84,3 para 79,1% nos teores de fibra em detergente neutro (FDN) e elevação de 37,3 para 55,5% na digestibilidade in vitro da matéria seca (MS) em relação ao grupo controle. A variação na umidade não alterou de maneira significativa a ação da amônia, cujos valores médios foram 77,6% de FDN e 57,3% de digestibilidade in vitro da MS. O feno com 5% de ureia reduziu os teores de FDN de 84,3 para 79,6% em relação ao feno não-tratado, o que tornou necessário o aumento da umidade para 30% para maior efeito sobre a digestibilidade da MS, que aumentou 12 unidades percentuais.

Nutritional evaluation of elephant-grass silages with byproduct of annato

Objetivou-se avaliar o valor nutritivo de silagens de capim-elefante contendo subproduto do processamento do urucum. Vinte ovinos machos, não-castrados, foram distribuídos em delineamento inteiramente casualizado com cinco dietas (0; 4; 8; 12 e 16% de subproduto de urucum na silagem) e quatro repetições, e utilizados para estimar o consumo, a digestibilidade aparente de nutrientes, o teor de nutrientes digestíveis totais e o balanço de nitrogênio. A adição de subproduto de urucum elevou os consumos de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), extrato etéreo (EE), carboidratos não-fibrosos (CNF), carboidratos totais e nutrientes digestíveis totais (NDT), tanto em relação ao peso vivo (%PV) quanto em relação ao peso metabólico (g kg-1PV0,75). As digestibilidades de MS (55,95%), MO (58,19%), PB (45,34%), FDN (52,79%), FDA (45,79%), EE (34,96%) e CNF (99,86%) não foram influenciadas pela adição de subproduto de urucum. A inclusão de subproduto de urucum na silagem de capim-elefante promoveu aumento na digestibilidade dos carboidratos totais, no teor de NDT e no balanço de nitrogênio. A adição de subproduto de urucum em níveis de até 16% da matéria natural na ensilagem de capim-elefante melhora o consumo de nutrientes e o balanço de nitrogênio.

Morphogenetic and tillering dynamics in Tanzania grass fertilized and non-fertilized with nitrogen according to season

The objectives of this study were to evaluate morphogenetic characteristics and tillering dynamics in Tanzania grass fertilized and non-fertilized with nitrogen, under intermittent grazing, in the spring and the summer. The main plots were composed of four nitrogen rates (0, 100, 200 and 300 kg/ha) and the subplots were growth seasons: spring (October, November and December) and summer (January, February and March). The experimental design was of randomized block with plots subdivided by time (seasons of the year) and four replications. Urea was used as nitrogen supply and was divided into two applications: one in the spring and another in the summer. The experimental units fertilized with N rates of 200 and 300 kg/ha showed six cycles of pasture, with an average of 27 days of pasture interval, while the treatments with no fertilization and 100 kg/ha of N showed only four and five cycles of pasture, respectively. Leaf elongation rate (LER) and the leaf appearance rate (LAR) increased linearly with increasing of N rates. The greatest population density occurred in summer with the higher nitrogen rates. The treatment without N fertilization showed the lowest growth of tiller population, while the other treatments exhibited growth rates above 50% when compared with non-fertilized samples. Nitrogen rates significantly affect the leaf appearance rate and the leaf elongation rate, as well as the number of live leaves in plants of Tanzania grass in both spring and summer.