Leaching of sulfentrazone herbicide in soils with different textures

Abstract

The objective of this study was to evaluate the leaching potential of sulfentrazone herbicide through bioindicator plants after the occurrence of natural rainfall in soils with clayey and sandy textures. The experimental design was completely randomized in a 3 x 8 factorial with four replications, with three levels of rainfall (30-40, 60-80 and 100-120 mm) and eight depth of soil profile (0-3, 3-6, 6-9, 9-12, 12-15, 15-20, 20-25 and 25-30 cm). The collections of samples occurred after sulfentrazone application at doses of 800 g ha-1 and 600 g ha-1 for the clayey and sandy soils, respectively, and subsequent accumulation of rainfalls. For the collection of soil samples, PVC columns with 30 cm and 15 cm in diameter were introduced in soil profile. The columns were carefully removed by digging around him and maintaining the original soil integrity during the collection. Subsequently, the columns were separated with cross section for the sowing of bioindicator species, sorghum and Bidens pilosa. After sowing, for evaluations of bioindicator plants in columns, it was adopted range of 0% to 100% of phytotoxicity, at 5, 7, 10 and 12 days after sowing. Leaching of sulfentrazone was dependent on rain accumulation and soil texture. In larger rain accumulations, sulfentrazone can be found deeper in soils of sandy textures. Sorghum was more suitable as bioindicator plant to demonstrate the herbicide presence at greater depths.

Bidens pilosa L. (Asteraceae) control in sunflower with residual herbicides

“…High doses of S-metolachlor applied to sandy soils and soils with low organic matter can cause injury to sunflower (Brighenti et al, 2013). In addition, the leaching potential of S-metolachlor is strictly correlated with rainfall (Inoue et al, 2010 The adsorption of sulfentrazone to the soil is also influenced by pH and organic matter content (Silva Júnior et al, 2016). The value of organic matter was lower in Valença (2.8 dag kg -1 ) than in Coronel Pacheco (3.3 dag kg -1 ).…”

Leaching of sulfentrazone in Brazilian “Cerrado” soils by chromatographic and biological methods

“…Another fraction (250g) of each treatment was placed in pots of 300 cm 3 capacity, where the bioindicator Sorghum bicolor was planted. S. bicolor was selected as an indicator of sulfentrazone residues in soil based on several studies (Faustino et al, 2015, Silva Junior et al, 2016, Madalão et al, 2017 that confirmed the high sensitivity of this species to sulfentrazone.…”

“…This technique is based on the use of plants that are sensitive to the tested herbicides, so that the presence of residues in the soil is evidenced by changes in physiological and morphological characteristics of the key-plant species. In the literature, several studies involving bioassays for determination of leaching of herbicides such as amethrin (Silva et al, 2012), sulfentrazone (Silva Junior et al, 2016), imazethapyr, imazapyque and imazapyr (Bundt et al 2014) have been reported. On the other hand, to test the efficiency of this method, it would be interesting to compare it with already consolidated methods such as HPLC.…”