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“Spatial Analysis of Ujjain Tehsil Grassland status by using remote sensing and GIS techniques.”
Dr. Prithwiraj Sahu
Integrated Research and Development(IRADe), India
In terrestrial ecosystem, grassland is the pioneer producer, which covers major area on any landscape. The uniform distribution of the grassland cover plays the significant role in conservation of soil, participating in life support system. The morphology and structural design of grasses supports in synthesis of carbohydrates, which acts as a natural boon to the herbivores in terrestrial ecosystem.
The status of any grassland is mainly controlled by the various factors which may be natural or anthropogenic factors. Grassland is obviously constrained by environmental factors such as soil characteristics, climate, topography, and vegetation. But, it also reflects the importance of land as a key and infinite resource to cattle and other grazing animals depending on it and for most human activities including agriculture, industry, forestry, energy production, and through much of the course of human history, it has been tightly coupled with economic growth (Nagamani and Ramachandran, 2003).
Often improper land use is causing environmental degradation. For sustainable utilization of the grassland cover, it is essential to know the natural characteristics, extent and location, its quality, productivity, suitability, and limitations of various land uses. Land use is a product of interactions between a society’s cultural background, state, and its physical needs on the one hand, and the natural potential of land on the other (Balak Ram and Kolakar, 1993).
In order to improve the economic condition of the area without further deterioration of the natural grassland cover and bio environment, it requires meaningful utilization of the land cover in a rational way. This requires the present and the past land use /land cover data of the area (Chaurasia et al., 1996). Temporal changes in land cover have become possible in less time, at lower cost and with better accuracy through remote sensing technology (Kachhwaha, 1985).
In India, about 12.5 Mha area has been estimated to be under permanent pasture and grazing lands (Lal, 1989). No precise information however on the actual area under grasslands in the country is available. Pilot studies have been carried out by Department of space for developing remote sensing based methodology for grassland mapping in different climatic regions of the country. Many workers studied the status of grassland of different geographical regions of India using multi-temporal satellite data. They used satellite data to estimate the total grassland cover and its spread, grazing land area, mapping of grassland area, carrying capacity of grassland etc. (Jadhav et al., 1992; Roy et al., 1992a; 1992b). The study has brought out that grasslands/grazing lands in the district. Studies in all these regions are currently being carried out to assess the carrying capacity of these grasslands/grazing lands. With the success of the pilot studies, the grassland mapping studies based on space borne remote sensing techniques are being extended to other parts of the country.
The present study was carried out to evaluate the effectiveness of data in and around the Ujjain Tehsil on 1:50000 scale by using satellite data of IRS 1A, 1D and base information from Survey of India Toposheet.
2. Study area:
Ujjain tehsil, the study area lies between 23d 00’00.00”N -23d 16’48.46” N Latitude and 75d37'00.38" E -75d59'34.48" E Longitude in the state of Madhya Pradesh. It is situated in the Ujjain district of Madhya Pradesh on the bank of Shipra river. The tehsil covers an area about 75337 Sq. Km. (7533700 Hectares) (District Statistical Data, 2002). Physiographically, the region is a part of Malwa Plateau. Geologically the study area is occupied by Clayey Calcareous soil (Black Cotton Soil), ideal for cultivation of various crops such as cotton, groundnut, wheat etc. the region is important not only from historical point of view but also geographically, as the tropic of cancer passes through this region. The entire geographical area is less undulating that shows the feature of naturally plain area. Naturally the tehsil has no forest but its land cover is covered with tall and luxuriantly growing grassland in entire land masses except the agricultural lands and Urban settlement. The mean average annual rainfall was 98.725 mm in 1990 and 84.825 mm in 2000 respectively (District Statistical Data, 2002). Around 65- 70 of the total annual rainfall is received from mid June to September due to the South-west Monsoon. The Population of Ujjain tehsil is 5,64,345 (Census India, 2001).
3. Data used:
Survey of India topographical map on the 1:50000 scale for the year 1972, and IRS 1A LISS II and IRS 1D LISS III False color composites (FCCs) for the year1990 and 2000 have been used in the present study.
4. Materials & method:
Satellite imagery in the digital form was procured from NRSA Data Centre of IRS 1A LISS II data of 5th January 1990 of Path 29 and Row 51, 52 and IRS 1D LISS III data of 27th January 2000 of Path 96 Row 56, 57. Survey of India Toposheet No. 46 M 12, 15 and 16 and other secondary data were used in the present study. The digital image processing of satellite data has been carried out using Geomatica V.9.0 (EASI/PACE) software on PC based workstation and land use/land cover maps of 1990 and 2000 were prepared. The digital image processing techniques used for land use/land cover classification include image enhancement, image classification and data merging.
