Adsorption and Desorption of Imazapyr by Soil

Pusino, Alba; Petretto, S.; Gessa, C.

doi:10.1021/jf960214t

Cited by 51 publications

(42 citation statements)

References 14 publications

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“…Essa diferença de mobilidade pode estar relacionada a fatores que estariam agindo sobre os fenômenos adsortivos, como as características mineralógicas e teor e o tipo de matéria orgânica dos solos estudados. Pusino et al (1997) constataram que a adsorção do imazapyr é fortemente influenciada pelo pH e pela carga do componente adsorvente e que a presença de óxidos de ferro amorfo e matéria orgânica, a pH < 5, é efetiva na sua retenção.…”

Section: Resultados E Discussão Ensaio De Lixiviaçãounclassified

Lixiviação e persistência dos herbicidas sulfentrazone e imazapic

Monquero

Silva

Hirata³

et al. 2010

Planta daninha

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Em razão da escassez de informações quanto ao potencial de movimentação do sulfentrazone e imazapic em solos brasileiros, objetivou-se neste trabalho avaliar a lixiviação e a persistência desses herbicidas. A lixiviação de sulfentrazone (800 g ha-1) e imazapic (210 g ha-1) foi avaliada sob simulação de chuva de 40 e 80 mm, em diferentes profundidades (5, 10, 15, 20, 25, 30, 35 e 40 cm) e pHs de um Latossolo Vermelho Distroférrico e Latossolo Vermelho Distrófico. O ensaio de persistência consistiu da aplicação dos herbicidas sulfentrazone (600 e 800 g ha-1) e imazapic (190 e 210 g ha-1) em pré-emergência, além da testemunha sem herbicidas. Foram retiradas amostras de solo para determinação da persistência aos 0, 15, 30, 45, 60, 90, 120, 150 e 210 dias após a aplicação, sendo posteriormente levadas a um fitotron para crescimento do bioindicador Cucumis sativus. A lixiviação dos herbicidas foi mais pronunciada à medida que se aumentou a quantidade de chuva simulada. Para o sulfentrazone, na precipitação de 80 mm, foi constatada atividade residual até 40 cm de profundidade, sendo elevada no solo de textura média e menos pronunciada no de textura argilosa, independentemente do pH. Em relação ao imazapic na precipitação de 80 mm de chuva, houve atividade do herbicida até 40 cm de profundidade. No solo argiloso com pH 6,0 houve maior lixiviação em todas as profundidades, em relação ao mesmo solo com pH 4,7. Quanto à persistência, observou-se que o sulfentrazone e imazapic apresentaram atividade residual semelhante até 45 DAA, todavia, dos 60 aos 150 DAA, houve menor atividade do imazapic no solo; a partir deste período (150 aos 210 DAA), o sulfentrazone apresentou redução acentuada de sua atividade no solo.

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Section: Resultados E Discussão Ensaio De Lixiviaçãounclassified

Lixiviação e persistência dos herbicidas sulfentrazone e imazapic

Monquero

Silva

Hirata³

et al. 2010

Planta daninha

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“…Late emergence was an indication of late attachment, the crop was thus protected from Striga parasitism during the critical initial growth period (8 weeks) of the crop. The late attachments could be attributed to a decrease in herbicide activity with time due to dilution by infiltrating rainfall and herbicide breakdown (Pusino et al, 1997) and given that a very low dosage (30 g ha -1…”

Section: Resultsmentioning

confidence: 99%

Increasing imazapyr-resistant maize yield by increasing plant density under natural Striga hermonthica infestation

Illa¹,

Odhiambo²,

Dida³

2010

ABJNA

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Maize (Zea mays L.) is one of the most important crops in East Africa serving both as a staple food and cash crop to millions of people. As a vegetable, it is produced as green maize cobs, sweet corn or baby corn. Yields under farmers' conditions in the Lake Victoria Basin average 1.3 t ha -1 which is less than 25% of the potential yield. This is attributed to several factors; the greatest being Striga (Striga hermonthica) which is a parasitic weed attacking several crops in the grass family. A medium term technological breakthrough in form of a herbicide (imazapyr) resistant maize variety has been developed to help reduce Striga infestation. The optimum maize plant population for effective seedbank reduction and optimum grain yield has however not been determined. The main objective of this study was therefore to evaluate the performance of imazapyr-resistant (IR) maize at different plant densities on Striga weed incidence and crop growth. The study was conducted for two seasons on a naturally infested Striga field in Western Kenya. The experiment was laid out as a split plot with three replications. Maize variety (treated IR maize, untreated IR maize and WH505/H516 commercial checks) was the main plot factor and density (44,444, 66,666 and 88,888 plants ha -1 ) as the sub-plot factor. Data was collected on maize stand, days to first Striga emergence, Striga incidence, Striga biomass, maize biomass and its yield components. Treated IR maize delayed Striga emergence on maize thus suppressing Striga parasitism. Any late Striga attachments had little or no effect on maize growth. Increasing the plant density of treated IR maize from 44,444 to 88,888 plants ha -1 did not affect Striga incidence but increased maize yield from 1.60 to 3.48 t ha -1. It is therefore recommended that treated IR maize should be planted in Striga infested fields at 75cm x 15cm to hasten Striga seed bank reduction and maximize on maize yield to improve staple food availability.

