RESUMO -Objetivou-se com este trabalho avaliar a eficácia do herbicida penoxsulam em função do início da irrigação permanente e da época de sua aplicação e dose no controle de capim-arroz (Echinochloa crusgalli e E. colona), bem como sua seletividade à cultura do arroz irrigado, cultivar Qualimax-1. O experimento foi conduzido a campo em delineamento experimental de blocos ao acaso com quatro repetições, no esquema fatorial 2 x 3 x 4, representando épocas de início da irrigação por inundação (21 e 30 dias após a emergência -DAE), épocas de aplicação (pré-emergência e pós-emergência inicial e tardia) e doses do herbicida penoxsulam (0, 18, 36 e 72 g ha -1 ), respectivamente. As variáveis avaliadas foram o controle de capim-arroz, a fitotoxicidade do herbicida à cultura e a produtividade de grãos do arroz. A antecipação do início da irrigação permanente na lavoura aumentou a eficiência do penoxsulam para controle de capim-arroz, porém o atraso na entrada de água foi parcialmente compensado pelo aumento na dose do herbicida. Ao atrasar o início da irrigação na lavoura, ocorreu diminuição na produtividade de grãos, independentemente da época de aplicação e da dose de penoxsulam.Palavras-chave: Oryza sativa, dose, entrada de água, estádio de aplicação, penoxsulam.ABSTRACT -The objective of this work was to evaluate the efficiency of the herbicide penoxsulam as a function of the start of permanent irrigation and time and rate of application, in controlling Echinochloa crusgalli and E. colona, as well as its selectivity to the rice culture, cv. Qualimax 1. The trial was conducted under field conditions in a completely randomized block design, in a factorial scheme 2x3x4 with four replications. The factorial scheme were the irrigation starting times (21 and 30 days after emergence -DAE), application times (pre-emergence and early and late post-emergence) and penoxsulam rates (0, 18, 36 and 72 g h 1 ). The evaluated variables were Echinochloa control, rice plant phytotocixity, and rice grain yield. Early irrigation increased the efficiency of penoxsulam in Echinochloa control; however, the effect of late irrigation was partially offset by the increase in the penoxsulam rates. When irrigation started late, reduced grain yield was observed independently time and rate of herbicide application.
Palavras-chave: arroz-vermelho, arroz Clearfield ® , imidazolinonas, persistência no solo.ABSTRACT -The aim of this study was to evaluate the residual activity of the prepackage mix of the herbicide Only (imazethapyr+imazapic) in a Clearfield (CL) rice production system during one, two or three rice seasons. The study was carried out in the field at Centro Agropecuário da Palma/ Universidade Federal de Pelotas, Rio Grande do Sul, southern Brazil. Ryegrass (Lolium multiflorum) was planted after CL rice, cv. IRGA 422 CL. CL rice was considered as the main crop (summer) and ryegrass was planted following CL rice. The experimental design was a randomized complete block, with four replications. The treatments were arranged as a factorial: factor A, during the same season, compared herbicide residues during one, two or three years of CL rice and factor B, for herbicide rates. Herbicide (imazethapyr+imazapic) was applied at (0; 25+75; 37,5+112,5; 50+150) g ha -1 with surfactant Dash being added at 0.5% v/v. The results showed interaction
RESUMO -Os períodos de convivência das espécies daninhas têm grande influência no crescimento das plantas e na produtividade das culturas. Desse modo, objetivou-se com este trabalho determinar os períodos de competição, anterior à interferência (PAI), o crítico de prevenção à interferência (PCPI) e o período total de prevenção da interferência (PTPI) de B. plantaginea sobre a cultura do milho na Região Sul do Rio Grande do Sul. Adotou-se o delineamento experimental de blocos casualizados, no sistema de cultivo convencional com quatro repetições. Os tratamentos consistiram em manter a cultura do milho na presença e ausência de B. plantaginea por 0, 7, 14, 21, 28, 35 e 42 dias após a emergência (DAE) da cultura. B. plantaginea originou-se do banco de sementes do solo, com população média de 312 plantas m -2. Foram amostradas e analisadas 10 plantas de milho em cada unidade experimental, com vistas à avaliação da altura de plantas e da inserção da espiga (cm), do comprimento de espigas (cm), do número de fileiras por espiga, número de grãos por fileira e número de grãos por espiga, além da produtividade de grãos, que foi determinada pela colheita de três linhas centrais da área útil em cada unidade experimental. Considerando 5% de tolerância na redução da produção, conclui-se que o período total de prevenção à interferência (PTPI) foi de 27 DAE; o período que antecede a interferência (PAI), de 11 DAE; e o período crítico de prevenção à interferência (PCPI), de 11 a 27 DAE.Palavras-chave: competição, componentes do rendimento, Zea mays.ABSTRACT -Weed control period have great influence on plant growth and crop productivity. The objective of this work was to determine the competition periods, both previous to interference and critical interference prevention of B. plantaginea on corn crop in Southern Rio Grande do Sul. The trial was conducted in a completely randomized block design, under conventional tillage system, with four replications. The treatments consisted of maintaining the culture of corn in the presence and absence of B. plantaginea for 0, 7, 14, 21, 28, 35 and 42 days after crop emergence (DAE). B. plantaginea emerged from the soil seed bank, with an average population of 312 plants m -2 . Ten corn plants were sampled and analyzed in each experimental assay to obtain the following variables: plant and ear insertion height (cm), ear length (cm), number of rows per ear, number of grains per row, number of grains per ear. Grain productivity was determined by collecting three central lines of the useful area in each experimental unit. Considering a 5% tolerance in production reduction, it was concluded that the total period of interference prevention was 27 DAE, the period preceding interference was 11 DAE and the critical period of interference prevention was 11 and 27 DAE.
