Table 4.
The areas of modified land units in
the interflow of Amu-Darya and Murgab
rivers, km (After L.M. Grave,
V.P. Kostjuchenko, 1978)
= ‘ss 0 um (umm [ew lem we ame ams o cx» o up e sew | m ue e. mu wem aue dm sk amr MP m | m - m» 7"
?
Shallow Land units
Canal areas |! water and ' : T r
! bordering !hyáromor- | seni-hydro-|transi-|total
t (phous :morph phousitional j area
-- —— mà e o e d 2 2e ou ue a em eh jun jen. cm ed qal eie um om mj emt pent m
Amu-Darya borde-
Le 19 TI 5 36
(30-50 km)
Kelif solonchak
area (50-IO5)km 48 I80 79 25 240
Obruchev takyr .
area (I05-I80 km) 2 17 20 4 43
Murgab area with
sand ridges IT 51 38 14 II4
(I80-3I0 km)
Total - 62 265 148 56 555
The utilization of aerial photos to study the moderate human
pressure (the second key area) has showjthat process of sand stabili-
zation prevail here.
Blow-offs represent a characteristic feature by the wind
erosion process, They are often confined to lower and upper parts of
sand ridges where the wind direction perpendicular to the intensity of
wind gronten at different stages of its development (initial, developed,
final).
It is known that one time aerial photography allow to obtain
static critirea but not dynamic features of the objects or processes.
At the same time the study of geosystems dynamics is very important,
because we need to estimate the ternds. Application of repeated aerial
photography may solve the problem.
We have studied repeated aerial photos of the two missions
(I964 and I977). Estimated on the photos of !:the first mission the
coefficient of wind erosion efficiency was 0,36. The same criterium
estimated on the photos of the second mission was 0,38. These data show
that, the area under consideration belongs to one with active erosio-
nal process. The second idea is that the process of wind erosion beca-
me stable in the area.
While the process of wind eràsion become weaker barkhans on
sandy riges ovefvby vegetation. Takyrs in inter-ridges depressions are
also covered with vegetation. Eolian relief is transformed to barkhan-
hummock complex. Plant species composition and density is also changed.
658
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