Use of Landsat TM data in location of sites for afforestation
programmes in India
Test site
The study area lies between 25030' to 25045' N lat. And 81015' E long. And covers approximately 620 sq km of southern half of the Khaga Tahsil of Fatehpur district, and a small part of Allahabad district, Uttar Pradesh, and occupies most part of topographic map sheet no. 63 G/2 (Fig. 1).
The river Yamuna and its tributary Sasur Khaderi Nadi (=river) traverse through this area. The ravine and gully formation along these river systems has led to land degradation. Furthermore, land degradation has also taken place due to salinisation and waterlogging.
Fig. 1 Location Map of the study area
Materials and methods
The study area falls under Landsat - 5 Scene path-rows No. 143-042. Multispectral Thematic Mapper TM data of 23.2.1986 in the form of False Colour Composite (FCC) of part of two sub-scenes covering the study area with frame No. 2 & 3 on approximately 1:50,000 scale were interpreted. Survey of India topographical maps on 1:50,000 scale and Tahsil Maps on approximately 1:20,0000 scale were also used for base map preparation.
Visual interpretation of TM data based on image characteristics such as texture, pattern, colour, hue, shape etc. with limited field checks was carried out to delineate broad landuse categories with special emphasis on degraded lands. Base map information i.e. important habitations, means of transport, canals etc. were transferred on the thematic map from 1:50,000 topographic maps using Planvariograph 'Mapmaker'. Area under each category was computed using a Digital Electronic Planimeter.
Results
The thematic map showing sites of degraded land n 1:50,000 scale prepared form TM data indicates that most of the land in the study area is being utilised for agriculture (Fig. 2). There is no notified forest land in this area. The land has been classified into five major categories viz., agriculture had, scrubland, ravenous or gullied land, salt affected land and waterlogged or marshy land. Table 1 shows the broad landuse categories and the computed area under each category.
Table 1.: Area under each landuse category in the study area
| Categories |
Area(ha) |
Percentage to study area |
| Agriculture Land |
55,800 |
90.00 |
| Scrub Land |
273 |
0.44 |
| Ravinous or Gullied Land |
1,313 |
2.12 |
| Salt affected Land |
1,073 |
1.73 |
| Waterlogged or Marshy Land |
202 |
0.33 |
| Other Miscellaneous Categories |
3,339 |
5.38 |
-
Agriculture Land
About 90% of the total study area is being used for agricultural crops. It forms a part of Yamuna Flats comprising of low lands having dark clay soil. The main Kharif crop is Sorghum while paddy is also grown where irrigation facilities are available. The main Rabi crops are Gram and Wheat.
- Ravinous or Gullied Land
Nearly 1313 ha of land is ravinous or gullied which is about 2.21% of the study area. Most part of this land is confined along Sasur Khadari Nadi (river). Some ravenous or gullied lands are also seen along Yamuna river mainly around Kishanpur, Garha and Kot village. This class represent only those ravenous gullied which are devoid of any vegetation cover.
- Salt Affected Land
Salt affected land in the area is mainly confined to north of Dhata-Nodki (via Ghazipur) Road. It occupies an area of about 1073 ha which is 1.73% of the study area.
- Scrub Land
In the study area, the vegetation cover is generally poor and is reprinted only by low scrub. Scrub vegetation, which is mainly confined to ravenous or gullied lands, have sparse and bushy growth with less than 30% crown density. It occupies an area of about 273 ha which is only 0.44% of the study area.
- Waterlogged or Mashy Land
About 202 ha of land has been classified as surface waterlogged which is only 0.33% of the study area.
