Fjölrit RALA - 05.12.1999, Blaðsíða 122

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Desertification and rangeland managementin India
Table 2. Tíme sequence of regeneration of rangelands in various habitats of the Thar desert.
(Source: K.A. Shankarnarayanan in Ishwar Prakash (ed.) 1988, Desert Ecology).
Duration of
Desert habitats enclosure (in years) Grass cover
Hills 7 Chroysopogon fulvus, Eremopogon foveolatus, Heteropogon contortus
Rocky/gravelly pediments 12 Eleusine compressa Dactyloctenium sindicum
Rocky/gravelly pediments with contour bunding 6 Eleusine compressa Dactyloctenium sindicum
Flat buried pediments (high rainfall and heavy soils) 6 Dichanthium annulatum
Sandy undulating buried pediments (low rainfall) 6 Lasiurus sindicus, Panicum antidotale
Flat aggraded older alluvial Plains 4-6 Lasiurus sindicus Panicum antidotale
Sand dunes 18 Panicum turgidum Cenchrus prieurii
Shallow saline Depressions 6 Sporobolus marginatus Dichanthium annulatum
POTENTIAL FOR RANGELAND DEVELOPMENT 1N THE THAR DESERT
Natural regeneration of trees, shrubs and grasses in the Thar desert is very slow (see
Tables 1 and 2). The biotic pressure is so intense in the arid region of Rajasthan that
the forest floor is grazed clean and the plants are browsed severely by the huge popu-
lation of livestock hampering the regeneration process.
Improved strains of pasture grasses and legumes for Thar desert
For achieving a breakthrough in the yield of different promising grasses and legumes,
an exhaustive germ-plasm of over 1600 plants has been built up at the Central Arid
Zone Research Institute (CAZRI) Jodhpur, Rajasthan and maintained in nursery. An
active variety construction programme with manifold objective is under way. A num-
ber of promising cultivars have been identified. The important cultivars are: CAZRI-
358, 75, Molopo, Buffel of Cenchrus ciliaris; 76, 175, 296 of C. setigerus; 317, M-20-
5, 319 oíLasiurus sindicus; 490, 491 of Dichanthium annulatum; 331, 333 oíPani-
cum antidotale; 144, 1258, 1462, 1626 oíLablab purpureas; 752, 466, 1433 of Clito-
ria ternatea. These varieties provide high and nutritive forage over a greater part of
the year. They are drought hardy, stable, persistent and aggressive in rangeland and
possess high seed yield ability, fast regeneration and good germination.
Several areas of the Thar desert are highly saline which hinders growth of grasses
and palatable herbs. Salt tolerance of various pasture species has been identified after
yearly monitoring of their occurrence and yield and the results have been successfully
utilized in the rangeland development in the salt affected areas of the Thar desert (see
Table 3).