Unit 3:Natural Resources:

Dr. Kumar Anandam

Unit 3: Natural Resources:

Land resources and landuse change: Land as a resource, land degradation, landslides

(natural & man-induced), soil erosion and desertification.

Forests & forest resources: Use and over-exploitation, deforestation, case studies.

Impacts of deforestation, mining, dam building on environment, forests, biodiversity and

tribal populations. Resettlement and rehabilitation of project affected persons; problems

and concerns, case studies

Water resources: Use and over-exploitation of surface and ground water, floods,

drought, conflicts over water (international & inter-state).

Food resources: World food problems, changes caused by agriculture and overgrazing,

effects of modern agriculture, fertilizer-pesticide problems, water logging, salinity, case

studies.

Energy resources: Renewable and non-renewable energy sources, use of alternate

energy sources, growing energy needs, case studies.

Introduction to Natural Resources:

Any material which can be transformed in a way that it becomes more valuable and useful

can be termed as resource. In other words, it is possible to obtain valuable items from any

resources. Resource, therefore, are the means to attain given ends. The aspect of satisfaction

is so important that we consider a thing or substance a resource, as so long it meets our

needs. Life on this planet depends upon a large number of things and services provided by

the nature, which are known as Natural Resources. Thus water, air, soil, minerals, coal,

forests, crops and wild life are all examples of natural resources.

2.1.1 Classification of natural resources:

Depending upon availability of natural resources can be divided into two categories such as

(1) Renewable

(2) Nonrenewable resources

1.Renewable resources: Renewable resources are in a way inexhaustible resources. They

have the ability to replenish themselves by means such as recycling, reproduction and

replacement.Examples of renewable resources are sunlight, animals and plants,soil,water,etc.

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2. Non-Renewable Resources: Non-renewable resources are the resources that cannot be

replenished once used or perished. Examples of non-renewable resources are minerals, fossil

fuels, etc. Resources can also be classified as biotic or abiotic.

a)Biotic resources: These are living resources (e.g. forest, agriculture, fish and wild life) that

are able to reproduce or replace them and to increase.

b)Abiotic resources: These are non-living resources (e.g. petrol, land, minerals etc.) that are

not able to replace themselves or do so at such a slow rate that they are not useful to consider

them in terms of the human life times.

Problems associated with natural resources

1. The unequal consumption of natural resources: A major part of natural resources today

are consumed in the technologically advanced or ‘developed’ world, usually termed ‘the

west’. The ‘developing nations’ of ‘the east’, including India and China, also over use many

resources because of their greater human population. However, the consumption of resources

per capita (per individual) of the developed countries is up to 50 times greater than in most

developing countries. Advanced countries produce over 75% of global industrial waste and

greenhouse gases.

2. Planning land use: Land is a major resource, needed for not only for food production and

animal husbandry, but also for industry and growing human settlements. These forms of

intensive land use are frequently extended at the cost of ‘wild lands’, our remaining forests,

grasslands, wetlands and deserts. This demands for a pragmatic policy that analyses the land

allocation for different uses.

3. The need for sustainable lifestyles: Human standard of living and the health of the

ecosystem are indicators of sustainable use of resources in any country or region. Ironically,

both are not in concurrence with each other. Increasing the level of one, usually leads to

degradation of other. Development policies should be formulated to strike a balance between

the two.

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Land resources and land use change: Land as a resource, land degradation,

landslides (natural & man-induced), soil erosion and desertification.

Land resources:

Landforms such as hills, valleys, plains, river basins and wetlands include different resource

generating areas that the people living in them depend on. Many traditional farming societies

had ways of preserving areas from which they used resources. Land, a critically important

national resource, supports all living organisms including plants as well as every primary

production system such as roads, industries, communication and storage for surface and

ground water, among others. Land is a major resource for agricultural development

worldwide. Land resource refers to the land available for exploitation, like non-agricultural

lands for buildings, developing townships etc. Land resources (natural resources)

(economically referred to as land or raw materials) occur naturally within environments that

exist relatively undisturbed by mankind, in a natural form.

Land Degradation:

Land degradation is the process of deterioration of soil or loss of fertility of soil. The causes

of land degradation can be divided into natural hazards, direct causes, and underlying causes.

