Sorption of Acetochlor, Atrazine, 2,4-d, Chlorotoluron, MCPA, and Trifluralin in Six Soils From Slovakia

Abstract

Sorption of the herbicides (acetochlor, atrazine, 2,4-D: , chlorotoluron, MCPA and trifluralin) in their commercially available formulations was characterized on six agricultural soils from Slovakia. Weak acid herbicides (2,4-D: and MCPA) were the least sorbed, whereas weak base such as atrazine and nonionic herbicides were the most sorbed in the order: atrazine < acetochlor approximately chlorotoluron < trifluralin, which was closely related to the hydrophobicity of herbicides expressed as logKOW. The KF values positively correlated with soil organic carbon content for all herbicides. Moreover, all herbicides were the most sorbed by Vertisol with relatively high smectite clay content in proportion to organic carbon content. The KOC values for each herbicide showed a smaller variation among soils (excluding Vertisol) than the KF and were used to compare soil mobility potential of herbicides.

Retention characteristics of acetochlor in soils collected from different depths in relation to soil properties (Žitný ostrov area, SW Slovakia)

“…Statistical analyses (Table 3) showed that the sorption of acetochlor in soils was highly correlated with soil organic carbon content (R = 0.99, P < 0.001), and the humic acid and fulvic acid carbon contents (R = 0.98 and R = 0.97, P < 0.001). Several studies have suggested that soil organic matter exhibits a high affinity for acetochlor and plays the most prominent role as a sorbent of acetochlor in soils (Wang et al 1999;Hiller et al 2008;Bedmar et al 2011). The calculated K oc values for acetochlor were similar among the soils, confirming that organic matter of the soils had similar sorption affinity for the herbicide and that TOC was the most important factor for acetochlor sorption in soils.…”

“…The different shapes of sorption isotherms might be attributed to the occurrence of more sorption mechanisms included in the acetochlor sorption, likely due to differences in composition of the soils and their heterogeneous nature. Several authors have reported non-linear isotherms of L-and S-types for acetochlor sorption in soils with contrasting physico-chemical properties (Taylor et al 2004;Hiller et al 2008;Bedmar et al 2011). Based on the K fs values, the extent of acetochlor sorption decreased with increasing soil depth for each soil type (Table 2).…”

“…Tubes were rotated for another 24 h and subsequently centrifugated at 1160× g for 15 min, followed by filtration (Whatman, 0.45 μm, nylon). Previously, Hiller et al (2008Hiller et al ( , 2009 showed that the sorption and desorption of acetochlor in soils similar to those used in the present study reached an equilibrium state within 12 h. Soil extracts were transferred in glass vials and analyzed for acetochlor by high-performance liquid chromatography (HPLC) as described below. Desorption experiments followed immediately after sorption with an initial concentration of 20.02 mg/l.…”

“…(1-1/n) .l (1/n) /kg and from 0.84 to 7.11 l/kg, respectively (Nemeth-Konda et al 2002;Zheng & Ye 2002;Hiller et al 2008Hiller et al , 2009). Sorption of acetochlor decreases with soil depth and becomes negligible in sandy aquifer materials with low organic carbon contents (Janniche et al 2011).…”

Simulating the Transport and Fate of Trifluralin in Soil

“…These authors studied trifluralin (α,α,α-reifluoro-2,6-dinitro-N,N-dipropyl-ρtoluidine) volatilization losses from a soybean field at Watkinsville, GA, USA. This 1.26-ha soybean research field comprised of Cecil soil with 63.35% sand, 23.6% 56 silt, 12.5% clay, and 0.55% organic carbon; a pH of 6.5; a slope of 3.0%; and trifluralin KOC of 3750 to 9253 (Hiller et al, 2008). Trifluralin was surface-applied as a spray to the bare soil surface, using a ground sprayer equipped with flat-fan nozzles, at a rate of 1.12 kg/ha.…”