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Highly managed biotic systems, such as agricultural crops and managed turf, often require multiple applications of pesticides that may be transported with runoff to areas beyond the intended target site. Pesticides have been detected in surface waters of rural and urban watersheds raising questions concerning their source, potential environmental effects and a need for strategies to reduce their inputs. Experiments were designed to quantify pesticides transported with runoff from agricultural plots representing fresh market tomato production and turf plots maintained as a golf course fairway to evaluate the efficacy of management practices to mitigate chemical transport from these systems. Reported runoff-to-surface water scenarios were used to extrapolate pesticide loads in runoff to estimated environmental concentrations of pesticides in surface waters receiving the runoff. Surface water concentrations of the pesticides were compared with published toxicity data to assess reductions in the ecological risk associated with implementation of the management practices. Runoff from tomatoes grown on raised beds covered with polyethylene mulch with bare-soil furrows was found to present a greater risk to sensitive aquatic organisms than the vegetative hairy vetch mulch. In the managed turf system, replacing solid tine core cultivation with hollow tine core cultivation reduced surface water concentrations of the pesticides to levels below the median lethal concentration of sensitive aquatic organisms; lessening risk associated with pesticides in runoff from the fairway turf. Our results demonstrate that management practices can enhance the sustainability of intensely managed biotic systems, which provides growers and managers with strategies for improving the retention and efficacy of pesticides at targeted locations while reducing adverse impacts to non-target organisms.
