PENDIMETHALIN AND FLUMETRALIN DEGRADATION UNDER CONTROLLED CONDITIONS IN FOUR SOILS

Abstract Degradation of flumetralin and pendimethalin in soil was examined under controlled environmental conditions. A complete factorial arrangement of four soils (representing the major tobacco production regions), two temperatures (15 and 30°C), and two soil moisture contents were examined. Additionally, the persistence of each herbicide was examined alone and in the presence of the other herbicide from 0 to 180 d. Soil moisture had a minor effect on flumetralin and pendimethalin degradation, but higher temperature encouraged herbicide degradation. Soil type had a major influence, as pendimethalin degradation was negatively correlated to both soil pH and clay content. This research indicated that both pendimethalin and flumetralin have the potential to persist in the environment for a time interval sufficient to affect subsequently planted small grain cover crops. Flumetralin half-life at 30°C was >180 d in all four soils. Given the use pattern of pendimethalin in tobacco, this research indicated that...