HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Related articles in JEQ Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Potter, T. L. Articles by Culbreath, A. K. Search for Related Content PubMed PubMed Citation Articles by Potter, T. L. Articles by Culbreath, A. K. Agricola Articles by Potter, T. L. Articles by Culbreath, A. K. Related Collections Case Studies Pesticides Organic Compounds Agricultural Pesticides

TECHNICAL REPORTS

Organic Compounds in the Environment

Accelerated Soil Dissipation of Tebuconazole following Multiple Applications to Peanut

^a USDA-ARS, Southeast Watershed Research Laboratory, P.O. Box 748, Tifton, GA 31793
^b Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695
^c Department of Plant Pathology, University of Georgia Coastal Plain Experiment Station, Tifton, GA 31794

^* Corresponding author (tpotter{at}tifton.usda.gov)

Received for publication December 14, 2004. Repeated application may increase rates of pesticide dissipation in soil and reduce persistence. The potential for this to occur was investigated for the fungicide, tebuconazole (-[2-(4-chlorophenyl)ethyl]--(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol), when used for peanut (Arachis hypogaea L.) production. Soil samples were collected from peanut plots after each of four tebuconazole applications at 2-wk intervals. Soil moisture was adjusted to field capacity as necessary and samples were incubated in the laboratory for 63 d at 30°C. Untreated plot samples spiked with the compound served as controls. Results indicated accelerated dissipation in field-treated samples with the time to fifty percent dissipation (DT₅₀) decreasing from 43 to 5 d after three tebuconazole applications. Corresponding increases in rates of accumulation and decay of degradates were also indicated. Best-fit equations (r² = 0.84–0.98) to dissipation kinetic data combined with estimates of canopy interception rates were used to predict tebuconazole and degradates concentration in soil after each successive application. Predicted concentrations compared with values measured in surface soil samples were from twofold less to twofold greater. Use of kinetic data will likely enhance assessments of treatment efficacy and human and ecological risks from normal agronomic use of tebuconazole on peanut. However, the study indicated that varying soil conditions (in particular, soil temperature and water content) may have an equal or greater impact on field dissipation rate than development of accelerated dissipation. Results emphasize that extension of laboratory-derived kinetic data to field settings should be done with caution.

Abbreviations: DAP, days after planting • DT₁₀, DT₅₀, and DT₉₀, time to 10, 50, and 90% dissipation, respectively • K_oc, soil organic carbon–water partition coefficient • LAI, leaf area index • t_1/2, half-life

Related articles in JEQ:

This Issue in Journal of Environmental Quality

JEQ 2005 34: v. [Full Text]