1. Social processes modifying the quality of the soils from the Equator to the polar regions. Case studies. 12. The lithosphere and the soil as power equipment and hazard

2. 1. Anthropogenic causes of desertification in Africa Geographical position od Sahel and the rate of vegetation covering (www.earthobservatory.nasa.gov) The world's great deserts have been formed by natural processes interacting over long intervals of time. During most of these times, deserts have grown and shrunk independent of human activities. The largest hot desert is the Sahara todays, which is currently expanding south at a rate of up to 48 kilometers per year.

3. Sensitive areas of the Earth for desertification

4. Degraded, poor-quality soil in the Sahel (www.churlsonewild.files.worlspress.com) Historically, dryland livelihoods have been based on a mixture of hunting, gathering, cropping, and animal husbandry. This mixture varied in composition with time, place, and culture. At least 90% of the inhabitants of drylands live in developing nations, where they also suffer from poor economic and social conditions. Population pressure, however, has led to a growing tension between two main land uses: pastoral rangeland and cultivated land use. In some areas, this led to intercultural conflicts and desertification as herders and farmers claim access to and use of the same land. In other cases, it led to synergistic interaction and integration between the two land uses, with herders cultivating more land, farmers holding more livestock, and an increased exchange of services between the two groups. This situation is exacerbated by land degradation because of the reduction in productivity, the precariousness of living conditions and the difficulty of access to resources and opportunities.

5. 2. Forest at the desert Negev Geographical position of Yatir forest Yatir Forest is the largest planted forest in Israel; the forest covers an area of 30 square kilometers. It is located on the southern slopes of Mount Hebron, on the edge of the Negev Desert. Over the years of measurement, Yakir’s group has found that the semi-arid forest, even though it’s not as luxuriant as temperate forests farther north, is a surprisingly good carbon sink – better than most European pine forests and about on par with the global average.

6. 3. Environmental effects of irrigation in Mesopotamia The land of Mesopotamia and the irrigated area (www.2.bp.blogspot.com)

7. Agriculture began around 10,000 to 12,000 years ago. It has been supplemented by nomadic pastoralism, where tent-dwelling nomads herded sheep and goats from the river pastures in the dry summer months, out into seasonal grazing lands on the desert fringe in the wet winter season. In the marshlands to the south of the area, a complex water-borne fishing culture has existed since prehistoric times, and has added to the cultural mix. The first documented agriculture occurred 11,500 year ago between Jericho in the Jordan Valley and Mureybet in the Euphrates Valley.

8. 4. Effects of red alumina mud to the soil The red mud involved in the accident is a waste product of the Bayer process, which refines bauxite into a form of aluminium oxide called alumina. The mud primarily contains non-aluminium compounds present in the bauxite ore and left as residues after its refining along with sodium hydroxide used to dissolve aluminium oxide. There was an industrial accident here on 4 October 2010. the northwestern corner of the dam of reservoir no. 10 collapsed, freeing approximately one million cubic metres of liquid waste from red mud lakes. Red mud catastrophe at Devecser, Hungary (www.wikipedia.hu))

9. Thank you for your attention!