Strategic Approach to Management of Soil Erosion

2. SOIL EROSION AND ITS CONTROL FOR MAINTAINING SOIL
HEALTH

3. INTRODUCTION TO SOIL EROSION
Definition :
 Soil erosion is the detachment, transport & deposition of soil particle on land
surface - termed as loss of soil.
 Measured as mass /unit area - tonne/ha or Kg/sq.m
Soil loss is of interest primarily On-site effect of erosion such as loss of crop
productivity.
Off site effect of erosion are siltation in ditches, streams , reservoirs.
Sediment generated by erosion processes are prime carrier of agricultural
chemicals that pollutes stream or lakes.

4. SOIL EROSION PROBLEM
 Soil is the most precious gift of nature –Prime resource -for food,
fodder etc. -Soil mismanaged = less productivity.
 In India, more than 100 million hectares -soil degraded.
 Ab ou t 17 tones/ha soil detached annually->20% of this is transported
by river to sea -10% deposited in reservoir results 1 to 2% loss off
storage capacity.
 Soil erosion deteriorates soil quality & reduces productivity of natural,
agricultural & forest ecosystem.
 Soil erosion deteriorates quality of water.
 Increased sedimentation causes reduction of carrying capacity of
water bodies.

5. FACTORS AFFECTING EROSION

6. MAN MADE CAUSES

7. NATURAL CAUSES

8. STRIKING FACTORS

9. DEGENERATING FORCES
Erosion is directly proportional to square root of length of slope

10. FACTORS AFFECTING EROSION

11. MECHANISM OF EROSION
 Begins with raindrops striking bare soil dislodging particles.
 Intense rains seal surface.
 W H E N r a i n f a l l exceeds infiltration water is stored in small depressions.
 O N C E depressions are filled, runoff begins.
 INITIALLY water flows in a discontinuous sheet.
 Eventually it concentrates into small channels or rills.
 T h e runoff now has energy to break off particles and cut deeper.
 T h e amount of erosion caused by sheet and rill erosion increases with
slope and distance.
 Rills may eventually form gullies.

12. SOIL EROSION PARAMETERS
 S o i l erosion – function of:
Erosivity – ability to erode : depends on rainfall.
Erodibility – Resistance offered to restrict erosion
(property of soil)
Topography – property of land.
Management – contributed by man.
 Erodibility: Detachability & transportability.
 Topography: Slope, length, relation to other land
Management: Land use & crop management.

13. TYPES OF SOIL EROSION
 Geological erosion, Natural erosion & Erosion from activities of
human & animals.
 Geological erosion: -Soil forming anddistribution-Long time process
 H u m a n and animal: Tillage, removal of plants and Tillage, removal
of plants and other vegetation- accelerated erosion
 Stream bank erosion
 Landslide, Volcanic eruption, flooding
 W a t e r and wind: major factors of soil erosion

14. SOIL EROSION
PROCESSES

15. SURFACE EROSION BY WATER
• It is caused by the action of
rain water , which removes the
soil byfallingasrain dropsas well
as by its surface slope action.

16. UNDERSTANDING WATER EROSION
20- 40 feet / s
300 – 900 PSI
1) Detachment
2) Transport
3) Deposition

17. WATER EROSION
SPLASH EROSION
1. This type of soil erosion occurs when the falling drops splash on
the soil.
SHEET EROSION
1. Thesoil is removed in small but uniform amounts from all over and
therefore, does not leave a mark behind.

18. SPLASH EROSION
SHEET EROSION

21.  RILL EROSION
1. Therun off water moves rapidly & cuts small stream like structure
 GULLY EROSION
1. Several rills converge towards the steep slopes & join to form board channels of
water called gullies.
 STREAM BANK EROSION
1. The rivers during floods splash their water against the banks &
through them.

22. RILL EROSION
Rills result from concentrated flow and can
be filled by normal tillage operations

23. RILL EROSION
GULLY EROSION

24. Streambank
Erosion
When a stream is straightened or widened,
streambank erosion increases. Accelerated
streambank erosion occurs until the stream
reestablishes a stable size and pattern.
When land use changes occur in a
watershed, such as clearing of land for
agriculture or development, runoff
increases. With this increase in runoff the
stream channel will adjust to accommodate
the additional flow, increasing streambank
erosion.

