A barrier of trees and shrubs planted to protect fields from wind and storms and to reduce soil erosion is called a:

A shelter belt (or windbreak) is a long row or belt of trees and shrubs, usually several rows deep, planted across the direction of the prevailing wind. It slows down the wind, protects crops, soil and settlements, and reduces wind erosion.

How shelter belts work:

• The trees act as a barrier that forces the wind to rise over them and reduces its speed on the sheltered (leeward) side.
• The protected area extends to a distance of roughly 10 to 20 times the height of the trees on the downwind side.
• Reduced wind speed means less soil is blown away, less moisture evaporates from the soil and crops, and sand dunes are less likely to move.

Design:

• Shelter belts usually include tall trees in the middle and shorter trees and shrubs on the sides, to form a dense, sloping barrier.
• Hardy, drought-resistant species are chosen in dry areas, such as Prosopis, Acacia, Albizia, khejri (Prosopis cineraria) and Casuarina (in coastal areas).

Benefits:

• Protect crops from strong, hot or cold winds, sand and dust storms.
• Reduce soil erosion and the spread of desert sand.
• Conserve soil moisture and increase crop yields.

Shelter belts in India:

They have been planted in the Thar Desert region of Rajasthan, Haryana and Gujarat to check the spread of the desert and protect farmland, including along the Indira Gandhi Canal.

Famous examples around the world:

• The Great Plains Shelterbelt in the USA, planted in the 1930s after the "Dust Bowl" disaster.
• China's "Three-North Shelter Forest Programme", often called the "Great Green Wall", started in 1978 to check the spread of the Gobi and other deserts.

Why not the other options?

• ✗A check dam is a small barrier built across a stream to slow water flow and trap silt.
• ✗A gully plug is a small structure that blocks a gully to stop it from growing.
• ✗A contour bund is an earthen embankment built along contour lines to conserve soil and water.