सोमवार, 3 दिसंबर 2012

Desertification in India



In recent times, the loss of vegetation in the area has vastly degraded their once fertile land, and water has become a rare commodity. Since 1999, the failure of the monsoon has adversely affected the soil and the land has become barren. In order to regenerate it, ravines and ridges were treated by constructing gully plugs and digging out contour trenches. Earth check dams with spillways on either side were built to allow the water overflow to run off without damaging the dams.  Ponds were also constructed to hold larger volumes of water.
As farmers witnessed the effects of lack of water and soil erosion and its detrimental impact on agricultural production and yields, the concept of watershed management gained credence amongst them. Many are convinced that the local environment can be regenerated through a well-managed watershed programme.
Many now understand the fact that as the groundwater increases, normal farming patterns and agricultural output levels can be maintained despite changing weather conditions. The community has now learned to conserve their water and soil. Not a single drop of water runs off in their village. Caritas India has run public information campaigns trying to persuade local communities to take similar measures to stop desertification. Even though India’s land area is only 2.4 percent of the world’s total land area, it supports 16.67 percent of the world’s population and 18 percent of its livestock. These pressures alone play a major role in promoting desertification.
As the human and animal population increases, these stresses will become greater and the demand on natural resources will increase leading to permanent loss of vegetation and plant species. This may also lead to the conversion of large areas into wastelands and to the frequent occurrence of natural disasters. Half the land in India is now affected by desertification and this impairs the ability of land to support life. It is particularly devastating because of its self-reinforcing nature.

The causes of desertification are extensive cultivation of one crop, use of chemical fertilisers and pesticides, shifting cultivation without adequate period of recovery, industrial and mining activities, overgrazing, logging and illegal felling, forest fires and unsustainable water management. Desertification is a global phenomenon of land degradation, which reduces the natural potential of the ecosystems and has a direct impact on people in terms of vulnerability to food shortages and natural disasters, depletion of natural resources and deterioration of the environment.
4 important Causes of Desertification
1. Water Erosion
Soil erosion through fluvial processes affect large areas in the Saurashtra and Kutch uplands, and along the eastern margin of the Thar Desert where the average annual rainfall varies from 350 to 500 mm, but has very few occurrence to the west of 250 mm isohyets in the Thar.

