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Conventional treatments, such as ripping or mole draining, were not feasible be-
cause of the shallow soil cover, and, in any case, one of the aims of the experiment
was to see if they could be avoided. Even the use of fertilizers at the outset risked
the too luxuriant growth of creeping bent before the sown species were established. A
rather low level of fertility is actually desirable if one wants to maintain floristic di-
versity ( cf Wendlebury Meads ) , and one is not too impatient about achieving results.
In the event, 28 of the 31 sown species were successfully established within the first
four years after sowing, producing a short, herb-rich sward in which several species
of butterflies were able to build up strong colonies.
The establishment of shrubs and trees on this site is, at the time of writing, still
undergoing trials to determine the best species and methods of planting. It will be an
even slower process because of the limitations on deep rooting for many years. Even-
tually, trees will promote marked changes in the soil ecology by bringing up nutrients
from the buried organic matter, and enriching the surface layers through the shedding
of their leaves.
This chapter concludes with the description of an attempt to transfer and re-es-
tablish particular grassland communities using the same principles of soil handling as
at Shepperton described earlier. The opportunity for this experiment arose during the
construction of the M25 motorway near London Airport in 1980, when gravel was
extracted from a small part of Staines Moor. Three small, discrete areas were located
which supported plants characteristic of dry grassland, damp grassland and marsh:
species such as bird's-foot trefoil Lotus corniculatus and lady's bedstraw Galium ver-
um in the first case, jointed rush Juncus articulatus and creeping buttercup Ranuncu-
lus repens in the second, and yellow flag Iris pseudacorus and water forget-me-not
Myosotis scorpioides in the third.
These areas were surveyed and pegged out on a 6 m grid, each square being
bored with a soil auger to determine the nature and depth of soil and overburden.
Some 400 m away a receptor pit, filled with clay and rubble five years previously, was
graded to the appropriate levels, and in November 1980 the stripping and transfer took
place. First the top 10-15 cm of vegetation and soil was scraped off and stored tem-
porarily, then a second layer varying from 20 to 40 cm depending on the bore samples,
and finally an underlying zone of unwashed sandy gravel, to give a total thickness of
about one metre. These layers were straightway placed in correct sequence in the new
area but in adjacent strips; at no time did vehicles travel on the undug donor site or on
the placed material at the receptor site. The finished levels sloped down from the dry
grassland zone to the marshland zone, and the correct water tables were maintained
by pumping and by reference to a water level gauge.
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