3. Patterns in environmental quality and sustainability - Soil and change

Soil and change

Source: http://byjus.com/biology/soil-profile/

Soil degradation is the decline in soil quality caused by its improper use, usually for agricultural, pastoral, industrial or urban purposes. 

Source: http://www.environment.nsw.gov.au/soildegradation/

Source: http://greenfieldgeography.wikispaces.com/Soil+and+change

Universal soil loss equasion

Source: http://ag.arizona.edu/oals/malawi/Reports/ANNEX4.html

Types of soil erosion

Wind and water: Rain or wind blowing away topsoil and causing degradation.

Biological: The loss of humus and or plant/animal life.

Physical: The loss of soil structure or change in permeability.

Chemical: The change in the chemical composition of soil. This could be acidification, salinisation or chemical pollution or loss of nutrients.

Source: http://greenfieldgeography.wikispaces.com/Soil+and+change

Causes of soil degradation

HUMAN CAUSES OF SOIL DEGRADATION

PHYSICAL CAUSES OF SOIL DEGRADATION

Overgrazing: Allowing to much livestock to graze on a piece of land which means all the vegetation is eaten making the ground susceptible to wind and water erosion. (Lesotho starves in rich SA's shadow - BBC article) Overcultivation: If you farm land to intensively and don't have fallow (periods of not growing anything) periods then all the nutrients in the soil get used. Deforestation: Cutting down trees which not only means the land will be receiving less nutrients, but it also means it is more vulnerable to erosion because there is no interception and less stability because the root systems have been removed. Overpopulation: As the world population continues to grow (now nearly 7 billion) the demand for agricultural products (crops and meat) is increasing causing more land to be deforested, overcultivated and overgrazed. Fertiliser and Pesticide Use: By using fertilisers and pesticides you can artificially increase yields of crops. However, the process is unnatural and prolonged periods of use can all naturally produced nutrients to be used and local water sources to become polluted reducing the ability of land to cultivate crops and therefore making it vulnerable to chemical degradation as well as wind and water erosion. HYV and GM Crops: Like with fertilisers and pesticides, it is argued that HYV and GM crops have encouraged overcultivation, diminishing natural nutrients in the soil. Industrial Pollution: Chemicals, metals and other pollutants leaked from industrial processes can chemical degrade soil making it useless or dangerous for farming. Acid rain caused by pollution can also cause soil degradation. Unsustainable Water Use (aquifer depletion, unsustainable irrigation): If aquifers or rivers are used unsustainably then areas can become increasingly arid as water resources are used up. A classic example of unsustainable irrigation happened in the Aral Sea (Irrigation and agriculture). Toyotarisation: This is basically the increased use of 4x4s to travel across grasslands, deserts, etc. damaging topsoil and increasing wind and water erosion. Conflict: During times of war biological and chemical weapons can be used which degrade the quality of the soil. During the Vietnam war large quantities of agent orange were used to defoliate forests. Much of the land in Vietnam is still degraded because of this 40 years on.

Rising Temperatures: As global temperatures increase it is becoming increasingly hard for vegetation to grow thus reducing vegetation cover and increasing the risk of wind and water erosion. Falling Rainfall: As the amount of rainfall reduces in some areas like the Sahel, then it is increasingly hard for vegetation to grow again making the ground more vulnerable to wind and water erosion. Flash floods: Intense periods of rainfall can also cause erosion of topsoil which leads to land degradation. Wind: If a region is particularly windy then the amount of wind erosion is likely to increase. Topography: If land is relatively flat then it is much less vulnerable to water erosion, but maybe vulnerable to wind erosion. Alternatively hilly land is vulnerable to water erosion, but maybe protected more from wind eros

Source: http://greenfieldgeography.wikispaces.com/Soil+and+change

Consequences of soil erosion

• Desertification 
• Dust storms 
• Reduction of soil buffering capacity 
• Impact on water bodies 
• Loss of biological diversity 
• Mud flows and floods 

Sources: https://en.wikipedia.org/wiki/Desertification

http://www.lastwordonnothing.com/2014/05/07/what-dust-does/

http://melaniemoorehead.com/carbon-dioxide-capture-sequestration/

http://greenliving.lovetoknow.com/How_to_Stop_Water_Pollution

http://www.eurowildlife.org/news/the-black-triangle-of-european-biodiversity-austria-hungary-the-czech-republic/

http://pubs.usgs.gov/gip/msh/mudflows.html

Management strategies

Crop Rotation and Fallow Periods: Growing different crops each year, so different nutrients are used and to allow periods of rest (fallow periods) so that soil can regain its fertility.

Terracing and Contour Ploughing: By ploughing with the contours (shape) of the land rather than against it you not only reduce water erosion, but you also reduce the need to irrigate as much. Terraces work on the same principal, they hold water in place rather than encouraging water erosion.

Shelter Belts: Shelter belts (sometimes called wind breaks) are areas of forest or hedge that is left untouched to protect farmland from the affects of water and wind erosion. Shelter belts will often appear around the outside of fields.

Reforestation and Afforestation: By reforesting or afforesting areas you can help return land to its natural state, making it more fertile and stable, thus reducing wind and water erosion and ultimately land degradation.

Fertilisers: Although as we have already learnt fertiliers can cause overcultivation and eventual land degradation, they can also help to add nutrients back into the soil and allow continued cultivation.

Irrigation: It is possible to water areas of land that have become arid to try and the productivity of the soil. However, if water is not used sustainably then irrigation can cause water shortages and land degradation elsewhere.

Grazing Quotas: Placing limits on the number and types of animals that can graze on land, reducing the destruction of vegetation and eventual desertification.

Population Control: The main reason we are putting more pressure on the earth's resources (including soil) is because the world's population has reached 7 billion and is still growing rapidly. If we can control population growth then we can limit the amount of agricultural land we need and the intensity of our farming.

Urban Planning: Controlling growth of cities and using more brownfield sites will reduce the need to deforest areas of land. By keeping forest cover in place, the risk of land degradation should be reduced.

GM Crops: GM stands for genetically modified. GM crops can be engineered to withstand poor soil and water shortages. By growing some types of vegetation you maybe able to add nutrients back to the soil. However, it might it encourage people to farm on unsuitable land causing even further land degradation.

Organic Farming: Organic farming is farming without the use of chemicals. If you farm organically you are less likely to overcultivate and reduce the soil nutrient levels, but you also not going to degrade the soil chemically.

Source:http://greenfieldgeography.wikispaces.com/Soil+and+change