Land Resources Land As A Resource Environmental Sciences Essay

Land or soil is one of the natural bases for human life and social development. Soils are defined and characterized on the basis of their morphological profiles because the assemblage of obvious physical features represented by these units are often related to the less obvious features of their chemical composition, chemical properties, and fertility.

Men have tilled the soil and irrigated and drained it for at least six millennia. This is basic to civilization. Systematic scientific study of agriculture began in the first half of the nineteenth century, along with physical studies of the soil. In its natural state, the soil is normally a three-component porous medium consisting of solid soil particles, water, and air. Much of the water involved in the hydrologic cycle is located in soil between the time of its arrival as rain at the soil surface and that of its return to the atmosphere. The processes of water movement in soil play a central part in the scientific study of the terrestrial sector of the hydrologic cycle and in the problems of dry-land and irrigated agriculture, of plant ecology, and of soil biology. These determine the transport of materials in solution such as natural salts, fertilizers, and urban and industrial wastes through the soil. Properties such as infiltration, drainage, and retention of water in the soil layers; extraction of water by plant roots; and the evaporation of water from the soil are also important.

The solid phase of the soil has mineral and organic matter, which is usually highly colloidal, seldom exceeds 5-10% by weight of soil. In an agricultural context, the main interest in soil structure is in terms of soil tilth, which is related to the ability of aggregates to maintain their integrity when the soil is irrigated, tilled, or otherwise worked so that water retention and drainage and aeration are kept at favorable levels.

As soil is a complex mixture of many components there is usually little value in determining the amount of a chemical element present without any indication of the fraction of the soil in which it occurs and its form of combination. Indeed, fractions that comprise only a small proportion of the total soil mass are often very important in determining its behavior. The following is a convenient classification of soil fractions:

The Organic Fraction,

The Mineral Fraction,

Soluble in water: Simple inorganic ions,

Soluble in dilute acids: Carbonates,

Insoluble in dilute acids.

Primary minerals mainly occur in sand and silt fractions; secondary minerals usually occur in the clay fraction (< 2 µm diameter).

Organic Fraction

Organic materials are added to soils as dead plant and animal remains. They are decomposed by the microflora and microfauna to form humus, an amorphous material distinct from undecomposed litter. Well-humified organic matter contains about 58 % carbon, so the amount of the soil organic fraction is usually specified by determining the organic carbon content and multiplying it by 1.73. Organic contents range from zero in some mineral subsoils, through 1 to 10 % in arable topsoils, to nearly 100% (of the dry weight) in some peat and muck soils. The amounts in surface soils depend on the balance between accumulation and decomposition, and these processes in turn are influenced by temperature and moisture content.

Apart from carbon, hydrogen, and oxygen, the organic fraction contains nitrogen, sulfur, and phosphorus. The proportions of these elements are often expressed as ratios compared to nitrogen taken as 10, and typical values are C:N = 80-150:10, S:N = 1.2-1.5:10, and P:N = 0.2-3.0:10. Metals such as aluminum, iron, manganese, and copper are also found in small amounts in humic complexes.

The organic compounds in humus are very different. The main portion appears to consist of polymers, some of which are formed by random condensation of phenols, amino acids, and other related microbial degradation products. A large number of compounds have been isolated from humus extracts, but many of these must be artifacts. Of particular interest, apart from the polyphenols, are amino acids (implying that humus contains protein), sugars (indicating carbohydrate fractions), and amino sugars. The sulfur seems to be part of the main humus fraction, probably as sulfur-containing amino acids and organic sulphates. In some soils, much of the organic phosphorus is present as inositol polyphosphates, which appear not to be an integral part of the humus.

Water-soluble Components

The soluble-salt content of most soils is low so that the soil solution typically contains between 5 and 25 mmol/L of calcium and magnesium salts, mainly as nitrate. In saline soils, however, the salt content is of the order of 100 mmol/L, and although still less than 1% of the soil mass, the soluble salts dominate the behavior of the soil and include also sodium (Na+), chloride (Cl-), bicarbonate (HCO3-), and sulphate (SO4–) ions.

The salt content is normally determined in a saturation extract prepared by wetting the soil until it is just saturated with water and filtering off the extract under reduced pressure. The filtrate may be analyzed chemically, but a rapid indication of the degree of salinity is given by measuring its electrical conductivity. Conductivity values above 4 milliSiemens (mS) indicate that crop production may be reduced by salt damage, while above 20 mS only salt-tolerant species can survive. The approximate conductivity at 25°C of a 100 mmol/L solution referred to above is 8-10 mS.

The “reaction” of soil is one of its most important diagnostic parameters. It is given by a pH measurement on the saturation extract or on a suspension of soil in water or in a dilute electrolyte solution. Strongly acid soils may have pH values down to 3.5, and strongly alkaline soils as high as 9.5, but more typical pH values of soils range from 5 to 8.

Carbonates

In soils formed from limestone rocks or other carbonate-containing sediments, carbonates occur mainly as calcite (CaCO3) but sometimes also as dolomite [(Ca, Mg)CO3]. They are important in the buffer system that controls the pH and cation balance of soil, and also for their reactions with anions, particularly phosphate. In their reactions with anions, the particle size and surface area of the soil carbonates are more important than the amount.

