Biodegradation of Trifluralin in Harran Soil

Abstract

Degradation of trifluralin (alpha, alpha, alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) was investigated in soils taken from three different locations at Harran region of Turkey under laboratory conditions. Surface (0-10 cm) soils, which were taken from a pesticide untreated field Gürgelen, Harran-1 and Ikizce regions in the Harran Plain. were incubated in biometer flasks for 350 days at 25 degrees C. Ring-UL-14C-trifluralin was applied at the rate of 2 microg g(-1) with 78.7 kBq radioactivity per 100 g soil flask. Evolved (14)CO2 was monitored in KOH traps throughout the experiment. Periodically, soil sub-samples were removed and extracted by supercritical fluid extraction (SFE). Unextractable soil-bound 14C residues were determined by combustion. During the 350 days incubation period 6.6, 5.4, and 3.3/' of the applied radiocarbon was evolved as (14)CO2 from the Harran-1, Gürgelen, and Ikizce soil, respectively. At the end of 350 days the SFE-extractable and bound 14C-trifluralin residues were 39.0 and 29.2% of the initially applied herbicide in Gürgelen soil. The corresponding values for Harran-1 and Ikizce soils were 36.2, 28.4% and 41.6, 18.5% respectively.

Persistence and behavior of pesticides in cotton production in Turkish soils

“…This means that 61% and 69.8% of trifluralin was degraded under laboratory conditions in Gurgelen soil and Harran plain, respectively. The degradation of trifluralin in Harran soils were between 53.8% and 71.6% and in Ikizce soils from 59.4% to 78.5% (Tiryaki et al 2004).…”

“…Trifluralin has a log K ow 4.91 and 4 × 10 −5 mPa (20 • C; Cooke et al 2004). Since Trifluralin is hydrophobic, it is strongly sorbed by soil organic matter (Tiryaki et al 2004;Oldal et al 2006). Once bound, it persists in the soil and can injure sensitive crops grown in the years following herbicide application.…”