WHAT DO YOU KNOW ABOUT DESERTIFICATION  Desertification is a form of  land degradation occurring in arid, semiarid and dry subhumid areas of the world. It is a process where in fertile lands become arid through land mismanagement or climate changes. Many deserts in the world are man-made. Desertification is taking place much faster worldwide than historically and usually arises from the demands of increased populations that settle on the land in order to grow crops and graze animals. These susceptible dry lands cover 40 percent of the earth’s surface and puts at risk more than 1 billion people who are dependent on these lands for survival. Around 80 % of the productive land in the arid and semi-arid regions of the world is estimated to be converting into deserts and around 600 million people are threatened by desertification (according to UN EP). Globally around 2 billion acres of land have become deserts in the past 50 years.  The current rate of desertification is around 15 million acres per year, the worst being in sub-saharan Africa. Thar desert in Rajasthan covers about 12,000 hectares of land. Causes of desertification: 1. Overgrazing: By pounding the soil with their hooves, livestock compact the substrate, increase the proportion of fine material, and reduce the percolation rate of the soil, thus encouraging erosion by wind and water. Grazing and the collection of firewood reduce or eliminate plants that help to bind the soil.2. Increased population: Livestock pressure on marginal lands accelerates desertification.3. Deforestation practices: Loss of vegetation results in surface run off as there are no plants to bind the soil and resulting in soil erosion and depletion of nutrients.Increased food production from marginal lands in arid or semi- arid areas.Irrigation projects in areas with no drainage facility.4. Shifting of sand dunes by wind storms Effects:  A major impact of desertification is biodiversity loss, and loss of productive capacity, such as the transition from grassland dominated by perennial grasses to one dominated by perennial shrubs. In extreme cases, it leads to the destruction of lands’ ability to support life. But all is not lost we still have time to combat and control the rate of desertification through... 1. Afforestation and planting of soil binding grasses can check soil erosion, floods and water logging.2. Crop rotation and mixed cropping improve the fertility of the soil. It would increase production which can sustain large population.3. Desertification can be checked by artificial bunds or covering the area with proper type of vegetation.4. Shifting of sand can be controlled by mulching (use of artificial protective covering.)5. Salinity of the soil can be checked by improved drainage. Saline soil can be recovered by leaching with more water, particularly where water table of the ground is not very high.