Fatores ambientais na distribuição de populações de Brachiaria subquadripara presentes no Reservatório de Barra Bonita-SP
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Data
2011-03-01
Autores
Domingos, V.D.
Martins, D. [UNESP]
Costa, N.V.
Marchi, S.R.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira da Ciência das Plantas Daninhas
Resumo
Este estudo teve como objetivos monitorar a distribuição de populações de Brachiaria subquadripara e caracterizar seu ambiente de ocorrência em duas épocas (seca e águas). As coletas foram realizadas em julho de 2004 e janeiro de 2005 em pontos previamente selecionados e georreferenciados, os quais se constituíram de 13 pontos no reservatório Barra Bonita (sete pontos no braço do rio Piracicaba e seis no braço do rio Tietê). Foram realizadas coletas de solo nas margens dos rios, sedimento, água e plantas. A distribuição em relação à área de infestação das populações de B. subquadripara observada na estação chuvosa foi influenciada pela variação sazonal, a qual ocorreu de forma heterogênea em relação à densidade populacional. O rio Tietê foi considerado um ambiente mais eutrófico do que o rio Piracicaba tanto em relação ao solo quanto em relação à coluna d'água. As amostras de água coletadas no rio Tietê apresentaram valores médios de pH na estação seca de 7,02 a 7,82, e na estação das águas registrou-se maior amplitude de variação (6,80 a 8,0). A maioria dos pontos amostrados apresentou altos teores de matéria orgânica no sedimento, sendo observados teores menores que 1,3% em dois pontos de coleta na época da seca e em cinco pontos na época das águas.
The objectives of this work were to study the distribution of Brachiaria subquadripara populations and to characterize their environment of occurrence in two seasons (dry and rainy). Surveys were carried out in July, 2004 and January, 2005, in 13 previously selected and geo-referred sites in the Barra Bonita reservoir (seven in the Piracicaba River effluent and six in the Tietê River effluent). Soil, sediment, water and plant samples were collected on the river banks at these sites for analysis. Distribution in relation to infestation area of B. subquadripara populations was influenced by the seasonal variation distribution of the populations, which occurred heterogeneously in relation to population density. Tietê River was considered a more eutrophic environment than the Piracicaba river, regarding both soil and water column. The water samples collected in Tietê River showed mean pH values in the dry season from 7.02 to 7.82, and a wider variation (6.80 to 8.0) in the rainy season. Most of the sites sampled showed high concentrations of organic matter in the sediment, with concentrations lower than 1.3% being observed in two sites in the dry season (winter) and in five sites in the rainy season (summer).
The objectives of this work were to study the distribution of Brachiaria subquadripara populations and to characterize their environment of occurrence in two seasons (dry and rainy). Surveys were carried out in July, 2004 and January, 2005, in 13 previously selected and geo-referred sites in the Barra Bonita reservoir (seven in the Piracicaba River effluent and six in the Tietê River effluent). Soil, sediment, water and plant samples were collected on the river banks at these sites for analysis. Distribution in relation to infestation area of B. subquadripara populations was influenced by the seasonal variation distribution of the populations, which occurred heterogeneously in relation to population density. Tietê River was considered a more eutrophic environment than the Piracicaba river, regarding both soil and water column. The water samples collected in Tietê River showed mean pH values in the dry season from 7.02 to 7.82, and a wider variation (6.80 to 8.0) in the rainy season. Most of the sites sampled showed high concentrations of organic matter in the sediment, with concentrations lower than 1.3% being observed in two sites in the dry season (winter) and in five sites in the rainy season (summer).
Descrição
Palavras-chave
braquiária, habitat, levantamento, planta aquática, planta daninha, Brachiaria, habitat, survey, aquatic plant, weed
Como citar
Planta Daninha. Sociedade Brasileira da Ciência das Plantas Daninhas , v. 29, n. 1, p. 37-49, 2011.