Bench terraces are constructed for the areas having land slope above:

✅Explanation:
Bench terraces are a soil conservation measure implemented in hilly or sloping areas to control erosion and conserve water. They are typically constructed when the land slope is above 15%. Slopes steeper than this are prone to severe erosion, and bench terraces help to create level areas that reduce water runoff and soil loss.
🔑Key Points

• Mechanical Measures:
-Slope is more than 2%.

✏️Includes the following practices:

✏️Contour Bunding:
-Adopted up to 6% slope of land.
-Used in arid and semi-arid areas with high infiltration and permeability.

✏️Graded Bunding:
-Recommended in areas receiving rainfall of more than 800 mm per year.
-Suitable for lands with slopes ranging from 2% to 10%.
-Commonly used in India.

✏️Sub-Soiling:
-Involves breaking the hardpan of soil using a sub-soiler.
-Depth: 30-60 cm.
-Interval: 90-180 cm.

✏️Broad Bed and Furrow (BBF) System:
-Suitable for managing rainwater in deep black soils.
-Particularly useful in areas where surface drainage is a problem during the monsoon period.

✏️Bench Terracing:
-Adopted in lands with slopes ranging from 16-33% on steep, sloping, and undulating land.
-Reduces soil erosion.

✏️Zing Terracing:
-Suitable for lands with slopes of 3-10%.
-Constructed in medium to deep soils in moderate to high rainfall areas.

✏️Vegetative Barriers:
-Closely spaced plantations (usually grasses or shrubs) grown along contours for erosion control.
-Khus (Vetiveria zizanoides) is the most suitable plant for this purpose.

✏️Vertical Mulching:
-Involves digging narrow trenches across the slope at intervals and placing straw or crop residues in these trenches.
-Mostly practiced in coffee gardens.