Christine Wiese

Nutrient Leaching during Establishment of Simulated Residential Landscapes.

Research evaluating nutrient losses during the establishment of plant material in mixed residential landscapes is limited. The objectives of this study were to determine the effect of vegetative cover type, compost application, and tillage on nutrient losses during the establishment of landscape plants. Twenty-four small plots constructed with subsoil fill were planted with St. Augustinegrass [ (Walter) Kuntze] and mixed ornamental species in a randomized complete block design. Plots received composted dairy manure solids at a rate of 0 or 50.8 m ha- in combination with shallow tillage or aeration. Cumulative leachate loads and flow-weighted mean concentrations of NH-N, NO + NO-N, and dissolved reactive P (DRP) were calculated periodically and annually to assess nutrient leaching from landscape plots. Higher cumulative leachate volume, inorganic N and DRP loads, and mean NO + NO-N and DRP concentrations were observed under ornamental cover during one or more study periods, which we attribute to differences in root density and shoot biomass between mixed ornamental species and turfgrass during establishment. Greater cumulative leachate inorganic N loads were reported from composted soils than from unamended soils or soils receiving only tillage or aeration. Inorganic N and DRP loads were similar in magnitude to reported leaching losses from agricultural systems. Better management of nutrients and water in woody ornamental plant beds during plant establishment is needed due to differences in plant growth habits compared with turfgrass. Nutrient content of organic amendments should be considered when applying these materials as a soil conditioner in new residential landscapes.

Nutrient Leaching from Mixed-Species Florida Residential Landscapes

Nutrient losses from residential lawns and landscapes can negatively impact water quality. Information about nutrient leaching from established residential landscapes containing a mixture of woody ornamental plants and turfgrass is limited. The objective of our study was to determine the effect of vegetation cover (turfgrass vs. woody ornamental) on nutrient leaching from established landscapes. Nine drainage lysimeters were planted with three vegetation treatments with the following coverage: (i) 60% turfgrass, 40% ornamental; (ii) 75% turfgrass, 25% ornamental; and (iii) 90% turfgrass, 10% ornamental. Daily leachate samples were collected and combined to produce weekly flow-weighted samples for 1 yr. Leachate samples were analyzed for total Kjeldahl N (TKN), nitrate (+ nitrite)-N (NO), ammonium-N (NH-N), and dissolved reactive phosphorus (DRP). The ratio of actual evapotranspiration (ET) to reference evapotranspiration (ET) was similar among treatments. However, drainage from the 90% turfgrass lysimeters was periodically higher than from the 60 and/or 75% turfgrass treatments. In most cases, leachate N and P concentrations and loads followed the same trend as drainage. The addition of shrubs in the 60 and 75% turfgrass treatments reduced leachate when rainfall was low and irrigation was the main water input. We suggest that established woody ornamental plants are more effective at absorbing water and nutrients than turfgrass due, in part, to increased root biomass and deeper rooting of established woody plants, which allows for more efficient uptake of soil water and nutrients. The use of woody plants in residential landscapes can reduce nutrient leaching in urban areas.

Effect of Season and Number of Glyphosate Applications on Control of Invasive Mexican Petunia (Ruellia simplex)

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Suppression of the Ornamental Invasive Mexican Petunia (Ruellia simplex) by Native Species

Mexican petunia (Ruellia simplex) is a commonly planted herbaceous ornamental known for densely invading floodplain forests in the southeastern United States. While the use of herbicides is a typical management approach, revegetation strategies are needed not only to restore the native plant community, but also to limit reinvasion. We identified four native species appropriate for floodplain revegetation in Florida, US: bushy bluestem (Andropogon glomeratus), common rush (Juncus effusus), redtop panicgrass (Coleataenia longifolia sp. longifolia), and pinebarren goldenrod (Solidago fistulosa). In a controlled greenhouse container study, we investigated competition between Mexican petunia and native species compositions grown from seeds under varying hydrologic conditions and seeding densities. Results showed that number of Mexican petunia individuals and biomass decreased when seeded together with either pinebarren goldenrod or a mix of four native species (bushy bluestem, common rush, redtop panicgrass, and pinebarren goldenrod). Pinebarren goldenrod and bushy bluestem had a short establishment period (2–4 weeks), similar to Mexican petunia (2–5 weeks). Data from this container study suggests that revegetation with these native species could effectively compete with and suppress Mexican petunia in field conditions.

Germination of Native Species: Efforts to Guide Revegetation in a Mexican Petunia-Invaded Floodplain in Florida

Ecological Restoration Vol. 33, No. 3, 2015 ISSN 1522-4740 E-ISSN 1543-4079 ©2015 by the Board of Regents of the University of Wisconsin System. Germination of Native Species: Efforts to Guide Revegetation in a Mexican PetuniaInvaded Floodplain in Florida Adrienne M. Smith (corresponding author: Department of Environmental Horticulture, University of Florida, P.O. Box 110675, Gainesville, FL 32611, amsmith@ufl.edu), Sandra B. Wilson (Department of Environmental Horticulture, University of Florida), Carrie Reinhardt Adams (Department of Environmental Horticulture, University of Florida) and Christine Wiese (Department of Environmental Horticulture, University of Florida).