Soils in their environment - Fundamentals of the Physical Environment - page 447

1m

Sphagnum Peat Sphagnum Peat

Raised moss
stage

Mixed Eriophorum
and Sphagnum Peat

Mixed Eriophorum
and Sohanum Peat

0

Grass-sedge Peat Grass-Sedge Peat

Low moor
stage

Lake Muds

1m

Figure 18.13 Different types of peat in a raised bog or raised moss in lowland Britain.
Source: Adapted from Bourton and Hodgson (1987)

Plate 18.18 Salt crusting in a field irrigated by a sprinkler system on desert sand, Libya. Main factors are high rates of
evaporation in summer, and chemicals added as fertilizers to the irrigation water. Scale in cm.
Photo: Ken Atkinson

surface, such as in river flood plains and low-lying
depressions. Also, salts will accumulate where waters in
inland drainage accumulate, or where lakes exist or existed
in the past. Coastal areas can also accumulate salt from
aerial sea spray, called cyclic salt , and from the incursion
of salt water into the coastal aquifer. However, poorly

planned and poorly maintained irrigation schemes have
frequently been a major reason for the spread of salt-
affected soils in the arid zone. Misuse by agriculture has
resulted from the over-application of irrigation water or
the failure to provide efficient drainage to remove surplus
water from the soil. As the water table rises, capillary