Amounts of soil carbonate are estimated from the carbon dioxide evolved when the soil is treated with dilute acid, the results being expressed as a percentage by weight of the soil. In a leaching environment, soil carbonate is gradually removed by solution in carbonated water [CaCO3 + H2O + CO2 = Ca(HCO3)2] so that topsoils contain less carbonate than subsoils or the parent material. The leached carbonate may be concentrated by chemical precipitation at depth in the soil profile.

Primary Minerals

Soil analysis includes the separation and determination of sand, silt, and clay fractions by sieving and sedimentation. The mineral matter of soils is directly inherited from the parent material, although its composition is usually different depending on the age of the soil and the resistance of minerals to weathering. The minerals in the sand and silt fractions are mainly quartz and feldspars, plus a host of accessory minerals. Only the most resistant primary minerals remain in advanced stages of soil development, i.e., quartz (SiO2) as the major component, with smaller amounts of heavy metal oxides such as hematite (Fe2O3), magnetite (Fe3O4), and rutile (TiO2).

Secondary Minerals

The clay-sized (< 2 µm effective diameter) fractions of many soils contain microcrystalline aluminosilicate layer minerals, and smaller amounts of hydrous oxides such as goethite, (FeO.OH), and gibbsite, (Al(OH)3). The gibbsite is more abundant in soils formed from basic rocks than from acidic rocks and are often amorphous. The clay fractions of some soils such as those derived from volcanic ash consist almost wholly of amorphous aluminosilicates of variable composition (allophane), and similar material is associated with the surfaces of many crystalline particles.

Land Degradation

Land degradation making the land unsuitable for habitat construction and agriculture has become a major problem in recent times. This has threatened the world food production as soil quality degradation results in severe reduction in crop yield. It is estimated that 15 percent of the world’s total land area has not maintained its quality due to a number of problems that include erosion, nutrient decline, salinization and physical compaction. The countries which are mainly dependent on agriculture as a national resource suffer more from the effects of land degradation.

Some of the major soil degradation processes and the causes for them are given below.

Loss of topsoil by erosion/surface wash. This results in a decrease in depth of the topsoil layer due to more or less uniform removal of soil material by run-off water. The possible causes are inappropriate land management especially in agriculture (insufficient soil cover, unobstructed flow of run-off water, deteriorating soil structure) leading to excessive surface run-off and sediment transport.

“Terrain deformation” is an irregular displacement of soil material (by linear erosion or mass movement) causing clearly visible scars in the terrain. The possible causes are inappropriate land management in agriculture forestry or construction activities, allowing excessive amounts of run-off water to concentrate and flow unobstructed.

Fertility decline and reduced organic matter content resulting in a net decrease of available nutrients and organic matter in the soil. This is likely to be due to imbalance between output (through harvesting, burning, leaching, etc.) and input (through manure/fertilizers, returned crop residues, flooding) of nutrients and organic matter.

Soil contamination indicates the presence of an alien substance in the soil without significant negative effects and soil pollution signifies soil degradation as a consequence of location, concentration and adverse biological or toxic effects of a substance. The source of pollution may be waste dumps, spills, factory wasted, etc. The source can also be diffuse or airborne (atmospheric deposition of acidifying compounds and/or heavy metals.

Eutrophication with the presence of an excess of certain soil nutrients, impairing plant growth. The possible causes are imbalanced application of organic and chemical fertilizer resulting in excess nitrogen, phosphorus; liming.

Compaction resulting in deterioration of soil structure by trampling by cattle or the weight and/or frequent use of machinery. The possible causes are repeated use of heavy machinery, having a cumulative effect. Heavy grazing and overstocking may lead to compaction as well. Factors that influence compaction are ground pressure (by axle/wheel loads of the machinery used); frequency of the passage of heavy machinery; soil texture; soil moisture; climate.

Sealing and crusting which is clogging of pores with fine soil material and development of a thin impervious layer at the soil surface obstructing the infiltration of rainwater. The possible causes are poor soil cover, allowing a maximum “splash” effect of raindrops; destruction of soil structure and low organic matter.

Waterlogging that results from effects of human induced hydromorphism (i.e. excluding paddy fields). The possible causes are rising water table (e.g. due to construction of reservoirs/irrigation) and/or increased flooding caused by higher peak-flows.

Lowering of the soil surface resulting from subsidence of organic soils, settling of soil. The possible causes are oxidation of peat and settling of soils in general due to lowering of the water table; solution of gypsum in the sub-soil (human-induced) or lowering of soil surface due to extraction of gas or water

Loss of productive function which results from soil (land) being taken out of production for non-bio-productive activities, but not the eventual “secondary” degrading effects of these activities. The possible causes are urbanization and industrial activities; infrastructure; mining; quarrying, etc.

Aridification, which is the decrease of average soil moisture content. The possible causes are lowering of groundwater tables for agricultural purposes or drinking water extraction; decreased soil cover and reduced organic matter content.

Salinisation / alkalinization which is a net increase of the salt content of the (top)soil leading to a productivity decline. The possible causes are a distinction can be made between salinity problems due to intrusion of seawater (which may occur under all climate conditions) and inland salinisation, caused by improper irrigation methods and/or evaporation of saline groundwater.

Dystrification, which is the lowering of soil pH through the process of mobilizing or increasing acidic compounds in the soil.

