Not long ago, we posted a one-year-later update from a Biotic Earth project at a critical waterwater facility rehabilitation. And while the one-year results are exemplary, it’s important to know that hydraulic growth medium (HGM) installations go back further and continue to produce fantastic results.

In 2004, the large energy generation company, Hydro-Québec, wanted to combine peat moss with its wheat-based straw mulch to help reclaim road sides that were being built on their northern construction sites near James Bay.

This project was located in the Northern Boreal forest where salvaging topsoil was impossible. Importing topsoil to this area was not possible. To further complicate matters, the subsoil was highly erodible sand and their growing season extremely short.  Vegetation needed to be established within one season to make it sustainable without the use of topsoil.

To accommodate this requirement, a Verdyol Biotic Earth™  HGM was applied at a rate of  2000kg/ha—a decent speed of application and one that perhaps helps underscore the time savings realized on sites that utilize hydraulic application of erosion controlling, soil-improving growth mediums. A great deal of space can be covered quickly and effectively.

Another attractive feature of these HGM applications is that a good operator can incorporate a smart seed mix to get the variety of plantings many project teams prefer. The seed mix established with Hydro-Québec consisted of:

34% Creeping red fescue
8% Timothy
5% Bent Grass
20% Birdsfoot trefoil
15% White Clover
15% Barley
3% Reed Canary grass

That mix was applied at a rate of 175 kg/ha. It was also a key element to working with this company, which has a very good reputation for renewable energy production. Environmental responsibility is part of its corporate identity. As such, coming up with a seed mix that met the company’s goal of “re-naturalization” of the land and incorporating the right tackifier to hold this HGM system intact and allow the soil amendment and vegetation to develop was extremely important.

Additionally, a 12-18-12 fertilizer was used and 25% of this fertilizer was slow release. The tackifier was applied at a rate of 80 L/ha on the steeper slopes to firm up those sections and make sure they would not lose cohesion during storms that might come prior to full vegetation.

Grass grew within the first season and within the second season the birdsfoot trefoil bloomed. This is the typical pattern with Verdyol Biotic Earth HGM systems: strong, thick-rooted grasses at the outset that get the site into and through first winter, followed by more advanced growth of additional vegetation in the next season.

More than six years later, this site continues to function well and Hydro-Québec still specifies in its northern areas a straw-and-peat mix as developed for this project.

While hydraulic growth mediums have been shown to be magnificently effective in spurring the growth of strong, long-term vegetation, few of these advanced formulas would succeed without the inclusion of tackifiers.

Tackifiers are specially engineered to create a bond in the hydraulic growth medium. Without them, all the time spent creating the biotic-rich growth medium might go to waste as storm events could wash the growth medium away before vegetation establishes itself. Tackifiers strengthen the hydraulic growth medium, providing the time needed for vegetation to flourish and real long-term erosion control to be created.

Tackifiers are made from a number of sources, but the technical nature behind their develop truly sets some producers apart. EarthBound® 2000 Soil Stabilizer & Tackifier*, for example, is formulated from both long chain and cross-linking molecules in conjunction with a hydrocolloid vegetable gum-based tackifier. It provides effective soil structure stabilization and water infiltration. Most importantly, it adheres mulch to the soil surface.

EarthBound 2000 Soil Stabilizer & Tackifier is engineered for mild to moderate slopes.

Even tougher formulas are available. EarthBound® Scientific Soil Stabilizer & Tackifier is engineered for effective erosion control, mulch and soil stabilization for moderate to extreme slope gradients and extremely erosive conditions.

You can find these tackifiers and Ver-Tack Hydroseeding Tackifier utilized by Verdyol Hydraulic Growth Mediums.

Hydraulically applied growth mediums are very economical, but the science behind them is complex. The choice of tackifier plays a huge role here. And whether you’re a hydroseeding contractor or the client benefitting from all of the science, you can be sure that when you use a Verdyol Hydraulic Growth Medium you’re getting a strong, well-engineered system.

Learn more at BioticEarth.com.

(NOTE: EarthBound® is a registered trademark of EarthChem, Inc.)