Insecticide-induced responses in an old field ecosystem: Persistence of diazinon in the soil.

To obtain insight into the problem of soil contamination by pesticides, a long-range project has been initiated to investigate insecticide-induced responses in an abandoned field. Old field ecosystems are comparatively simple and allow more thorough considerations of the major biotic components than are possible for most other natural ecosystems. Although typical pesticide treatments of cropped fields consist of multiple applications of several chemicals, a single application of a relatively short-lived insecticide was used in this study. It was felt that a moderately heavy dose rate of such an insecticide would induce most ecological interactions that might occur in a contaminated ecosystem. At the same time, a short residue might permit the system to recover and equilibrate within a reasonable amount of time.