Desertification is a major problem in the drylands of India, affecting 173.64 million hectares, or 53% of the total area (Government of India 2006) and about 177 million people (Bai et al. 2008). The problem is more severe in the arid lands in the north-western part of the country, especially in the desert regions of Rajasthan, which is the largest state of the Republic of India in terms of area. Rajasthan has little forest cover, but is rich in flora and fauna. Approximately 92% of the area in Rajasthan is currently affected by desertification, with about 76% from wind erosion, 13% by water erosion, and another 4% area is affected by water logging and salinity/alkalinity (Narayan 2006). Water erosion and salinity seriously affect agriculture, aggravating poverty and threatening the food and water security in this area. Understanding the causes of land degradation in Rajasthan is crucial to help the Indian government draft policy to protect and improve the livelihoods of the communities living there.
Dryland Degradation in Rajasthan, India
Over 110 million hectares of agricultural land in India alone are known to be significantly degraded (Pohit 2009).
About 5.3 billion tons of top soil is eroded annually, . Almost with 24% of this soil loss is eroded annually, . Almost with 24% of this soil loss is carried by rivers as sediments and deposited in the sea, with and another 10% deposited in reservoirs, thus reducing their storage capacity by 2% (Pohit 2009).
With only 2.4% of world’s geographical area, India supports about 16.2% of the world’s human population. Although just having 0.5% of the world’s grazing area it feeds 18% of the world’s cattle (Kumar et al. 2007).
The arid zones of countryIndia cover about 3.2 million sq. km (12% of the geographical area), and cold desert covers an additional 70 thousand sq km. Rajasthan occupies the greater part of the Indian arid landscape and about 60 % of the country, followed by Gujarat (19%), Karnataka & Andhra Pradesh (10 %), and Punjab & Haryana (9 %)(Kumar et al. 2007).
Wind erosion (See figure 2) is a major problem in the desert regions of Rajasthan resulting in loss of top soil , damaging crop plants, and burying viable agricultural lands.
Water erosion tends to occur in the wetter parts of the arid zone and the semi-arid areas of India
Rapid population growth contributes to land degradation in India. On one hand, the growing population has disrupted traditional systems of land tenure and inheritance extending agricultural activities to marginal lands which are much more vulnerable to land degradation. On the other hand, slums are built on some of the region's best agricultural land. People have the imperative to produce more food on shrinking plots, and then turn to adopt intensive agricultural techniques which make soil resources face a constant danger of depletion (Pohit 2009).
Unsustainable land use can also lead to land degradation. Much of the land currently under cultivation was regarded, until recently, suitable only for animal husbandry (Pohit 2009), which causes two problems: first, growing food crops on such land has led to the development of unsustainable agricultural practices such as intensive irrigation and over-cropping; second, it has pressed grazers onto more marginal land which may lead to overgrazing. Both have contrubute to the growing problem of erosion.
Irrigation of soils makes them prone to stalinization, alkalinization or even waterlogging.
Over-cropping reduces the available organic matter in the soil. Humus loss decreases the ability of the soil to hold water, speeds precipitation runoff, increases the chance of flooding and water erosion, and makes the area more vulnerable to drought.
Mine spoils are becoming a driver of land degradation in the arid lands of India (Pohit 2009).
Trade and globalization contribute to land degradation in India as well. The importance of cash crops and food crop exports is likely to grow. This development is predicted to force more food production onto marginal areas, which will augment existing problems, especially related to erosion (Pohit 2009).
Land degradation leads to a loss of agricultural productivity, thereby threatening the food security and sustainable development of the region and the country. It is especially concerning given India's massive population and increasing rates of growth in both numbers of people and standard of living.
Land degradation has also aggravated rural poverty and influenced resident health. For example, Singh et al. (2006) studied the nutritional status of children aged 0–5 years in western Rajasthan and observed that among a total of 914 children, stunting (Chronic malnutrition measured as by the stunted growth of children) was observed in 53% of children. Additionally, 60% were underweight, and 28% were wasting, indicating extremely acute malnutrition
India’s government has taken action against wind erosion control. So far, the Indian government has sponsored large-scale wind erosion control projects.Farmers protect and manage their fields especially through crop residue management and fencing during critical periods. Two major activities of wind erosion control are sand dune stabilization and shelter belt plantation (Faroda 1998).
There is a need to conserve soil and water in this region.The method to counter crusting of soil and its subsequent erosion from the agricultural fields includes contour bunding (see figure 3) or graded bunding, contour tillage, and contour sowing, among other options (Singh 1990).
Cropland management should be developed in this region. Minimum tillage and strip cropping are two of the available cropland management methods.
Farmers may be encouraged to grow grasses and small shrubs in permanent pastures and rangelands and even in the short and long fallow lands.By planting grasses like Lasiurus sindicus, Cenchrus ciliaris and C. setigerus, as well as multipurpose trees and shrubs like Prosopis cineraria, Ziziphus nummularia, Capparis decidua and Acacia militiathe permanent pastures growing in sandy soil could increase their carrying capacity from 2.5 sheep per ha to 4.5-6.9 sheep per ha, and the permanent pastures growing in loamy sand soils could increase their carrying capacity to 9.0-13.8 sheep per ha. (Abrol and Venkateswarlu, 1995).
Irrigation practices should be improved since most waterlogging and salinity-alkalinity hazards are associated with poor irrigation planning.
Revegetation of the mine spoils is very challenging but necessary in India.Saxena et al. (1997) listed the suitable tree, shrub, and grass species for rehabilitation of different kinds of mine spoils. For instance, species like Prosopis juliflora, Salvadora persica, Acacia tortilis andAlbizzia amara can help the rehabilitation of Fuller’s earth and clay mine areas
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Bai, Z. G., D. L. Dent, L. Olsson & M. E. Schaepman. 2008. Global assessment of land degradation and improvement. 1. Identification by remote sensing. Report 2008/01, ISRIC –World Soil Information, Wageningen.
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