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Native Seeded Compost Blanket

27 Brenchley Road, Lyttelton, Christchurch
Turning the Land Stabilization Site into the Nursery Site.
Area : 1020 m2
Date : May 2017

Backstory

The purpose of this trial was to develop a methodology that would facilitate erosion control and cover crop establishment, whilst at the same time provide a seedbed for the regeneration of native species.

We wanted to explore an alternative growing medium to topsoil, using instead a fertile medium with inherent binding properties.

We trialed a 50 mm Engineered Compost Blend (Enviroblanket) over a clay base, applied up to a 1:1 gradient.

Challenges

This site has experienced periods of inundation and near drought in the ten-month establishment period. The Eviroblanket absorbs and holds moisture for rapid plant establishment.

The Enviroblanket’s are usually 50 mm to 100 mm thick. They are installed by blowing the product pneumatically onto slopes with gradients up to 2: Slopes 1:1 with additional support from Envirosocks and Enviroberms.

Compost blends used for erosion control and seed germination purposes have larger particle sizes to allow rainfall to be absorbed and rapidly filter sheet flow. The Enviroblanket makes excellent ground surface contact that prevents the soil from rilling underneath.

The Solution

Native Seeds were sourced in the Port Hills Ecological District in 2017. Clover establishes quickly in Spring, tolerates clay and drought, clover always has a fresh, lush appearance and generally grows 15 - 25 cm in height making it an ideal weed suppressant.

Clover root system is tenacious, binding and has no difficulty penetrating clay. Consistent and well spaced germination of three species, mainly Hebe, Coprosma and Ribbonwood. The high stocking rates of Ribbonwood are probably due to self seeding from parent tree.

Canopy cover in standard re-vegetation growing in prime conditions at 1.5m spacings will take three years. This trial has achieved canopy cover in ten months.

Our Outcome

Nearly one year on the results on the ground speak for themselves. Canopy cover in standard re-vegetation growing in prime conditions at 1.5m spacings will take three years. This trial has achieved canopy cover in ten months.

The Enviroblanket when applied is free of weeds and pathogens and 11 months on is relatively weed free. We have had a good strike rate with all species introduced into the blanket, Coprosma and Hebe have been most successful.