Avaliação do potencial produção de sementes de híbridos de Brachiaria decumbens

2015

Ruminal methane emission by dairy cattle in southeast Brazil.

ABSTRACT: Ruminal gases, particularly methane, generated during the fermentative process in rumen, represent a partial loss of feed energy and are also pointed to as an important factors in greenhouse effect. This study aimed at quantifying methane (CH 4) emission rates from lactating and dry cows and heifers, 24 month-old in average, on pasture under Southeast Brazil tropical conditions, using the tracer gas technique, sulphur hexafluoride (SF 6), four animals per category, distributed in four blocks. Measurements were performed in February and June, 2002, with Holstein and Brazilian Dairy Crossbred (Holstein ¾ x Gir (Zebu) ¼), maintained on fertilized Tanzania-grass (Panicum maximum Jacq. cv. Tanzania) and fertilized Brachiaria-grass (Brachiaria decumbens cv. Basilisk) pastures. Heifers of both breeds were maintained on unfertilized Brachiaria-grass to simulate conditions of extensive cattle farming systems. CH 4 and SF 6 levels were measured with gas chromatography. Differences in CH4 emissions were measured (p < 0.05) for genetical groups. Holstein produced more methane (299.3g day?1) than the Crossbred (264.2 g day?1). Lactating cows produced more methane (353.8 g day?1) than dry cows (268.8 g day?1) and heifers (222.6 g day?1). Holstein, with greater milk production potential, produced less CH4 (p < 0.05) per unit of dry matter intake (19.1 g kg?1) than the Crossbred (22.0 g kg?1). Methane emission by heifers grazing fertilized pasture (intensive system) was 222.6 g day?1, greater (p < 0.05) than that of heifers on unfertilized pasture (179.2 g day?1). Methane emission varied as function of animal category and management intensity of production system.

Avaliação de gramíneas na microrregião do Médio-Mearim, MA.

Em Bacabal, MA, Foram avaliados o rendimento forrageiro, a percentagem de folhas e de FDN e FDA de Brachiaria brizantha cv. Marandu. Brachiaria decumbens cv. Basilisk, Panicum maximum cvs. Massai, Mombaça, Tanzânia e Tobiatã. O plantio foi realizado no inicio das chuvas (janeiro) de 1999 e os cortes para avaliação, em número de oito, realizaram-se de abril de 1999 até julho de 2000. Foi usado o delineamento inteiramente casualizado com parcelas de 3 x 5 m e três repetições.

Qualidade química e física do solo sob vegetação arbórea nativa e pastagens no pantanal Sul-Mato-Grossense.

A busca por aumento de produtividade da pecuária pantaneira tem motivado o desmatamento de áreas florestadas para a implantação de pastagem cultivada, gerando preocupação quanto à sustentabilidade dos recursos naturais. Para estudar alguns aspectos de uso do solo no Pantanal Sul-Mato-Grossense, este trabalho teve por objetivo avaliar as alterações nos atributos químicos e físicos do solo em razão da conversão da vegetação arbórea nativa em pastagem cultivada, bem como da submissão da pastagem nativa ao sistema de pastejo contínuo. Os ambientes de estudo consistiram de três remanescentes de vegetação arbórea nativa, representadas por uma floresta semidecídua (FN) e dois cerradões (CE1 e CE2), três pastagens de Brachiaria decumbens com 27, 26 e 11 anos de formação, implantadas em substituição a FN, CE1 e CE2, respectivamente, e uma pastagem nativa caracterizada pela predominância de Mesosetum chaseae e Axonopus purpusii, submetida a três diferentes sistemas de pastejo (contínuo e sem pastejo por 3 e 19 anos). Amostras de solo, deformadas e indeformadas, foram coletadas em cada ambiente de estudo, nas profundidades de 0?10 e 10?20 cm, com três repetições. A substituição da vegetação arbórea nativa por pastagem cultivada e o sistema de pastejo contínuo da pastagem nativa determinaram redução da qualidade química do solo, evidenciada principalmente por perdas de matéria orgânica do solo, notadamente na profundidade de 0?10 cm. Embora a qualidade física do solo também tenha apresentado tendência à redução nas pastagens cultivada e nativa sob pastejo contínuo, a densidade do solo, porosidade total, macroporosidade, microporosidade, condutividade hidráulica do solo saturado eresistência do solo à penetração não atingiram valores considerados limitantes ao desenvolvimento do sistema radicular.

