V.K. Verma, P.K. Sharma, L.B. Patel, D.C. Loshali and G.S. Toor
Punjab Remote Sensing Centre, PAU Campus
Ludhiana – 141 004
The state of Punjab is intensively cultivated and is contributing large share in the grain basket of the country. However, thirty years after green revolution, we have started experiencing the limitation of intensive resource use without taking care of its long term sustainability. There has been a large scale degradation of land resources due to erosion, salinization and water logging etc. Nearly 25 per cent area of the state is suffering from one or the other land degradation problems. In order to use the land resources judiciously and maintain their productivity, there is a need for sustainable development of these resources. In view of this, the requirement for both accurate and timely information on resources had expanded considerably over the last decade for intedrated resource management with watershed or block as a unit of planning.
An integrated approach using remote sensing offers technologically the appropriate method of studying land and water resources, characterising the coherent agricultural zones and identifying constraints for natural resource management. Integrated studies in selected blocks or watersheds in 175 districts of 25 States of the Country are being undertaken under the Project “Integrated Mission for Sustainable Develompent (IMSD)” coordinated by ISRO, Department of Space. In order to tackle the problems of thick sand cover, soil salinity and water logging and poor quality of ground water in Mansa district of Punjab, India, the integrated resource study for sustainable development was undertaken under the aegis of the project “Natural Resource Development and Management System (NRDMS)” sponsered by the Department of Science and Technology, Govt. of India. The present study reports the resource management needs of Bhikhi block of Mansa district.
The Bhikhi block of Mansa district (Punjab) covering an area of 402.37 Km2 forms a part of the Indo Gangetic alluvial plain. The Western Himalayas in the north and the Thar desert in the south and south west mainly determine the climatic conditions. The south west monsoon during summer brings the much needed rain bearing depressions from July to September. The area comprises of Indo Gangetic alluvium of Quaternary age. It is an alluvial complex of fluviatile origin deposited by the ancestral tributaries of the Indus River System which include the ancient Satluj River. The area is nearly level, with imperceptible slopes, except for the sand dunes. The study area has the problems of arid climate, thick sand cover (sand dunes), low inherent soil fertility, brackish underground water etc.
Material and Methods
- Black and white aerial photographs of March, 1988 on 1:50,000 scale.
- IRS 1A/1B LISS II FCC (print form) of May 1992, October 1992, March 1993 and April 1996.
- Survey of India toposheets pertaining to the area on 1:50,000 scale.
- Block map with village boundaries on 1:50,000 scale (published by Director Land Records, Punjab).
The IRS 1A LISS-II, satellite data (geocoded false colour composites) of March/April, 1996 generated from bands 2, 3 and 4 were visually interpreted. Simultaneously the black and white aerial photographs on 1:50,000 scale were also interpreted using mirror stereoscope. Various thematic maps viz. geomorphology, soils and landuse were prepared on 1:50,000 scale following the standard procedures outlined in the IMSD Manual. The water samples were collected randomly from the study area and analysed for water quality parameters following standarad procedures to prepare water quality map. All the maps were integrated to come out with a resource constraint map. Based on resource constraints site specific recommendations were made and action plan map generated for the management and conservation of under utilised areas for optimal returns on sustainable basis.
Results and Discussion
On the basis of physiographic analysis of the satellite data and aerial photographs two major physiographic units viz. alluvial plain and sand dunes were delineated. These were further subdivided based on the tone, texture, pattern, slope and landuse. The alluvial plain is nearly level, intensively cultivated and mostly irrigated. The alluvium was later modified and/or new deposits laid by the occasional shifting of the Satluj river. Originally the Satluj river was an independent river, not belonging to the Indus system, before it joined the Ghaggar in Bikaner. Finally, it abandoned its course in the thirteenth century and joined the Beas river. Due to change in the river course, the tributaries got silted up in due course and resulted in the formation of sand bars. The sand bar deposits seem to have been modified at a later stage by the aeolian action to form sand dunes locally known as tibbas. On the imagery and aerial photographs these can be seen as elongated stretches along the abandoned or filled up channels or both. The present landscape is the result of combined effect of the localised reworking of the previously existing sand dunes by aeolian activity and mechanical shifting of sand in the recent past. Sand dunes occur as elongated stretches, 2 to 8 metres above the general elevation and their strike is parallel to the prominent wind direction.
