Effect of long-term changes in soil chemistry induced by road salt applications on N-transformations in roadside soils

Of several impacts of road salting on roadside soils, the potential disruption of the nitrogen cycle has been largely ignored. Therefore the fates of low-level ammonium-N and nitrate-N inputs to roadside soils impacted by salting over an extended period (decades) in the field have been studied. The use of road salts disrupts the proportional contributions of nitrate-N and ammonium-N to the mineral inorganic fraction of roadside soils. It is highly probable that the degree of salt exposure of the soil, in the longer term, controls the rates of key microbial N transformation processes. primarily by increasing soil pH. Additional influxes of ammonium-N to salt-impacted soils are rapidly nitrified therefore and, thereafter. increased leaching of nitrate-N to the local waterways occurs, which has particular relevance to the Water Framework Directive. The results reported are important when assessing the fate of inputs of ammonia to soils from atmospheric pollution. (c) 2007 Elsevier Ltd. All fights reserved

Evaluating the Potential Effects of Deicing Salts on Roadside Carbon Sequestration

This project sought to document patterns of road deicing salts and the effects of these salts on the amount of carbon being sequestered passively along Montana Department of Transportation roads; it was designed collaboratively with a related roadside project that tested three different highway right-of-way management techniques (mowing height, shrub planting, disturbance) to determine whether they have the capacity to increase soil organic carbon. Our sampling did not reveal elevated salt levels at any of the nine locations sampled at each of the three I-90 sites. The greatest saline concentrations were found at the sample locations farthest from the road. This pattern was consistent across all three sites. The range of soil organic matter (SOM) was broad, from ~1% to >10%. Generally, SOM values were lowest adjacent to the road and highest farthest from the road. We found no or weak evidence of a relationship between our indices of soil salinity and SOM levels, with electrical conductivity, exchangeable calcium, and cation exchange capacity. Results imply that if road deicing salts are altering patterns of roadside SOM and potential carbon sequestration, this effect was not captured by our experimental design, nor did deicing salts appear to have affected roadside vegetation during our most recent sampling effort. Our findings highlight the value of experimentally separating the multiple potentially confounding effects of winter maintenance operations on roadside soils: roads could focus the flow of water, salts, and sands to roadside soils. How these types of mass inputs to roadside soils might influence medium- or long-term carbon dynamics remains an open question, but their fuller characterization and possible flow paths will be essential to clarifying the role of roadside soils in terrestrial soil organic carbon sequestration strategies

Improving Wildflower Longevity in Roadside Seeding Areas

Re-vegetation efforts on bare roadsides of newly-constructed highways are primarily focused on the stabilization of soil to reduce rates of erosion. The Nebraska Department of Transportation (NDOT) seeds roadsides with a diverse mixture of grasses and wildflowers for site stabilization as well as to enhance the visual quality of roadsides. Although grasses dominate roadside plantings in terms of cover and density, wildflowers are largely responsible for the visual enhancement of recently-seeded roadsides. In addition to the visual component, wildflowers provide essential ecological functions on roadsides. Wildflowers improve water and nutrient cycling in the compacted roadside soils by increasing water infiltration and nutrient availability. Leguminous wildflower species increase nitrogen content of soil. The variability of wildflower leaf size, shape and orientation provides a more continuous soil cover than grass alone. The diversity of wildflower growth habits and life cycles also allows for a greater range of stand establishment and persistence when compared to sites seeded to grasses alone. This article presents strategies for increasing wildflower success in roadside plantings

The Effects of Biogeotextiles on the Stabilization of Roadside Slopes in Lithuania.

Soil erosion, Water erosion, Soil conservation, Geotextiles, Geotextile mats, Roadside slopes, Vegetation cover, Biogeotextiles , Palm mat geotextiles - Borassus aethiopum - Mauritia flexuosa - Buriti mats - BORASSUS Project - LithuaniaBiogeotextiles constructed from the leaves of Borassus aethiopum and Mauritia flexuosa are investigated at the Kaltinėnai Research Station of the Lithuanian Institute of Agriculture, which is participating in the EU-funded BORASSUS Project. Biogeotextiles are potentially excellent biodegradable and environmentally-friendly materials useful for soil conservation. Field studies on a steep (21–25°) roadside slope in Lithuania suggest biogeotextile mats are an effective and sustainable soil conservation technique. Biogeotextiles have a potential as a biotechnical soil conservation method for slope stabilization and protection from water erosion on steep industrial slopes and may be integrated with the use of perennial grasses to optimize protection from water erosion. The investigations demonstrated that a cover of Borassus and Buriti mats improved the germination and growth of sown perennial grasses. The biomass of perennial grasses increased by 52.0–63.4% under cover of Borassus mats and by 18.6–28.2% under cover of Buriti mats. Over 2 years, the biogeotextiles (Borassus and Buruti, respectively) decreased soil losses from bare fallow soil by 90.8% and 81.5% and from plots covered by perennial grasses by 87.9% and 79.0%, respectively

Plant species first recognised as naturalised for New South Wales in 2002 and 2003, with additional comments on species recognised as naturalised in 2000–2001

