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IAPRS & SIS, Vol.34, Part 7, *Resource and Environmental Monitoring", Hyderabad, India, 2002
farmers. Most of these lands are private holdings and farmers
take rainfed crops during good rainfall years.
B-2 Stabilized Sand Dunes in more than 250 mm Annual
Rainfall Zone:
B2-V Semi- stabilized to stabilized high sand dunes and
major obstacle dunes: Such types of sand dunes (above 40
meters height) in more than 250 mm annual rainfall zone are
mainly private holdings and used for rainfed agriculture up to
their middle flanks. Government holdings are either permanent
' pastures or classified under culturable waste. Windward side of
such dunes excepting the crest, is put under cultivation during
the favorable rainfall years but the productivity is very poor.
These are marginal lands with intensity of cultivation below 30
%.
B2-E Semi-stabilized to stabilized moderately high dunes
and minor obstacle dunes: Moderately high sand dunes range
from 15 to 40 meters height. Both stabilized and semi-stabilized
dunes as well as minor obstacle dunes located in more than 250
mm annual rainfall zone are included in this category. These
dunes are primarily used for rainfed arable farming and hence
these lands are under heavy biotic pressure. Frequent
cultivation of these dunes aggravates wind erosion hazard and
loss of productivity and fertility.
B2-D Semi-stabilized to stabilized low dunes, highly
hummocky and shrub coppice dunes: In between highly duny
complex lie low sand dunes (6 to 15 meters height), highly
hummocky terrain and shrub-coppice or fence line dunes.
Fence line dunes and highly hummocky topography is created
by deposition of sands from the adjoining high active sand
dunes. The deposition of fine and loose sands has declined the
productivity and ultimately the use capability of land.
B3 Interdune Area:
Inter-dune area is a dominant landform of the desertic terrain.
These areas are found in between the moderately high-to-high
sand dunes or between sand dunes and sandy plain. Sandy
undulating older alluvial plain and sandy undulating buried
pediment are other landforms associated with this category. The
soils of interdunal areas are loamy fine sand and slightly
calcareous. Inter-dune areas are further classified into vital,
essential and desirable categories.
B3-V Closely spaced Inter-dune Area: Closely spaced inter-
dune areas occur mainly in the highly infested duny complex
region with chains of sand dunes. These areas are characterized
by undulating topography created by hummocks and low sand
dunes. Such lands occur dominantly in eastern part of Barmer;
western part of Jodhpur, Churu (Anon., 1988) Sikar (Singh et
al, 1996), Jhunjhunun and southern part of Ganganagar and
Hanumangarh (Sen and Gupta, 1980) districts.
B3-E Widely spaced Inter-dune Area:
These inter-dune areas occur in the region where sand dunes are
found in isolated form or in a small group. As such there occurs
a wide gap between one dune and another dune. Such a terrain
can be observed in lesser dune infested region distributed in
western part of Jalor, eastern part of Churu, Hanumangarh,
western part of Sikar and Jhunjhunun and northern part of
Jodhpur districts. The fringes of widely spaced inter-dune are
subject to slight to moderate wind erosion / deposition hazard.
B3-D Sandy Undulating Plain:
Undulating topography is created by deposition of sands from
adjoining dunes in form of hummocks and fence line dunes.
Most of such lands are under agriculture with intensity of
cultivation 30 to 60 per cent. Such topography can be observed
almost in entire sandy soil regions in western Rajasthan.
3.2.3 C SANDY RAINFED AREA IN CANAL COMMAND
ZONE:
The rainfed sandy areas with hummocks and low sand dunes
within the Command area of Gang Canal, Bhakhra Canal and
Indira Gandhi Canal system, have been brought under this
category since these are on the threshold of new economic
order and subject to second generation issues. Leveling of sand
dunes, their regular cultivation and keeping surface clear from
all sorts of vegetation have aggravated wind erosion/
deposition process. Formation of fresh barchan dunes on the
good crop fields and piling of sands on roads became a menace
during summer months. Such lands are widely distributed in
northern part of Hanumangarh (Balak Ram, 1999) and
Ganganagar districts and in small patches (within IGNP
command area) in north western part of Bikaner and north
eastern part of Jaisalmer districts.
3.3 STABILIZATION AND MANAGEMENT OF SAND
DUNES :
Stabilization and management of sand dunes can be done
through the technology developed by CAZRI. The first
requirement to stabilize shifting or active sand dunes is
protection from biotic interference and thereafter micro wind
breaks should be erected in chess board pattern using available
under shrubs and shrubs. Transplantation/ Re-vegetation with
drought hardy seedlings, disease resistant and fast growing
trees and shrub species recommended by CAZRI should be
undertaken during monsoon period.
Over the active parts of stabilized sand dunes life chess board
system may be made and thereafter ground flora can be
enriched by growing the adopted grasses and suitable tree and
shrub species. Local farmers should be trained through
demonstrations to cover active part of sand dunes and check
further sand movement.
4. CONCLUSIONS
IRS LISS-III data in conjunction with ground truth proved very
much useful to identify, delineate and map out desertic sandy
areas in arid Rajasthan for development. Semi-stabilized to
stabilized sand dunes occurring between 100 to 250 mm rainfall
and active sand dunes in 250 to 500 m m rainfall zone, are more
potentials for developmental activities involving the
government intervention. No development is feasible or
needed for sandy wastelands located in hyper arid region.
Sandy areas involving the second generation issues are
identified in IGNP command areas.
5. ACKNOWLEDGEMENT
The author is highly grateful to Dr. Pratap Narain, Director and
Dr. M.A.Khan, Head Division of Natural Resources and
Environment, Central Arid Zone Research Institute, Jodhpur for
providing all the facilities during the course of this study.
767