Page 164 - Arabian Studies (II)

156 Arabian Studies II

than a small proportion of the holding with sufficient irrigation
water while the high temperatures preclude the fruiting of crops.
However, it would seem that a greater proportion of the holding
could be cultivated, both in summer and winter, if there was a
willingness on the part of the smallholder to use new ideas and
techniques. It is the commercial smallholders who have benefited
most from the proximity of Digdaga Agricultural Trials Station — the
latter has been important in introducing new crops, in seed selection
and in carrying out fertiliser trials. As a result, most of the
smallholders now apply ammonium sulphate to ‘leafy’ vegetables
such as cabbages, in order to alleviate the low nitrogen status of the
soil. Organic manures are also applied being mainly obtained from
local Bedu or hill tribes, while one or two cultivators also use humus
imported from the Lebanon. A very recent feature has been an
increasing use of urea by the more progressive farmers.

3. The Effects of Cultivation Practices on Soil Characteristics

(i) Uncultivated soils
In a reconnaissance survey of the soils of the Trucial States (Stevens,
1968) the soils of Ras al-Khaimah were classified in three major
groups — sierozems, non-saline alkali and saline-alkali soils. These
groups were subdivided into lower categories on the basis of their
texture and carbonate content. This was an artificial classification
scheme but it was suitable for the type of reconnaissance survey
undertaken, in that the categories were descriptive of the soils and
highlighted their salient features in terms of their effect on potential
cultivation.
! The soils have now been reclassified according to the FAO/
i UNESCO scheme and the distribution of soil orders and units is
shown in Fig. 4. The soils of the Jiri Plain are basically xerosols
having organic matter contents in excess of 0.5 per cent, reflecting
the sparse cover of Haloxylon salicornicum. The soils are generally of
light texture and have a weak angular blocky structure in close
proximity to the surface which consists, where undisturbed, of a thin
platey crust. Gravel horizons often occur within 50 cm. of the
surface. The xerosols are characterised by moist colours of
10YR4/3—4/4 (dark brown), pH values of below 9.0 and conductiv­
ities less than 1 mmho./cm. at 25°C. The cation exchange capacity is
dominated by the calcium cation, though in some profiles there is an
increase in exchangeable magnesium at depth. A belt of heavier
textured xerosols is found along the western edge of the plain and

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