Sewan grasslands occupy areas with low rainfall. They were spread across Bikaner, Jaisalmer and Barmer districts, but can no longer be seen now. Irrigation became possible with water from the Indira Gandhi Canal, and the grasslands were transformed into agricultural fields. But flood irrigation has also increased soil moisture, threatening the survival of species.

Sewan is very well-adapted to the desert. Highly energy-efficient, it produces substantial biomass with little water. Sewan is one of the most nutritious grasses known (protein content 7-11 per cent). Locals say that butter milk of cattle fed on this grass is highly rich in protein.

Sewan's roots lie dormant for years at a stretch, despite recurring droughts. Growing to a height of 75 to 100 cm, it is a tough grass. Vegetative growth begins in July and the seed is ready by August or September. It is cut and stored by the villagers for use in times of drought and scarcity, and can last up to 10 years. But excess water is harmful for the grass, which can only thrive in a harsh and dry environment.