Unit 5
Land and Mineral Resource

Learning Outcomes

Prerequisites

Key words

Soil erosion, Desertification, Mineral Resources, Landslides

Discussion

1.5.1 Land resources

Land forms such as hills, valleys, plains, river basins and wetlands include different resource generating areas that the people living in them depend on. It is an essential natural resource, both for the survival and prosperity of humanity, and for the maintenance of all terrestrial ecosystems. Land is a major resource for agricultural development worldwide. Over millennia, people have become progressively more expert in exploiting land resources for their own ends. The limits on these resources are finite while human demands on them are not. Increased demand, or pressure on land resources, shows up as declining crop production, degradation of land quality and quantity, and competition for land. Attention should now be focused on the role of humankind as stewards rather than exploiters, charged with the responsibility of safeguarding the rights of unborn generations and of conserving land as the basis of the global ecosystem.

1.5.2 Land degradation

Have anybody thought of how land degradation happens? Land degradation is a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land. It is viewed as any change or disturbance to the land perceived to be undesirable. Natural hazards are excluded as a cause; however human activities can indirectly affect phenomena such as floods and bush fires. This is considered to be an important topic of the 21st century due to the implications land degradation has upon agricultural productivity, the environment, and its effects on food security. It is estimated that up to 4% of the world’s agricultural land is seriously degraded.

According to the Special Report on Climate Change and Land of the Intergovernmental Panel on Climate Change, “About a quarter of the Earth’s ice-free land area is subject to human-induced degradation (medium confidence). Soil erosion from agricultural fields is estimated to be currently 10 to 20 times (no tillage) to more than 100 times (convention-al tillage) higher than the soil formation rate (medium confidence).” The United Nations estimate that about 30% of land is degraded worldwide and about 12 million hectares of productive land– which roughly equals the size of Greece– is degraded every year. This happens because people exploit the land with-out protecting it. The United Nations Sustainable Development Goal 15 has a target to restore degraded land and soil and achieve a land degradation-neutral world by 2030.

The usage of agriculture, deforestation, and climate change are the main causes of land degradation, which is a global issue. Land clearing, including clear-cutting and deforestation, agricultural soil nutrient depletion due to inefficient farming methods, livestock overgrazing and overdrafting, inappropriate irrigation, urban sprawl, commercial development, vehicle off-roading, quarrying for stone, sand, ore, and minerals, increase in field size due to economies of scale, and reduced shelter for wildlife, such as hedgerows and corpses, are some of the causes.

1.5.3 Man induced landslides

Human-induced landslides (HIL) refer to landslide events that are directly triggered or partially aggravated by anthropogenic factors such as modification of the topography, change of the water circulations, land use changes, ageing of infrastructure, etc. Human-induced landslides usually occur on cut slopes due to excavation, which can cause many fatalities and severe destruction.

Landslides are aggravated by human activities, such as:

• Deforestation, cultivation and construction.
• Vibrations from machinery or traffic.
• Blasting and mining.
• Earthwork (e.g., by altering the shape of a slope, or imposing new loads);in shallow soils, the removal of deep-rooted vegetation that binds colluvium to bedrock.
• Logging, and urbanization, which change the amount of water infiltrating the soil.
• Temporal variation in land use and land cover (LU/LC): It includes the human abandonment of farming areas, e.g. due to the economic and social transformations which occurred in Europe after the Second World War. Land degradation and extreme rainfall can increase the frequency of erosion and landslide phenomena.

1.5.4 Soil erosion

What is soil erosion? When will it happen? Soil erosion is a major worldwide threat to agroecosystem sustainability and land productivity. More than 36 billion tons of fertile soil is lost from world agricultural systems each year through soil erosion. Erosion is a serious problem for productive agricultural land and for water quality concerns. Controlling the sediment must be an integral part of any soil management system to improve water and soil quality. Eroded topsoil can be trans-ported by wind or water into streams and other waterways. Sediment is a product of land erosion and derives largely from sheet and rill erosion from upland areas, and to a lesser degree, from cyclic erosion activity in gullies and drainage ways.

Types of Erosion

• Sheet erosion (water) is almost invisible. Lighter colored soils are a sign that over the years erosion has taken its toll.
• Wind erosion is highly visible. Although it is a problem, water erosion is generally much more severe.
• Rill erosion occurs during heavy rains, when small rills form over an entire hillside, making farming difficult.
• Gully erosion makes gullies, some of them huge, impossible to cross with farm machinery.
• Ephemeral erosion occurs in natural depressions. It differs from gully erosion in that the area can be crossed by farm equipment.

1.5.5 Desertification

Do you know what Desertification is? Desertification basically implies degradation, deterioration and impoverishment of the world dry-land regions. It can be defined as the reduction or destruction of the biological-potential of land resulting in the appearance of desert conditions. In other words, it refers to a loss of productivity of the land. This however does not mean that there is an expansion of deserts. In this context it is necessary to focus on the fact that desertification is essentially adverse in nature. The problem is global in scale affecting nearly one fourth of the world’s land area. It can take place anywhere; however the fertile land near the existing deserts usually becomes victims to the process of desertification very easily. Desertification essentially is the result of human activities rather than by natural factors.

