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Gardens used to reduce landslides
24 September 2013
Investigación y Desarrollo
With a technology developed at the National Autonomous University of Mexico (UNAM), the slopes of the roads could become monumental gardens, reducing the number of landslides and isolation between populations.
The main objective is to use it in rocky slopes because, besides obtaining green areas next to the roads, they can be safer with the planting of proper vegetations, given that the function of the plants is to retain the soil.
The researcher at UNAM, Aracadio Monroy Ata, has studied the procedures of a technique called hydroseeding that allows “green upholstery” to populate the slopes bounding the roads.
Currently in use, hydroseeding allows plants to spread on rock surfaces; it contains seeds, moisture-retaining substances, adhesives and chemical fertilizers, among other components. If done during rainy season the vegetation is established and plants seek to make roots, therefore growing without soil or in a steep slope. However, all this components are of artificial origin, whose chemicals have an environmental impact.
Now, the scientific team at UNAM has developed a completely organic formula that solves the pollution problem, improves the plantation growth and has a lower cost than those already in the market. Besides, hydroseeding has proved to be a better method than geogrid (polymer mesh that provides reinforcement to the soil) and a more advantagable ecotech.
To do this, the university researchers have substituted the chemical products of the original technique for organic ones. For example, to retain moisture they use sawdust or moss instead of hydrogels; they apply mycorrhizae (fungi that associates with plants and generate a mutually beneficial symbiosis) instead of chemical fertilizers, and have developed a nopal (type of cactus) based polymer to ensure the adhesion of plants to the slopes.
By using mycorrhizae, soil aggregates giving stability and allowing a better adhesion to the rock or substrate. In hydroseeding, environmentally harmful chemicals are also use for fungi and bacteria control; in the case of the academic development the researchers used rosemary essence oil that works for the same purpose.
The mexican development can be used for almost any type of vegetation in soilless or steep slopes, with an inclination up to 45 degrees; if a higher inclination is the case, up to 90 degrees, a yute (high resistance fiber from an herbaceous plant) mesh would be used, given that rain or another meteorological phenomenon could unstabilize the hydroseeding.