Floating treatment wetlands (FTWs) are a plant-based treatment technology shown to remove excess nutrients and metals from surface waters under a variety of conditions. Plants established in FTWs can accumulate and store nutrients within their tissues, but the amount of uptake and storage is dependent on plant species and nutrient influent concentration. This research was designed to quantify the influence of nutrient load and two plant species on nutrient uptake and partitioning patterns within plant tissues (shoots and roots) so that management recommendations for FTWs can be developed to better protect surface water quality. Treatments consisted of (1) two nutrient loads: a high concentration of 15 mg⋅L-1 nitrogen (N) and a low concentration of 5 mg⋅L-1 N supplied as water soluble fertilizer, and (2) four mesocosm treatments: (a) open water, (b) artificial mat only, no plants, (c) artificial mats planted with Pontederia cordata L., and (d) artificial mats planted with Juncus effusus L.. Plant growth, N, and phosphorus (P) uptake of both P. cordata and J. effusus were greater in the high nutrient treatment than in the low. Pontederia cordata facilitated the highest rates of N (0.31 mg.L.day-1) and P (0.34 mg.L.day-1) removal. The nutrient removal rates facilitated by Juncus effusus in the high nutrient treatment were much lower for both N (0.03 mg.L.day-1) and P (0.02 mg.L.day-1). Peak N and P accumulation in J. effusus occurred in September within both root (50 g N and 4.8 g P) and shoot tissues (98 g N and 12.5 g P). The uptake of N and P in P. cordata was highest in root tissues in August (307 g N and 30.5 g P) and in shoot tissues in September (1490 g N and 219.5 g P). In both species, shoots accumulated more N and P than the roots, resulting in a small root:shoot ratio at all stages of the experiment. Harvest of plants from FTWs should occur before plants senesce in the fall, which using P. cordata and J. effusus as model species, occurred from mid- to late-September in USDA Hardiness Zone 8a in the Southeastern United States.

While governments and individuals strive to maintain the availability of high-quality water resources, many factors can “change the landscape” of water availability and quality, including drought, climate change, saltwater intrusion, aquifer depletion, population increases, and policy changes. Specialty crop producers, including nursery and greenhouse container operations, rely heavily on available high-quality water from surface and groundwater sources for crop production. Ideally, these growers should focus on increasing water application efficiency through proper construction and maintenance of irrigation systems, and timing of irrigation to minimize water and sediment runoff, which serve as the transport mechanism for agrichemical inputs and pathogens. Rainfall and irrigation runoff from specialty crop operations can contribute to impairment of groundwater and surface water resources both on-farm and into the surrounding environment. This review focuses on multiple facets of water use, reuse, and runoff in nursery and greenhouse production including current and future regulations, typical water contaminants in production runoff and available remediation technologies, and minimizing water loss and runoff (both on-site and off-site). Water filtration and treatment for the removal of sediment, pathogens, and agrichemicals are discussed, highlighting not only existing understanding but also knowledge gaps. Container-grown crop producers can either adopt research-based best management practices proactively to minimize the economic and environmental risk of limited access to high-quality water, be required to change by external factors such as regulations and fines, or adapt production practices over time as a result of changing climate conditions.

Favored for their rapid growth and brilliant fall color, maple (Acer spp.) trees are among the most commonly grown deciduous shade trees in urban lan

The feasibility of using floating treatment wetlands (FTWs) to treat runoff typical of commercial nurseries was investigated using two 8-week trials with replicated mesocosms. Plants were supported by Beemat rafts. Five monoculture treatments of Agrostis alba (red top), Canna × generalis ‘Firebird’ (canna lily), Carex stricta (tussock sedge), Iris ensata ‘Rising Sun’ (Japanese water iris), Panicum virgatum (switchgrass), two mixed species treatments, and an unplanted control were assessed. These plant species are used for ornamental, wetland, and biofuel purposes. Nitrogen (N) and phosphorus (P) removals were evaluated after a 7-day hydraulic retention time (HRT). N removal (sum of ammonium-N, nitrate-N, and nitrite-N) from FTW treatments ranged from 0.255 to 0.738 g·m⁻²·d⁻¹ (38.9 to 82.4% removal) and 0.147 to 0.656 g·m⁻²·d⁻¹ (12.9 to 59.6% removal) for trials 1 and 2, respectively. P removal (phosphate-P) ranged from 0.052 to 0.128 g·m⁻²·d⁻¹ (26.1 to 64.7% removal) for trial 1, and 0.074 to 0.194 g·m⁻²·d⁻¹ (26.8 to 63.2% removal) for trial 2. Panicum virgatum removed more N and P than any other FTW treatment and the control in both trials. Results show that species selection and timing of FTW harvest impact the rate and mass of nutrient remediation. FTWs can effectively remove N and P from runoff from commercial nurseries.