Irrigating Nursery Crops with Recycled Run-off: A Review of the Potential Impact of Pesticides on Plant Growth and Physiology

Abstract

<jats:p>Interest in capturing and reusing runoff from irrigation and rainfall in container nurseries is increasing due to water scarcity and water use regulations. However, grower concerns related to contaminants in runoff water and other issues related to water safety are potential barriers to the adoption of water capture and reuse technologies. In this review, we discuss some of the key concerns associated with potential phytotoxicity from irrigating container nursery crops with recycled runoff. The concentration of pesticides in runoff water and retention ponds is orders of magnitude lower than that of typical crop application rates; therefore, the risk of pesticide phytotoxicity from irrigation with runoff water is relatively low. Nonetheless, some pesticides, particularly certain herbicides and insecticides, can potentially affect crops due to prolonged chronic exposure. Pesticides with high solubility, low organic adsorption coefficients, and long persistence have the greatest potential for crop impact because they are the most likely to be transported with runoff from container pads. The potential impact on plant growth or disruption of physiological processes differs among pesticides and sensitivity of individual crop plants. Growers can reduce risks associated with residual pesticides in recycled irrigation water by adopting best management practices (e.g., managing irrigation to reduce pesticide runoff, reducing pots spacing during pesticide application, use of vegetative filter strips) that reduce the contaminant load reaching containment basins as well as adopting remediation strategies that can reduce pesticide concentrations in recycled water.</jats:p>

Effect of Substrate Stratification on Growth of Common Nursery Weed Species and Container-grown Ornamental Species

“…Weeds in most ornamental crops can be successfully managed with regular preemergence herbicide applications paired with hand weeding (Case et al, 2005;Gilliam et al, 1990). However, there are several negative consequences associated with frequent use of preemergence herbicides, including high costs (Stewart et al, 2017), potential leaching, runoff, or related concerns when recycling irrigation water (Poudyal and Cregg, 2019;Wilson et al, 1995). Additionally, it is inefficient because up to 80% of the applied herbicide fails to reach the container substrate surface, where it is needed for weed control (Gilliam et al, 1992).…”

Dose-Dependent Phytotoxicity of Pesticides in Simulated Nursery Runoff on Landscape Nursery Plants

“…We specifically selected taxa that had shown sensitivity to pesticides in similar studies, but it is possible that some taxa may have lower thresholds for pesticide impacts than those studied here. Likewise, in addition to the three pesticides studied, other compounds including mefenoxam, oryzalin, glyphosate, acephate, and bifenthrin may be found in nursery retention ponds [39]. We suggest that researchers conduct similar studies with other commonly used pesticides in a nursery and also determine the pesticide sensitivity of the plants that are different from ours.…”

“…Visible injury is of concern to nursery producers, even if growth is not affected, because aesthetic appearance is important in marketing ornamental plants. Pesticide injury to leaves depends on the dose and type of pesticide used [39]. In this study, oxyfluorfen produced dose-dependent visible injury in all three taxa.…”

Clean WateR3: Reduce, Remediate, Recycle—Using Transdisciplinary Science to Help Specialty Crop Producers Conserve Water and Resources

“…The eight articles in this series expand the body of information available to growers, researchers, and extension professionals related to efficient use of water and agrichemicals, contaminant management (pesticide, nutrient, and plant pathogen), the water footprint of plant producers, and opportunities to enhance adoption of water treatment practices. Some of the information resources developed include technologies that can help growers 1) increase water use efficiency and reduce pesticide movement (Abdi and Fernandez, 2019;Poudyal et al, 2019), 2) select effective management practices (Mack et al, 2019), 3) remove contaminants from irrigation runoff (Garcia Chance et al, 2019;Ridge et al, 2019), and 4) understand critical control points for mitigating disease and pesticide movement at grower production facilities (Parke et al, 2019;Ridge et al, 2019). Additional socioeconomic information resources were developed to help research and extension professionals understand how water use (application, consumption, and footprint) changes by region and operation (Knight et al, 2019) and how to identify opportunities to present information to stakeholders to encourage adoption and continued use of underused treatment technologies or practices (Lamm et al, 2019).…”