The soil samples were collected and analysed for particle size distribution, pH, EC, CaCO3, organic carbon, cation exchange capacity and exchangeable cations. The soils are slightly alkaline (pH 8.5-8.9), having low electrical conductivity (0.05-0.8 dsm-1), low organic carbon (0.01-0.4%) and variable calcium carbonate content. The low organic carbon content (7.0). These waters have varying levels of salinity (0.31 to 2.36 dS m-1), SAR (0.40 to 21.57 [me L-1]½) and RSC (nil to 10.60 me L-1) with a mean value of 1.24 dS m-1, 9.97 (me L-1)½ and —- me L-1 respectively. Sodium is the dominant cation and its value ranged from 0.43 to 34.78 me L-1. Among the anions, HCO3- concentration varied from 1.0 to 13.0 me L-1 with a mean value of 5.88, whereas concentration of Cl- and SO42- varied from 0.75 – 12.25 and 0.21 – 14.17 me L-1, respectively.
Depending upon the EC and RSC values (Sood et al., 1998), the ground waters of the area have been grouped into three ground water quality categories viz. good, marginal (sodic) and poor. The ground water quality map (Fig. 2) of the area shows that the category-I (good) occupy 35 per cent of total geographical area of the block. Since these good quality ground waters have least salinity and sodicity hazard, their use over the years is not likely to be hazardous in the soils having clay content even >30% which are fairly to moderately well drained with water table not shallower than 1.5 metre.
Marginal-sodic ground waters occupy highest area (59%) of the block. These waters are low in EC and calcium but high in sodium and bicarbonate. The indiscriminate use of these waters will result in precipitation of calcium and magnesium as insoluble carbonates thereby, building up higher levels of exchangeable sodium in the soil exchange complex. This will lead to formation of dispersed and relatively impermeable soils. These waters can preferably be used in light textured, well drained and permeable soils, if good quantity of organic manures are added. The poor quality ground waters which are unsuitable for irrigation due to high EC, RSC or both occupy six per cent of total area. These waters should not be used for irrigation purposes otherwise they will cause serious problems of soil salinization and sodification ultimately severely restricting the crop yields and deteriorating the soil healthy.
Landuse mapping of the study area has been undertaken using two dates IRS 1B LISS II data. Five major landuse categories at level I were identified and mapped (Fig. 3). These categories have been subdivided based on the differences in tone, texture, pattern, association etc. and eleven categories at level II were identified and mapped. The map was rechecked using April 1996 data. There are 34 inhabited and one uninhabited villages in this block. The study reveals that more than 89 per cent of TGA of the block is double cropped and only 4.32 per cent area is single cropped. The area under settlements and village ponds is 3.46 and 0.36 per cent respectively. Nearly, 2.28 per cent of TGA is under wasteland category which includes salt-affected, waterlogged and sandy areas.
The study area has a variety of problems associated with soil and water which are listed below :
- Arid and semi-arid climate
- Low, erratic, ill-distributed rainfall
- High wind velocity especially during summer months (April-June)
- Poor underground water in large area (65%)
- Thick sand cover (sand dunes) in some area.
- Poor retention of water and nutrients in coarse textured soils.
- Inadequate and erratic supply of canal water.
- Poor marketing facilities and absence of processing units especially for horticultural produce.
Based on the information on landuse, soils and ground water quality, the following major constraints in the study area were identified (Table 1) and a resource constraint map of the area was prepared on 1:50,000 scale (Fig. 4)
- Poor ground water quality.
- Coarse textured soils primarily in sand dune areas.
On the basis of resource constraints in the area, action plan for sustainable development has been prepared on 1:50,000 scale (Fig. 5). To address the major problems of the study area, certain measures like sand dune stabilisation, arresting water logging and soil salinity, proper use of poor quality ground water and improvement of soil physical properties etc. are recommended.
- Levelling of low sand dunes and bringing them under agroforestry /agrohorticulture with the provision of drip irrigation system.