Microwave-assisted solvent extraction and analysis of shikimic acid from plant tissues.

A better method for determination of shikimate in plant tissues is needed to monitor exposure of plants to the herbicide glyphosate [N-(phosphonomethyl)glycine] and to screen the plant kingdom for high levels of this valuable phytochemical precursor to the pharmaceutical oseltamivir. A simple, rapid, and efficient method using microwave-assisted extraction (MWAE) with water as the extraction solvent was developed for the determination of shikimic acid in plant tissues. High performance liquid chromatography was used for the separation of shikimic acid, and chromatographic data were acquired using photodiode array detection. This MWAE technique was successful in recovering shikimic acid from a series of fortified plant tissues at more than 90% efficiency with an interference-free chromatogram. This allowed the use of lower amounts of reagents and organic solvents, reducing the use of toxic and/or hazardous chemicals, as compared to currently used methodologies. The method was used to determine the level of endogenous shikimic acid in several species of Brachiaria and sugarcane (Saccharum officinarum) and on B. decumbens and soybean (Glycine max) after treatment with glyphosate. The method was sensitive, rapid and reliable in all cases.

Bioecology of Spodoptera frugiperda (Smith, 1757) in different cover crops.

The objective of this work was to evaluate the biological variables of Spodoptera frugiperda on species of cover crops. The experiments were conducted in laboratory and greenhouse using the following species: sunflower (Helianthus annuus), sun hemp (Crotalaria juncea), brachiaria (Urochloa decumbens e Urochloa ruziziensis), millet (Pennisetum americanum), black oat (Avena stringosa), white lupin (Lupinus albus), forage turnip (Rafanus sativus) and maize (Zea mays). In laboratory the S. frugiperda larval survival varied from 57%, on L. albus, to 93% on H. annuus and the survival of the pre-imaginal phase varied from 45% on U. decumbens to 81.6% on Z. mays. On C. juncea the larval biomass was lower and the development period of the young and larval stage was higher. The adaptation index was less on C. juncea in greenhouse and laboratory. In greenhouse the larval survival at 14 days was similar for all plants and at 21 days was the lowest on C. juncea. There was less accumulation of biomass at 14 days on C. juncea and at 21 days on C. juncea and A. stringosa. Regarding damage, C. juncea presented less susceptibility to Spodoptera frugiperda attack, which together with the other evaluated parameters, indicated this plant as the most appropriate for soil cover before cultivation of maize.

Parametrage du modèle de culture STICS pour simuler la croissance des prairies de Brachiaria brizantha cv. BRS Piatã en conditions du Cerrado brésilien.

2015

Methodology for climate risk assessment of maize intercropped with Brachiaria in the Cerrado of Brazil.

2015

Organic management of Brachiaria brizantha cv. Marandu pasture mixed with Stylosanthes spp. in the Cerrado.

2016

Familia defensiva de peptideos antimicrobianos em urochloa decumbens cv. Basilisk

2015

Analise e comparação filogenética de expansivas presentes em urochloas decumbens cv Basilick

2015

Brachiaria brizantha cv. BRS Paiaguás e brachiaria híbrida BRS RB331 Ipyporã: seletividade de herbicidas pós-emergentes em campos de produção de sementes

2015

Efeito de populações crescentes de Pratylenchus brachyurus no desempenho agronômico de Brachiaria brizantha cv. piatã

2015

Causas e superação de dormência em Brachiaria humidicola cv. BRS Tupi

2015

Produção de sementes de Brachiaria brizantha B4 sob diferentes densidades de plantio

2015