Natural hazards are the conditions of the physical environment which lead to the existence of

a high degradation hazard, for example steep slopes as a hazard for water erosion. Direct

causes are unsuitable land use and inappropriate land management practices, for example the

cultivation of steep slopes without measures for soil conservation. Underlying causes are the

reasons why these inappropriate types of land use and management are practiced; for

example,-the slopes may be cultivated because the landless poor need food, and conservation

measures not adopted because these farmers lack security of tenure.

Causes of land degradation

• Population: The indirect activities included pressure on agricultural intensification and

population growth. About 220 million hectares of tropical forest have been degraded 1975

and 1990 mainly for food production. With the increase in population, more land is needed

for producing food, fiber, and fuel wood leading to increasing pressure on the limited land

resources. Therefore, the land gets degraded due to over exploitation.

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• Human Activities: Human induced causes many human activities are leads to land

degradation directly or indirectly include deforestation, overgrazing by livestock, wrong

irrigation practices, urban sprawl and commercial development, pollution from industries,

quarrying, and mining activities, Problems arising from planning and management of canal

irrigation etc.

• Urbanization: Increased urbanization due to population growth reduces the agricultural

land. To compensate for loss of agricultural land, new lands comprising of natural

ecosystems such as forests are cleared. Therefore, urbanization leads to deforestation which

in-turn affects millions of plant and animal species.

• Fertilizers and Pesticides: Increased application of fertilizers and pesticides are needed to

increase farm output in new lands thereby leading to pollution of land, water and soil

degradation.

• Damage to top soil: Increase in food production generally leads to damage of top soil

through nutrient depletion.

Some specific causes are:

a) Soil erosion: It is wearing away of the land surface by physical forces such as rainfall,

flowing water, wind, ice, temperature change, gravity or other natural or anthropogenic

agents.

b) Soil contamination: It includes contamination by heavy metals, acidification, nutrient

surplus (eutrophication), etc.

c) Soil salinisation: The salts which accumulate include chlorides, sulphates, carbonates and

bicarbonates of sodium, potassium, magnesium and calcium.

d) Soil sealing: The covering of the soil surface with impervious materials as a result of

urban development and infrastructure construction.

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e) Overgrazing: Overgrazing occurs when plants are exposed to intensive grazing for

extended periods of time, or without sufficient recovery periods.

f) Acidification of Soil: Acid soils are toxic to plants because they can release toxic levels of

aluminium and other mineral elements.

g) Mining and quarrying activities: Due to this excavation process alter the structure of the

land, stacking of top soil, loss of soil due to dumping of the mine wastes.

h) Improper crop rotations: It decreases fertility of soil.

Impact of land degradation

• Loss of soil organic matter and nutrients.

• Loss of soil structure.

• Loss of soil biodiversity.

• Loss of water holding capacity and water infiltration.

• Soil pollution.

• Reduced yields of crops.

• Reduced land value and resilience to future events.

• Impact on food security.

•Reduces ability to adapt to climate change.

Sustainable Land Management:

Thus Sustainable Land Management (SLM) is crucial to minimizing land degradation,

rehabilitating degraded areas and ensuring the optimal use of land resources for the benefit of

present and future generations. Sustainable Land Management is based on four common

principles: • land-user-driven and participatory approaches; • Integrated use of natural

resources at ecosystem and farming systems levels.

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Some of the methods for sustainable management of land are:

• Management on overgrazing: Management practices like water development, placement

of salt and supplements, fertilizer application, fencing, burning can control the overgrazing.

• Managing irrigation: Irrigation system can be controlled like drip irrigation to reduce soil

erosion. Using high and low salt water was most effective in maintaining the productive

capacity of the clay soil.

• Managing urban sprawl: The urban planning is the most important factor, to control the

urban sprawl. Fertile field near by the urbane area need to be protected by the local

government rules. There should be a proper waste management system dumping of these

waste generated as part of urban sprawling will degrade the land, can cause soil salinity,

acidity and loss of it vegetative properties.

• Managing mining and quarrying: The impact can be reduced by proper management of

mining process, using advanced technologies rather than conventional methods. After mining

by proper back filling, spreading the soil back over the top, the land can be reclaimed.

• Managing agricultural intensification: Agricultural intensification need to be managed

properly to reduce the environmental effect. This can be done through education of the

farmers.

