T. N. Shaver

Fate of ethephon andN-methyl-2-pyrrolidone in soil and cotton plants

Abstract[14C]ethephon and [14C]N-methyl-2-pyrollidone (NMP) dissipated rapidly from three different soils. Half-life of [14C]ethephon was 3.3, 4.9, and 9.7 days, respectively, in clay, loam, and sand. The half-life of NMP was 3.9, 7.9, and 11.6 days, respectively in clay, loam, and sand when combined with nonlabeled ethephon, and was 4.0, 8.7, and 11.5 days, respectively, when applied alone to these soils. Soil treated with NMP contained less than 0.1 ppm NMP equivalents after 21 days and soils treated with [14C]ethephon contained less than 0.1 ppm ethephon equivalents after 28 days. In leaching studies with soils coated on thin layer chromatography plates, ethephon had frontal Rf values of 0.66, 0.59, and 0.20 in silt, loam, and clay, respectively, and streaked from the origin to near the solvent in sand. Frontal Rf values for NMP were 0.74, 0.65, 0.67, and 1.0 in silt, loam, clay, and sand. In cotton plants 14 and 21 days after treatment with [14C]ethephon or NMP, only a small portion of the applied doses were detected in plant tissues, and none remained on leaf surfaces after 21 days. An unidentified metabolite was detected along with NMP in leaf and terminal extracts of cotton plants treated with NMP.