Development of a Laboratory Bioassay and Effect of Soil Properties on Sulfentrazone Phytotoxicity in Soil

Abstract

Sulfentrazone is a phenyl triazolinone herbicide used for control of certain broadleaf and grass weed species. Sulfentrazone persists in soil and has residual activity beyond the season of application. A laboratory bioassay was developed for the detection of sulfentrazone in soil using root and shoot response of several crops. Shoot length inhibition of sugar beet was found to be the most sensitive and reproducible parameter for measurement of soil-incorporated sulfentrazone. The sugar beet bioassay was then used to examine the effect of soil properties on sulfentrazone phytotoxicity using 10 different Canadian prairie soils. Concentrations corresponding to 50% inhibition (I50values) were obtained from the dose–response curves constructed for the soils. Sulfentrazone phytotoxicity was strongly correlated to the percentage organic carbon (P = 0.01) and also to percentage clay content (P = 0.05), whereas correlation with soil pH was nonsignificant (P = 0.21). Because sulfentrazone phytotoxicity was found to be soil dependent, the efficacy of sulfentrazone for weed control and sulfentrazone potential carryover injury will vary with soil type in the Canadian prairies.

Atividade residual de herbicidas pré-emergentes aplicados na cultura da soja sobre o milheto cultivado em sucessão

“…Mesmo Tabela 1 -Porcentagem de redução do estande de plantas de milheto aos 30 dias após a emergência, cultivadas em solo após a aplicação de herbicidas na cultura da soja, em diferentes épocas de semeadura quando cultivado aos 120 DAA, o milheto sofreu redução de 39% no acúmulo de matéria seca da parte aérea das plantas, evidenciando a grande sensibilidade da espécie a esse herbicida. Szmigielski et al (2009) observaram efeitos negativos desse herbicida em plantas de beterraba por um período de 302 dias, evidenciando a necessidade de maior intervalo de segurança entre a aplicação de sulfentrazone e a semeadura de milheto. Com a aplicação de flumioxazin, observaram-se efeitos significativos em cultivos inferiores a 80 DAA, porém de baixa magnitude.…”

Use of Sugar Beet as a Bioindicator Plant for Detection of Flucarbazone and Sulfentrazone Herbicides in Soil

“…Typically, ALS-herbicides are detected using root inhibition bioassays, and various susceptible plant species including oriental mustard (Eliason et al 2004;Szmigielski et al 2008), corn (Mersi & Foy 1985Hsiao & Smith 1983), red beet (Jourdan et al 1998), and sunflower (Helianthus annuus L.) (Hernández-Sevillano et al 2001;Günther et al 1993) have been used. Protoxinhibiting herbicides influence mainly shoot development of sensitive plants, and cotton (Main et al 2004;Grey et al 2007) and sugar beet (Szmigielski et al 2009;Blanco & Velini 2005) have been reported as a suitable species for sulfentrazone detection in soil.…”

“…A quantity of 100 g of soil is wetted to 100% field capacity, and then hand mixed in a plastic dish and www.intechopen.com Six sugar beet seeds are planted and the soil surface is covered with a layer of plastic beads to reduce water evaporation. Plants are then grown in a fluorescent canopy with light intensity of approximately 16 µmol m -2 s -1 (Szmigielski et al 2009) and watered to 100% field capacity daily by adding water to the predetermined weight. After a 6-day growth period, length of shoots is measured with a ruler from the soil level to the node where the cotyledons split from the stem.…”

“…Instrumental methods such as gas chromatography or high performance liquid chromatography require solvent or solid phase extractions before sample analysis, and these highly efficient extractions enable the determination of total amount of herbicide in soil. In contrast, bioavailable herbicide is determined by bioassay procedures because plant response varies with soil type and generally decreases in soils of high organic matter and clay contents and low soil pH (Thirunarayanan et al 1985;Renner et al 1988;Che et al 1992;Wang & Liu 1999;Wehtje et al 1987;Grey et al 1997;Szmigielski et al 2009). Typically bioassay detection of herbicides that belong to different groups with different modes of action requires use of different plant species and/or measuring different plant parameters.…”

Sorption of oxadiazon in soils cultivated in the brazilian cerrado

“…Alternatively, test plants (bio-indicator) are used, which exhibit high sensitivity to the herbicide of interest (Eliason et al, 2004;Szmigielski et al, 2009). This technique is more affordable than the chromatographic quantitative methods.…”