Extent of Work The work included in this contract is as follows: Straw Mulching of Roadside Batters,etc on slopes generally less than 3:1.
Contractors Qualifications Each tenderer shall submit documentary evidence of his proven ability to carry out this type of work. Such evidence shall include a list of similar projects satisfactorily completed together with a statement of the qualifications and/or experience of the personnel to be employed on the works.
Site Preparation It is recommended that whenever possible, areas to be seeded should be topsoiled. Prior to topsoiling, the area should be ripped (up to 200mm deep). If topsoiling is impracticable, the area should be ripped using a suitable machine or a chain designed for this purpose. Wherever possible the area should be free of weed growth, large stones or other debris.
Application Rates The required areas shall be treated by the Contractor with the following:
a. Cover Crop Seed and usually includes a cover crop
25 - 35 kgs per Hectare.
b. Native Seed
5 - 15 kgs per Hectare
c. Fertiliser
200kg - 500 kg per hectare. Selection will depend on soil analysis results and client requirements.
d. Straw
Average bale = 20kg. 250 bales per hectare ( minimum).
e. Binder
Anionic Bitumen Emulsion 50/50 bitumen water 1500 - 3500 litres per hectare.
Polymer binder maximum 350 litres per hectare.
Note: The seed and fertiliser rates are a representative sample only of the quantities that should be applied per hectare.
Operation
Application of Seed and Fertiliser Seed and fertilise can be sown in several ways but the method will depend on the topography of the site.
On slopes less that 3:1
Apply by conventional tractor drawn sowing equipment or spread with spinner broadcaster and then harrowed in. In some cases where the area is smaller, seed and fertiliser can be spread by hand and raked into the surface.
On slopes greater than 3:1
Seed & Fertiliser should be hydroseeded through a hydromulching machine. This method can also be used in those larger difficult and inaccessible areas where conventional equipment could no operate or where it would not be safe or prudent to hand broadcast the seed and fertiliser.
Note: Where lime or Gypsum is required in some cases this can be applied in the same mix as the seed and fertiliser. Higher quantities may need to be applied as a separate operation.
Application of Bitumen and Straw
Straw shall be applied through a Straw mulching machine or machine designed for this purpose that can operate in the same or similar way.
There are two approaches:
Both the Straw and Bitumen Emulsion can be applied at the same time through the Straw Mulching machine.
Straw can be applied as a separate operation followed by an overspray of Bitumen Emulsion.
Note: In this approach other binders, such as Polymer, can be used to tack down the straw.
Application rates for this operation will vary according to the product used. The suggested rates are as follows:
Liquid Polymer Binder 300 350 Kg per hectare Powder Envirotack 40 60 Kg per hectare
After Care Maintenance Where possible, water adequately to ensure a continuous vigorous and healthy growth of grass. A great deal will depend on natural rainfall, but as a general guide, 25mm of water should be applied to al seeded areas weekly. It is important that the seed bed under the Straw Mulch Mat be kept moist until germination occurs. After germination, sufficient watering must be kept up until a healthy sward of grass is achieved.
