|
|
More news |
| The effect of de-icing salts on urban greenery | |
| It is important that landscapers select salt-resistant species for planting in urban areas and along roadsides. De-icing salts applied to roads and paths represent a serious problem to plants in regions with cold winters climates. The salts damage plants at the margins and guardrails of flower beds and other urban greenery of the streets, inducing the presence of dry leaves, necrosis, malformations and anomalies, often incorrectly diagnosed as an attack by pathogenic organisms. In most cases the first visible effects of a high salt content in the soil are necrotic areas on the leaves. This necrosis is caused by the accumulation of salts causing partial or total destruction of chlorophyll and therefore the death of the plant tissue. The speed and intensity of the necrosis depends above all on the biological properties of the salt and on the kind of salt in the soil. Three types of salts were used in an experiment with plants of the widely used shrub Cotoneaster salicifolius. The 3 salts were sodium chloride, calcium chloride and sodium sulphate at two different concentrations. The most important damage is caused by root absorption of solutions salts containing chloride ions. To further evaluate the effect of the root absorption of sodium chloride solutions, leaf yellowing and necrosis was observed in a number of evergreen species after the application of sodium chloride at 0.25 N. The damage was very evident with Viburnum davidii, Berberis candidula and Pyracantha coccinea. On the other hand, Viburnum tinus, Elaeagnus pungens and Ligustrum ovalifolium showed little damage. M. Devecchi, D. Remotti, ISHS Acta Horticulturae 643: International Conference on Urban Horticulture www.actahort.org |
|