Levantamento fitossociológico em pastagens de várzea no Estado do Amazonas

Abstract

O levantamento fitossociológico em pastagens é uma importante ferramenta de suporte às recomendações de manejo. Objetivou-se com este trabalho realizar um levantamento fitossociológico em pastagens de várzea do município de Autazes-AM. O estudo foi realizado em duas áreas de várzea sazonalmente inundadas, localizadas nesse município. No estudo, utilizou-se o método do quadrado, aplicado por meio de um quadrado de 1,0 m², lançado ao acaso 31 vezes em cada área de três hectares. Nas duas áreas foram encontrados 27.706 indivíduos, distribuídos em 12 famílias e 22 espécies. As famílias mais importantes em número de espécies nas duas áreas foram Poaceae (7) e Cyperaceae (4). Brachiaria subquadripara mostrou, nas duas áreas, maiores valores de frequência, densidade, abundância e IVI. As espécies que apresentaram maiores valores de IVI na área 1 foram: B. subquadripara (118,45), Paspalum fasciculatum (51,25), Cynodon dactylon (46,99) e Lindernia crustacea (25,25), e na área 2 foram: B. subquadripara (111,66), C. dactylon (55,44), Acroceras zizanioides (33,70) e L. crustacea (24,91). Em ambas as áreas, a família Poaceae representou mais de 90% do total de indivíduos encontrados, e algumas espécies apresentaram bom potencial forrageiro.

Floristic and phytosociology of weeds in pastures in Maranhão State, Northeast Brazil

“…The number of species found in this study was higher than those observed by Mascarenhas et al (2009) in degraded pastures in savannah in Minas Gerais State and by Schuster et al (2013) in Paraná State, but lower than those observed by Mitja and Miranda (2010) in Brazilian Amazonian rainforest, by Tuffi Santos et al (2004) in degraded pastures in flooded lowland conditions in Minas Gerais State, by Blackwell et al (2011) in pastures in South Island, New Zealand, by Galvão et al (2011) in lowland conditions in Amazonas State, by Inoue et al (2012) in savannah areas of Mato Grosso State, by Caporal and Boldrini (2007) in Rio Grande do Sul State, probably due to differences in edaphic and climatic factors, management, forage species, fire and grazing history.…”

“…On the other hand, most of the species of the Fabaceae and Amaranthaceae families produce seeds with high longevity in the soil due to hard integument The dominance of these families was also observed in weed survey in pastures in Pará State (MITJA; MIRANDA, 2010), Amazonas State (GALVÃO et al, 2011), in savannah areas of central Brazil (MUNHOZ;FELFILI, 2008) and southern Brazil (CAPORAL; BOLDRINI, 2007;FERREIRA;SETUBAL, 2009, MAGALHAES;LOPES;MANTOVANI, 2013;QUADROS et al, 2003). For Holm et al (1977), these families have the more aggressive and competitive weeds of agroecosystems in the world.…”

Phytosociology of Weeds in Off-Season Maize Crops in the Middle Paranapanema

“…In the last 10 years in Brazil, the main studies related to weed surveys have involved studies in pastures (Galvão et al, 2011;Froufe and Seoane, 2011;Inoue et al, 2012) and in forest areas (Moretti et al, 2013). For maize crops in the country during the same period, the main surveys were only in Roraima (Albuquerque et al, 2013), in Maranhão (Mesquita et al, 2016) and in the region of the Middle Paranapanema (Hirata et al, 2017).…”

Phytosociological and floristic survey of weeds in Western Paran

“…Due to the great importance of identifying weed species, several floristic composition works have been carried out in diverse cultures, such as Albertino et al (2004) with guarana culture in the Amazon; Marques et al (2010) with the cultivation of cowpea; Galvão et al (2011) in pasture. The same is observed with phytosociological surveys in irrigated rice (Erasmo et al, 2004); in sugarcane production (Oliveira and Freitas, 2008); in green sugarcane (Kuva et al, 2007); in sunflower crops (Adegas et al, 2010) and in soybean (Pereira et al, 2000).…”