Information is provided on the taxonomy and distribution of 71 taxa of naturalised or naturalising plants newly recorded for the state of New South Wales during the period 1 January 2002 to 31 December 2003. Of these taxa, 32 are new records for Australia (prefaced with a †). These species are: Abutilon pictum, Acanthus mollis, †Aesculus indica (naturalising), Agapanthus praecox subsp. orientalis, Ajuga reptans, †Anigozanthos flavidus, Aquilegia vulgaris, Arbutus unedo, †Athertonia diversifolia (naturalising), †Bergenia x schmidtii (naturalising), Bromus catharticus subsp. stamineus, Bryophyllum daigremontianum, Bryophyllum fedtschenkoi, Calyptocarpus vialis, †Ceiba speciosa (naturalising), Cereus uruguayanus, †Cestrum x cultum, †Chamaecyparis lawsoniana, Cistus salviifolius, †Clematis montana, †Coprosma x cunninghamii, Coprosma robusta, Cornus capitata, Cotoneaster simonsii, Cotoneaster x watereri group, Crinum moorei, Cupressus lusitanica, †Cylindropuntia fulgida var. mamillata forma monstrosa, †Cylindropuntia prolifera, Cylindropuntia tunicata, Desmanthus virgatus, Drosanthemum candens, †Elaeagnus umbellata (naturalising), †Eragrostis trichophora, †Eupatorium lindleyanum, †Gibasis pellucida, Glechoma hederacea, †Hesperis matronalis, Hieracium aurantiacum subsp. carpathicola, †Inga edulis (naturalising), †Juniperus conferta (naturalising), †Justicia caudata, Lamium galeobdolon, Lathyrus tingitanus, †Lysimachia fortunei, †Maackia amurensis, †Monstera deliciosa, †Murdannia keisak, Odontonema tubaeforme, Oxalis vallicola, Phoenix canariensis, †Physostegia virginiana, Pinus patula, Pittosporum eugenioides, †Pittosporum ralphii, Pittosporum tenuifolium, Plectranthus ecklonii, †Potentilla vesca, †Prunus campanulata, †Rhododendron ponticum, Rosa luciae, Rubus rugosus, Ruellia squarrosa, †Senna multijuga, Stapelia gigantea, Stephanophysum longifolium, Strobilanthes anisophylla, †Tabebuia chrysotricha, †Tabebuia impetiginosa, †Tradescantia pallida and Ulmus x hollandica. Additional notes and name changes are recorded for plants first recognised as naturalised for New South Wales over the period 2000–2001. The identification of several naturalised taxa occurring in New South Wales has been corrected. Plants formerly identified as Pinus nigra var. corsicana are now considered to be Pinus halepensis; Cylindropuntia arbuscula is Cylindropuntia kleiniae, Cylindropuntia tunicata is Cylindropuntia rosea, Abrus precatorius subp. precatorius is now Abrus precatorius subsp. africanus and Cotoneaster ?horizontalis is Cotoneaster microphyllus. Further field studies have revealed that Cylindropuntia leptocaulis, Cylindropuntia spinosior, Hypericum kouytchense and Chamaesyce ophthalmica are more widespread than previously thought

Are calcareous soil ecosystems and associated drainage waters less susceptible to damage from winter road salting than acidic soil ecosystems?

Previous studies of upland roadside soils in Cumbria, that would normally be naturally acidic, have highlighted that (a) runoff from roads subjected to long-term road salting can dramatically raise soil pH down slope in upland areas; (b) the soil pH increase dramatically changes N cycling in soils down slope, increasing mineralisation of organic matter, ammonification, ammonium leaching down slope and nitrification and nitrate leaching; (c) the increase in nitrification substantially increases nitrate leaching to down-slope rivers, and this is readily detectable in field studies; and (d) loss of soil organic matter over decades of salting is so great that organic matter is no longer substantially solubilised by high salt concentrations found in soil solution below road drains. This paper tests and supports the hypothesis that such effects are minimal for more calcareous soil ecosystems. It examines the soil and soil solution chemistry on another Cumbrian upland highway, the A686 near Leadgate, Alston. Sodium % of soil CEC values for soil transects affected by spray containing road salt are similar at both the A6 and A686 sites. However, spatial trends in calcium, magnesium, ammonium, and nitrate concentrations as well as pH differ, as a direct result of the higher weathering rate of parent material and possibly also the presence of limestone walls above both spray-affected and control transects at the A686 site

Master\u27s Project: Assessing Unpaved Road Runoff in the Mad River Watershed of Central Vermont

Over half of the local town roads in Vermont are unpaved (VBB, 2009). In the Mad River Watershed of central Vermont, 58% of the roads are unpaved. These compacted surfaces, despite their lack of tar, provide hundreds of miles of impermeable surfaces that extend the stream network, and transport runoff and pollutants to our water bodies. In this project, 12 sites within the Mad River watershed were monitored with the goal of evaluating the amount of runoff that is generated on the road surface itself as compared to flow that enters roadside ditches via groundwater seeps and overland flow from adjacent land. Each site was monitored for stage using an ISCO 6712 Automated Water Sampling Unit with an attached pressure transducer, and rating curves were developed from manual volume measurements in order to connect stage values with runoff volumes. Each site was mapped to determine the contributing road surface drainage area, and these values were compared to the slope of linear regressions developed for storm precipitation and runoff totals. Modeled road surface hydrographs were developed for 11 of the 12 sites, using the rational method, and were compared to hydrographs developed using measured runoff. One-quarter of the sites appear to have regular runoff contributions that originate outside of the bounds of the mapped drainage area. Five of the eleven sites also displayed seasonal variations where runoff originated outside of the mapped road surface area during times of greater land saturation. These results indicate that roads can sometimes contribute far more than just the runoff that is generated on their surface alone, and that the quantity and occurrence of these external contributions may increase with an increase in the drainage source area that can be seen in seasons when the ground is saturated