Doses de paraquat e volumes de calda na dessecação de Brachiaria ruziziensis antes do cultivo do milho safrinha

Costa, Nivan B. da; Sontag, Daniel Adriano; Scariot, C.A.; Pereira, G.R.; Vasconcelos, Edmar Soares de

doi:10.7824/rbh.v13i2.264

Cited by 4 publications

(3 citation statements)

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“…Para o talhão 35 (Figura 1), em todos os tratamentos, na maior extensão de áreas, os valores foram inferiores a 0,75, demonstrando que em somente uma pequena parcela das áreas foram aplicadas doses dentro ou próximas ao intervalo ideal. Costa et al (2014) avaliando diferentes doses de um herbicida de contato e volumes de calda na dessecação de folhas estreitas, observaram que doses mais baixas desse herbicida aplicado no menor volume de calda foram mais eficientes em dessecar as plantas. O uso de defensivos em doses elevadas, pode ser benéfico em volumes de aplicações mais baixos (CALABRESE, 2005).…”

Section: Resultsunclassified

Espectro de gotas e distribuição de calda herbicida associada a fertilizante foliar em áreas de reforma florestal

Medauar¹,

Silva²,

Carvalho³

et al. 2018

Sci. For.

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O objetivo do trabalho foi avaliar as variáveis relacionadas à qualidade da pulverização e a distribuição espacial de taxas ótimas de aplicação em diferentes talhões para erradicação de brotações de eucalipto. O estudo foi conduzido em talhões de plantio de eucalipto, no município de Itabela-BA, em atividades de aplicação de herbicida pré-plantio, em áreas de reforma florestal. A aplicação foi realizada em diferentes talhões, sendo os mesmos considerados como unidades amostrais de diferentes tratamentos (T01, T02 e T03). A qualidade da aplicação foi avaliada a partir do estudo do espectro de gotas. Para isso, foram espalhadas etiquetas hidrossensíveis em seis plantas por tratamento, sendo amostradas nos terços inferior, médio e superior das brotações. Após a aplicação, as etiquetas foram analisadas em um programa computacional para determinação das variáveis número de gotas, dispersão de gotas, densidade de gotas, diâmetro de gotas, cobertura do alvo e volume de calda. Os dados foram submetidos à análise de variância em delineamento experimental de parcelas subdivididas no espaço e, em caso de significância pelo teste F, as médias de cada tratamento foram comparadas pelo teste de Tukey ao nível de 95% de probabilidade. Para avaliar a taxa de aplicação, foram construídos cenários de probabilidade de ocorrência utilizando o interpolador geoestatístico da krigagem indicativa. Houve diferença no espectro de gotas gerado pelo herbicida aplicado individualmente e em associações com fertilizante foliar e outro herbicida. A taxa de aplicação apresentou elevada variabilidade, com distribuição espacial de pertinências muito distantes dos valores ótimos.Palavras-chave: krigagem indicativa; pulverização; silvicultura de precisão; tecnologia de aplicação.

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Section: Resultsunclassified

Espectro de gotas e distribuição de calda herbicida associada a fertilizante foliar em áreas de reforma florestal

Medauar¹,

Silva²,

Carvalho³

et al. 2018

Sci. For.

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“…Owing to the limited translocation, the action of diquat tends to be more efficient with a high application rate (>200 L of spray solutions ha -1 ) and adjuvants, which allow the spreading of the spray drops, resulting in an increase in leaf cover and, consequently, herbicide absorption (Costa et al 2014;Gitsopoulos et al 2014). Translocation is also self-inhibited in applications under full sunlight, and the efficiency of the herbicide is restricted to plants in the initial growth stage or in sequential applications, after the application of systemic herbicides (Tahmasebi et al 2018).…”

Section: Growth Inhibition Of Sourgrass As a Function Of Period Of Da...mentioning

confidence: 99%

Growth inhibition of sourgrass as a function of period of darkness after diquat application

2022

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Photosystem-inhibiting herbicides, such as diquat, act by inducing oxidative stress. However, oxidative damage impairs translocation, resulting in regrowth of the plants. The aim was to evaluate the effectiveness of diquat in controlling the growth of sourgrass exposed to different periods of darkness after application of the herbicide, as well as to evaluate the photosynthetic activity and the production of reactive oxygen species. Two experiments (field and greenhouse) were conducted by applying diquat (200 g a.i. ha-1) on sourgrass plants at the 3 to 4 tiller stage. The treated plants were subjected to different periods of darkness after diquat application (0, 1, 2, 3, 4, 5, and 6 h), in addition to the control treatment without any application. Growth inhibition and mass evaluations of the sourgrass plants were performed in both experiments, whereas photosynthetic activity and H2O2 accumulation in the leaves were evaluated in the greenhouse experiment. The results showed an increase in the sourgrass growth inhibition with an increase in the period of darkness after application. There was a need for a minimum of 6 h of darkness after diquat application to fully inhibit growth (100%) of the sourgrass, whereas plants that remained in the sun since application exhibited less than 50% inhibition. The increase in the period of darkness after diquat application resulted in a reduction in photosynthetic activity and, consequently, lower accumulation of H2O2. Thus, the maintenance of sourgrass in the dark for at least 6 h enables total control of the growth of the plants, preventing regrowth.

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“…In this system, the species of the genus Urochloa are the most used for straw formation (TIMOSSI et al, 2006) and the cultivar Marandu has become the most relevant of this genus in Brazil (RIBEIRO JÚNIOR et al, 2017). Generally, no-tillage burndown is done with systemic herbicides, such as glyphosate (COSTA et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Influence of Time of Glyphosate Application in the Control of Brachiaria

Moraes¹,

Souza²,

Faria³

et al. 2020

Reveng

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The no-tillage system is considered an important tool for sustainable production. In this system, the burndown of brachiaria is usually performed with the application of systemic herbicides, such as glyphosate. As a result of environmental conditions (temperature, relative humidity and winds), the timing of spraying can directly interfere in the control efficiency. Therefore, the objective was to study different times of application of glyphosate in the control efficiency of Urochloa brizantha cv. Marandu. The glyphosate was applied in the morning, afternoon and evening, at doses of 0; 360; 720; 1080; 1440 and 2160 g a.e. ha-1. To analyse the efficiency of U. brizantha burndown, the phytotoxicity was evaluated at 21 days after application. At 42 after application a mowing was done and 90 days after mowing, the dry matter accumulation and the Leaf Area Index of regrowth were determined. The best control results of Urochloa brizantha cv. Marandu were obtained in the applications of glyphosate during the morning and afternoon. Evening applications of glyphosate should be avoided.

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Doses de paraquat e volumes de calda na dessecação de Brachiaria ruziziensis antes do cultivo do milho safrinha

Cited by 4 publications

References 10 publications

Espectro de gotas e distribuição de calda herbicida associada a fertilizante foliar em áreas de reforma florestal

Espectro de gotas e distribuição de calda herbicida associada a fertilizante foliar em áreas de reforma florestal

Growth inhibition of sourgrass as a function of period of darkness after diquat application

Influence of Time of Glyphosate Application in the Control of Brachiaria

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