Degradation of Arid Rangelands in Thar Desert, India: A Review

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ABSTRACT Land degradation has recently been exacerbated in rangelands of arid Rajasthan by heavy grazing pressures. The total livestock population in the arid region of Rajasthan has reached 29.25 million in the year 2001 from 10.34 million in the year 1951. In terms of adult cattle units (ACU) the livestock pressure was 9.58 million in 1983, which increased to 11.27 million in 2001. Local grazing pressures are surpassing the recommended stocking rates of the rangelands at an enormous pace. The pressure was 0.87 ACU ha−1 in 1981 which increased to 1.02 ACU ha−1 ha in 2001 against the optimum desirable density of 0.2 ACU ha−1. Excellent, good, fair, poor and very poor condition rangelands (having approximate productivity of 2.0, 1.5, 1.0, 0.75, and 0.5 Mg ha−1, respectively) can safely provide year long grazing to 0.25–0.30, 0.20, 0.17, 0.13, and 0.01–0.06 ACU ha−1 blocks, respectively, during normal years. The carrying capacities of the rangelands were estimated several decades ago, however, qualitative evidence is available regarding changes in soil and vegetation patterns. There is need to evolve practices for improving the long-term productivity and sustainability of rangeland ecosystems. An increase of 639% in forage yield was observed over control by adopting moisture conservation technique. Increase in forage yield was recorded in the range of 30 to 122% in “poor” and 29 to 107% in “fair” class rangelands after 3–5 years of reseeding. Premonsoon sowing of grass seeds give 36% higher forage yield over monsoon sowing. Application of 22.5 kg N ha−1 during normal year resulted in additional increase in forage yield by 20 to 70%. If sustainable productivity increases are to be achieved, mechanisms must be developed to involve fully range users (herders) in all aspects of project planning and implementation. A flexible stocking rate, dependent on seasonal and annual variation in feed availability, is suggested as a key element in any improved range and livestock management strategy.