Afforestation techniques for degraded lands

Afforestation Techniques for Degraded lands

1. Vikas Kumar
[email protected]

2. Deterioration in the quality of land, top soil, vegetation and
water resources caused by exclusive or inappropriate
exploitation.


The term ‘degradation’ refers to irreversible decline in the
‘biological potential’ of the land.

3.  Biophysical factors: land use and management, deforestation
and tillage methods.

 Socio-economic factors: land tenure, marketing, institutional
support, income and human health.

 Political factors: political stability forces that influence the
effectiveness of processes and factors of land degradation.

4. Wind erosion
Water erosion
Physical degradation
Chemical degradation

5. Climatic conditions
Terrain and landscape position
 Vegetation
 Edaphic factor
Management practices

6. Use of remotes sensing data

Direct observation and measurements

10. Ravine means “network of gullies”.

Causes of ravine formation
Destruction of forests
Unplanned cultivation
Destructive grazing
Severe water erosion

12. Integrated approach of soil conservation and vegetative
measures and restricted cutting of vegetation .
Protected these areas from biotic agencies

Soil conservation measure like
In moderate slopes ,contour trenching or bunding are done .
Steep gullies are stabilized by construction of gully plugging
and check dams.

13. .
Grasses :Panicum antidotale,Cenchrus ciliaris,which helps in
stabilisation of contour bunds.

Trees :Accia catechu and Dalbergia sissoo ,acacia nilotica
,prosopis julifera are selected for planting

14. Moving wind dislodges the soil particles and transported to
considerable long distances particularly in absence of
vegetation cover leads to formation of sand dunes.

These soils are having low organic matter, poor structure, low
clay content ,low microbial activity and moisture.

15. Sand dune fixation and stabilization through micro wind
breaks

Creation of wind breaks and shelter belts

Trees: prosopis julifera,acacia albida,azdirachta indica.etc

Shrubs and grasses: callygnum ppolygonoides,cenchrus ciliaris
pannicum antidotal,etc.

16. Hills have become barren and denuded because of large scale
and unrestricted felling's in forest areas
 soil is shallow,stony,poor moisture content and low in nutrient
status
Run-off is excessive and erosion is severe
Grazing and illicit incidence are very high

17. Staggered contour trenching is practiced to help the soil and
water conservation .
 Where slopes are very steep ,shallow “thallies” are prepared
for direct sowing.
Area fenced and closed for grazing.
In steeper slopes pits of size 30-40cm are dug and planting is
done.
Very hard trees is chosen for planting like Acacia ,eucalyptus
prosopis ,etc for tropical region and pinus roxburgii,cedrus
deodara,etc for temperate regions

18. Mining activities that extract ore or raw material from earth both
from surface as well as subsurface.

Open cast mining

Surface mining

19. Covering toxic or infertile material with soil or waste of better
quality.
Use of lime or gypsum to neutralize the acidic or alkaline soils
Leaching of salts by means of rainwater .fertilizing with
organic and inorganic fertilizers
Stabilizing of surface of very fine particles by mulching
Pits of size 60cm3 are usually dug up at spacing of 2m.
The pit should be filled with the fertile soil
Planting activities are carried out.

20. Areas exceeding optimum moisture content ,pore space become
partly filled ,aeration become difficult and less favourable for tree
growth these conditions are called water logged areas.

Afforestation of such lands needs special treatment which
includes
Drainage of excessive water
Reduction of salinity
Planting with suitable trees.

21. Improving drainage facilities by deepening drains
Removing of salinity by constructing series of mounds and
ditches
Tall and high transpiration rate of seedlings should be prefer
for planting
Suitable tree species: Casuarina equisetifoia
Syzyzium cumni
Terminalia arjuna
Eucalptus sps,etc

22. Skeletal soils
These soils are very shallow ,coarse,poor,eroded and
degraded.
These occurs both in low and high rainfall areas

Afforestation techniques
Contour trenches are or staggered trenches are made in order
to conserve soil moisture.
In rocky areas ,where soil particles are absent ,digging of deep
pits and filling them with soil brought from outside and
planting is done .

23. High rainfall areas:
cupressus torbolusa and C.arizonica
Pinus ponderosa ,etc

Low rainfall areas:
Eucalyptus terticornis
Acacia sps
Prosopis sps.,etc

24. Total precipitation usually less than 50mm.
Soils are neutral or alkaline in nature
Wind erosion is common
Short growing season

25. Trench cum pit type:
gentle slope areas
Digging of staggered contour trenches 4.3m long,60cm wide
at bottom and 1m wide at top at a spacing of 10m.
In between trenches pits of 60 cm and 1m deep are dug at 2m
spacing.
Trenches and pits are filled with 50;50 mixture of dug up soil
and fine silt

26. Trench cum drianage type
Low lying areas such as river banks and marshy lands.
To leach out salts from the root zone of plants, planting is
done in crow bar holes of 45 to 50 cm deep .

Choice of species:
Salix alba
 S.fragilis
Populus alba
P.ciliata,etc

27. Saline soils
pH<8.5
exchangeable Na <15%
Dominance of neutral salts such as chlorides and sulphates.

Alkaline soils
pH>8.5
Exchangeable Na>15%
Carbonate of sodium are dominant soluble salts

30. Production of loose soil by breaking the clay pan or kankar
pan
Replacement of exchangeable sodium by addition of
amendments
Maintenance of soil fertility
Trench ridge method is used rather than the pit method of
planting
Digging of pits upto 90 to120cm are also followed for planting
purposes.

31. The species should be tolerant to salt and alkalinity.

Pongamia pinnata
Terminalia arjuna
Prosopis julifera
Albizzia amara,etc

34. Ridge-trench method

Sub-surface planting in auger holes of 30-45 cm deep.

Planting in deep trenches or furrows.

35. Eucalptus hybrid
Madhuca latifolia
Xylia xylocarpa
Pterocarpus santalinus
Tectona grandis
Pterocarpus marsupium

36. Land degradation will remain an important global issue for the
21st century because of its adverse impact on productivity,
environment, and its effect on food security and the quality of
life.
So there is an urgent need to address these issues through a
multi-disciplinary approach, but the most urgent need is to
develop an objective, quantifiable, and precise concept based
on scientific principles to solve these land degradation
problems.

37. Eswaran.H., Lal .L and Reich.P.F . An overview of land
degradation.

Degraded and Wastelands of India ICAR publications