Desertification in india

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Desertification: causes, occurences

and control stategies

Immanuel Chongboi Haokip10537

Division of Soil Science and Agricultural Chemistry

IARI

SSAC - 605

TERM PAPER

on


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DesertificationAubreville(1949) defined it as the changing

of productive land into a desert as the result of ruination of

land by man-induced soil erosion.

He associated it with the humid and subhumid tropics where

he worked.

UNEP (1992) defined desertification as land degradation in

the arid, semi-arid, and sub-humid areas resulting from

various factors, including climatic variations and human

activities.

Desertification usually begins as a spot on the land-scape

where land abuse has become excessive.


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The causes and development of desertification

Desertification


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classes of desertification: Slight: Little or no degradation of the soil and plant cover has

occurred.

Moderate:

(1) 26-50% of plant community consists of climax species, or

(2) 25-75 % of original topsoil lost, or

(3) soil salinity has reduced crop yields 10 to 50 percent.

Severe:

(1) 10-25 % of plan community consists of climax species, or

(2) erosion has removed all or practically all of the topsoil, or

(3) salinity controllable by drainage and leaching has reduced cropyield by more than 50%.

Very Severe:

(1) Less than 10% of plant community consists of climax species, or (2) land has many sand dunes or deep gullies, or

(3) salt crusts have developed on very slow permeable irrigated soils.

Dregne (1986)


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OCCURRENCE OF DESERTIFICATION

Desertification affects nearly all of the arid

regions, to varying degrees, except for theextremely arid climatic deserts such as the

Sahara, Atacama, and Taklimakan.


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Process wise desertification in India

(mha)

Ajai et al., 2009


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State-wise statistic of desertification

Ajai et al., 2009


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Consequences of desertification

Reduces the landsresilience to natural climate variability.

Soil becomes less productive.

Vegetation becomes damaged.

Downstream flooding, reduced water quality, sedimentation

in rivers and lakes, and siltation of reservoirs and navigation

channels.

Food production is undermined.

Desertification contributes to famine.

UNCCD


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National Action Programme to Combat Desertification

India is a party to UNCCD and MoEF is the NationalCoordinating Agency for the implementation of the UNCCD

in the country. The objectives are:-

1. Community based approach to development

2. Activities to improve the quality of life of the localcommunities

3. Awareness raising

4. Drought management preparedness and mitigation

5. R&D initiatives and interventions which are locally suited6. Strengthening self governance leading to empowerment of

local communities


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Case study

2.34 million sq. km.

85% in India

91% in Rajasthan

covers 61% of Rajasthan

100-500mm90% -July and September.


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1.Introduction of fast growing exotic tree

species

indigenous tree species are few and

extremely slow growing.

about 115 Eucalyptus spps, 73 Acacia spps.

and 170 miscellaneous spp. were introduced.

Acacia tortilisfrom Israel has been adjudged

the best fuel-cum-fodder species for the

desert.


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2. Stabilization of shifting sand-dunes

Low-rainfall areas (150 mm to 400 mm), huge shifting sand

dunes

Techniques of afforesting standardized after 10 yrs

Techniques consist

(i) protection against biotic interferences;

(ii) treatment of shifting sand-dunes by fixing barriers using thelocal shrub material to protect the seedlings from burial or

exposure by the blowing of sand;

(iii) afforestation of such treated dunes by direct seedling and

planting.

Both indigenous and exotic species have proved successful

Phog (Calligonum polygonoides),a naturally growing shrub,

root which works as effective sandbinder

Acacia albida was used to stabilize 60,000 ha of sand-dunes


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3. Shelterbelt plantations to reduce wind velocity

Shelterbelts and tree-screens consisting of a row of trees viz.

Acacia tortilis, Tamarix articulata and Azadirachta indica

flanked by two rows (one on each side) of smaller trees like

Acacia senegal, Prosopis juliflora etc., with two rows (one on

each side) of shrubs like Aerva tomentosa, Zizyphus

spinachristi, Calligonum polygonoideswere found to be veryeffective.

Shelterbelts reduced the wind velocity by 2046% on the

leeward side for 2H10H during the monsoon period.

Rajasthan State Forest Department has so far covered about38,000 row km area under shelterbelt


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4.Ecological regeneration through aerial seeding

Aerial seeding of seed pellets was done in 56 ha of military

range areas in Barmer district at two sites: the duny sandy

plain of Jalipa and the rocky hill ranges of Jasai village.

Two methods of seeding-helicopter and manual

broadcasting of pellets were used

Manual broadcasting of pellets was found better than aerial

seeding by helicopter.

Under controlled conditions in the Jasai area, the plant

population at sandy and rocky area were 6 and 3 individuals

per sq. m. , respectively.


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5. Ecological restoration and regeneration of the minedwastelands

Gypsum and limestone mined wastelands

Four plots-1 ha each-4 treatments

Control, micro-catchment area, half moon structure andridge and furrow system.

Seven indigenous and exotic species of trees, four of shrubs

were selected for plantation and rooted slips of grasses.

More than 90% of the plants survived


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Time sequence of regeneration of rangelands in

various habitats of the Thar desert.

Shankarnarayanan in Ishwar Prakash,1988,


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Conclusions

Overgrazing, extraction of food, fodder and fuelwood causeddesertification.

The degraded rangelands of the Thar desert show

tremendous resilience for regeneration when the influence

of biotic factors are removed.

However it is possible to recover these desertified land

through different practice.

Therefore, strenuous efforts should made towards

desertification control.


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Desertification in india