Effect of different rejuvenation techniques and fertilization on sewan (Lasiurus sindicus) pasture in hot arid region of Rajasthan

A field experiment was conducted during 2005 and 2006 at Bikaner to evaluate the different rejuvenation techniques and sources of nutrient supplementation on the productivity of old sewan (Lasiurus sindicus L.) pastures. Stubbles burning treatment proved superior, recording maximum growth attributes, viz. number of tillers/tussock, tiller height and tussock diameter, green fodder (7.75 and 9.49 t/ha), dry matter (2.78 and 3.26 t/ha), crude protein (230.0 and 276.1 kg/ha), NPK uptake, energy ratio (10.98), energy productivity (679 g/MJ), net returns (Rs 2,563/ha), benefit: cost ratio (1.51), and residual soil available P (8.86 and 9.14 kg/ha), and available K (174.3 and 167.1 kg/ha) compared with other treatments. Among fertilization sources, 50% each through organic and inorganic source of plant nutrients (20 kg each NPK + 5 t/ha sheep manure) being on a par with 100% inorganic sources recorded higher growth attributes, viz. green fodder (7.66 and 9.37 t/ha), dry matter 2.81 and 3.24 t/ha, crude protein 243.7 and 281.3 kg/ha, NPK uptake, energy output (48,833 MJ/ha) gross returns (Rs. 7,573/ha) and available N, P and K status. However, maximum net returns (Rs 3,035/ha) were given by 100% application of inorganic sources. Rejuvenation of old sewan pastures through stubble burning and fertilized with 50% each organic and inorganic source of plant nutrients gave maximum biomass yield. However, 100% application of inorganic sources (40 kg each NPK/ha through chemical fertilizers) gave the most economical pasture-grass production.