Agriculture Reference
In-Depth Information
6 weeks at 6.5 and 15
C, to examine whether vegetation cover was a major
source of DON in soil leachate.
°
Materials and Methods
Site description
Soil samples were collected from Glensaugh in NE Scotland. The soil
is a peaty podzol of the Gaerlie series (Stagni-Placic Haplic Podzol:
FAO/UNESCO, 1994) which is underlain by quartz-mica schists of
Dalradian age. Associated with this soil type is acid moorland vegetation
dominated by
Calluna vulgaris
L. and
Vaccinium myrtillus
interspersed with
Deschampsia flexuosa
,
Nardus stricta
,
Vaccinium vitis-idea
and
Erica cineria
and which is grazed by sheep. In our study, the vegetation present on
the soil cores was dominated by the moss
Rhytidiadephus squarrosus
and the
grasses
Agrostis capillaris
and
Anthoxanthum odoratum
. The presence of the
latter indicated that the area had been improved agriculturally in the past.
Soil incubation experiment
Forty-five soil cores (diameter 7.8 cm, length 10 cm) were sampled at
random locations, within an area of 400 m
2
, using PVC tubes. In the
laboratory, the soil cores were removed from the tubes and the vegetation
and surface litter separated from each core. The cores were trimmed, from
the base, to a length of 6 cm and weighed. Fifteen cores were placed inside
each of three incubators set at 5, 10 and 15
C. Three replicate cores were
harvested at each temperature after incubation for 0, 7, 14, 28 and 56 days.
The soils were sieved (< 2 mm) to remove stones and roots and sub-
sampled for pH and water and 0.5 M K
2
SO
4
-extractable inorganic and
organic N determinations. Soil moisture content was determined on day 0.
The dried soil was then milled and analysed for total C and N.
°
Soil leachate experiment
Twelve intact soil cores were sampled by inserting hollow PVC tubes
(diameter 15 cm, length 10 cm) into the soil at random locations. At six
sites, the surface vegetation and root mat (2-3 cm thick) were removed
prior to inserting the PVC tubes. In the laboratory, three cores with and
three cores without vegetation were placed inside each of two controlled
environment cabinets set at 6.5 and 15
C, a relative humidity of 65% and a
day length of 12 h. After 48 h, the soil cores were leached with artificial rain
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