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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004
land degradation; it is what a population does to the land that
determines the extent of degradation. People can be a major
asset in reversing a trend towards degradation.
Two major agricultural seasons can be distinguished viz.,
Kharif (from June to October) and Rabi (November to March).
About 33.8% of the study area is irrigated (including both the
Kharif and Rabi seasons). Average rainfall in the rabi season is
only 158.7 mm, therefore rabi crops are mostly grown where
irrigation sources exist or in heavy black cotton soils that retain
moisture from the monsoon rains. Crops such as jowar
(Sorghum bicolor (L.) Moench) and bajra (Pennisetum L. Rich.
(Poaceae)), with low water demands, are grown in these soils.
In heavy textured soils, sorghum is the principal crop, followed
by cotton while other crops include safflower (Carthamus),
bengal gram (Cicer arietinum) and dry chillies (Capsicum
annuum; C. frutescens). Under assured irrigation on heavy
textured clay loam soils, rice and sugarcane are the principal
crops. Rice is cultivated in both the Kharif and Rabi seasons.
On light textured soils (sandy loams and loamy sands),
groundnut, sunflower, green gram and vegetables are the
principal crops (Rao, 1995).
3. DATA
3.1 Map data
Land use maps depicting spatial cropping patterns were
generated from Indian remote sensing satellite data for both,
Kharif and Rabi of the same agricultural year. The maps were
generated through visual interpretation techniques and use of
topographic maps, district records and field investigations. Soil
maps at scale 1:50,000 were generated within the IMSD project
in India, up to series level, following the USDA approach for
classification. Soils within a series are developed from the
same parent material in the same environment and their profiles
are almost alike with horizons that are similar in their
properties (Dent and Young, 1981). The procedures adopted
for generating the database are discussed in detail in the IMSD
Technical Guidelines (NRSA, 1995). GIS data have been
generated according to the National Natural Resources
Information Systems (ISRO, 2000) standards.
3.2 Fieldwork Data
Fieldwork in the study area, consisting of field observations,
interviews with farmers, and mandal and district line
department officials, was conducted in two phases during May-
July and September-December 2002. Digitizing/geo-
referencing was facilitated through the use of a mobile GIS
system; in the field, coordinates of the field interviews were
recorded. Farmers’ responses were defined as attribute data.
4. RESULTS
4.1 Analysis
The method is illustrated in Figure 3. Land use data were
‘unioned’ with soil data using standard GIS operations. The
relationship between soil series and the overlaying land use was
inventoried using the query facility in ArcView®, yielding data on
areas of the major land use classes, Kharif-crops, Rabi-crops,
(Kharif + Rabi)-crops, and non-cropped (divided into land with
scrubs and land without scrubs) for each soil series.
Following the inventory of the relationships between soil series and
the overlying land use classes, a method was developed to categorise
the relationship as the basis for theoretical interpretations. The
method is based on interpreting (i) percentage of cropped and non-
cropped areas occurring in each of the soil series and their spatial
distribution, (ii) data on spatial distribution of cropping pattern. The
interpretation was to derive the land use analysis objectives for the
study area. It is formulated as described below:
e Let S;be the area of soil series (i7 1, 2....n).
e Let LU, be the area of major land use class cropped land (Kharif
only, Rabi only and Kharif + Rabi, split in predominantly cropped
to a single crop and cropped to many crops).
e Let LU, be the area of major land use class non-cropped land
(split in two cover classes, with and without scrubs).
Multi-temporal Remote sensing
Remote Land use Soil Series imagery.
sensing > Classes 4-4 Landform. ground |
imagery, field
truth, chemical |
verification
and physical
analvsis
GIS overlay & Inventory
beo
Interpretation of the inventoried data apriori
knowledge &
| Statistical Terrain Soil Pr GIG CUI
| data data properties If. Soil Series has Agrci |
| cover > 25% & < 75%
|
|
Then LUAObj = CON d
Y LL. S hei io
Identify LUA If. Soil Series: 75% of
Objectives Agric Cover and the LU, =
multiple crops
Then LUAObj = CS
Spatial representation Er Fr
Log If Soil Series > 75% of
Agric Cover and the
LU, = single crop
Then LUAObj = CMI
Field Interviews
with Farmers
LUA = Land Use Analysis; LUAObj = Land Use Analysis Objective; CMI =
Crop Management Improvement; CS = Crop Selection; CON =
Conservation; PRA = Participatory Rural Appraisal
Figure 3: Schematic presentation of the analysis method
Appraisal
Two groups of soil series have been distinguished, say A and B:
Group A, those series in which agricultural land use exceeds 75%
and Group B, series in which agricultural land use is less than 75%.
The t-test to test if the two groups are statistically
different reveals a value of 1.60 at df 17 which is significant at 95%
confidence level, i.e. the two groups are significantly different.
® : .
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