- In situ stabilization of high sand dunes by planting species like Sarkanda (Saccharum munja), Ber (Zizyphus nummularia), Pahari Kikar (Prosopis juliflora), Jand (Prosopis cineraria), Subabul (Leucaena leucocephala), Kikar (Acacia nilotica) along the periphery of fields to check the movement of sand by wind action.
- Agriculture I: Sodium tolerant crops like wheat, barley, berseem, cotton, raya, and sugarcane are recommended in areas having light to medium texture soils and sodic ground waters. The amendments like gypsum should be used alongwith the sodic ground water to reduce the harmful effects of sodium.
- Agriculture II: In alluvial plain (double cropped) with medium to heavy texture soils and sodic ground water, high sodium tolerant crops like rice, sugarbeet and bermuda grass are recommended. The ground waters in these areas should be used alongwith gypsum.
- Reclamation of salt affected cum waterlogged area and bring them under plantation with species such as Safeda (Eucalyptus spp.), Pahari Kikar (Prosopis juliflora), Kikar (Acacia nilotica) and Neem (Azadirachta indica), which act as biopumps.
- Forestry in low sand dune areas with species like Pahari Kikar (Prosopis juliflora), Kikar (Acacia nilotica), Jand and Ber.
- In alluvial plain areas with brackish ground waters, in addition to the above mentioned forestry species, Eucalyptus and Dek can also be grown, however, if there is assured availability of canal water, agriculture can be the best practice.
- Agrohorticulture I: Promotion of horticultural crops like Grapes and Kinnow in marginal lands having good under ground waters, alongwith gram, groundnut and moong.
- Agrohorticulture II: Promotion of agrohorticulture with fruit plants like Ber, Guava and Amla and oilseeds (Mustard, Toria) in sand dune area having saline or sodic ground waters, after their levelling and/or clearing.
- Assured irrigation with good quality water during the first two years of horticultural plantation.
- Increase in canal command area with the provision of effective surface and sub surface drainage.
- Release of additional canal water during the months of April and May and the supply of water should be reduced during the months of June to September. This arrangement in turn will help in reducing the insect and pest attack on cotton crop.
- Installation of deep tubewells, wherever feasible, by Government agencies to tap good quality deeper aquifer.
- Application of recommended doses of gypsum should be applied alongwith irrigation waters having moderate to high residual sodium carbonate.
- Advising farmers to adopt drip irrigation in horticultural crops and sprinkler irrigation in other agricultural lands where good quality underground water is available or have adequate supply of canal water. This will help in efficiency.
- Alternate furrow irrigation should be advocated in cotton to save water.
- Power connections on priority for shallow tubewells installed in sweet water zones.
Authors are indebted to Department of Science and Technology, Govt. of India for providing financial support to accomplish this study.
References Table 1: Resource Constraints in Bhikhi Block
Mapping Units Cropping Pattern Geomorphology Soil Texture Ground Water Quality Constraints 1 Barren Sand Dunes Sandy Variable Coarse Textured Soils, Active Sand Dunes 2 Dominantly Single Cropped Sand Dunes Sandy Good – Low EC, Low RSC Coarse Textured Soils 3 Dominantly Single Cropped Sand Dunes Sandy Marginal – High EC, Low RSC Coarse Textured Soils & Saline Ground Water 4 Dominantly Single Cropped Sand Dunes Sandy Marginal – Low EC, High RSC Coarse Textured Soils & Sodic Ground Water 5 Dominantly Single Cropped Sand Dunes Sandy Poor – High EC, High RSC Coarse Textured Soils & Brackish Ground Water 6 Dominantly Barren Old Filled Up Channel Coarse Loamy Variable Soil Salinity Associated With Water Logging 7 Double Cropped Alluvial Plain Coarse Loamy To Fine Loamy Marginal – High EC, Low RSC Saline Ground Water, Irrigation & Management 8 Double Cropped Alluvial Plain Coarse Loamy To Fine Loamy Marginal – Low EC, High RSC Sodic Ground Water, Irrigation & Management 9 Double Cropped Alluvial Plain Coarse Loamy To Fine Loamy Poor – High EC, High RSC Brackish Ground Water, Irrigation & Management 10 Double Cropped Alluvial Plain Coarse Loamy To Fine Loamy Good – Low EC, Low RSC No Constraint