ABSTRACT
Given the difficulty in controlling dayflower, the aim was to identify what herbicide provides the better control of Commelina benghalensis and the better developmental stage for its application. The plants were grown in pots containing 2 L Bioplant substrate and soil being maintained throughout the trial at a greenhouse. Experimental design was completely randomized with four replications in factorial 8 x 5, so seven herbicides in recommended commercial rates (atrazine, carfentrazone, flumioxazin, glyphosate, MSMA, nicosulfuron and paraquat) and control applied at 5 phenological stages adjusted to BBCH scale. It was observed that the plant phenological stage affects the efficiency of chemical control. Plants at early development stages (BBCH 11 and 12) were more susceptible to herbicides, occurring control in its entirety only with atrazine, carfentrazone, MSMA and paraquat. Despite suffering injuries, C. benghalensis showed tolerance to others treatments.
Em face a dificuldade no controle da trapoeraba, o objetivo deste trabalho foi identificar qual herbicida proporciona o melhor controle de Commelina benghalensis e qual o melhor estádio fenológico para sua aplicação. As plantas foram cultivadas em vasos de 2 L contendo substrato Bioplant e solo, sendo mantidas durante todo o experimento em casa de vegetação. O delineamento experimental utilizado foi inteiramente casualizado com 4 repetições, em esquema fatorial 8 x 5, composto por sete herbicidas em (atrazina, carfentrazone, flumioxazin, glyphosate, MSMA, nicosulfuron, paraquat) e uma testemunha, aplicados em 5 estádios fenológicos ajustados à escala BBCH. Observou-se que o estádio fenológico das plantas tem influência na eficiência do controle químico. Plantas em estádios iniciais de desenvolvimento (BBCH 11 e 12) mostraram-se mais suscetíveis aos herbicidas, ocorrendo controle em sua totalidade somente com atrazina, carfentrazone, MSMA e paraquat. Apesar de sofrer fortes injúrias a C. benghalensis apresentou tolerância aos demais tratamentos não ocorrendo a morte das plantas.
Subject(s)
Commelina , Plant Weeds , HerbicidesABSTRACT
RESUMO Estudo realizado no período de fevereiro de 2010 a janeiro de 2011, no Baixo São José dos Dourados (BSJD), inserido na Unidade de Gerenciamento de Recursos Hídricos 18 (UGRHI), com o intuito de determinar o grau de trofia da água por meio do cálculo do índice de estado trófico (IET). Os pontos de coletas contemplavam as entradas diretas e difusas no trecho represado do curso d'água (pontos 1 e 2), intermediário (3) e próximo de sua confluência com o Rio Paraná (ponto 4). As amostras coletadas foram superficiais, de meio e de aproximadamente 1 m acima do leito. Em laboratório, foram determinados a clorofila-a, o fósforo total e o ortofosfato; a transparência da água foi determinada no local da coleta. Após determinados os parâmetros necessários foi possível classificar as águas como sendo oligotróficas e ultraoligotróficas.
ABSTRACT This Study conducted from February 2010 to January 2011, in the Baixo São José dos Dourados (BSJD), in the Unidade de Gerenciamento de Recursos Hídricos (UGRHI) 18, in order to determine the trophic level of the water calculating the trophic state index (TSI) The points of collection were at the direct and diffuse inputs and dammed stretch of the watercourse (points 1 and 2), intermediate (3) and confluence with the Paraná River (point 4). The samples were superficial, medium and approximately 1 m above the riverbed. At the laboratory was determined chlorophyll-a, total phosphorus and orthophosphate, water transparency was determined at the collect place. After those parameters was possible to classify the waters as oligotrophic and ultraoligotrophic.
ABSTRACT
The general objective of this work was to develop a monitoring and management model for aquatic plants that could be used in reservoir cascades in Brazil, using the reservoirs of AES-Tietê as a study case. The investigations were carried out at the reservoirs of Barra-Bonita, Bariri, Ibitinga, Promissão, and Nova-Avanhandava, located in the Tietê River Basin; Agua Vermelha, located in the Grande River Basin; Caconde, Limoeiro, and Euclides da Cunha, which are part of the Pardo River Basin; and the Mogi-Guaçu reservoir, which belongs to the Mogi-Guaçu River basin. The main products of this work were: development of techniques using satellite-generated images for monitoring and planning aquatic plant control; planning and construction of a boat to move coating plant masses and an airboat equipped with a DGPS navigation and application flow control system. Results allowed to conclude that the occurrence of all types of aquatic plants is directly associated with sedimentation process and, consequently, with nutrient and light availability. Reservoirs placed at the beginning of cascades are more subject to sedimentation and occurrence of marginal, floating and emerged plants, and are the priority when it comes to controlling these plants, since they provide a supply of weeds for the other reservoirs. Reservoirs placed downstream show smaller amounts of water-suspended solids, with greater transmission of light and occurrence of submerged plants.