Worldwide, almost 2,000 million hectares of land show at least minor signs of degradation, corresponding to approximately 1% of the ice-free surface. Around 300 million hectares of land surface are already seriously degraded. Soil degradation situation in India is shown in Fig. 2.10.

Population growth and soil

Population growth exerts enormous pressure on soils, and the soil degradation is due to additional migration and urbanization processes. The higher the rate of global population growth, the higher is the demand on the soil functions. There is already a growing disparity between growth-related demand and the availability of land. Many states are no longer capable of feeding their own populations with domestic agricultural products because they do not have enough land. Given the speed of population growth and the level of soil degradation already apparent, an increasing scarcity of soils available for meeting competing demands is expected.

Two case studies of soil degradation

1. The Sahel Region

The problems of soil degradation and desertification in the Sahel can be attributed to changes in nature as well as to socioeconomic causes.

The nomadic groups in the Sahel are increasingly restricted in the mobility and flexibility that once provided them with a secure basis for ecological adaptation. Growing competition from other forms of land use, political measures and unclear or disadvantageous land-use rights led to their sedentarisation; they were pushed into more marginalized locations much less suitable for grazing livestock. The sensitive soils and ecosystems in the region are degraded as a result, mainly due to overgrazing.

Subsistence farmers are similarly affected by displacement to marginal land that is unsuitable for farming. Greater mechanization without parallel soil protection measures (erosion protection, and suitable irrigation) has negative effects on the soils.

Finally, “cash crops” (cotton, groundnuts) on fertile soils is not pursued in a sustainable fashion. These monocultures are farmed with the help of machines and pesticides, both of which can cause great problems.

The Sahel also undergone tremendous social changes caused by internal and external conditions. Of importance is the general neglect of rural concerns and the orientation to agrarian export production through large-scale capital-intensive projects in the agricultural sector. External factors can be identified both in the global economic conditions (agricultural subsidies and/or export policies of the industrial nations, international debt) and in the practice of international development organizations, which in the past were not geared to the principle of sustainability, and which through their orientation to production technology gave too little consideration to the existing development potential. If the complex problems faced by the Sahel are to be solved, greater attention must be given to the socioeconomic causes and to organizational and financial decentralization.

2. The “Leipzig-Halle-Bitterfeld” region

The soils in the “Leipzig-Halle-Bitterfeld” region are contaminated, in some cases alarmingly, by depositions of airborne pollutants through deliberate depositing of inorganic and organic substances. A prime cause of this contamination was the concentration of chemical industries, mining and energy production, all of which used outdated production methods. Since the turn of the century, there have been five brown coal mining fields, and large-scale chemical plants developed in Bitterfeld (paints and dyes), Leuna (methanol, nitrogen) and Buna (synthetic rubber). For economically and environmentally sound development of the region, soil remediation and the removal of contaminated soil are a matter of urgency, which requires considerable support from the state or from outside the region.

Fig. 2.10. Soil degradation in India

Landslide

In a landslide, masses of rock, earth, or debris move down a slope. Landslides may be small or large, slow or rapid. They are activated by:

storms,

earthquakes,

volcanic eruptions,

fires,

alternate freezing or thawing, and

steepening of slopes by erosion or human modification.

Debris and mudflows are rivers of rock, earth, and other debris saturated with water. They develop when water rapidly accumulates in the ground, during heavy rainfall or rapid snowmelt, changing the earth into a flowing river of mud or “slurry.” They can flow rapidly, striking with little or no warning at avalanche speeds. They can travel several miles from their source, growing in size as they pick up trees, boulders, and other materials.

Landslide problems can be caused by land mismanagement, particularly in mountain, canyon, and coastal regions. In areas burned by forest and brush fires, a lower threshold of precipitation may initiate landslides. Land-use zoning, professional inspections, and proper design can minimize many landslide, mudflow, and debris flow problems.

Protection from a landslide or debris flow

(a) Guidelines for the period following a landslide:

Stay away from the slide area. There may be danger of additional slides.

Listen to local radio or television stations for the latest emergency information.

Watch for flooding, which may occur after a landslide or debris flow. Floods sometimes follow landslides and debris flows because they may both be started by the same event.

Check for injured and trapped persons near the slide, without entering the direct slide area. Ask for rescuers and give them correct locations.

Help a neighbor who may require special assistance – infants, elderly people, and people with disabilities. Elderly people and people with disabilities may require additional assistance. People who care for them or who have large families may need additional assistance in emergency situations.

Inform appropriate authorities about damaged roadways, railways, electricity lines and other utilities. Reporting potential hazards will get the utilities turned off as quickly as possible, preventing further damage.

Check building foundation, chimney, and surrounding land for damage. Damage to foundations, chimneys, or surrounding land may help assess the safety of the area.

Replant damaged ground as soon as possible since erosion caused by loss of ground cover can lead to flash flooding and additional landslides in the near future.

Seek advice from a geotechnical expert for evaluating landslide hazards or designing corrective techniques to reduce landslide risk. A professional will be able to advise you of the best ways to prevent or reduce landslide risk, without creating further hazard.

(b) During a Landslide or Debris Flow

What one should do if a landslide or debris flow occurs:

Stay alert and awake. Many debris-flow fatalities occur when people are sleeping. Listen to radio or television for warnings of intense rainfall. Be aware that intense, short bursts of rain may be particularly dangerous, especially after longer periods of heavy rainfall and damp weather.