27. PRINCIPLE OF SOIL & MOISTURE CONSERVATION
• Ridge to valley treatment.
• Maximum possible rain water should be conserved where it falls.
• Adequate vegetal cover during rainy season.
• Storage/ disposal of excess water with safe velocity.
• Checks/ barriers along the contour to control soil erosion &
ground water recharge.
• Integration of biological and mechanical measures.

29. SOIL CONSERVATION

30. AGRONOMIC MEASURES

31. AGRONOMIC MEASURES

33. EROSION CONTROL
Erosion control is the practice of preventing or controlling wind or water
erosion in agricultural land development, river banks ,coastal areas, and
construction
 Thethreemainprinciples:
Use land according to itscapability.
Protectthesoilsurfacewith some form of cover.
Controlrunoff before it develops by an erosiveforce.

34. 1. VEGETATION
Thesimplest and most natural wayto prevent erosion.
Plants establish root systems,which stabilizessoil and prevents soilerosion.

36. SOILSTABILIZATION:
 THEPLANT ROOT SYSTEMBINDTHESOILAT THE SURFACE.
 INCREASE STRENGTH OF THE SOIL.
 SOIL EROSION BY RUNOFF WATER AND WIND IS DECREASED.
 Water managementmechanisms:
 The root system abstract water from the soil which decreases erosion bywater

37. FOR SLOPPY
LAND
For Gully Treatment

38. 2. CONTOUR FARMING
Contour farming or Contour plowing or Contour bunding
is the farming practice of level rows around a hill, as
opposed to farming up and down onthe hill.

39. CONTOUR CULTIVATION

40. STRIP CROPPING

41. It reduces :-
1)Amount and
2) Velocity of water moving acrossthesoil surface
or hill surface
 The water break allows more time for moving the water by
infiltration into the soil.
 Can reduce soil erosion by as much as 50% as compared to
uphill/downhill farming.

42. AFFORESTATION

43. COVER CROPPING

44. 3.RETAINING WALLS
A. A retaining wall is a structure that keeps soil, rock and water in
place so that it won’t be washed away from the rain.
B. The retaining wall serves the purpose of preventing erosion of soil by
wind, rain and flowing water, that is most likely to be due to the
wind and the rain.

45. Retaining walls

46. 4. WIND BREAKS
Field windbreaks are linear planting of trees/plant
designed to reduce wind speed in open fields, preventing soil
erosion and protecting crops from wind damage.
Field wind breaks are typically planted in multiple rows
perpendicular to prevailingwinds.

48. MULCHING
In mulching, a material is placed on the soil surface to
maintain moisture, reduce weed growth, reduce soil
erosion and improve soilconditions.
Mulching can help to improve crop yield and optimise
water use&reducesoiland watererosion.

49. EXAMPLES OF ORGANIC MULCHES
GrassClippings,
SmallLeaves, Wood
Chips, PineNeedles,
BananaLeaves, Palm
Fronds, Coconut
Husks, Branches.

50. EXAMPLES OF INORGANIC MULCHES
1.BLACK MULCH
 Doesn’t allow sunlight to pass,
hence arrests the weedgrowth.
2. TRANSPARENT MULCH
OAllows sunlight to pass&weeds
grow.

51. CONSERVATION DITCHES

52. AGRI-HORTI SYSTEM ( MANGO+ G.NUT)

53. AGRI-SILVICULTURE (A.mangium + SESAME)

54. SILVI-PASTORALSYSTEM
(A.mangium +guinea grass)
Horti-Pastoral System
(Banana +Grass)

55. TERRACING

56. CONTINUOUS CONTOUR TRENCHES

57. STAGGERED TRENCHES

59. WATER ABSORPTION TRENCH (WAT)

60. CONTOUR STONE BUNDING

61. PERCOLATION TANK

62. SUNKEN GULLY PIT

63. DIVERSION WEIR

64. MASONARY CHECK DAM

65. MASONARY MULTIPLE ARCH TYPE CHECK DAM

66. WATER HARVESTING STRUCTURE

67. RUNOFF MANAGEMENT STRUCTURE

68. FARM POND IN LOWER REACHES