Initially, the digital data of both scenes were geo-referenced. The 27th January 2000 image was considered as the base (Master) since it is very sharp and clear. This image was first geo-referenced by taking various control points from the SOI Topo-sheets. The Projection type used is “Geographic Lon/Lat” with the spheroid datum as Modified Everest. Sub-sequentially, the image to image registration was performed in order to register the second image of 5th January 1990. Some sharp and easily identifiable features like crossing of roads, railways, canals, bridges etc. were located on both images and were selected as ground control points (GCP). Some GCP with root mean sqaure error beyond threshold were deleted and replaced by other points so as to maintain acceptable positional accuracy. The supervised classification was done as per the training site collection and followed by accuracy assessment.
5. Result and Discussions:
Originally the studied region comes under natural grassland of Madhya Pradesh state. Due to the population pressure, advancements in tools and techniques, mechanical boom has caused a lot of alterations in the grassland cover.
The grassland cover assessment was based on the digital interpretation of two different years of satellite data between 1990 and 2000. The study area has a total area of 75337 sq. km (7533700 Hectares). Total population of Ujjain tehsil was 1,07,118 (Census India, 1991) 5,64,345 (Census India, 2001) respectively. The overwhelming population growths required more resources to manage and fulfill their basic needs. For that the developmental activities such as constructions of human settlements (colonies), buildings, roads, roads, railways, agriculture fields etc., cause encroachment of area of natural grasslands (of both type protected by forest department, grazing grassland).
There are some natural factors which are also affecting the growth of the grass in the grass land, the succession acts as major natural process for immigration of different species of grasses and other plant in the grassland (table:4). Grassland is very susceptible to succession process, which leads the gradual changes in the status of it.
The annual rain fall of this area was varying from year to year, which results the irregular growth of the grass cover on the landscape (Table: 2). The black cotton soil is highly rich in nutrients, which helps in the luxuriantly growth of grassland of the region.
The analysis of IRS 1A, 1D Linear Imaging Self-scanning sensors data revealed that the status of spatial signatures of the grasses in the grassland is used to analyzed in the visible and near infrared regions of the electromagnetic spectrum and are frequently used for analysis of land cover types. The visible region of the spectrum is represented by the three primary colors of blue (400 to 500 nm), green (500 to 600 nm), and red (600 to 700 nm). The green grass in the visible region of the spectrum appears green because it is reflecting green and absorbing blue and red light. On the other hand, an object appearing black is absorbing all three primary colors of the visible region while an object appearing white is reflecting all three primary colors of the visible region. The near infrared region of the electromagnetic spectrum ranges from approximately 700 to 1100 nm. Reflectance in the near infrared region is an indication of plant health and vigor.
The near-infrared region depicts healthy green grass reflecting strongly while grass under stressed condition has a weaker reflectance in that range. Near-infrared reflectance is based on a plants physiological structure and health. Therefore, reflectance in this region is not based on a plant’s color but on how well a plant’s cell structure reflects solar energy. Absorption characteristics of vegetation vary due to seasonal cycles. Healthy green vegetation absorbs in the blue and red regions of the spectrum because of chlorophyll absorption bands in the blue and red regions. If a plant is diseased or stressed, chlorophyll production decreases, resulting in less absorption of blue and red energy. When red energy is not absorbed but reflected, leaves appear yellow—a combination of red and green energy. For vegetation, spectral reflectance is highest in the range between 700 – 1300 nm, as plant leaves typically reflect 40%-50% of the energy incident upon it. These high reflectance values result from the internal structure of plant leaves. The remote sensing data reveals the real status of the standing biomass of grass situated in the grass bid (fig: 1). But, as the time passes the grass lands were occupied by the different land-use classes of the region. According to IRS 1A LISS II satellite data of the year 1990, the area of grassland was 11151.003 Hectares (0.148 % of the total geographic region), where in IRS 1D LISS III satellite data shows the changes in the status of grassland area as 1289.1172 Hectares (0.017 %) in the year 2000 (figures A-B). As per the two satellite data it was noticed that a drastic change was observed with a decrease in the grassland status. The change detected during the decade (1990-2000) from the satellite was 9861.8858 Hectares, which was 0.130 % of the total geographic area of the Ujjain tehsil. Same trend was also observed from the statistical data collected from the District Statistical Department, Ujjain.
According to statistical data (manually collected by the government agencies) the grassland status in the year 1990 was recorded as 620400 ha, whereas it was 582200 ha in 2000. An overall decrease up to 38200 ha in grassland area was observed during the decade (1990-2000), which was 6.09% of the total geographic area (table 1). Such type of decrease in the area of the grassland was indicating the adverse impact on the fodder quality and economic growth with fodder supply of this region.
