Fen Management Handbook - Scottish Natural Heritage

generally more acidic than silts and clays. Clay soils will always give rise to fertile
vegetation types due to their high nutrient holding capacity. If there is a significant
quantity of clay it is likely that reed will dominate. There are exceptions to these
general principles and the alkalinity of groundwaters reaching the wetland will also
significantly affect the type of fen vegetation that will establish. It may be necessary
to lower substrate fertility by removing top soil from former agricultural land.
In order to establish moderately species-rich fen vegetation, nutrient levels should
ideally be low, especially phosphate concentrations which should be lower than
15 ppm, ideally below 9 ppm. High concentrations of calcium in any groundwater
feeding the proposed site will reduce the availability of phosphate through the
process of co-precipitation.
9.7.6 Soil analysis
Digging a soil test pit,
Cayton and Flixton Carrs,
Scarborough (N. Droy)
Soil analysis is used to determine nutrient status and pH of a soil. It usually includes
pH, available potassium, phosphorus and magnesium, total nitrogen and sometimes
an assessment of soil texture. Analysis is usually undertaken by a specialist
laboratory, but the reliability of the analysis depends on sampling accuracy.
Further information and advice is provided in Natural England Technical Advice
Notes TAN 20 Soil sampling and analysis for habitat restoration and recreation
in agri-environment schemes, and TAN 31 Soils and agri-environment schemes:
interpreting soil analysis for habitat creation and restoration.
Key points to consider when collecting soil samples:
– Use the correct tool e.g. a cheese corer, screw auger or pot corer
– Sample to the correct depth: 0-20 cm on arable land, 0-7.5 c.m on
permanent pasture
– Include the top few centimetres of soil, which may have differing pH
or nutrient values
– Take account of variations in soil depth, texture and past
management over the sample area
– Take the correct number of sub-samples (at least 25 cores totalling
0.5-1 kg)
– Dispatch samples for analysis as soon as possible
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