Degradation and metabolism of imazapyr in soils under aerobic and anaerobic conditions

Wang, Xuedong; Wang, Huili; De-fang, Fan

doi:10.1080/03067310500410730

Cited by 23 publications

(27 citation statements)

References 17 publications

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“…A degradação de imazapyr foi 2,3 a 4,4 vezes mais lenta em solos estéreis, quando comparada com a de solo em condições naturais (Wang et al, 2005); já para imazethapyr e imazaquin, foi determinado que 100% dos herbicidas foram degradados em solos não estéreis e 15% em solo estéril após cinco meses (Flint & Witt, 1997). A degradação microbiana pode acontecer exclusivamente em condições de aerobiose, como é o caso de imazethapyr (Shaner & O'Connor, 1991), ou em condições de aerobiose e anaerobiose, como no caso de imazapyr (Wang et al, 2006). Quando as condições ambientais favorecem o desenvolvimento dos microrganismos e a biodisponibilidade dos herbicidas, a degradação das imidazolinonas aumenta.…”

Section: Degradação Microbianaunclassified

Destino ambiental dos herbicidas do grupo das imidazolinonas: revisão

Kraemer¹,

Marchesan

Avila

et al. 2009

Planta daninha

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RESUMO -Os herbicidas do grupo das imidazolinonas controlam um amplo espectro de plantas daninhas, sendo absorvidos pelas raízes e folhas e translocados pelo floema e xilema, acumulando-se nos pontos de crescimento. Esse grupo de herbicidas atua inibindo a enzima acetolactato sintetase (ALS), essencial no processo de síntese de aminoácidos de cadeia ramificada em plantas. Quando aplicados nas lavouras, uma proporção significativa deles atinge o solo, onde são passíveis de serem absorvidos pelas raízes das plantas, sorvidos aos coloides do solo ou dissolvidos na sua solução, podendo sofrer fotólise, hidrólise, degradação microbiana ou lixiviação. A sorção das imidazolinonas é rápida e regula os outros processos. Altos conteúdos de argila e matéria orgânica e pH menor que 6,0 em solos aumentam a sorção e a persistência das imidazolinonas no solo. Condições que favoreçam o desenvolvimento de microrganismos aumentam a degradação das imidazolinonas, por ser essa a principal via de sua degradação.Palavras-chave: degradação, fotólise, hidrólise, mecanismo de ação, persistência, sorção.ABSTRACT -The herbicides of the imidazolinone group control a wide range of weed species. They are absorbed by weed roots and leaves and transported through the phloem and xylem, accumulating in the plant growing points. They inhibit the enzyme acetolactate synthase (ALS), which synthesizes the branched chain amino acids. When used in the field, a large portion of these herbicides reach the soil, where they can be absorbed by the roots of plants, sorbed into the soil colloids, or dissolved in soil solution, going through photolysis, hydrolysis, microbial degradation or leaching. The sorption of imidazolinone is faster and affects other processes. High contents of clay, organic matter and pH lower than 6.0 contribute to enhance the sorption and persistence of imidazolinones in soil. The most important way of dissipation is by microbial degradation, thus conditions favoring microbial development will also enhance imidazolinone degradation.

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Section: Degradação Microbianaunclassified

Destino ambiental dos herbicidas do grupo das imidazolinonas: revisão

Kraemer¹,

Marchesan

Avila

et al. 2009

Planta daninha

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“…The lower dry matter of sorghum at 135 and 150 DAA, when applied to the commercial mixture of imazethapyr and imazapic (Figure 1), is due to the low degradation of the photolytic decomposition (Wang et al, 2006;Espy et al, 2011).…”

