SoilJenalyn A. Sampang

Celeste R. Desingaño

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

Soil Profile/Soil Horizon

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

Gradual movement of soil down a slope in response to gravity.

Soil Creep

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

◦avoiding construction during erosion prone periods

◦intercepting runoff

◦terrace-building

◦use of erosion-suppressing cover materials

◦planting trees or other soil binding plants.

Techniques that will limit soil erosion

The formation of deserts by changes in climate or by human-aided processes.

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.

Causes of Desertification

Worsening drought Famine Economic losses Lower living standards Environmental refugees

Consequences of Desertification