Nutrient Leaching from Mixed-Species Florida Residential Landscapes

Abstract

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.

Variability of drainage and solute leaching in heterogeneous urban vegetation environs

“…Root distributions in the MT zone were denser and deeper due to its mix of trees, shrubs and turf grasses and this will have led to higher moisture uptake rates. These results are consistent with a previous study by Qin et al (2013) who evaluated the effect of vegetation cover (turf grasses vs. woody ornamental) on drainage rates and nutrient leaching collected from lysimeters. Three different vegetation zones (60 % turf-40 % ornamental, 75 % turf-25 % ornamental and 90 % turf-10 % ornamental) were investigated.…”

Storm water contamination and its effect on the quality of urban surface waters

“…The first includes nitrates, nitrites, and iron, correlated with the runoff of heavy storms from industrial areas and the second, which includes Ca, Mg, N org., TP, and DRP, correlated with river water upstream and downstream of the sewer outlet during moderately intense rain events and partially dependent on the multi-family settlement. Leaching of these elements from soils was frequently reported (e.g., Watmough et al 2005; Qin et al 2013). Their correlation with river water, whose quality depends on the agricultural catchment, is thus reasonable.…”

Habitat complexity influences fine scale hydrological processes and the incidence of stormwater runoff in managed urban ecosystems

“…Therefore, a more pronounced ecological management of urban habitats that draws upon the natural ecosystem processes (McDonnell and Pickett, 1990) could result in substantial savings in terms of ongoing maintenance costs over both short and long term timespans. The increased capacity of urban ecosystems to filter pollutants, leachates and sediments (Nouri et al, 2013;Qin et al, 2014;Yang and Zhang, 2011), promote evapotranspiration and mitigate the microclimate (Oke, 1989) could provide indirect economical and ecosystem service benefits. Improving the complexity of urban habitats could also increase their hydrological resilience under climatic change, as well as improving habitat and resources for urban biodiversity (Le Roux et al, 2014).…”