Degradation of Trifluralin in Soil Suspensions as Related to Redox Potential1
- G. H. Willis,
- R. C. Wander and
- L. M. Southwick2
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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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