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

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Willis, G. H. Articles by Southwick, L. M. Search for Related Content PubMed Articles by Willis, G. H. Articles by Southwick, L. M. Agricola Articles by Willis, G. H. Articles by Southwick, L. M.

Degradation of Trifluralin in Soil Suspensions as Related to Redox Potential¹

ABSTRACT

A system for controlling redox potential in soil suspensions was used to investigate the relationship between oxidation-reduction potential (Eh) and the rate of trifluralin (a-a-a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) degradation. Redox potentials of +450, +250, +150, +50, 0, and –50 mV were imposed on trifluralinamended (1 ppm oven-dry weight soil basis) soil suspensions (100 g soil in 300 ml H₂O) for 21 days. Results indicated that exclusion of O₂ by soil flooding initiated rapid trifluralin degradation only when the Eh decreased below a critical range between +150 and +50 mV. There was no clear-cut relationship between trifluralin degradation and microbiological respiratory activity (CO₂ evolution).

If soil flooding is to be a practical cultural technique for accelerating the rate of degradation of persistent pesticides, steps may have to be taken to ensure that soil Eh decreases below a critical value for some required period of time. This may include soil incorporation of a readily available carbon or energy source to stimulate an active soil microbial population to enhance lowering of the soil Eh.

Key Words: herbicide • Eh • redox control • pesticide decontamination

¹ Contribution from the Mississippi Valley Area, Southern Region, Agricultural Research Service, USDA, in cooperation with the Louisiana Agr. Exp. Sta., Baton Rouge, 70803.

² Soil Scientist, former Chemist, and Chemist, respectively.

Received for publication September 4, 1973.