If you are in areas susceptible to landslides and debris flows, consider leaving if it is safe to do so. Remember that driving during an intense storm can be hazardous. If you remain at home, move to a second story if possible. Staying out of the path of a landslide or debris flow saves lives.

Listen for any unusual sounds that might indicate moving debris, such as trees cracking or boulders knocking together. A trickle of flowing or falling mud or debris may precede larger landslides. Moving debris can flow quickly and sometimes without warning.

If one is near a stream or channel, he should be alert for any sudden increase or decrease in water flow and for a change from clear to muddy water. Such changes may indicate landslide activity upstream, so be prepared to move quickly. Don’t delay! Save yourself, not your belongings.

Be especially alert when driving. Embankments along roadsides are particularly susceptible to landslides. Watch the road for collapsed pavement, mud, fallen rocks, and other indications of possible debris flows.

(c) What to do in case of Imminent Landslide Danger

Contact your local fire, police, or public works department. Local officials are the best persons able to assess potential danger.

Inform affected neighbors. Your neighbors may not be aware of potential hazards. Advising them of a potential threat may help save lives. Help neighbors who may need assistance to evacuate.

Evacuate. Getting out of the path of a landslide or debris flow is your best protection.

Curl into a tight ball and protect your head if escape is not possible.

(d) Before a Landslide or Debris Flow

Protect yourself from the effects of a landslide or debris flow:

Do not build near steep slopes, close to mountain edges, near drainage ways, or natural erosion valleys.

Get a ground assessment of your property.

Contact local officials, geological surveys or departments of natural resources, and university departments of geology. Landslides occur where they have before, and in identifiable hazard locations. Ask for information on landslides in your area, specific information on areas vulnerable to landslides, and request a professional referral for a very detailed site analysis of your property, and corrective measures you can take, if necessary.

If you are at risk from a landslide talk to your insurance agent. Debris flow may be covered by flood insurance policies.

Minimize home hazards

Have flexible pipe fittings installed to avoid gas or water leaks, as flexible fittings are more resistant to breakage (only the Gas Company or professionals should install gas fittings).

Plant ground cover on slopes and build retaining walls.

In mudflow areas, build channels or deflection walls to direct the flow around buildings.

Remember: If you build walls to divert debris flow and the flow lands on a neighbor’s property, you may be liable for damages.

Recognize Landslide Warning Signs

Changes occur in your landscape such as patterns of storm-water drainage on slopes (especially the places where runoff water converges) land movement, small slides, flows, or progressively leaning trees.

Doors or windows stick or jam for the first time.

New cracks appear in plaster, tile, brick, or foundations.

Outside walls, walks, or stairs begin pulling away from the building.

Slowly developing, widening cracks appear on the ground or on paved areas such as streets or driveways.

Underground utility lines break.

Bulging ground appears at the base of a slope.

Water breaks through the ground surface in new locations.

Fences, retaining walls, utility poles, or trees tilt or move.

Faint rumbling sound that increases in volume is noticeable as the landslide nears.

The ground slopes downward in one direction and may begin shifting in that direction under your feet.

Unusual sounds, such as trees cracking or boulders knocking together, might indicate moving debris.

Collapsed pavement, mud, fallen rocks, and other indications of possible debris flow can be seen when driving (embankments along roadsides are particularly susceptible to landslides).

Desertification

The most critical and increasing threat to sustainable land use is desertification. It is estimated that desertification affects one-quarter of the total land area of the world, or about 70 percent of all dry lands, and threatens the livelihoods of over 1 billion people in more than 100 countries. Desertification is closely linked with rural poverty and hunger. It exacerbates conditions leading to famine, migration, internal displacement, political instability and conflict.

Desertification is the degradation of land in arid, semi arid and dry sub-humid areas resulting from various climatic variations, but primarily from human activities. Current desertification is taking place much faster worldwide and usually arises from the demands of increasing population that settle on the land in order to grow crops and graze animals.

A major impact of desertification is loss of biodiversity and productive capacity, for example, by transition from grassland to perennial shrubs. The change in vegetation induces desertification. In the Madagascar, 10% of the entire country has been lost to desertification due to zoom agriculture by indigenous people. In Africa, with current trends of soil degradation, the continent will be able to feed just 25% of its population by 2025 according to one estimate.

Deserts may be separated from the surroundings by less arid areas, mountains and other landforms. In other areas, there is a gradual transition from a dry to a more humid environment, making it more difficult to determine the desert border. These transition zones have very fragile, delicately balanced ecosystems. Desert fringes are a mosaic of microclimates. Small hollows support vegetation that picks up heat from the hot winds and protects the land from the prevailing winds. After rainfall the vegetated areas are distinctly cooler than the surroundings. In these marginal areas human activity may stress the ecosystem beyond its tolerance limit, resulting in degradation of the land. By pounding the soil with their hooves, livestock compact the substrate, increase the proportion of fine material, and reduce the percolation rate of the soil, thus encouraging erosion by wind and water. Grazing and collection of firewood reduce or eliminate plants that help to bind the soil.

In large desert areas, sand dunes can encroach on human habitats. Sand dunes move through wind. In a major dust storm, dunes may move tens of meters. And like snow, sand avalanches, falling down the steep slopes of the dunes that face away from the winds, move the dunes forward.

