Spreading of deserts to the green areas is called desertification. Desertification occurs due to human activities. Desertification occurs in grasslands and forests. Earlier, vegetation was present there. But over exploitation of these natural resources changes them deserts. These are not natural deserts. But they arc man made deserts. Deserts are characterized by few vegetation and arid land. The ruins of Moenjodaro arid Harappa are example of deseitification. There are following causes of desertification.
- Overgrazing and Trampling: These are two main causes of desertification. Overgrazing destroy all the vegetation in the grasslands and forests. Trampling makes the soil unfit for vegetation. Therefore, few plants are left on land. Such lands are unable to support vegetation.
- Deforestation: The clearing of forests is called deforestation. Deforestation is another wise of desertification. The humans are cutting trees for fuel WOO(‘ and timbers. It destroys the forest. The process of regeneration is too slow. Thus the forest is changed into desert.
- Aridity: The low Moisture in the soil is called aridity. Aridity is another cause of desertification.
- Water logging and salinity: Water logging and salinity is another causes of desertification.
- Soil erosion: Most of land of Pakistan is sandy. It has low content of silt and clay. Therefore, it can be easily eroded by water or wind. It makes the land unfit for cultivation.
Checking the process of Desertification
- The unstable sandy surface of soil is stabilized temporarily or permanently. This can be done by spreading litter mulch or by spraying some binding chemicals.
- Quick growing plants (shrubs, grasses) are Planted at close spacing.
- Hand watering or water sprinkling should be done during very early stages of vegetation establishment.
- First phase of vegetation should be protected carefully.
- Seedlings of other species are inter-planted. This vegetation will gradually replace first phase of vegetation.
- Thinning and pruning must be delayed.
- Peripheral farm lands of adjoining deserts should be provided with frequent tree shelter belts.
- Crops or their stubbles be left standing in the field during hot dry summers.
- Ploughing should be minimized
- Maximum quantities of a litter (organic mulch) should be added to fields.
- Fertilizers should be added in many light doses. This will increase total production and will increase amount of litter/manure.