Dissipation of Massive Quantities of 2,4-D and 2,4,5-T n-Butyl Esters in Field Mini-Lysimeters1
- Joseph T. Majka,
- H. H. Cheng and
- T. J. Muzik2
The patterns of dissipation of 2,4-D (2,4-dichlorophenoxyacetic acid) and 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) n-butyl esters, applied in 1:1 mixtures at 560 or 2,800 kg/ha of each herbicide to soils in field mini-lysimeters, were monitored periodically from December 1976 to April 1979. The lysimeters were located in Pullman, Wash., and packed with soils from Washington, Wyoming, and Mississippi. Both 2,4-D and 2,4,5-T were dissipated to < 1% of the initial concentration at the lower application rate in the Washington and Wyoming soils; however, at the higher application rate, dissipation of 2,4-D was greatly impeded and dissipation of 2,4,5-T was negligible in these soils. Dissipation of both herbicides in the acidic Mississippi soil was extremely slow even at the lower application rate. Surface soil pH was lowered following herbicide application. Some downward movement of both herbicides from the 0- to 5-cm to the 5- to 10-cm soil layer was evident. By the end of the experimental period, revegetation had begun only on the Washington and Wyoming soils treated at the lower application rate.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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