Comparison of Different Soil Leaching Techniques with Four Herbicides

Abstract

Herbicide mobility in soils was compared by three laboratory methods. The Rf values calculated from soil thin-layer chromatography correlated closely with those obtained from soil thick-layer chromatography (r = 0.96). Herbicides leached slightly further in slotted column chromatography as compared with the other methods. The working hours required to conduct a study with each method were in the increasing order of thin-layer, thick-layer, and column chromatography. However, the thin-layer method required the longest waiting times, followed by the column and thick-layer chromatography. If radioactive herbicides are not available or obtainable, the thick-layer chromatography is simplest and quickest. The relative mobility of herbicides studied was fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] > napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide] > terbutryn [2-(tert-butyl-amino)-4-(ethylamino)-6-(methylthio)-s-triazine] > trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine). Less herbicide mobility was observed in heavier soil than in sandy soil.

Soil metabolism of the herbicide napropamide in cereals, maize, sugar beet and vegetable field replacement crops

“…Thus all three compounds remained in the 0-10 cm surface soil layer; no leaching occurred, even when there were heavy rains ( Table 1). The data for the field trials were therefore consistent with the low mobility of napropamide observed with soil TLC and soil columns (Wu et al, 1975). No residues of napropamide or its metabolites 2 and 3 were detected in the cereal grains, in the edible parts of the vegetables, or in the roots of the sugar beet.…”

“…Soil thin-layer chromatography has indicated that napropamide has poor leaching properties in soil (Wu & Santelmann, 1975). The surfaceapplied herbicide did not move deeper than approximately 6 cm in a sandy loam soil after a water application of 102 mm (Wu et al, 1975). Hurle (1977) reported that the soil half-life of napropamide under laboratory conditions at 17°C was 266 days, whilst Gerstl and Yaron (1983) observed that both temperature and soil water content influence the soil half-life of napropamide.…”

Pesticide soil sorption parameters: theory, measurement, uses, limitations and reliability

“…The results are less precise than adsorption–desorption or soil leaching columns, and the method is not much used today. However, results compare well or at least correlate with batch results 298–301…”

Influence of Pine Bark Substrate Age on Performance and Leaching of Nursery Preemergence Herbicides

“…Leaching study. Column leaching through substrates was accomplished using the segmented column technique (Weber et al, 1986;Wehtje et al, 2012;Wu and Santelman, 1975). This technique is more economical than chemical assay and can be very sensitive if proper species are chosen for the herbicide being evaluated (Lavy and Santelmann, 1986).…”