Test: Environmental Awareness (Soil Pollution) - Software Development MCQ

• Soil contamination or soil pollution as part of land degradation is caused by the presence of xenobiotics (human-made) chemicals or other alterations in the natural soil environment. It is typically caused by industrial activity, agricultural chemicals, or improper disposal of waste.
• Fungi and bacteria found in the soils cannot bind the soil due to chemical changes and this causes soil erosion. Large tracts of land become barren; unable to support any life on it. Even the plants that do grow on these lands will absorb the toxins and transfer them to the food chain.

Key-Points

Hydropower 

• Hydropower is electrical energy produced through the power of moving water. In modern technology, hydropower moves turbines that pass on their energy to a generator which then produces electric power. Hydropower is a type of renewable energy, and once the power plant is constructed it produces little to no waste.
• Hydropower plants convert potential energy into mechanical energy through water turbines, which then generate electricity.
• The main purpose is to store energy by pumping water up into the upper reservoir during low-demand periods and generate (peaking) power by releasing the water back to the turbine during high-demand periods.

Additional Information

Transport sector

• The environmental impact of transport is significant because transport is a major user of energy, and burns most of the world's petroleum. This creates air pollution, including nitrous oxides and particulates, and is a significant contributor to global warming through the emission of carbon dioxide.
• Transportation, as a component of the tourism industry, has many side effects on the environment due to carbon dioxide emissions, pollution, etc. The work mainly emphasizes the way in which air, road, rail, and water transportation influence the quality of the environment, contributing to global warming at the same time.

Agriculture sector

• Agriculture and livestock activities pollute soil through the excessive application of pesticides and fertilizers, the use of untreated wastewater for irrigation, and the use of manure and sewage sludge with high antibiotic, antimicrobial-resistant bacteria, and heavy metal content.

Thermal power plants

• Since the thermal power plants and the ash ponds are located in densely populated areas, there is a potential chance for contamination of soil and groundwater of the surrounding areas from the toxic trace elements in the ash. These elements are also enriched in the pond ash.

Since Hydropower plants are not a source of pollution in soil

Therefore Option 4 is the correct answer.

The correct answer is Pedology.

Key Points

• Pedology is a subject that deals with the scientific study of soil.
• It deals with soil formation, soil genesis, soil classification, and the description of soil properties.

Additional Information

Void ratio (e): 

• Void ratio is usually defined as the ratio of the volume of voids to the total volume of soil solid.

Porosity (n): 

• Porosity is defined as the ratio of the volume of voids to the total volume of the soil.

The relationship between void ratio and porosity are as follows:

The Correct Answer is Option (3) i.e. Nitrogen Oxides.

• The two most common and hazardous oxides of nitrogen are nitric oxide and nitrogen dioxide.
• The oxides of nitrogen are the major pollutants of air pollution and global warming.
• Soil pollution refers to the contamination of the soil with anomalous concentrations of toxic substances.
• The different types of pollutants that are found in contaminated soil are given below :
  • Hydrocarbons - 42%
  • Heavy Metals - 31%
  • Mineral Oil - 20%
  • Other - 7%

Concept:

Pollution:  It's the addition of any substance (solid, liquid, or gas) or any form of energy (such as heat, sound, or radioactivity) to the environment.

Types of Pollution:

• Air Pollution
• Water Pollution
• Soil Pollution
• Light Pollution
• Noise Pollution
• Thermal Oluution
• Radioactive Pollution

Explanation: 

Soil Pollution: It refers to the contamination/degradation of soil due to the followings:

• Excessive use of chemicals
• Excessive use of fertilizers
• Excessive use of insecticides
• Industry waste
• Acid Rain
• The presence of heavy metals, like lead and mercury.
• Nuclear Waste
• Oil leaks during the storage or transport of chemicals.

Key PointsReasons for air pollution:  

• Burning of fossil fuels such as coal, oil, and natural gas
• Exhaust from automobiles and industries
• Indiscriminate cutting of trees (deforestation)
• Excessive discharge of greenhouse gases like carbon dioxide and nitrous oxide
• Chlorofluorocarbons (CFCs) released from aerosols sprays, refrigerants, and air conditioners
• Heavy usage of vehicles

Reasons for water pollution: 

• Industrial and domestic sewage discharge
• Oil spills and natural gas leakage into water bodies 
• Acid rain
• Agricultural runoff containing pesticides, fertilizers
• Mining and drilling sometimes make underground water contaminated
• Floods and storms carry dust and debris to the water bodies

 The correct answer is Black soil.

