Detention and recycling basins for managing nutrient and pesticide runoff from nurseries

Production nurseries may be significant sources of nutrients and pesticides in runoff as a result of the intensity at which fertilizers, pesticides, and irrigation water are applied. Concentrations of nutrients and pesticides in runoff from production nurseries are not extensively documented. Runoff from 11 production nurseries in southern California using either recycling or detention basins was monitored for nutrients and pesticides. For six sites, runoff volume was determined and nutrient loads in runoff were calculated. Water use data, percentage of water recycled, and construction costs were determined for sites with recycling systems. Nutrient concentrations, mass loads, and pesticide detections in runoff from some sites would have been of concern without the implementation of detention or recycle basins. There were few differences in nutrient concentrations or pesticide detections between runoff from irrigation and that from precipitation events. This suggests the need for management practices and technologies that address runoff from both irrigation and precipitation events. Water use and cost data suggested that the implementation of recycling systems may be more beneficial and cost-efficient for larger facilities.