Droughts by themselves cannot cause desertification. Drought is just a contributing factor. The causes are social and economic, having to do with access to resources, power and economics. Droughts are common in arid and semiarid lands, and well-managed lands can recover from drought when the rains return. Continued land abuse during droughts, however, increases land degradation. Increased population and livestock pressure on marginal lands has accelerated desertification. In some areas, nomads moving to less arid areas disrupt the local ecosystem and increase the rate of erosion of the land. Nomads are trying to escape the desert, but because of their land-use practices, they bring the desert with them.

Some arid and semi-arid lands can support crops, but additional pressure from greater population or decreases in rainfall can lead to the disappearance of the few plants present. The soil becomes exposed to wind, causing soil particles to be deposited elsewhere. The top layer becomes eroded. With the removal of shade, rates of evaporation increase and salts become drawn up to the surface. This is salinisation, which inhibits plant growth. The loss of plants causes less moisture to be retained in the area, which may change the climate pattern leading to lower rainfall.

The degradation of formerly productive land is a complex process. It involves multiple causes, and it proceeds at varying rates in different climates. Desertification may intensify a general climatic trend toward greater aridity, or it may initiate a change in local climate. Desertification does not occur in linear, easily mappable patterns. Deserts advance erratically, forming patches on their borders. Areas far from natural deserts can degrade quickly to barren soil, rock, or sand through poor land management. The presence of a nearby desert has no direct relationship to desertification. Unfortunately, an area undergoing desertification is brought to public attention only after the process is well under way. Often little data are available to indicate the previous state of the ecosystem or the rate of degradation.

Combating desertification is complex and difficult. Over-exploitation of the land and climate variations can have identical impacts, which makes it very difficult to choose the right mitigation strategy. Measures like reforestation cannot achieve their goals if global warming continues. Forests may die when it gets drier, and more frequent extreme events could become a threat for agriculture, water supply, and infrastructure.

Current desertification

Overgrazing and to a lesser extent drought in the 1930s transformed parts of the Great Plains in the United States into the “Dust Bowl”. During that time, a considerable fraction of the population abandoned their homes to escape the unproductive lands. Improved agricultural and water management have prevented a disaster of the earlier magnitude from recurring, but desertification presently affects millions of people with primary occurrence in the less developed countries.

Desertification is widespread in many areas of the People’s Republic of China. The populations of rural areas have increased along with an increase in the livestock; the land available for grazing has decreased. Importing of European cattle, which have higher food intakes, has made things worse.

Human overpopulation is leading to destruction of tropical wet and dry forests, due to widening practices of zoom cultivation. Deforestation has led to large scale erosion, loss of soil nutrients and sometimes total desertification.

Overgrazing has made the Rio Puerco Basin of central New Mexico one of the most eroded river basins of the western United States and has increased the high sediment content of the river. Overgrazing is also an issue with some regions of South Africa such as the Waterberg Massif, although restoration of native habitat and game has been pursued vigorously since 1980.

The Desert of Maine is a 40-acre dune of glacial silt near Freeport, Maine. Overgrazing and soil erosion exposed the cap of the dune, revealing the desert as a small patch that continued to grow, overtaking the land. Ghana and Nigeria currently experience desertification; in the latter, desertification overtakes about 1,355 square miles of land per year. The Central Asian countries, Afghanistan, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan, are also affected. More than 80% of Afghanistan’s land is subject to soil erosion and desertification. In Kazakhstan, nearly half of the cropland has been abandoned since 1980. In Iran, sand storms were said to have buried 124 villages in Sistan and Baluchestan Province in 2002, and they had to be abandoned. Latin America, Mexico and Brazil are also affected by desertification.

Controlling desertification

A number of solutions have been tried in order to reduce the rate of desertification and regain lost land. Leguminous plants, which extract nitrogen from the air and fix it in the soil, can be planted to restore fertility. Stones stacked around the base of trees collect morning dew and help retain soil moisture. Artificial grooves can be dug in the ground to retain rainfall and trap wind-blown seeds.

In Iran, petroleum is being sprayed over semi-arid land with crops. This coats seedlings to prevent moisture loss and stop them being blown away. Windbreaks made from trees and bushes to reduce soil erosion and evapotranspiration are widely encouraged by development agencies in the Sahel area of Africa.

With many of the local people using trees for firewood and cooking, the problem has become acute. At the local level, individuals and governments can help to reclaim and protect their lands. In areas of sand dunes, covering the dunes with large boulders will interrupt wind regime near the face of the dunes and prevent the sand from moving. Sand fences are used throughout the Middle East and the US, in the same way snow fences are used in the north. Placement of straw grids, each up to a square meter in area, will also decrease the surface wind velocity. Shrubs and trees planted within the grids are protected by the straw until they take root. In areas where some water is available for irrigation, shrubs planted on the lower one-third of a dune’s windward side stabilize the dune. This vegetation decreases the wind velocity near the base of the dune and prevents much of the sand from moving. Higher velocity winds at the top of the dune level it off and trees can be planted atop these flattened surfaces.

