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Hydraulic seeding on sand dunes
Hydraulic seeding using mulches and fertilisers it can be effective in helping
to establish seeds of dune grasses. This is especially valuable in areas where
sand movement prevents the successful establishment of seedlings when seed only
is sown. Typically in the UK, a clover and grass seed mixture containing species
such as Trifolium repens, Festuca
rubra, F. ovina and Agrostis
tenuis sibth. (capillaris L.) is used. Where rapid colonisation
is required the application of a water-based slurry with added fertiliser and/or
seed can be applied. Mulches may be added to bury the seed and chemical stabilisers
to reduce seed loss by erosion. These methods have varying degrees of success
and are probably most applicable in areas with little or no conservation interest
and where recreational use is high.
Research trials are reported in sand wastes produced by the china clay industry
(Roberts & Bradshaw 1985) show the importance
of mulching, substrate characteristics and climatic conditions on seedling establishment.
It is suggested more attention is paid to legumes since many commercial hydraulic
operations fail not through failure of grass establishment, but through subsequent
nitrogen deficiency.
At Camber
Sands, East Sussex the method employed involved disc-harrowing chopped
straw into the surface sand, spraying seed and fertiliser in a water slurry
and topping off with a second layer of straw covered with bitumen. Seed mixture:
40% creeping fescue; 20% Westerworld rye-grass; 20% perennial rye-grass (S.23);
5% common bent (Agrostis tenuis); 5% meadow
grass; 5% broom (Cytisus scoparius) and 5%
white clover (Pizzey 1975).
Comment: The Scottish Natural Heritage 'Beach
Management Guide' and the British Trust for Conservation Volunteers
(BTCV
Guide) cover this approach in some detail.
References
Pizzey, J.M.
1975.
Assessment of dune stabilisation at Camber, Sussex, using air photographs.
Biological Conservation, 7., 275-288.
Roberts, R.D. & Bradshaw, A.D.
1985.
The development of a hydraulic seeding technique for unstable sand slopes. II Field evaluation.
Journal of Applied Ecology, 22/3., 979-994.
Abstract...
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