Eficiência de roçadas no controle de Bidens pilosa e Commelina benghalensis em competição com a cultura do milho

• Ano de defesa: 2011
• Autor(a) principal: Lemos, João Paulo
• Orientador(a): Galvão, João Carlos Cardoso
• Banca de defesa: Corrêa, Maria Lita Padinha
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Características fisiológicas; Morfologia; Plantas daninhas; Sistema plantio direto orgânico
• Palavras-chave em Inglês: Physiological and growth characteristics; Morphology; Weeds; Organic direct planting system
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4542

Among the factors that difficult the expansion of the area cultivated with organic corn is the control of weeds. On this crop system only the cultural and mechanical control methods are allowed, which most of the times are little efficient and not adequate to the direct planting system. On this work the efficiency of weed clearing was evaluated (Bidens pilosa and Commelina benghalensis) about the physiological and growth characteristics of corn plants. Three experiments were conducted: the first one evaluated the influence of weed clearing over the growth of corn plants; the second one evaluated the effects of clearings on the development of B. pilosa and C. benghalensis species; and the third evaluated the effect of clearings over the physiological characteristics of corn crops. When in competition without using clearings, C. benghalensis did not interfere on the radicular dry mass rate and on the relationship aerial part/radicular system of corn plants. On the opposite, B. pilosa species, when in competition with corn crops, affected all evaluated characteristics, except the crop stalk diameter. Two clearings of weeds provided the biggest benefits to the culture. It was not observed the influence of corn plants over the development of B. pilosa plants, for the evaluated characteristics. However, corn plants affected the accumulation of root dry matter mass and seeds from C. benghalensis plants. Two clearings reduced the interference of B. pilosa and C. benghalensis weeds over the morphological characteristics of corn (total dry matter mass, aerial part/radicular system rate, radicular mass rate and foliar mass rate). Still, these clearings did not influence the physiological aspects (photosyntetical rate, stomatal conductance, internal carbon/external carbon rate, carbon consumed, transpiration and efficiency of water use) evaluated on corn plants in competition with weeds. The C. benghalensis species reduced the photosyntethic rate and the transpiration of corn plants when in competition with this culture.