Using a Top Soil Alternative and Prescriptive Formulations for Slope Stabilization and Turf Establishment
There can be two different approaches to slope stabilization and turf establishment after earth work is completed on a construction project. The approach taken depends on the objective and motivation of the decision maker(s). The Contractor’s objective may be to achieve an initial stand of grass, complete a regulatory requirement, receive final payment, and then move on to the next project. Many commercially available mulch products, combined with seed, fertilizer and some really good luck with Mother Nature can get there, and the contractor meets his goal… but will it last?
On the other hand, the Owner, who will live with the result indefinitely, may have a significantly different objective. Instead of simply initial vegetation, the owner is more likely to be interested in slope stabilization and turf establishment that is sustainable. This can certainly be achieved, but requires some investigation and planning. And while somewhat more costly, a more holistic approach to the challenge can consistently yield an outcome that enhances property value and is more environmentally responsible.
It is commonly known that the two most important variables when seeking to establish vegetation are: availability of water and soil conditions.
When excavation occurs, in order to build a pond for example, the soil characteristics in excess of 8-10 inches below the natural surface are typically very low in nutrients and organic material which are critical elements of a healthy growth zone and seed bed. Faced with this reality, the typical recommendation is to cover the area with several inches of rich, fertile topsoil prior to planting. The problem, however, is that good topsoil is usually scarce and/or very costly to import and spread.
Profile Products, the world’s largest manufacturer of hydraulically applied erosion control technologies, has developed ProGanics Biotic Soil Media as a topsoil alternative. This product is designed to accelerate the development of depleted soils that have low organic matter and very limited biological activity. ProGanics is easily applied with a conventional hydro seeding machine, via tower gun or hose, which is especially helpful when needed on challenging sites with limited access, or in sloped areas where topsoil placement is difficult or impossible.
In order to insure successful slope stabilization and turf establishment for our clients, Construction EcoServices collects a soil sample for each area to be stabilized. These samples are sent to an independent laboratory to determine soil conditions/characteristics. The soil analysis will determine:
- Soil pH
- TDS (Total Dissolved Salts – ppm)
- SAR (Sodium Absorption Ratio)
- Organic Matter %
- Sodium (As % Base Saturation Cation Exchange Capacity (CEC)
- Soil composition (% Sand, Silt & Clay)
In addition to determining the appropriate soil amendments and application rates necessary to mitigate potential problems, the analysis also recommends the appropriate quantity of ProGanics BSM to be applied, should good topsoil be unavailable, too expensive to import or difficult to apply. Our experience has shown ProGanics to be significantly more cost effective in most cases.
These proscriptive agronomic formulations are added to the mix of seed, fertilizer and ProGanics to create a rich environment for germination and growth. For slope stabilization, the final ingredient in this solution would typically be Flexterra Flexible Growth Medium (FGM) or ProMatrix Engineered Fiber Matrix (EFM). These robust mulch products provide a top layer of mechanical stabilization to resist erosion and provide a protected growth environment even in very challenging conditions.