The manifestations can be deciphered the pattern of sheet, rill and gully erosion features. Increased ploughing and destruction of vegetation cover for fuelwood, overgrazing and other destructive uses, must have accelerated the erosion in recent decades, but in the absence of specific data, it is difficult to suggest how much of the gulling activity is due to human activities alone and how much due to the natural processes. In Kutch region, a part of the problem is related to a slow natural uplift of the terrain over the centuries, which leads to a change in base level and increased erosion.
2. Wind Erosion/Deposition
The most vulnerable landforms to wind erosion/deposition are the sand dunes and other sandy landforms in the Thar. A closer look, however, indicates that the sandy landforms in the east are more stable than the similar landforms in the west. Rainfall gradient and wind strength are both responsible for the spatial variability in sand reactivation pattern.
The introduction of the tractor for deep ploughing, instead of the traditional animal-driven wooden plough, has increased the sand load manifold for the Aeolian processes in large parts of the desert, and accelerated the mobility of sand.
Increased destruction of the natural land cover in grazing lands for fuel and fodder and enlarging the frontiers of cultivation to less suitable sandy areas are also the responsible factors. In the foothills of the Aravali hill ranges along the wetter eastern part of the desert, such activities are also leading to accelerated water erosion, as manifested through the formation of rills and gullies.
The farmers are aware of headword progress of the gullies in the east, but do not believe that their agricultural activities hasten the process, unless tractors are used to loosen the soil. Many of them believe that the agricultural crop residues which they leave in the field are good sand binders and whatever land is being lost through gully erosion is a slow natural phenomenon. In other parts of the desert, farmers agree that deep ploughing with tractors, cultivation along dune slopes, or non-practising of long fallow systems and other traditional farming systems lead to accelerated sand movement and land degradation, but they have very few choices, as population pressure and economic consideration override environment consideration.
3. Mining
In western Rajasthan, about twenty major minerals and nine minor minerals are being mined. More than 90 per cent of the mine owners have open cast mining. The rest are underground mines. The area occupied by the mines is increasing and by 2000 AD 0.05 per cent of Jaisalmer district and 1.15 per cent of Jhunjhunu district are reportedly under mining activities.
The surface mining activity causes immediate degradation of land. The mining sites are abandoned after the excavation work is over, without adopting any reclamation measure. Mining on agricultural land, either surface or underground, reduces the productivity of land by way of excavation, disposal of debris and tailing. Mineral processing like grinding of limestone for cement industry, calcite and soapstone for ceramic industry, have three-fold adverse effects.
The fine dust, generated and released in the atmosphere, leads to surface scaling of the adjacent land after it settles down, consequently the infiltration rate is reduced and the run-off increases.
Mining activity restricts the sub-surface movement of water. With the removal of vegetation, the rate of evapotranspiration is reduced and as a result, there is a change in the hydrological balance in the area.
Due to this change, the perched water table rises and causes salinity. When the mining debris of minerals like ball clay, china clay, Fuller's earth, bentonite and gypsum are dumped on the sandy plain, a semi-impermeable surface layer is developed. These areas get flooded during the monsoon and gradually develop salinity. Sodium salt mining activity increases the surface salt concentration, causing total loss of vegetation.
4. Vegetation Degradation
One of the first casualties of desertification is natural vegetation. Degradation of natural vegetation is also one of its major causes. With increasing pressure on land vegetation, degradation is increasing at an alarming rate.
The common grazing lands around the villages are now some of the very severely degraded sites, as these are highly exploited and most neglected. Many good grazing lands have also been encroached upon for agriculture.
Programmes Controlling Desertification
India has always maintained that desertification is a function of the interplay of a number of causative factors and thus only a multi-sectoral approach alone will be able to arrest and reverse the process of desertification. Some major schemes/ programmes that have contributed to desertification control are  Drought Prone Areas Programme (DPAP), 1973-74; Watershed Development Project in Shifting Cultivation Areas (WDPSCA), 1974-75; Desert Development Programme (DDP), 1977-78; Reclamation & Development of Alkali Soil (RAS), 1985-86; Watershed Development Fund (WDF),  Integrated Wasteland Development Programme (IWDP), 1989; National Watershed Development Project for Rain fed Areas (NWDPRA) – 1990-91 and Soil Conservation in the Catchment of River Valley Projects (RVP) 1992. National Afforestation Programme (NAP) 2002-03 is also one of the major programmes in which  Association of Scheduled Tribes and Rural Poor in Regeneration of Degraded Forests (ASTRP), launched in 1992-93 and  Integrated Afforestation and Eco-Development Projects Scheme (LAEPS) 1989-90 were  merged into the  National Afforestation Programme.
The year mentioned against the name of the schemes above designates the year of inception. The three schemes of Desert Development Programme, Drought Prone Area Programme and Integrated Wasteland Development Programme have been consolidated into a single programme of Integrated Watershed Management Programme (IWMP) with effect from 01.04.2008. Recent initiatives include sustainable Land and Ecosystem Management (SLEM Programmatic Approach) 2007; Common Guidelines for Watershed Development Programme- 2008; Integrated Watershed Management Programme (IWMP) and Guidelines for Convergence between NREGA and NAP 2009.
The basic object of the programme is to minimise the adverse effect of drought and control desertification through rejuvenation of natural resource base of the identified desert areas, achieve ecological balance and overall economic development in the programme areas. The programme has covered in 235 blocks of 40 districts in 7 States. The corresponding physical area under the programme is about 4.57 lakh sq. kms. 

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