Behavior of sulfentrazone in ionic exchange resins, electrophoresis gels, and cation-saturated soils

Abstract

Sulfentrazone persistence in soil requires many crop rotational restrictions. The sorption and mobility of sulfentrazone play an important role in its soil persistence. Thus, a series of laboratory experiments were conducted to mimic the soil properties of cation and anion exchange with different intermediates. The molecular characterization and ionization shift of sulfentrazone from a neutral molecule to an anion were determined using a three-dimensional graphing technique and titration curve, respectively. Sorption and mobility of 2.6 × 10−5 M 14C-sulfentrazone were evaluated using a soil solution technique with ion exchange resins and polyacrylamide gel electrophoresis, respectively. Solution pH ranged from 4.0 to 7.4. As pH increased, sulfentrazone sorption to an anion resin increased and its sorption to a cation resin decreased. Percent sulfentrazone in solution was pH-dependent and ranged between 0 to 18% and 54 to 88% for the anion and cation resins, respectively. Mobility of sulfentrazone on a 20% polyacryalmide gel resulted in Rf values of +0.02 and +0.39 for pH of 4.0 and 7.4, respectively. A double peak for sulfentrazone was detected in the polyacrylamide gel when the pH (6.0 and 6.8) was near the reported pKa of 6.56. There was no clear interaction for the sorption of sulfentrazone at 1.0 mg kg−1 to Congaree loamy sand or Decatur silty clay loam saturated with either calcium or potassium. Sulfentrazone behavior with the polyacrylamide electrophoresis gels and ion resins indicate the potential for this herbicide to occur as a polar or Zwitter ion. Sulfentrazone was adsorbed by potassium, calcium, and sodium saturated resins and subsequently desorbed using variable pH solutions. The level of sulfentrazone adsorption will vary among soil types and the amount of desorption into solution may be soil cation-dependent.

Persistência de sulfentrazone em Argissolo Vermelho-Amarelo cultivado com cana-de-açúcar

“…Considerando a longa persistência do sulfentrazone (Grey et al, 2000;Polubesova et al, 2003) e os problemas ocasionados pelo seu efeito carryover em rotação de culturas (Main et al, 2004), avaliou-se neste trabalho a persistência e o efeito desse herbicida na microbiota do solo, em Argissolo VermelhoAmarelo (PVA) -MG cultivado com cana-deaçúcar, visando definir técnicas para o uso seguro de sulfentrazone.…”

Residual Herbicide Dissipation in Vegetable Production

“…Half-life of metolachlor varies with soil temperature, moisture, and organic matter content (Parker et al, 2005;Vencill, 2002 a). Previous research indicated that the adsorption and mobility of sulfentrazone is pH and soil type-dependent and that it does exhibit hysteresis (Grey et al, 2000). Reddy & Locke (1998) confirmed the conclusion that sulfentrazone availability was both pH and soil series-dependent.…”

“…The residual effects of sulfentrazone on rotational cotton have been established with rates exceeding 0.4 kg ha -1 applied the previous year (Main et al, 2004;Ohmes et al, 2000). Persistence, dissipation, and degradation of halosulfuron (Kuwatsuka & Yamamoto 1997a, metolachlor (Gaynor et al, 1993, Parker et al 2005Weber et al, 2003), and sulfentrazone (Grey et al, , 2000Ohmes et al, 2000;Reddy & Locke, 1998) have been previously investigated in agronomic and/or vegetable soils. These investigations emphasized soil and/or organic cover scenarios in separate experiments.…”

Mobilidade Do Sulfentrazone Em Solos Com Diferentes Características Físicas E Químicas

“…Possui atividade em pré e pós-emergência, sendo recomendado para controle de plantas daninhas no pós-plantio da cultura do eucalipto (ANVISA, 2011). Apresenta meia-vida estimada no solo entre 110 e 280 dias, variando de acordo com as condições edafoclimáticas locais, sendo a atividade microbiológica seu mecanismo inicial de degradação (Grey et al, 2000;Polubesova et al, 2003;Vivian et al, 2006 ). O sulfentrazone apresenta pKa a 6,56 e Kow = 1,48, solubilidade em água de 490 mg L -1 e pressão de vapor de 1 x 10 -9 mm Hg a 25 o C. No solo, sua mobilidade é moderada em razão de apresentar baixa sorção (Koc médio = 43) (Rodrigues & Almeida, 2005).…”