Section: Haplic Plinthosol (Fx)mentioning

confidence: 99%

Persistence of Imidazolinones in Soils Under a Clearfield System of Rice Cultivation

et al. 2016

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-The commercial mixture of imazethapyr and imazapic herbicides has been used for the control of red rice and several other species of weeds found in rice crops; this system called Clearfield. However, its use may limit the succession of non-tolerant crops for long residual activity. The research objective with this work was to determine the persistence of imazethapyr, imazapic and their mixture in three soils in the Brazilian state of Tocantins. Three experiments were conducted in a completely randomized design with four replications, each corresponding to the evaluated soil (Haplic Plinthosol (FX), red-yellow Latosol (LVA) and Haplic Gleysol (GX)). The treatments were arranged in a split plot design, with the allocated plots herbicides (imazethapyr and imazapic alone and commercial mixture) and the plots allocated the 11 evaluation times (1, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150 days after treatment (DAT)), and a control without application. Contacted up long residual effect of imazethapyr and commercial mixture of imazethapyr and imazapic, regardless of assessed soil. After 150 days of applying herbicides or the commercial mixture, their residues in the soil also inhibited approximately 94% of the mass of the dry matter accumulation of the indicator plants. When imazapic was applied alone, there was a higher dry matter accumulation of the indicator plants, indicating less residual effect of this herbicide in the soil and this was attributed to the lower dose of this herbicide applied. The attributes of the soil pH, texture and iron oxides were what most affected the persistence of the herbicides. It can be concluded that the persistence of imazethapyr and imazapic is too long in the Brazilian state of Tocantins soils and the use of these herbicides in the region should be avoided due to the high risk of the occurrence of carryover,or be well planned, as land use in rotation for susceptible crops. (1, 15, 30, 45, 60, 75, 90, 105, 120, 135 Keywords

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“…Microbial degradation may occur under aerobic conditions only, such as imazapic (Mangels, 1991), or aerobic and anaerobic conditions, as in the case of imazapyr (Wang et al, 2006).…”

Section: Podem Persistir No Ambiente E Causar Danos àS Culturas Não Tmentioning

confidence: 99%

Carryover of Imazethapyr + Imazapic on Ryegrass and Non-tolerant Rice as Affected by Thickness of Soil Profile

et al. 2015

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-Herbicides used in Clearfield ® rice system may persist in the environment, damaging non-tolerant crops sown in succession and/or rotation. These damages vary according to soil characteristics, climate and soil management. The thickness of the soil profile may affect carryover effect; deeper soils may allow these molecules to leach, reaching areas below the roots absorption zone. The aim of this study was to evaluate the effect of the thickness of soil profile in the carryover of imazethapyr + imazapic on ryegrass and nontolerant rice, sown in succession and rotation to rice, respectively. Lysimeters of different thicknesses (15, 20, 30, 40, 50 and 65 cm) were constructed, where 1 L ha -1 of the imazethapyr + imazapic formulated mixture was applied in tolerant rice. Firstly, imidazolinone-tolerant rice was planted, followed by ryegrass and non-tolerant rice in succession and rotation, respectively. Herbicide injury, height reduction and dry weight of non-tolerant species were assessed. There was no visual symptoms of herbicide injury on ryegrass sown 128 days after the herbicide application; however it causes dry weight mass reduction of plants. The herbicides persist in the soil and cause injury in non-tolerant rice, sown 280 days after application, and the deeper the soil profile, the lower the herbicides injury on irrigated rice.Keywords: degradation, imidazolinone, Lolium multiflorum, leaching, Oryza sativa. (15, 20, 30, 40, 50 RESUMO -Os herbicidas usados na cultura do arroz

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Degradation and metabolism of imazapyr in soils under aerobic and anaerobic conditions

Cited by 23 publications

References 17 publications

Destino ambiental dos herbicidas do grupo das imidazolinonas: revisão

Destino ambiental dos herbicidas do grupo das imidazolinonas: revisão

Persistence of Imidazolinones in Soils Under a Clearfield System of Rice Cultivation

Carryover of Imazethapyr + Imazapic on Ryegrass and Non-tolerant Rice as Affected by Thickness of Soil Profile

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