Bioindicator demonstrates high persistence of sulfentrazone in dry soil1

Abstract

In sugarcane crop areas, the application of preemergence herbicides with long residual effect in the soil has been frequently necessary. The herbicide persistence in the soil must be high especially because of applications during the dry season of the year, after sugarcane harvest. This study aimed at estimating the sulfentrazone persistence and dissipation in dry soil using bioindicator. Five experiments were carried out, divided into two phases. In the first phase, three dose-response curves were adjusted to select the best bioindicator to be adopted in the second phase. Niger was adopted due to its lower sensibility to sulfentrazone. In the second phase, a new dose-response curve was carried out, with six doses of sulfentrazone, in order to standardize the bioindicator sensibility to sulfentrazone. At the end, another experiment with six periods of sulfentrazone persistence in dry clay soil was developed. Persistence periods were: 182, 154, 125, 98 and 30 days. The bioindicator was seeded at the application day in treated plots and control. In this experiment, the sulfentrazone dose applied was 800 g ha-1. Niger was considered a good species to estimate the sulfentrazone persistence in dry soil. The sulfentrazone phytotoxic activity was identified up to 182 days after application, and its average dissipation rate was 2.15 g ha-1 day-1, with half-life higher than 182 days.

Interação entre herbicidas e nematicidas na cultura da cana-de-açúcar

“…As well as the control effectiveness, sulfentrazone becomes a good option when a prolonged residual for weed control is desired; Lourenço and Carvalho (2015) verified that at 182 DAA, this herbicide still had phytotoxic activity over the plant that was used as a bioindicator, Guizotia abyssinica Cass. ns Nonsignificant; * Significant at 5% probability level by F test.…”

Seletividade do herbicida sulfentrazone em pós-emergência sobre mudas de café recém implantadas

“…Essa constatação, possivelmente, foi consequência da pulverização e persistência do sulfentrazone no substrato dos vasos, após aplicação em área total. O sulfentrazone é uma molécula do grupo das fenil-triazolinonas com elevado efeito residual no solo (MELO et al, 2010;MONQUERO et al, 2010;LOURENÇO;CARVALHO, 2015). O equipamento Minolta SPAD-502, que mede a intensidade da coloração verde das folhas, tem sido utilizado na quantificação de clorofilas, caracterizando-se pela rapidez, simplicidade e, principalmente, por possibilitar uma avaliação não destrutiva do tecido foliar (RAMOS; MONNERAT; PINHO, 2013).…”

Sulfentrazone: Environmental Dynamics and Selectivity

“…Higher rainfall and soil moisture levels cause increased sulfentrazone availability in the soil solution, and some situations increase the phytotoxic effect on the plants (Alves et al, 2004;Reiling et al, 2006). The availability of sulfentrazone increases significantly in saturated soils; however, the opposite is observed when sulfentrazone is applied in dry soils, where there is a reduction in its availability in soil solution and control efficiency, and an increase in its persistence (Rizzi, 2003;Lourenço and Carvalho, 2015).…”

“…In periods of drought or low soil moisture, the persistence of sulfentrazone in the soil is greater and the half-life can be extended to 180 days (Lourenço and Carvalho, 2015) as a consequence of the higher soil sorption of the herbicide (Rizzi, 2003). The slow desorption of sulfentrazone from the soil particles reduces its availability in the soil solution, and consequently, the dissipation processes are reduced (Reddy and Locke, 1998;Ohmes and Mueller, 2007).…”