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Bench terracing
- 2. Benching (Bench Terracing) Presented to: Dr. Abdul Rehman Presented by: Ali Adnan BAGF14E260 7th Agronomy College of Agriculture, University of Sargodha
- 3. Definition Bench terraces are a series of level or virtually level strips running across the slope at vertical intervals, supported by steep banks or risers. • It is an engineering soil conservation practice • It is also called bench terracing.
- 5. History • Concept of bench terracing is old as agriculture itself. • Philippines started bench terracing 2500 years ago. US soil conservation services collected evidences: • In Israel, citrus orchard in southern France, ShanSi province(China) and Lebanon hill side.
- 6. Objectives • To reduce run-off or its velocity and to minimize soil erosion. • To conserve soil moisture and fertility and to facilitate cropping operations. • To promote intensive land use and permanent agriculture on slopes and reduce shifting cultivation
- 7. Applicability This practice can: • Be manage on soil having slopes up to 30 %. • Be done where there is deep heavy clay soil rather than in very sandy soil. • Typically not applicable for slopes of decomposed granitic material, or any significantly sandy soil, because of excessive sloughing of material and construction difficulties.
- 8. Locations and conditions for use Bench terraces are particularly suited to countries or communities with the following macro conditions: • Severe erosion hazards • Areas with small holdings and a dense population. • Areas where there are food shortages or high unemployment rates. • Areas where crops require flood irrigation
- 9. Cont.. For micro or site conditions, bench terracing is suitable in the following cases: • Where there are relatively deep soils. • On slopes not exceeding 25 degrees. • On sites which are not dissected by gullies and not too stony.
- 10. Cut and Fill method
- 11. Types of Bench Terracing 1. Level or Table top bench terrace 2. Sloping inwards bench terrace 3. Sloping outwards bench terrace 4. Conservation type bench terrace
- 12. Level or Table top bench terrace Table top bench terrace are suitable for: • Areas receiving medium rainfall • Areas having highly permeable and deep soils
- 14. Sloping inwards bench terrace Sloping inwards bench terrace are suitable for: • Areas receiving heavy rainfall. Sloping inwards bench terrace Sloping inwards bench terrace are suitable for • It is useful for crops susceptible to water lodging. • Runoff towards hillside.
- 16. Sloping outwards bench terrace: Sloping outwards bench terrace are suitable for: • Areas receiving low rainfall & permeable soil of medium depth. at lower ends graded channels are provided for safe disposal of runoff
- 18. Conservation type bench terrace In this type of terrace: • Modified form of level terrace • Use moisture of uncropped area • Barrier is established across the land at suitable interval and the terrace is developed by pushing soil downhill and subsequent natural leveling.
- 20. Advantages • Reduces the soil erosion. • Aesthetical value • Intensive land use. • Economically beneficial. • Availability of food for local area. • Flood chances can be reduce. • Improves the condition of the slope for plant establishment. • Reduces runoff velocities and increases infiltration.
- 21. Disadvantages • Highly labor demand and time consuming. • Increased cost relative to alternative slope stabilization techniques. • Can be complicated to design and install, and may fail if not properly designed and installed
- 22. Some examples over the world
- 23. Terraces in northern Luzon Philippines 2000-B.C
- 24. Citrus Orchard in southern France
- 26. Level bench terracing in Japan
- 27. Tea on bench terraces, Bhutan
- 28. Outward bench terrace in Korea
- 29. Terraces on eroded soils of Israel
- 30. Terraced Fields in Sa Pa, Vietnam
- 31. Rice Terrace Panorama in Bali
- 33. Grassy Terraces in Chitral, Pakistan
- 35. Thank You