Submitted to: International Journal of Ecology and Environmental Sciences
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/1/2005
Publication Date: 7/4/2005
Citation: Deaver, E., Moore, M. T., Cooper, C. M., Knight, S. S. 2005. Efficiency of three aquatic macrophytes in mitigating nutrient runoff. International Journal of Ecology and Environmental Sciences. 31(1):1-7. Interpretive Summary: Excessive nutrients from storm runoff continue to contaminate rivers, streams, and lakes of the United States. Mesocosm experiments were conducted to examine the efficiency of three aquatic plants for nutrient uptake. While no single plant worked best on both nitrogen and phosphorus species, Ludwigia peploides (yellow primrose) and Juncus effusus (soft rush) efficiently removed nitrate, ammonia, and orthophosphate. By studying specific plant uptake, better planning for remediation techniques through best management practices may be obtained.
Technical Abstract: Ditches lining agricultural fields are used to convey runoff water and are typically mowed to reduce vegetative growth. If agricultural ditches are viewed as a type of wetland, vegetation within the ditch might be utilized to remove excess nutrients in runoff water. It was hypothesized that particular species of ditch vegetation would be more effective than others at removing nutrients in runoff water. Replicate 379L Rubbermaid tubs were planted with individual species of soft rush (Juncus effusus), yellow primrose (Ludwigia peploides) and cutgrass (Leersia oryzoides), common wetland macrophytes found in Mississippi agricultural drainage ditches. Nutrient enriched water (5 mg/L NO3, 5 mg/L PO4, and 5 mg/L NH3) was pumped in at a 4 h hydraulic retention time (HRT) at one end of the tub and discharged at the far end. Water samples were collected from the discharge hose at 1 h intervals for 9 h and analyzed for nutrient concentrations. Nutrient removal rates were compared for all plant treatments and an unplanted sediment-water control. Results indicated that no single species was most effective at removing both nitrogen species and orthophosphate, although all three plant treatments lowered nutrient concentrations in water relative to unplanted controls. Ammonia concentrations in water were most decreased in L. peploides tubs and total orthophosphate was decreased most by J. effusus. These same two plant species decreased nitrate concentrations at a similar rate. L. oryzoides was the least effective at removing nitrate and ammonia concentrations. By determining specific plant uptake of various nutrients, improved planning can be accomplished for the construction of best management practices and remediation techniques such as constructed wetlands or vegetated agricultural drainage ditches.