Fitossociologia de plantas daninhas na cultura do feijão

Abstract

RESUMONesta pesquisa objetivou-se caracterizar a fitossociologia de plantas daninhas na cultura do feijão (Phaseolus vulgaris L.), cultivado nos períodos de outono-inverno (2010), primavera-verão (2010/2011) e verão-outono (2011) em Urutaí, GO. Foram efetuadas 144 amostragens na colheita dos feijoeiros por meio do lançamento, ao acaso, de um quadrado metálico de 0,25 m 2 . As espécies foram identificadas, contadas e pesadas e, em seguida, se calcularam as frequências, densidades e dominâncias, absolutas e relativas, o índice de valor de importância e a importância relativa (IR) das espécies. Foram identificadas 24 espécies distribuídas em 22 gêneros e em 8 famílias. A família mais representativa foi a Poaceae, seguida por Asteraceae, Euphorbiaceae, Solanaceae, Amaranthaceae, Commelineaceae, Convolvulaceae, Fabaceae e Cyperaceae. A Zea mays apresentou o maior IR, seguida por Cyperus rotundus na safra de outono-inverno, enquanto no período primavera-verão a espécie Ageratum conyzoides foi a mais importante. Digitaria horizontalis e Bidens pilosa foram, respectivamente, as espécies mais importantes nos feijoeiros cultivados na época de verão-outono. Palavras-chave: comunidade infestante, ecofisiologia, Phaseolus vulgaris Phytosociology of weeds in bean crop ABSTRACTThis research aimed to characterize the phytosociology of weeds in the bean crop (Phaseolus vulgaris L.) cultivated in the autumn-winter periods (2010), spring-summer (2010/2011) and summer-autumn (2011) in Urutaí GO. A metallic square of 0.25 m 2 was randomly launched in 144 sampling spots of the bean crop, at the harvest. Species were identified, counted and weighed, and then frequencies, densities and dominances, both in absolute and relative terms, were calculated. The index of importance value and the relative importance (RI) of the species were also determined. Twenty-four species were identified in 22 genera and 8 families. The family Poaceae was the most representative, followed by Asteraceae, Euphorbiaceae, Solanaceae, Amaranthaceae, Commelineaceae, Convolvulaceae, Fabaceae and Cyperaceae. Zea mays presented the highest RI, followed by Cyperus rotundus in autumn-winter season, while during spring-summer specie Ageratum conyzoides was the most important. Digitaria horizontalis and Bidens pilosa were, respectively, the most important species in bean cultivation in summer-autumn season.

Growth and physiological characteristics of the weed false johnsongrass ( Sorghum arundinaceum (Desv.) Stapf)

“…The height of plants is an important feature and can influence the competition relations between plants, depending on the neighboring species, their growth behaviors and coexistence period (Zanine & Santos, 2004). The coexistence of S. arundinaceum with smaller crops, such as soybeans (Rezende at al., 2012), beans (Tavares at al., 2013) and corn (Silva at al., 2004), helps to reduce penetration of light in the canopy of these crops, resulting in greater production losses.…”

Phytosociological Survey of Weeds in Cultivars of Common Beans With Different Types of Growth in the North of Minas Gerais

“…Tavares et al (2013), when assessing the phytosociology in bean crops in Urutaí-GO, saw that the most important species in the weed community were Zea mays and Cyperus rotundus in autumn-winter crops, Ageratum conyzoides and Eleusine indica in spring-summer crops and Digitaria horizontalis and Bidens pilosa in the summer-winter period.…”

“…Common bean (Phaseolus vulgaris) is one of the main Brazilian foods, with significant social and economic importance mainly due to its high protein value (Tavares et al, 2013). Brazil is the greatest producer of beans in the world, with an average annual production in 2014 of 2.7 million tons, and Minas Gerais is the second greatest national producer, with around 573 tons (Embrapa, 2015).…”

“…However, factors that involve competition with weeds are considered limiting to the low productivity presented by the crop (Tavares et al, 2013).…”

Weed community composition in different agro-systems

“…Similarly, changes in the composition of weed communities were also observed in different agricultural crops, such as sugarcane (Kuva et al, 2007;Soares et al, 2011), pastures (Ferreira et al, 2014), bean (Tavares et al, 2013), cover crops (Lima et al, 2014;Lamego et al, 2015), manioc (Cardoso et al, 2013;Soares et al, 2015), corn (Correa et al, 2011), corn intercropped with legumes (Oliveira et al, 2014) and corn intercropped with forage (Batista et al, 2014;Concenço et al, 2015), millet (Teodoro et al, 2015), lettuce (Ferreira et al, 2013), Jatropha curcas (Concenço et al, 2014) and coffee under organic management (Maciel et al, 2010a;Partelli et al, 2010).…”