With reference to Geography, Contour barriers, Mulching and Shelterbelts pertains to

🔑Key Points
Soil erosion and depletion are the major threats to the soil as a resource.
Both human and natural factors can lead to the degradation of soils.
Factors that lead to soil degradation are deforestation, overgrazing, overuse of chemical fertilisers or pesticides, rain wash, landslides and floods.
🛑Additional Information
Some soil conservation methods  
Mulching
A layer of organic matter like straw covers the bare ground between plants and helps to maintain soil moisture.
Contour barriers
To create barriers along contours, stones, grass, the soil is being used.
Trenches are made to collect water in front of the barriers.
Rock dam
Rocks are stacked up to slow down water flow and also help to stop gullies and further erosion of soil.
Terrace farming
On steep slopes, wide flat steps or terraces are designed so that flat surfaces are used for cultivation.Thus minimizing surface run-off and soil erosion.
Intercropping
Various crops can be grown in alternating rows and are planted at varying times to protect the soil from rain washing.
Ploughing of contours
Ploughing parallel to the contours of a hill slope creates a natural obstacle for fluid to drain down the slope.
Shelterbelts
​In the coastal and dry areas, rows of trees are cultivated to track the passage of air and preserve the cover of the soil.