Oases and farmlands in windy regions can be protected by planting tree fences or grass belts. Sand that manages to pass through the grass belts can be caught in strips of trees planted as wind breaks 50 to 100 meters apart adjacent to the belts. Small plots of trees may also be scattered inside oases to stabilize the area. On a much larger scale, a “Green Wall of China”, which will eventually stretch more than 5,700 kilometers in length, nearly as long as the Great Wall of China, is being planted in north-eastern China to protect “sandy lands” – deserts believed to have been created by human activity.

More efficient use of existing water resources and control of salinization are other effective tools for improving arid lands. Better use of surface-water resources such as rain water harvesting or irrigating with seasonal runoff from adjacent highlands has been tried. New ways are being sought to find and tap groundwater resources and to develop more effective ways of irrigating arid and semiarid lands. Proper crop rotation to protect the fragile soil is being studied along with developing sand-fixing plants adapted to local environments, and preventing overuse of land and water resources.

Desertification is a major threat to biodiversity. Biodiversity Action Plans have been developed to counter its effects, particularly in relation to the protection of endangered flora and fauna.

2.7 Role of an individual in conservation of natural resources

Natural resources provide an array of basic processes that affect humans. Those processes include maintenance of the quality of the atmosphere, generation of soils, control of the hydrologic cycle, disposal of wastes, and recycling of nutrients. Humans are changing many of these basic processes and the changes may be detrimental to humans.

Natural resources can be grouped into eight categories:

Wildlife

Air and Wind

Soil

Water

Minerals

Fossil Fuels

Sunlight

People

Wildlife refers to plants, animals, and other living things in the wild. The category of Air and Wind refers to the mixture of gases in the atmosphere and the movement of these gases. Soil is the top layer of the earth that supports plant life, as well as our lives. It is considered the basis of all life. Water is the only natural resource found on the surface of our planet in three forms: solid, liquid, and vapor. Minerals refer to inorganic substances that do not have the biological structure of living things. Fossil fuels are materials used to generate energy. Sunlight is the light and warmth of the Sun, an element that makes our existence possible. It is interesting that experts include People as natural resources. We are not only the beneficiaries of these natural resources; we are the ones who figured out how to make them work to our benefit in the first place. Our creativity and labor are how we make these resources work for us. However, we are part of the ecological system of Earth.

The eight natural resources are all necessary for providing the basic needs of humans: food, clothing, and shelter. Our very lives depend on clean air and water. Our ability to feed ourselves rests on maintaining the fertility of the soil in which we plant our crops. Crops will grow only if sufficient sunlight and water are available. Modern society depends on fossil fuels for industrial energy. Natural resources form an unbroken chain of support for us, and it is not difficult to imagine the problems that would arise from the loss of any link in this chain. The wise use of our natural resources is important because our survival depends on these resources. It is to be remembered that

From the time of the Romans, it took nearly 1,700 years for the population to reach one billion.

It took slightly more than 200 years for the population to double to two billion.

It took less than a century for the population to triple to more than six billion.

The supply of most natural resources has remained at a static rate, so a key question is how large a population can our resources support and for how long.

Some resources are renewable. That means they can be replaced when used. Air, water, soil, and wildlife are examples of renewable resources. Nonrenewable resources are not replaced when they are used. Minerals, for example, cannot be replaced, which is why gold has become a valuable metal. Fossil fuels, such as coal and oil, are considered nonrenewable resources. Another way of looking at the supply of resources is whether they are exhaustible, which means that a resource can not be replenished as it is used. In some cases the renewing of a resource takes such a long time that the resource is considered to be exhaustible. Experts disagree on whether to classify soil as renewable or exhaustible because, although soil lost to erosion can be replaced, it may require far longer than the lifetime of any individual to do so.

Therefore, for human lifespan purposes, we consider nonrenewable resources exhaustible if they can never be replaced, as well as if they cannot be replaced in our lifetime.

Because some resources are not renewable, the issue of supply forces us to make decisions about the use of those resources. That is why Conservation is required. One of the major strategies is sustainable use. This means using a resource in a manner that allows it to last for a long time. Can you think of a resource that you use in a sustainable way? Another approach to saving natural resources is preservation. This means protecting a resource from being used up. For example, millions of acres of forest have been protected as National Parks. There are disagreements between those who believe in conservation and those who prefer preservation. For example, consider the issue of allowing oil companies to drill in protected Arctic areas. One side maintains that such drilling can be accomplished without destroying the beauty and ecological health of those preserves. The other argues that drilling will change the nature of the landscape forever. You may find yourself agreeing with one side regarding some resources and agreeing with the other side when different resources are involved.

We create waste through manufacturing, agricultural production, and daily living. Waste can contaminate the environment, especially air and water and soil, unless we adopt practices that conserve or preserve resources. Towns and cities are growing at a fast pace; new housing developments use up resources by destroying forests and removing land from agricultural use.

Recycling products or materials is a promising practice. Aluminum, iron, glass, paper, and plastic are products that we have learned how to use and reuse in a remanufacturing process. Many communities have adopted recycling programs, but there is a great disparity in how effective such programs are and how fully involved citizens have become. One area of recycling is to actually reuse a product, to avoid waste of any kind. It will be up to generations succeeding us to create new methods of recycling or reusing natural resources.

