To check the expansion of Thar desert which of the following measures should be tried?

Answer: (b) Afforestation

Afforestation and shelterbelts stop dunes from spreading.

The idea

Moving sand is controlled by reducing wind speed at the ground and binding loose soil. Vegetation does both through stems, leaves and roots. Adding water alone does not necessarily prevent wind erosion if the surface remains bare.

Plant suitable trees and shrubs → Shelterbelts slow wind → Roots bind soil → Less sand is lifted → Dune movement slows → Protected ground supports more vegetation

Why the others are wrong

(a) Dams don’t stop sand.

(c) Canals help farming but don’t hold dunes.

Also know

Shelterbelts are rows of vegetation planted across the prevailing wind. Drought-tolerant native plants are more suitable than water-demanding species in arid areas. Overgrazing can remove protective cover; contour bunds mainly address water erosion rather than windblown sand.