Disappearance of nicosulfuron residues in soil under laboratory conditions

Abstract

Sulfunyluares (SUs) present a new generation of herbicides which selectively control broad- and narrow-leaved weeds. Nonethel iiened utilization of SUs leads to increased concern about herbicides residues as the « msequence of their prolonged persistence in some soils. Nicosulfuron belongs to the group of SUs herbicide. A laboratory experiment at termostat (temperature of 25°C) was carried out to evaluate the effect of temn< ‘ture on the dissipation dynamics and final residues of nicosulfuron in soil type Calcie Chernozem Clayic, Pachic. The dissipation of nicosulfuron in soi! was described by using the Mittag-Leffler function ¢ E, (-hr), ere obtained from the experimental data. The residues of nicosulfuron iphy with diode array detection in the cted herbicide was applied as aqueous solution of commercial formulation nicosulfuron (K elvin", 40 ¢ L'). The starting coneentrations of nicosulfuron (measured in the samples soil taken on the ( th day, ! houirs afier the treatment) Sulfunyluares (SUs) pre 1 new Model coefficients a, h. « v were determined by uitra-performance liquid chromatog ultraviolet region. In order to invest gate dissipation

rye cs on 25°C were 389.84 ug ke ‘9.18 = : | ee E ¢ coe . pg kg, 649.02 ug kg 'and 797.69 ug kg! after the treatment with 40 grams active ingredient (a.i.) per hectare of nicosulfuron ig ai. ha'), 50 gal. ha”, 80.g ai. ha” and 100 gai. ha’. respectively. Atier two days, residues of nicosulfuron were lower more than 86% compared with the initial concentra ‘on. Pifty aays aficr the application of all doses the content of residues were below the LOQ for nicosulfuron (3.16 Hg kg'). The obtained half-time degradation (DT:») values of nicosulfuron vere in range of 0.34 d (80 g a.i. ha’ ') to 0.68 d (40 £att Significant reater Cissipation of nicosulfuron observed in this laboratory testing was influenced, most probably, by abiouc and biotic processes. Nicosulfuron poses low risks to the . imilar type soil because of their rapid dissipation,