We aimed with this study to evaluate the effects of residual activity in soil of formulated mixtures of the herbicides imazethapyr + imazapic and imazapyr + imazapic on ryegrass and on rice cultivars, IRGA 424 and BRS Querencia. Two experiments were conducted under greenhouse in randomized blocks design with four replications in split-plot and split-split-plot designs, respectively for the first (E1) and second (E2) experiments. For E1, main plots allocated herbicides (imazethapyr + imazapic and imazapyr + imazapic), and subplots the doses [(0, 0.5, 1.0, 1.5 and 2.0 fold the label dose of imazethapyr + imazapic (1 L•ha −1) and imazapyr + imazapic (140 g•ha −1) plus 0.5% of the adjuvant Dash ®)]; for E2, sub-subplots allocated rice cultivars (BRS 424 and IRGA Querência). Phytotoxicity, plant height and shoot dry weight (E1 and E2) and plant stand (E2) were evaluated. Results showed that the annual ryegrass and rice cultivars IRGA 424 and BRS Querencia are sensitive to imazethapyr + imazapic and imazapyr + imazapic, serving as bioindicators of its residual activity in soils following Clearfield ® rice. Imazapyr + imazapic, applied post-emergence in irrigated rice at doses of 1.0, 1.5 and 2.0× the label dose, present longer residual activity in soil compared to imazethapyr + imazapic for ryegrass and non-Clearfield ® rice.
RESUMO -Este estudo teve como objetivo avaliar a atividade residual, no solo, do herbicida (imazethapyr+imazapic) aplicado na cultura de arroz irrigado, instalado pelo sistema Clearfield ® e tendo como planta bioindicadora o milho, cv. Biomatrix 2202. Os trabalhos foram realizados em casa de vegetação da Universidade Federal de Pelotas, Capão do Leão-RS. O arroz, cv. IRGA 422 CL, foi semeado em caixas de polietileno (60 x 40 x 20 cm). Quando o arroz estava em estádio de 3 a 4 folhas, foram aplicados os tratamentos com o herbicida (imazethapyr+ imazapic) a 0; 25+75; 37,5+112,5; e 50+150 g ha no produto formulado. Após a colheita do arroz, o solo foi mantido sem irrigação por 45 dias, quando então foi semeada aveia-preta (Avena strigosa), colhida no início da primavera. Aos 360 e 540 dias após a aplicação dos tratamentos (DAA), foi transferido o solo das caixas de polietileno para dois conjuntos de vasos, onde foi semeado milho, os quais passaram respectivamente a ser identificados como experimentos safra (E1) e safrinha (E2). Nos primeiros 360 e 540 dias entre a aplicação dos herbicidas e a semeadura dos dois experimentos, o solo do E2 permaneceu sem irrigação. As plantas de milho foram colhidas, em estádios de 4 a 5 folhas. As variáveis avaliadas foram: massas secas dos sistemas radical e aéreo, altura de planta e índice de área foliar, sendo esta última avaliada somente no E2. Os dados experimentais foram submetidos à análise de variância (≤0,05); havendo significância, eles foram testados por modelos de regressão polinomial. Foram observadas reduções significativas nas massas secas de raiz e parte aérea, altura de planta e área foliar do milho, cv. Biomatrix 2202, semeado até 540 DAA do herbicida (imazethapyr+imazapic) na cultura do arroz, demonstrando que o milho pode ser utilizado como indicador da atividade desse herbicida no solo.Palavras-chave: arroz-vermelho, arroz Clearfield ® , imidazolinonas, persistência no solo.ABSTRACT -The objective of this study was to evaluate the residual soil activity of herbicide (imazethapyr+imazapic), labeled for the Clearfield (CL) system and using corn, cv. Biomatrix 2202, as a bioindicator. The study was carried out in a greenhouse, at the Universidade Federal de Pelotas, in southern Brazil. Rice, cv. IRGA 422 CL, was planted in boxes (60 x 40 x 20 cm). At the 3-4 leaf stage, the herbicide Only (imazethapyr+imazapic) was sprayed at 0; 25+75; 37.5+112.5 and 50+150 g ha -1 . After harvesting the rice, boxes were kept without flooding for 45 days. Black oat (Avena strigosa) was planted to keep the soil covered during the winter. In the spring, oat was harvested and 360 or 540 days after herbicide aplication (DAA), the soil from the boxes was transferred to two sets of pots labeled as experiment 1 (main corn crop) and experiment 2 (minor corn crop), respectively. The soil for experiment 2 was kept drained during the time period between seeding the two studies (360 to 540 DAA). Corn was planted in both studies and harvested at the 4-5 leaf stages. The variables evaluated were...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.