Paraffin Oil and Granules as Carriers for Trifluralin1

Abstract

AbstractThis study was conducted to determine the effects of the carrier on the stability of trifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) at the soil surface. Trifluralin concentrations were determined with a gas chromatograph equipped with an electron‐capture detector. In the laboratory, more trifluralin disappeared from wet soil (80% field capacity) after 24 hours when applied in water than when applied in paraffin oil. At 0 to 20% field capacity there was no difference between the carriers. Vapor sampling experiments showed no detectable volatilization of trifluralin from air dry soil over a 24‐hour period at 38C, and confirmed that less volatilization of the herbicide occurred from wet soil when applied in paraffin oil than when applied in water. About 20% less trifluralin was lost from granules than from aqueous sprays on wet clay soil, but no difference occurred on dry soil.In field, paraffin oil delayed the loss of trifluralin from wet soil (60% field capacity), but under relatively dry field conditions there was little difference between the effectiveness of water and paraffin oil carriers.