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IAPRS & SIS, Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad, India, 2002
establishing cold storage processing units and suitable sites for
aquaculture.
7.1 Crop Suitability Studies
The sustainable crop production in any area depends on its
climate, soil and site characteristics of the area. This can be
achieved through evaluation of soils of a given area for their
suitability to different crops considering the inherent soil
properties, topographical features and climatic parameters
independently as well as in combination. A study had been
carried out at NRSA (1998a) with the objective of assessing
soil suitability to groundnut crop through GIS approach. The
test site for the study is Tettavai vagu watershed falling in
Tungaturthi mandal of Nalgonda district of AP (Fig 2). The soil
maps for the study area was prepared using IRS-1B LISS-II
data at 1:50,000 scale. ARC/INFO GIS package had been used
in creation of data base required for crop suitability studies.
Suitability criteria for groundnut crop in terms of climate, soil
and site parameters were developed following FAO approach
and incorporated as decision rules in GIS environment. The
study revealed that in the test area about 69% of the total
geographical area is highly suitable for groundnut crop.
"LEGEND
SUITABILITY
CSI: 294-3546 HIGH
C$1 232-294 |
C$1.0-232 Low
9 NOT SUITAELE
WATER BODIES
QUARRIES
TOWN?!YILLAGE
Fig. 2. Soil suitability to groundnut crop in Tettavai vagu
watershed, Nalgonda district, Andhra Pradesh
7.2 Land Capability Classification
In one of the GIS studies at NRSA, land capability map was
generated for Ibrahimpatnam block of Ranga Reddy district,
Andhra Pradesh. The standard USDA land capability
classification approach was adopted in the study. Various
derivative maps covering the themes of soil erosion, slope,
depth, rock outcrops and gravel stones were generated from soil
map and other related information on 1:50,000 scale using
aerial photographs. The above maps have been prepared using
IDRISI GIS package on a PC system and a land capability
map was generated performing integrated analysis of above
mentioned thematic layers. For the test site, a total of 6 land
capability classes were delineated.
7.3 Watershed prioritization
The sedimentation in reservoirs / lakes / tanks at faster rate than
expected is an indicator of the continuing land degradation in
the catchments. Due to insufficient funds and manpower for
natural resources survey and for soil and water conservation
programmes, watersheds in the catchments have been
prioritised and watersheds with high priority are taken up for
709
treatment to control soil erosion and sediment inflow into the
water bodies. The important parameters considered for
prioritization of watersheds are physiography, slope, soil
properties like texture, depth etc., land use/land cover, soil
erodabilitv and existing soil conservation measures. GIS
approach has been used in prioritization of watersheds
following Sediment Yield Index (SYI) approach (Sarada et
al.,1993)
8. SOIL MOISTURE STUDIES
Soil moisture plays a critical role in many application in a
number of disciplines including agriculture, hydrology and
meteorology. The advantages and disadvantages of soil
moisture determination insitu or point, water balance and
remote sensing methods are discussed by Schmugge (1980).
Microwave region of the electromagnetic spectrum has the
potential to provide soil moisture information under all weather
conditions and has been pursued by investigators world wide
(Ulaby et al, 1979; Dobson et 31,1981). At NRSA, R&D
experiments with SAR data from ERS-1/2 satellites have been
attempted for soil moisture studied under different soil and
moisture conditions (NRSA, 1995a). The studies enabled to
understand the relation between soil moisture and back
scattering coefficient of SAR data; and also the influence of
surface roughness on soil moisture estimation. A study on soil
moisture with IRS-P4 MSMR data was also attempted for
regional level study. Efforts in the direction of root zone soil
moisture modeling with remotely derived surface soil moisture
content and soil profile characteristics are in progress.
CONCLUSIONS
The application of remotely sensed data from space borne
sensors for soil resources study is increasing day by day.
This technology need to be employed on regular basis for
monitoring soils / degraded lands. GIS based models for
automatic land evaluation need to be developed for
operational use. The utility of stereoscopic satellite data in
soils mapping has not been fully exploited and greater scope
is seen in this aspect. The hyper spectral remote sensing data
from sensors like MODIS need to be explored to establish
quantitative relationship between spectral reflectance and
soil properties. Future, remote sensing satellites with very
high spatial, spectral and radiometric resolutions will enable
to study soils and degraded lands at micro-level at 1:4000
to1:8000 scales for proper management of soil resources for
sustained agricultural production.
REFERENCES
AIS & LUS .1970. Soil Survey manual, IARI, New Delhi.
Dobson, M.C and Ulaby, F. T. 1981. Microwave backscatter
dependence on soil roughness, soil moisture and soil texture;
part III soil tension’, IEEE Trans, Geo & Rem. Sen.., GE-19,
51-61.
DOS, 1998. Application of Remote Sensing in soil resource
mapping.
