Every type of snow removal, from plowing parking lots to clearing sidewalks, affects its peripheral surroundings. The efficacy of the snow removal process depends on maintaining safe driving conditions on the roads. If good practices are not used, the removal process can have damaging effects on the surrounding environment.
The landscaping industry experiences difficulties if salt is thrown too far or bounces off roadways and lands on the grass or plants. Large quantities of misplaced salt can alter the salinity of the soil, making it more difficult for manmade landscape to flourish.
Unfortunately, these effects only become noticeable months after the last of the snow melts and roadside vegetation begins to grow again. Roads with adjacent trees, shrubs, plants or manmade landscape are of highest concern when it comes to salt and chlorides. High concentrations of chloride can interfere with a plant’s ability to absorb moisture from the soil and can disrupt soil structure and aeration.
Opposing Points of View
The Salt Institute initiated a formal partnership with the nation’s “Local Technology Assistance Programs (NLTAPA) to provide training for professional snow removal companies in how to use sensible salting. This is a way of reminding snow removal companies to use “just enough and no more” when clearing roads. The program has been successful in reminding professionals to be responsible in their salt application and maximizing customer service.
Although high concentrations of salt or chlorides would be dangerous for plant life, The Federal Highway Administration’s recent research concluded that, most often, no serious problems occurred from high soil salinity. The administration studied highway runoff and concluded that it was “generally cleaner than runoff from buildings, farms, harbors, or other non-point sources.”
Reversing the Effects
When salt does interfere with the landscaping, it is because chloride ions draw water out of the root and into the soil. Evaporation in the soil causes an accumulation of salt in the soil and dehydrates the plant. In areas with poor soil drainage, this can be a bigger problem because water flow is required to flush the chlorides below the root zone.
Landscapers have countered soil salinity in dry areas by leaching the area. Leaching is defined as dissolving out soluble constituents (like chlorides) from a solid (like soil) by percolation. See Figure 1 below for a visual example. If the soil is too compact, an additive must be incorporated to improve its permeability. Gypsum, a mineral compound which produces calcium when dissolved, has proven to be the most efficient and least expensive method for returning soil to a healthy balance.
An Ounce of Prevention
Professional snow removers can use smart application processes like “just enough and no more” as well as factoring in wind and spreading salt on the upwind side of the road, allowing gravity to distribute it naturally. Timing applications and prioritizing routes ensures that salt is applied early and properly. By using these processes, less salt is needed and the environment is better protected.
In addition, landscaping professionals can plant salt-tolerant trees, shrubs and grass in areas closest to sidewalks, drivelanes, and parking lots. They can alter the drainage patterns to avoid accumulation of salt runoff near plants. They can also protect salt sensitive plants with burlap wraps or wooden barriers.