Comparision of HPLC and Bioassay Methods for Analysis of Sulfosulforun Residues in Wheat Field Soil

Abstract

Abstract. Sulfosulfuron, a new sulfonylurea herbicide, is used to control certain broadleaf and grass weed species in wheat fields. Herbicides, when applied to the field may leave unwanted residues in the soil. Bioassay and chemical assay techniques are main methods for monitoring herbicides levels in agricultural soils. Thus, a set of field and greenhouse experiments was established to evaluate the reliability and accuracy of HPLC and bioassay techniques to detect sulfosulfuron residues in the soil of the wheat field. The experiment was conducted in a randomized complete block design with three treatments in three replications for each treatment in 2014-2015 and 2015-2016 growing seasons at Marvdasht location. Herbicide treatments included: sulfosulfuron (apirus) at 26.6 and 53.2 g a.i. ha -1 rates and no-herbicide control. Herbicide was sprayed at the end of tillering stage of wheat in a field experiment. Samples were collected randomly with an auger from 0-10 cm depth at different times i.e. 0, 3, 10, 20, 30, 60, 90 and 125 days after herbicide spray. The bioassay experiment showed that root parameter was more sensitive to sulfosulfuron as compared with the shoot. According to the results, among the studied plants, garden cress was recognized as the most sensitive plant to different rates of sulfosulfuron herbicide. At recommended (26.6 g a.i. ha−1) and double (53.2 g a.i. ha -1 ) rates of application sulfosulfuron residues were detected up to 60 and 90 days after treatment by HPLC and bioassay techniques in both years, respectively. According to the bioassay and HPLC techniques at two rates of application, residues decreased with time in 2014 and 2015.