2. Study area
Rajasthan (2340
e30110 N, 69290
e78170 E) is the largest state
in India with a geographical area of 34.22 million ha (Fig. 1). The
regional climate varies from semi-arid to arid with average annual
rainfall ranging from w480 mm to 750 mm with low values
(w150 mm) in the western arid region and w1000 mm in southeastern
plateau. Pre-monsoon (AprileJune) is the hottest season of
the year with temperature varying from 32 C to 45 C. In western
Rajasthan the air temperature often rises up to 48 C and the
prevailing westerly winds cause dust storms locally known as
“Andhi”. During monsoon season (JulyeSeptember), the area
receives w90% of the annual rainfall; however, it often suffers
from frequent drought due to poor and delayed monsoon rainfall,
abnormally high summer-temperature and insufficient water
resources. As a consequence, the arid environment of Rajasthan has
been