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“…The conclusion that can be drawn from the results is that when imazapyr is applied to tree trunks for coppicing control in commercial eucalypt plantations, it is likely the occurrence of exudation of herbicide and/or its possible metabolites, which can cause a detrimental effect on the growth of eucalypt cultivated between rows of the previous crop (reform). This may be caused by the greater persistence of the molecule in the soil (LIEBL and BRIDGES, 2000); the weak linkages with constituents, therefore strongly influenced by the pH variation (PUSINO et al, 1997); as well as by the reverse leaching, in other words, by the capillary mobility of the molecule (FIRMINO, 2001). …”

Section: Resultsmentioning

confidence: 99%

“…); besides, the toxicity of root exudates is more intense in the aerial part of the eucalypt plant used as bioindicator than in the root system. However, areas with increased quantity of organic matter (MCDOWELL et al, 1997) and humic acid (LEONE et al, 2002), allied to low pH values (PUSINO et al, 1997), high temperature and precipitation (MCDOWELL et al, 1997) have greater adsorption of imazapyr in the soil, and consequently fewer detrimental effects on eucalypt seedlings cultivated between the rows of the previous crop…”

Section: Discussionmentioning

confidence: 99%

Imazapyr root exudation from eucalypt seedlings cultivated in nutritive solution

Silva¹,

Ferreira²,

Ferreira³

et al. 2005

Rev. Árvore

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-Imazapyr has been used in Brazilian eucalypt cultivation for the maintenance of clearings and coppicing control in areas undergoing stand reform. However, inquiries have been made as to the final fate of the molecule. Imazapyr root exudation in eucalypt plants was evaluated through a bioassay under greenhouse conditions, by applying different herbicide doses (0.000, 0.375, 0.750, 1.125, and 1.500 kg ha -1 a.i.) on Eucalyptus grandis seedlings derived from vegetative propagation, hydroponically cultivated in 2.500 ml vases. Fortyday-old seedlings of the same clone were used as bioindicators, transplanted to the vases two days after herbicide application. After a period of 13 days of coexistence, the sprayed plants were removed and discarded; ten days later, the visual symptoms of toxicity were evaluated and the total dry biomass (aerial part and roots) of the bioindicators were determined. The lowest herbicide dose (0.375 kg ha -1 a.i.) affected the total biomass and growth, being most evident in the aerial part, with larger I 50 for root dry biomass. The E. grandis seedlings exuded imazapyr, and/or its metabolites, in concentrations capable of affecting the growth of plants of the same species.Keywords: Eucalyptus grandis, root exudates and herbicide. (0,000; 0,375; 0,750; 1,125; R. Árvore, Viçosa-MG, v.29, n.6, p EXSUDAÇÃO RADICULAR DE IMAZAPYR POR MUDAS DE EUCALIPTO CULTIVADAS EM SOLUÇÃO NUTRITIVA RESUMO -Na eucaliptocultura brasileira, vem-se utilizando o imazapyr para manutenção de aceiros e erradicação de cepas e brotações em áreas de reforma dos povoamentos. Entretanto, têm sido levantadas indagações quanto ao destino final da molécula. A exsudação radicular de imazapyr em plantas de eucalipto foi avaliada por meio de bioensaios em casa de vegetação, aplicando-se diferentes doses do herbicida

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Adsorption and Desorption of Imazapyr by Soil

Cited by 51 publications

References 14 publications

Lixiviação e persistência dos herbicidas sulfentrazone e imazapic

Lixiviação e persistência dos herbicidas sulfentrazone e imazapic

Increasing imazapyr-resistant maize yield by increasing plant density under natural Striga hermonthica infestation

Imazapyr root exudation from eucalypt seedlings cultivated in nutritive solution

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