Causes of desertification

1. Over cultivation- most countries need to cultivate commercial or cash crops. This displaces traditional agriculture to marginal lands. The marginal lands which were previously not used either decline in productivity or remain stagnant at the basic production level. Natural events such as droughts and famines lead to the process of deterioration and degradation.
2. Over grazing- low livestock prices tempt producers to rear as many as possible. The cattle over graze the green land. This leads to removal of vegetation cover and its nutrients. The loose soil particles, which basically contain the fertile characteristics, are blown away by the wind. This makes the land look like a desert. In other words, over-grazing over a period of time lead to desert like conditions.
3. Over irrigation- The irrigation schemes meant for the supply of water are important and hence they require adequate planning. Inefficient land irrigation schemes result in water logging of crops and consequent salination of soil. The saline soil brings up the salts to the surface and continued evaporation makes the soil unfit for cultivation. Subsequently, this causes desertification.
4. Deforestation- This is one of the significant causes of desertification. Forests are removed and cleared for various resources and for cultivation of cash crops, human settlement, creating space for increasing cattle etc. This process is called deforestation. Due to this the top-quality soil or fertile soil gets exposed to the forces of nature. Subsequently, it gets washed away. Thus, deforestation results in desertification.
5. Mining operation- Mining operations result in the disposal of rejects in fertile land. These mining rejects lead to total erosion of soil, further resulting in the desert like conditions.
6. Growth of population – large increase in population is taking place in many parts of the world. This causes severe pressure on land, subsequently causing desertification. In other words, land encroachment by human beings will lead to desertification.

Consequences of desertification

What are the consequences of desertification? Desertification is a severe problem as it causes exploitation of land which is one of most important natural resources. This problem is especially grave in the developing countries. Moreover, the seriousness of the problem increases because the negative consequences are irreversible.

1. Productivity of the land is almost eliminated or it reaches the lowest level.
2. The productivity of land is vital for the survival of mankind. If a particular area of land becomes dry land, the living conditions of the people in this affected area become miserable.
3. Once a land becomes a dry land or has desert like condition the result is loss of productivity or a loss of important means of survival. It means the drylands are incapable of producing food resources.
4. Desertification also leads to drying up of the water resources; it causes destruction of the natural resources of the environment.
5. There is also an adverse effect on the biotic and abiotic components of the environment.
6. The desert like conditions created due to desertification affects human being in a serious manner. It leads to less productive or relatively infertile land. All these factors basically create miserable living conditions or poverty for the people. Desertification is a serious problem because the consequences cannot reversed.

1.5.6 Mineral resources

Use of Minerals

The earth’s resources have been used by all cultures throughout history. The earliest uses of the earth’s resources involved water, salt and simple tools made from rocks. The quantities of various mineral resources used by particular societies vary widely but generally correspond per capita to the nation’s degree of development and standard of living.

The use of minerals depends upon its de-posits. Some countries are rich in mineral deposits, while others have no deposits. The greatest use of minerals depends on its properties. Minerals are used in almost all industries. Gold, silver and platinum are used in the jewellery industry. Copper is used in coin industry and for making pipes and wire. Silicon obtained from quartz is used in the computer industry. Aluminium is light, strong and durable in nature, so it is used for aircraft, shipping and car industries.

Exploitation of Mineral Resources

Exploitation of minerals refers to the use of mineral resources for economic growth. Exploitation of mineral resources at a mindless speed to meet the growing needs of modern civilization has resulted in many environ-mental problems. Although the exploitation of minerals began at a slow pace during the industrial revolution in Western countries, during the 20th century, the exploitation of some minerals, especially the fossil fuels, in-creased exponentially to meet the growing energy needs. Today about 80% of the world’s energy consumption is sustained by the ex-traction of fossil fuels, which consists of oil, coal, and gas.

Environmental effects of extracting

Mineral Extraction

Extracting and use of mineral resources can affect the environment adversely. Environ-mental effects may depend on factors such as mining procedures, ore quality, climate, size of operation, topography, etc. Some of the major environmental impacts of mining and processing operations are as under:

1. Degradation of land.
2. Pollution of surfaces and ground water resources.
3. Effect on growth of vegetation due to leaching out effect of minerals.
4. Surface water pollution and groundwater contamination lead to occupational health hazards etc.
5. Air pollution due to emission of gases.
6. Deforestation affects flora and fauna.
7. Rehabilitation of affected population.
8. Rapid depletion of high-grade minerals
9. Forced migration
10. Wastage of upper soil layer and vegetation
11. Soil erosion and oil depletion
12. Ozone depletion
13. Environmental pollution
14. Natural hazards

Recap

Objective type questions

Answer to Objective type questions

Self Assessment Questions

Assignment

Suggested Reading

Reference