Problems of Desertification and Degradation Prepared by M .U. Kale Assistant professor Irrigation & Drainage Engineering Dr. P.D.K.V. Akola

Desertification

Definitions - Desertification “The process of fertile land transforming into desert typically as a result of deforestation, drought or improper/inap -propriate agriculture"

Introduction Desertification seen as specific type of land degradation occurring mainly but not exclusively, in dry land regions. Issue since the 1970. Since viewed as one of the most pressing issues affecting human kind. In India about 24.8 % of country’s geographic area is undergoing desertification. Due to desertification each year 12 million hectares are lost.

Causes of Desertification Changes in climatic Condition High incident radiation. Strong Wind, Water Erosion. Intense rainfall & scattered rainfall. Low humidity. River flooding. Depletion of surface water, ground water.

Causes of Desertification cont’d Human Activities Overgrazing Deforestation Improper agricultural practices Over drafting of ground water

Impact of Desertification Desertification is a global issue. With serious implications worldwide for biodiversity, eco-safety, poverty eradication, socio-economic stability and sustainable development. Dry lands are already fragile. As they become degraded, the impact on people, livestock and environment can be devastating. Some 50 million people may be displaced within the next 10 years as a result of desertification.

Countermeasures and prevention Reforestation and tree regeneration. Water management — saving, reuse of treated water, rainwater harvesting, desalination. Fixating the soil through the use of sand fences, shelter belts, woodlots and windbreaks.

Countermeasures and prevention cont’d Enrichment of soil through planting Farmer Managed Natural Regeneration (FMNR), enabling native sprouting tree growth through selective pruning of shrub shoots. The residue from pruned tress can be used to provide mulching for fields thus increasing soil water retention and reducing evaporation

Degradation

Definitions - Degradation “ The loss of soil through erosion, salinization, nutrient depletion & loss of fertility.”

Introduction Includes - Soil erosion, Salinization, Nutrient depletion & Desertification. Degradation seen worldwide – both developed and developing countries. 40% of the world's agricultural land is seriously degraded.  

Introduction cont’d The largest areas are in Asia and Africa. Central America has the highest percentage and worst degrees of soil degradation. In India 32% of total land area is affected by Land degradation.

Causes of Degradation Loss of topsoil due to Overgrazing. Deforestation. Destructive agricultural activities. Exploitation of wood for fuel. Inappropriate irrigation & overdrafting. Poor farming practices. Land clearance, such as clear cutting. Urbanization & commercial development. These all leads to soil erosion.

Impact of Degradation Sustainable reduction in productivity of land. Lower soil porosity. Weak aggregates. More soil compaction. Accelerated soil erosion by wind & water. Sealing of surface. Loss of organic matter.

Loss of top soil due to inappropriate irrigation

Physical degradation of a soil as a result of intensive tillage

Saline spot on the land

Raindrop effects Time

Countermeasures and prevention Improving land use. Provide permanent vegetative cover to protect the soil, increase fertility. To develop land conservation plan. Reduce soil tillage to minimum. Leave as many as crop residues as possible. Replenish the nutrients removed by crop.

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