Land-capability classification
Land-capability
classification is a systematic classification of land where each unit of land is
classified according to what it is capable of producing and also according to
the risk or damage that would result if they are mismanaged. This classification
is made primarily for agricultural purposes and it enables the farmer to use the
land according to its capabilities and to treat it according to its needs. Land
is arranged in various capability classes after considering a number of soil
characteristics and associated land features and climate. The main soil
characteristics to be taken in to account are texture, depth, permeability,
salinity and alkalinity of top soil and sub-soil. The important associated soil
features are slope, effect of past erosion, natural soil drainage, frequency of
over flow etc.
A review of land classification methods used in different
countries indicate that the land capability classification system is most
universally applicable with little modification (Chaudhary
et al., 1962).
Land capability for Indian conditions have been suggested by Tejwani (1976). For
Himalayan region, the texture is very much influenced by the coarse fraction
larger than 2mm diameter. The soil is invariably found admixtured with gravel
and stone, which considerably affect the crop yields. Khybri (1979) suggested
that for developing land capability classes for steeper slopes, soil depth and
land slope are to be considered in combination, particularly for construction of
bench terraces on such slopes.
Soil surveys were carried out to determine the soil types in
the study area. The survey included determining soil depth, slope, texture and
erosion condition. General information was collected from the villagers, fields
and the block office. From the details of various soil profiles. landscape
features, the land capability classification was done as per Khybri (1979). The
land capability map indicate that the land in the watershed can be grouped in
three land capability classes viz. Class IV, class VI and class VII lands. The
details of each land-capability class is given below:
Class IV This category comprises of 93.01 hectares (20.65 %) of
watershed area. This land is fairly good and suitable for occasional or limited
cultivation. The area is characterized by moderately steep slope with moderate
erosion, slope percentage is less than 33%. The soil contains 10-50% gravel.
Class VI 44.13 % of the study area (198.77 hectares) fall under
this category. This land is suitable for grazing and agro-forestry. Some of the
characteristics of such land are susceptible to severe erosion by water and with
steep slopes and shallow soil. Slope percentage is greater than 33%.
Class VII This category comprises of 158.67 hectares (35.22 %)
of the study area. This class has land with steep slopes, rough stone or very
severely eroded soil. Slope percentage is greater than 50%. The soil is loam
with 20-50% gravel or stones and occurs on very steep slopes.
Generation of alternate land use plan
Various thematic
maps generated above were overlaid to arrive at an action plan (a set of
suggested landuse activities) for sustainable development of the area using
Geographic Information System (GIS). A database, chiefly derived from remote
sensing, on natural resources such as present landuse, land capability, slope,
soils, hydrogeomorphology etc were organised in different layers using
Integrated Land and Water Information System (ILWIS) software. An integrated
layer of Composite Land Development Units (CLDU) was created by intersecting the
resources layers. A set of decision rules were applied on CLUDs to generate
action plan map, showing location specific recommendations in the watershed. The
comparison between the existing landuse and proposed action plan gives
considerable amount of growth in vegetative cover. As can be seen from developed
alternate landuse plan that there is ample scope for development of this
watershed and a total of 69.94 hectare waste land can be brought under different
uses. Other location specific recommendations have also been suggested. It is to
emphasise here that to achieve proposed growth in vegetation in the watershed,
additional water conservation structures such as moisture conservation pits,
check dams and spring water storage tanks are required to be constructed at
suitable sites. It is recommended that 50 to 100 moisture conservation pits per
hectare be constructed in upper reaches of the watershed to augment spring
discharge and conserve monsoon rain water. In addition to this check dams are
required to be constructed at every 25 hectare upslope catchment area to store
rain water for augmenting irrigation facilities and to check gully advancement.
Suggested action plan landuse statistics is given in Table 5.
Table4. Suggested landuse statistics for Danda watershed
| Sl. No. |
Landuse category |
Area |
| Hectare |
% |
| 1. |
Forest plantation |
75.20 |
16.65 % |
| 2. |
Existing forest |
103.94 |
23.07 % |
| 3. |
Existing agriculture land |
95.83 |
21.27 % |
| 4. |
Agriculture (additional) |
6.53 |
1.45 % |
| 5. |
Existing agriculture (irrigated) |
26.04 |
5.78 % |
| 6. |
Fuel-fodder/fiber plantation |
33.90 |
7.53 % |
| 7. |
Shrubs (existing) |
25.61 |
5.68 % |
| 8. |
Grazing land |
54.90 |
12.19 % |
| 9. |
Waste land |
28.50 |
6.33 % |
Conclusions
An integrated approach where remote
sensing and GIS techniques have been utilised for evaluation of catchment
characteristics such as geomorphology, landuse, soil, slope etc. Quantitative
analysis of geomorphological parameters of this watershed was carried out and
various geomorphological parameters which are important from the hydrological
studies point of view have been evaluated. The linking of the geomorphological
parameters with the hydrological characteristics of the basin provides a simple
way to understand the hydrologic behaviour of the different basins.
Various thematic maps generated above were overlaid to arrive
at an action plan (a set of suggested landuse activities) for sustainable
development of the area using Geographic Information System (GIS). A database,
chiefly derived from remote sensing, on natural resources such as present
landuse, land capability, slope, soils, hydrogeomorphology etc were organised in
different layers using Integrated Land and Water Information System (ILWIS)
software. An integrated layer of Composite Land Development Units (CLDU) was
created by intersecting the resources layers. A set of decision rules were
applied on CLUDs to generate action plan map, showing location specific
recommendations in the watershed. The comparison between the existing landuse
and proposed action plan gives considerable amount of growth in vegetative
cover.
Reference
- Chow, V.T. (1966) Handbook of Applied Hydrology. McGraw
Hill Book Co., New York.
- Dhruva Narayan, V.V. (1995) research in soil and water
conservation in India with special emphasis on watershed management. Scientific
contribution No. INCOH/SAR-5/95, National Institute of Hydrology, Roorkee.
- Khybri, M.L. (1979) Suggestions for land capability
classification for the Himalayan region. Indian J. Soil Sciences. Vol. 7, No.
1.
- Klingebiel, A.A. and P.H. Montgomery. (1961) Land capability
classification. Agricultural Handbook No. 210, Soil Conservation Service,
USDA.
- Sehgal, J L, D K Mandal, C Mandal and S Vadivelu, 1992.
Agro-ecological Regions of India, NBSSLUP Publ. 24, NBSSLUP and Oxford & IBH
Publishing Company Pvt Ltd.
- Tejwani, K.G., S.K. Gupta and H.N. Mathur. (1975) Soil and
water conservation research 1956-71. Indian Council of Agricultural research,
New Delhi.