Such type of dynamic changes in the grassland cover may be operated by some of the biological as well as ecological factors. The lowering down of the water table from the aquifers, excessive exploitation of the ground water for the cash crop cultivation to achieve more yield and to improve the economic standard of the farmer, irregularity in seasonal rain fall, low recharge potential of black cotton soil, the changing crop pattern etc., create the devastating change in the land cover of the study region (table: 3).
On the other hand the population growth in the area results the encroachment of land cover which comes under grassland area, which was the resultant of the urban as well as the village areas where settlements sprawl. The unexpected changes in climate, irregular rain fall etc. may be responsible for vulnerable changes in the grasslands of the region.
Table: 1. Status of Grassland covers during past decade (1990-2000) in Ujjain Tehsil (Ujjain District).
Table: 2. Rain fall data of the decade (from 1990-2000).
Table: 3. Means of Irrigation and irrigated land of Ujjain Tehsil in 1990-2000 (in Hectare)
Table: 4. Major Grass species found in Ujjain tehsil grassland in the decade (1990-2000).
HGG- Heavily grazed grassland, PGB- Protected grassland/Grass Bid
(Courtesy: Forest Department, Ujjain, Madhya Pradesh, India)
|Name of the species
| ||HGG ||PGB||HGG ||PGB
|Alysicarpus rugosus DC. ||v|| X ||X ||v|
|Apluda mutica Linn. || X|| v|| X|| X|
|Blumea lanceolate ||v|| v ||v|| X|
|Bothriochloa purtusa (L) A. camus.|| v|| X|| X|| v|
|Cassia tora ||v|| v|| X ||v|
|Chrysopogon montanus Trin.|| X ||v|| X ||v|
|Crotalaria medicaginia|| v|| v|| X ||v|
|Cymbopogon mortinii (Forsk.) Wats.|| X ||v ||X ||v|
|Cynodon dactylon ||v ||v ||v|| X|
|Dicanthium annulatum (Forsk.) Stapf.|| X ||v|| v|| X|
|Dichanthium anulatum ||v ||v ||v|| X|
|Dichanthium caricosum A. camus.|| v ||X ||X|| v|
|Echinocloa species|| v|| v|| v ||X|
|Enicostema littoral Bl. ||v ||X|| X|| v|
|Euphorbia hirta ||v|| v|| v|| v|
|Euphorbia geniculata ||v|| v ||v|| X|
|Euphorbia thymifolia ||v ||v ||v ||v|
|Heleocharis atroperpurea (Retz.) Kunth.|| v|| v ||X ||v|
|Hemigraphis dura ||v ||v|| v|| v|
|Heplanthus verticilari ||v|| v|| v ||X|
|Indigofera linifolia Retz. Obs.|| v|| v|| v|| v|
|Indigophera glandulosa|| v ||v ||v|| X|
|Ischaemum pilosum (Klein) Wight.|| X ||v ||X|| X|
|Iseilema laxum Hack.|| v|| v|| v|| v|
|Knoxioa corymbosa|| v|| v ||X|| v|
|Lantana camara|| v ||X ||v ||X|
|Mimosa pudica ||v ||v|| v ||v|
|Parthenium species|| v|| X|| v ||X|
|Phyllanthus maderarspatensis|| v ||v ||X|| v|
|Phynchosia minima ||v ||v ||X|| v|
|Polygala arvensis L. ||v ||X|| X|| v|
|Saccharum spontaneum L. Mant. ||v|| v|| X|| v|
|Scleria tessesllata Wild.|| X ||v ||X ||X|
|Sehima nervosum (Rottl.) Stapf. ||X ||v ||v ||v|
|Setaria glauca|| v ||v ||v|| v|
|Sonchus species|| v|| v|| v ||X|
|Thelepogon elegans (Roth.) ||X ||v|| X ||X|
|Trichodesma species ||X|| v ||X ||v|
|Tridax procumbens|| v|| X ||v ||X|
Fig: 1. Spectral signature of the grassland in stressed and healthy stage
Figure: 2. (A) Grassland covers in 1990 and (B) Grassland covers in 2000: showing the status of Grassland cover of Ujjain Tehsil during the decade (1990-2000).
The major changes in any area are properly not recorded by the concerned administration of the study area. Manual survey and monitoring of the earth surface land cover and land use is easily covered up by the Remote sensing technology due to in time repeativity. The status of grassland observed by the satellite imagery and conventional study helps in the extraction of better information about the vegetation growing in around the region, their biomass conditions, i.e., whether they are stressed or unstressed condition which helps in further classification of the relevant land cover and land use strategies of the study area. The extrapolation of data of the decadal status of grassland may help the government in the planning of the different grass bid management in near future.
The author remain grateful to the Forest Department, Statistical Department of Ujjain, Govt. of Madhya Pradesh, India, for conventional data support, University Grant Commission, New Delhi for their financial support, and National Remote Sensing Agency for their timely supplying of data and technical support.