We develop our beliefs through knowledge. Developing beliefs about the role of the individual regarding our natural resources requires thoughtfulness. The solutions are neither simple nor are they clear-cut. People disagree on approaches. Some solutions seem impractical. For example, it is doubtful that we would ever give up the use of turbine engines. Think of all the sacrifices that would have to be made if such a decision were made. Therefore, it is not likely to happen. We seem to want our modern conveniences, so we need to discover ways to get the most out of resources without depleting them. The use of natural resources must be based on meeting the needs of people on a sustained basis. Determining which needs are worthy of sustaining becomes yet another question.

In a world, where space for landfills and toxic-waste disposal prompts political and scientific questions, it seems preferable to have decisions made by citizens who understand the complex nature of natural resources and their interplay with society. Whatever decisions are made, there will be a need for people to work in fields related to the conservation and use of natural resources.

For millennia humans have left their mark on the world’s forests, although it was difficult to see. By the twenty-first century, however, forests that humans once thought were endless are shrinking before their eyes. Forests are not only a source of timber; they perform a wide range of social and ecological functions. They provide a livelihood for forest dwellers, protect and enrich soils, regulate the hydrologic cycle, affect local and regional climate through evaporation, and help stabilize the global climate. Through the process of photosynthesis they absorb carbon dioxide (CO2) and release the oxygen humans and animals breathe. They provide habitat for half of all known plant and animal species, are the main source of wood for industrial and domestic heating, and are widely used for recreation.

Given the continued global demand for natural resources, the goal should be to ensure the equitable use and allocation of natural resources. Four important challenges may be identified:

Extending the Resource Base – reducing environmental footprint of fossil fuel and mineral use and identifying novel fuel sources;

Meeting the Renewables Challenge – optimising environmental gains from extraction of energy from renewable sources;

Water-Soil Life Support System – integrated approaches to sustain and improve water and soil quality;

Valuing Environmental Services – innovative methods to achieve parity for environmental services alongside economic indicators.

The following three actions can address these challenges:

(i) Environmental life cycle analysis of resource use for energy

The overall objective of this action is to forecast the optimum renewable and non-renewable environmental energy mix of the future. The action will counter arguments that the security of energy supply is a zero sum game for the environment by seeking to both recognise and optimise environmental gains. Success measures embedded in the deliverables include: (i) models to forecast the environmentally sustainable energy mix of the future, and (ii) methods to demonstrate how sustainable technologies can reduce the environmental footprint of existing resource use. Implementation is through four sub-actions, each with the same objective: to deliver independent and impartial evidence that demonstrates the benefits of incorporating environmental criteria in the development and implementation of energy technologies. The four sub-actions are:

The Sustainability of Carbon Capture and Storage – carbon capture and storage (CCS) is accepted technology for mitigating the risk of dangerous climate change. Technological interest in CCS is booming, but whole systems analysis of the environmental implications of CSS on geological resources is more limited. Research into the ‘storage’ as opposed to the ‘capture’ aspect of CCS is a particular need.

Living assets: the ‘energyscape’ of the future – More energy supply should be aimed to come from renewable sources; this may require deployment of less mature technologies, such as offshore wind, marine renewables and bioenergy.

Coastal and offshore renewable energy – the objective is to advance and integrate understanding of the cumulative impacts of large-scale investments in coastal and offshore power generation on estuarine, coastal and marine systems. This action will develop the knowledge base to deliver a range of sustainable, environment-enhancing and CO2-free supply of energy from the coastal and marine environment from a range of sources (eg kinetic, wind, solar, thermal).

Unconventional energy – Marine gas-hydrates may have the potential to meet future energy demands. Melting hydrates to release methane is technically challenging and the environmental implications are largely unknown and controversial. This action will combine novel measurements and modelling approaches to predict the environmental implications of the exploitation marine gas hydrates.

(ii) Developing an integrated water-soil life support system

Over the next 80 years, demographic and climate change will add further pressure to the water and soil life support systems on which we depend. The big challenge is to forecast the optimal mix of land and water use in the future to sustain these soil-water life support systems and ensure water security. This action provides an integrated soil and water framework via an umbrella action – the Virtual Observatory – and through a dynamic programme of activities to sustain and improve the quality of soil and water resources, the first of which focuses on the changing water cycle.

The Changing Water Cycle: we can no longer assume hydroclimatic stationarity as a foundation concept for water resource management; we need new non-stationary probabilistic models of relevant environmental variables to optimize water resource sustainability. Science challenges include: (i) understanding the relationship between soil microbial processes, soil carbon storage/release and water flux in catchments, (ii) developing water conservation measures to sustain water resources within river basins including the environmental implications of water metering on the whole system, (iii) protecting groundwater resources through integrated measurement and modelling of water abstraction, water quality and habitat needs.

(iii) Bringing environmental valuation into mainstream thinking

Many approaches exist to value environmental assets based largely on the pressure-state-response paradigm. Given that most state indicators rely on easily measured ecosystem values, for which we have agreed protocols, one of the biggest challenges is accounting for the uncertainties in our current data and understanding, and developing a rigorous method for combining incommensurate values and measures that go beyond simple scoring and weighting systems. The first priority of this action involves valuing the sustainability of natural resources. The second priority is to develop effective and cross-disciplinary networks that articulate better the needs of both science and policy communities in relation to the valuation of natural resources. The objective is to promote novel resource management centered on carbon, soil, water, and ecosystem conservation/regeneration as well as on more commonly used indicators linked to health and wealth generation.

Probable Questions and Discussion Points

What are renewable and non-renewable resources? Discuss with examples.

