Recycling Irrigation Reservoir Stratification and Implications for Crop Health and Production |
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| Authors: | Haibo Zhang Patricia A Richardson Bruk E Belayneh Andrew Ristvey John Lea‐Cox Warren E Copes Gary W Moorman Chuanxue Hong |
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| Affiliation: | 1. Hampton Roads Agricultural Research and Extension Center, Virginia Polytechnic Institute and State University, Virginia Beach, Virginia, 23455;2. Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland;3. Wye Research and Education Center, University of Maryland Extension, Queenstown, Maryland;4. Agricultural Research Service, United States Department of Agriculture, Poplarville, Mississippi;5. Department of Plant Pathology & Environmental Microbiology, The Pennsylvania State University, University Park, Pennsylvania |
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| Abstract: | Recycling irrigation reservoirs (RIRs) are an emerging aquatic ecosystem and water resource of global significance. This study investigated the vertical distribution of water temperature, dissolved oxygen (DO), and pH in eight RIRs at two nurseries each in Virginia and Maryland from 2011 to 2014. Monomictic thermal stratification was observed from April to October in all RIRs, despite their shallow depths (0.75‐3.89 m). The strongest stratification had a top‐bottom temperature difference of 21.53°C. The top‐bottom temperature difference was positively correlated with water column depth, air temperature, and daily light integral (p < 0.05). Wind speed did not impact the thermal stratification, likely due to their relatively small surface areas. Thermal stratification affected the vertical distribution of DO and pH. The top‐bottom differences in DO and pH were greater during stratification periods than nonstratification periods. Water pH in all RIRs was higher at the top than at the bottom with the greatest difference of 4.16 units. Discovery and characterization of thermal stratification in RIRs helps understand water quality dynamics in this novel ecosystem and promote safe and productive water reuse for irrigation. Specifically, water withdrawal depths should be adjusted according to variations in temperature, DO, and pH during the stratification and nonstratification periods to mitigate pathogen risk and improve water treatment efficacy and crop production. |
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| Keywords: | recycling irrigation reservoir thermal stratification recycled water quality dissolved oxygen pH water management |
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