One quarter of the earth’s land is threatened by desertification, according to estimates by the United Nations Environment Programme (UNEP). The livelihoods of over 1 billion people in more than 100 countries are also jeopardized by desertification, as farming and grazing land becomes less productive.
Desertification does not mean that deserts are steadily advancing or taking over neighbouring land. As defined by the UN Convention, desertification is a process of “land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities”. Patches of degraded land may develop hundreds of kilometres from the nearest desert. But these patches can expand and join together, creating desert-like conditions. Desertification is compared to guerrilla warfare with no real “front line”. In other words desertification is a patch of land degraded through human abuse that then spreads outward if the abuse continues. Desertification contributes to other environmental crises, such as the loss of biodiversity and global warming.
The World Environment Day is on June 5. The theme is Deserts and Desertification and the slogan is Don’t Desert Drylands! It reflects 2006 being the International Year for Deserts and Desertification. The slogan emphasizes the importance of protecting drylands, which cover more than 40% of the planet’s surface. This ecosystem is home to one-third of the world’s people who are more vulnerable members of society. World Environment Day, commemorated each year on 5 June, is one of the principal vehicles through which the United Nations stimulates worldwide awareness of the environment and enhances political attention and action.
Desertification is a major problem in the drylands of India, affecting the way of life for its inhabitants. Most of the endangered dryland regions lie near the world’s five main desert areas, including the Thar Desert in Rajasthan. Recurrent drought, high wind, poor sandy soils and very high human and livestock demand for food, fodder and fuel wood are causing over-exploitation of fragile resources, resulting in wind and water erosion, water logging, salinity-alkalinity and vegetation degradation. Dumping of mine and industrial wastes is also now contributing to desertification. Desertification in drylands is estimated to affect at least one-third of the geographical area in India. Drylands, constituting of arid, semi-arid and dry sub-humid regions, are more prone to degradation on account of climatic constraints, fragility of natural resources, and high pressures of humans and animals, as well as industrialization. Arid areas are the worst affected, especially in the western part of Rajasthan state that includes the Thar Desert, as well as in arid Gujarat.
Wind erosion is a major problem in the Rajasthan part of the desert, where the higher average wind speeds, a dominantly sandy terrain, sparse vegetation cover and high human activities on the sand dunes and sandy plains lead to accentuation of sand blowing. It often leads to erosion of top-soil containing precious little organic matter, damages to crop plants, burial of good agricultural lands and infrastructures, as well as disruption of transportation network. As a consequence, more than 90 % area in arid Rajasthan is now affected by desertification at various levels. About 76% area is affected by wind erosion of different intensities, and 13% by water erosion. Traditional practices of water storage and conservation and mixed farming that integrates perennial trees and grasses with crop cultivation and livestock rearing, which proved as best practices for sustainability and resource conservation, are now disappearing.
To combat the adverse impact of these processes on finite land and water resources, India embarked upon a national policy to bring land area under forest, as well as to implement desert and drought-prone area development programmes. The densely populated desert of India has a dominantly agricultural economy. Much of the land is under cultivation. Therefore, researches on desertification control technologies put more emphasis on vegetative control of any particular problem, so that the rural population gets tangible economic benefits out of the control measures being suggested, and become interested in becoming a partner in the control of degradation. Wind erosion control gets more emphasis because it is the single largest problem. Several alternatives for vegetative control of moving sand, involving different mixtures of trees, shrubs and grasses, are now suggested to the farming communities.
Restoration in drylands can, however, be very complex, as few species have developed the adaptations required to thrive in water-scarce, drought prone areas. As such, restoration programmes in drylands often rely on local species. For example, in Rajasthan emphasise is given to the local preservation of native species of plants, including medicinal and sacred plants. Restoration efforts in Rajasthan of native species of cultural and economic importance, which have high value as suppliers of fodder, fuel, fruit, and the stabilization of sand dunes, is gaining a momentum.
For water erosion control on arable lands and non-arable lands various methods advocated. These measures and appropriate land uses are integrated on catchment basis with due regard to capability of the land.
Rain water conservation, its harvesting and efficient utilization are in-built in watershed management programmes. Combating desertification through land care while enhancing agricultural productivity is the underlying principle for sustainable land management in the drylands of India, especially in Rajasthan.