LANDSLIDES (NATURAL & MAN-INDUCED)

Landslides refer to a rapid down-slope movement of rocks or soil mass under the force of

gravity. It is also known as slope failure and mass wasting. Landslides may be typed as

mudflow where there is down-slope movement of soil and debris flow, which is the down-

slope movement of coarse material and rocks. Landslides may occur when water from rain

and melting snow, seeps through the earth on a sloppy surface and encounters a layer of

loose, unstable material such as clay. Landslides mostly occur on unstable hillsides by the

action of rain or snow that seep through the soils and rocks. This results in the sliding of

earth and rock masses down the hill slopes. These are further triggered due to deforestation

and human encroachment on unstable slopes. All the hilly regions of our country are prone to

landslide.

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The important factors responsible for landslide occurrence are as follows:

1. Stability of slopes

2. The type of earth and rock material

3. The type of vegetation

4. The role of ground water conditions and precipitation

5. Presence of streams, etc.

Impact on the Environment:

Landslides, though local in nature, occur quite often in many parts of the world. Landslides

occur in the hilly regions; the Himalayan region in India is particularly prone to landslides.

Every year landslides occur, especially during the monsoon season and cause much damage

to life and property. For example, Malpa landslide in 1999 in the Kumaon hills, took the lives

of many pilgrims who were going to Mansarovar in Tibet.

The impact on the environment is manifested in the form of:

1. Uprooted trees and degraded soil

2. Buried building and settlements

3. Damage to crops and plantation

4. Frequent roadblocks in the hilly areas

5. Injuries and death to humans and animals.

Prevention, Control and Mitigation:

Though landslides are a natural phenomenon and may occur without human interference, in

certain cases human activities like deforestation, mining, etc. can also induce landslides.

Landslides can be controlled, to some extent, by adopting initiatives, such as providing slope

support and minimizing human encroachment.

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Providing slope support:

By building retaining walls made of concrete, gabions (stone filled wire blocks) and wooden

and steel beams, etc. ii. By providing drainage control measures so that water may not

infiltrate into the slope

Minimizing human encroachment:

Mining activities should be monitored in the hilly, unstable regions. ii. Plantation of trees

should be undertaken on the unstable hilly slopes. iii. By preventing human encroachment in

the form of buildings, roads, agriculture, grazing, etc. on unstable slopes.

SOIL EROSION

‘Soil erosion’ has been defined as the gradual removal of the top soil by running water, wind,

glacier, sea-waves, anthropogenic agents and animals. – Soil erosion is a universal

phenomenon. – According to one estimate about 75, 000 million tonnes of soil is removed by

these agents annually.

Types of soil erosion

• Normal erosion: This is caused by the gradual removal of topsoil by natural processes. The

rate of erosion is slow.

• Accelerated erosion: This is caused by manmade activities. In this case, the rate of erosion

is much faster than the rate of formation of soil.

Causes of soil Erosion

• Running water: a) Uniform removal of soil b) Rill erosion c) Gully erosion (e.g. northern

Punjab, Haryana, Rajasthan, M.P. U.P)

• Wind Erosion: Mainly in the arid and semi -arid regions.

• Anthropogenic factors: Farmland can be degraded in several other ways besides erosion.

Physical degradation from mechanical tilling can lead to compaction and crusting. Repeated

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cropping without sufficient fallow periods or replacement of nutrients with cover crops,

manure or fertilizer can deplete soil nutrients. In addition over application of chemical

fertilizers, insecticides and pesticides can kill beneficial soil organism. – Poor water

management on irrigated crop land is a leading cause of degraded farmland. – Inadequate

drainage can lead to water logging of the soil or to Salinization, in which salt levels built up

in the soil to toxic levels. About 15 to 20 percent of the irrigated land is suffering from some

degree of waterlogging and salinization.

• Biotic agents: Overgrazing, mining and deforestation are the major biotic agents causing

soil erosion. These processes disturb the top soil thereby exposing the soil to various physical

forces inducing erosion.

• Landslides cause soil erosion: Construction of dams, buildings and roads removes the

protective vegetal cover leading to soil erosion.

Harmful Effects of Soil Erosion

• Loss of fertile top soil leading to gradual loss of soil fertility and agricultural productivity.

• Loss of mineral nutrients from soil through leaching and flooding.

• Loss of soil ability to hold water and sediment

• Sediment runoff can pollute water courses and kill aquatic life

• Lowering of the underground water table and decrease in the percentage of soil moisture.

• Drying of vegetation and extension of arid lands.

• Increase in frequency of droughts and floods.

• Silting of river and canal belts.

• Recurrence of landslides.

• Adverse effect on economic prosperity and cultural development.

