Loose covering of broken rocky material and decaying organic matter overlying the bedrock of the Earth’s surface. Comprised of minerals, organic matter(called humus) derived from decomposed plants and animals, air and water. Is a renewable resource but for a longer period of time. Depending on climate, it takes 15 years to hundreds of years for the formation of just 1 centimetre soil. Pedology is the study of soil. Soil
The base of life on land. Provides the bulk of the nutrients needed for plant growth. Serves as primary filter of water as it passes through it. Helps decompose and recycle biodegradable wastes. Major component of the earth’s water recycling and water storage processes. Importance of Soil
Occurs when natural or human-induced processes decrease the ability of land to support crops, livestock, or wild species in the future. Due to the following reasons: Creep Erosion Desertification Soil Degradation
Soil Creep Gradual movement of soil down a slope in response to gravity.
The movement of soil components, especially surface litter and topsoil, from one place to another. Two main agents: Flowing water Wind Erosion may be natural or anthropogenic. Anthropogenic erosion due to farming, logging, construction, overgrazing by livestock, off-road vehicle use, and deliberate burning of vegetation. Soil Erosion
Two major harmful effects: Loss of soil fertility through depletion of plant nutrients in topsoil. Water pollution, kill fish and shellfish, and clog irrigation ditches, boat channels, reservoir, and lakes. Soil Erosion
Techniques that will limit soil erosion avoiding construction during erosion prone periods intercepting runoff terrace-building use of erosion-suppressing cover materials planting trees or other soil binding plants.
Desertification The formation of deserts by changes in climate or by human-aided processes.
Causes of Desertification Natural causes of desertification: decreased rainfall increased temperatures lowering of water table soil erosion Soil compaction Human-aided desertification Overgrazing Destruction of forest belts (Deforestation) Salinization Exhaustion of the soil by intensive cultivation without restoration of fertility.
Worsening drought Famine Economic losses Lower living standards Environmental refugees Consequences of Desertification