ABSTRACT
In Australia, one of the principal factors is the lack of data on the fate of herbicides in soils and their impact, particularly in aquatic systems. This chapter summarizes data on the persistence and movement of herbicides and considers the implications for Australian agriculture. A range of techniques have been developed to measure herbicide residues, but the measurement of minute amounts of herbicides and their metabolites poses formidable technical challenges for the residue chemist. Visual assessment of the variability in a distribution of a fluorescent marker under UV light suggests a major problem with incorporation of preemergence herbicides. Sorption is determined by the physiochemical properties of the herbicide and soil. Spatial separation of herbicide at the soil surface from crop roots deeper in the profile is a method of reducing crop injury. Changes in rainfall or indirect effects of temperature on soil water content are likely to be more important consequences of greenhouse warming in Australia.