What are perpetual energy sources?

Name some of the natural resources of the earth and the benefits derived from them.

Write a brief note about the forest resources of the world. Why they are vital to the human existence?

Name five countries where the per capita average forest cover is the highest.

What is a primary forest?

Show how the forests can be divided into several classes. What are mangroves?

What are tropical moist forests? Discuss their importance.

State why the other living organisms are important in sustaining the existence of mankind. Discuss the inter-relationships between man and other organisms.

Give a brief description of the forest resources of India.

Discuss the special features of the vegetation in the northeastern India.

What percentage of the total area of India is covered with forests? Is it sufficient?

Name a few Biosphere reserves in India. Why are they important?

Name a few major tiger reserves of India. Give reasons why the Tiger needs to be protected.

Name five states of India in order of highest forest cover.

The National Forest Policy requires that a minimum of 33 percent of country’s geographical area should be under forest cover. Have we been able to achieve this? If not, why?

How the forests can contribute to the country’s economic wealth?

What are the causes of deforestation? Discuss some of the measures required to be taken to prevent further deforestation.

What are the effects of deforestation? Does it have some relation to climate change?

How does deforestation affect the water cycle?

Discuss a case study describing the effects of deforestation.

Name some of the areas of the world where deforestation has created serious problems. Discuss at least one of the same.

What is forest management?

Is afforestation successful in reducing the impacts of deforestation on the environment?

Describe with at least one example how the dams have affected the forests?

A big dam is a curse. Explain.

Mining affects the forests in several ways. Discuss.

How mining activities affect the environment?

Why water is described as a ‘closed system’? Discuss the water cycle.

Write briefly about the water resources of the world.

Why fresh water is a rare commodity?

Glaciers and icebergs are the storehouse of fresh water. Justify.

What do you mean by water table? What are the factors that affect the water table?

State reasons why groundwater and surface water can be considered as a single resource.

What are the causes for the occurrence of flood?

Describe the different types of flood mentioning clearly how do they occur.

Discuss briefly the effects of flood.

Describe the basic emergency measures needed to be taken during a flood.

What can you do to protect property from flood damages?

A flood has occurred all of a sudden in your locality. What will you do to protect life and property?

What is drought? Why does it occur?

Describe the different types of drought.

Discuss the impacts of drought in India with a few examples.

What are the harmful effects of drought?

Why are dams required? Describe the world situation with respect to major dams on rivers.

Discuss briefly the major environmental impacts of dams.

How does a dam affect a river?

Discuss the biogeophysical and social impacts of big dams.

Describe a few major dams in India.

What do you mean by conflict over water? Discuss with examples.

Describe the water conflicts between India and Pakistan.

Trace the history of (i) the Ganges water dispute between India and Bangladesh and (ii) the water dispute between India and Nepal?

Discuss the Kaveri water dispute with the historical context.

Give a list of common and useful minerals.

What is open cast mining? Discuss its environmental impacts.

Describe the major minerals resources of the world.

Discuss the position of India with respect to production of major minerals.

What are the hazards of mining?

What is mine drainage? Why it is harmful?

How can you classify the food crops? Describe the features of each of the classes.

Out of the very large number of crops available, only a few are edible? What do you think is the reason for this?

How can you expand the food resources?

State the reasons for the food problem existing in different parts of the world.

What do you mean by food security? What are the ways to achieve it?

Discuss the achievements of the Grameen Bank in Bangladesh in reducing poverty.

Write a brief outline of World food production.

What is the position of India with respect to production of food crops? Is it self-sufficient?

What are the problems and effects of modern agriculture?

Why soil erosion is a major problem? What are the causes and effects?

Describe briefly the hazards paused by pesticides.

Name a few pesticides of common use.

What is salinity? How does it affect soil quality and agriculture?

How can you know that the soil has become saline?

How does salinity affect rice production?

Discuss briefly the growing energy needs of the world.

Describe the following renewable sources of energy: water power, wind power, solar energy.

What is a biofuel?

How biogas is generated?

What is geothermal energy?

How coal is mined?

How many types of coal do you know? Describe.

Describe different uses of coal.

What is petroleum?

Who are the major oil producers of the world? Give a short description?

Trace the history of oil in India.

Discuss the present position of oil industry in India in relation to the country’s needs.

What are the environmental effects of petroleum exploration, production and use?

What is soil? How it is formed?

Write briefly about (i) the organic fraction of the soil, and (ii) the minerals in soil.

What are the normally water soluble components of soil?

What is the origin of carbonates in soil?

Discuss briefly about the primary and the secondary minerals of soil.

What are different types of soil?

List the different processes that lead to soil degradation.

What do you mean by soil aridification?

Why desertification has become a major concern?

Discuss one of the case studies relating to soil degradation.

Discuss one of the following: (i) Environmental concerns in the Sahel Region, and (ii) Soil degradation in the Leipzig-Halle-Bitterfeld area.

Why landslide takes place?

What are the protective steps necessary in case of a land slide?

How to prevent a land slide?

What are the warning signs of a land slide?

Discuss of the steps that may be taken to prevent desertification.

Describe in brief the role of an individual in natural resource conservation.

What is equitable distribution of energy?

What do you mean by Environmental Life Cycle analysis?

Write how you can develop an integrated water-soil life support system.