Soil Conservation:

Unchecked soil erosion leads to poverty and reduces the strength of a nation. Some of the

important steps for soil conservation areas under:

• Conservational till farming or no-till farming: Traditionally, land is ploughed to make a

planting surface. This disturbs the soil and makes it susceptible to erosion. The no-till

farming method makes minimum disturbance to the top soil by making slits in the

unploughed soil. Seeds, fertilizers and water are injected in these slits.

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• Contour farming: In this method, crops are planted in rows along contours of gently

sloped land. Each row acts as a small dam to hold soil thereby slowing water runoff.

• Terracing: In this method, steep slopes are converted into a series of broad terraces that

run across the contour. This retains water for crops and reduces soil erosion by controlling

runoff.

• Alley cropping or Agro forestry: This method involves planting crops in strips or alleys

between rows of trees or shrubs that provide fruits and fuel wood. Hence, when the crop is

harvested, the soil will not be eroded as the trees and shrubs remain on ground holding the

soil particles.

• Wind breaks or shelter belts: In this technique, trees are planted in long rows along the

boundary of cultivated land which block the wind and reduce soil erosion. Wind breaks help

in retaining soil moisture, supply wood for fuel and provide habitat for birds.

DESERTIFICATION

Desertification is a type of land degradation in which relatively dry area of land becomes

increasingly arid, typically losing its bodies of water as well as vegetation and wildlife. It is

caused by a variety of factors, such as through climate change and through the

overexploitation of soil through human activity.

The cause of desertification

Desertification is caused by two main categories of factors: natural factors and, more

importantly, human activities. The natural factors causing desertification include the

following:

1. The climate has a major influence through rainfall, solar radiation and wind, which affect

the rates of physical and mechanical erosion as well as chemical and biological degradation

of soil.

2. The relief of a land affects the rate of soil erosion by water.

3. The textile, structure, and chemical and biological status of soil are predominant factors

determining the soil properties in dry sub-humid zones.

Human activities play a crucial role in the vulnerability of land to desertification. The

reasons behind these activities are the increasing demand for food due to the rapid population

growth, and inappropriate agricultural practices. The following are some of the human

activities that cause desertification:

1. Uncontrolled use of fire for regenerating pasture, for hunting or for agricultural clearing

2. Over-exploitation of woody resources, particularly for fuel wood and timber.

3. Over-grazing of selective vegetation

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4. Removal of hedges, which can act as wind breaks, on soil so that the soil is more

susceptible to erosion by wind

5. Over-harvesting which results in abandoned fields

6. Agricultural practices that destroy the soil structure such as intensive ploughing

7. Agricultural practices that result in continuous removal of soil nutrients

8. Monoculture of cash crops, leading to severe reduction in soil fertility

9. Inappropriate irrigation of soil, leading to salinization, waterlogging and abandoned fields

eventually.

Based on the above factors, we can see that soil erosion is in fact a process of desertification.

It usually involves the removal of nutrient-rich topsoil, leaving coarse, sandy particles with

poor water-retaining ability. As a result, the soil becomes unsuitable for vegetation growth

and is turned eventually into a desert.

The environmental impact of desertification

Farmlands are important natural resources. Humans rely on them for food. Desertification

results in the loss of farmlands, and significantly threatens the living standard and well-being

of people inhabiting the areas concerned. This also leads to social problems such as

environmental refugees whose lands are too eroded for cultivation or rearing livestock.

Desertification also has serious impact on the natural environment. It breaks down the fragile

balance that allows plant and animal life to develop in arid, semi-arid and dry sub-humid

zones. This breakdown of the equilibrium represents the start of a process that destroys the

natural and stable ecosystem.

Ecological implications of desertification

Drifting of sand and its accumulation on fertile agricultural land.

Excessive soil erosion by wind and to some extent by water.

Deposition of sand in rivers, lakes and other water bodies thereby decreasing their

water containing capacity.

Lowering of water table leading to acute water shortage.

Increase in area under wastelands.

Decrease in agricultural production.

Increase in frequency and intensity of droughts.

Measures of Controlling Desertification Intensive tree plantation in the transition zones.

Mulching shifting sand dunes in deserts with different plant species. Mulches serve as

an effective physical barrier to the moving sand. Grazing should be controlled and new

pastures should be developed.

Indiscriminate felling of trees should be banned.

Alternative sources of fuel can reduce the demand for fuel-wood.

Sandy and wastelands should be put to proper use by judicious planning

Unit 3:Natural Resources:

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