• Black soil has the property of 'self-ploughing'.

Key Points

• Regur or Black Soil:
  • These soils are of volcanic origin.
  • These soils are black in colour and are also known as black soils.
  • Since they are ideal for growing cotton, they are also called black cotton soils, in addition to their normal nomenclature of Regur soils.
  • They cover the plateaus of Maharashtra, Saurashtra, Malwa and southern Madhya Pradesh and extend eastward in the south along the Godavari and Krishna Valleys.
  • This soil has a high water-absorbing capacity and is known as self ploughing soil.
  • Crops grown in this soil are Cotton, Jowar, Wheat, Sugarcane, Linseed, Gram, Fruit and Vegetables.

Additional Information

• Alluvial Soil:
  • It covers 40% of the land area.
  • The entire Northern Plains are made up of these soils.
  • They have been brought down and deposited by three great Himalayan rivers–Sutlej, Ganga and Brahmaputra and their tributaries.
• Laterite Soil:
  • The Laterite soils are formed due to weathering of lateritic rock in high temperatures and heavy rainfall with an alternate dry and wet period.
  • They are found along the edge of the plateau in the east covering small parts of Tamil Nadu, Orissa and a small part of Chhotanagpur in the north and Meghalaya in the northeast.

The correct answer is Clay.Key Points

• Clayey soil retains the highest amount of water and sandy soil retains the lowest amount of water.
• Clay soil is soil that is comprised of very fine mineral particles and not much organic material. 
• Clay is the smallest particle among the other two types of soil.
• The particles in this soil are tightly packed together with each other with very little or no airspace.
• This soil has very good water storage qualities and makes it hard for moisture and air to penetrate into it.
  • It is very sticky to the touch when wet, but smooth when dried. 
• Clay is the densest and heaviest type of soil that does not drain well or provide space for plant roots to flourish.

Additional Information

• Sand is a granular material composed of finely divided rock and mineral particles.
  • Sand has various compositions but is defined by its grain size.    
• Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz.
  • Silt may occur as soil or as sediment mixed in suspension with water. 
• Loam is soil composed mostly of sand, silt, and a smaller amount of clay.
  • By weight, its mineral composition is about 40–40–20% concentration of sand–silt–clay.

The correct answer is Salinization.

• Salinization is an increase in the total dissolved solids (TDS) as the salt of the aquifer caused by natural or anthropogenic factors.
• Salinization is a global problem.
  • It tends to be concentrated in the world’s arid and semi-arid regions.
• Gypsum (calcium sulfate) or lime can be used to help leach salt from the soil.

Important Points

• Desertification is an environmental degradation that reduces the productivity of dryland ecosystems by reducing plant.
  • Overgrazing is the major cause of desertification worldwide.
  • Other factors that cause desertification are urbanization, climate change, overuse of groundwater, deforestation, natural disasters, and tillage practices in agriculture that make soils more vulnerable to wind.
• Carbonization is a process in which fuel is heated (900–1,200 °C) without air to leave solid porous carbon.
  • By this process, cole creates coke and sub byproducts.
• Oxygenation is a process where the addition of oxygen takes place to any chemical or physical system, including the human body.
  • By the process of oxygenation of the water, fish and seafood farmers can protect their stock against oxygen deficiencies during peak consumption and growth periods.

Additional Information

• The dissolved oxygen content of the water can be expressed as the absolute quantity of oxygen in one unit of water (mg/l, ppm) or as relative oxygen saturation (%).

When the soil has pH value greater than 11, it is termed as practically infertile.

Causes of high soil pH:

• Sources of alkalinity.
• Role of cations (Na and Ca)
• Influence of soluble salt levels
• Influence of carbon dioxide and carbonates.

Important Points 

1. If the pH in the case of saline soil is around 8.5, very good structure
2. And in the case of saline-sodic soil, it is from 8.5 to 10, good structure.
3. And in the case of sodic soil, it is generally greater than 10, structureless.

Note:

Why high pH soils are infertile:

The high pH caused due to the presence of sodium carbonate which is highly soluble.

This high pH causes fulvic and humic acid of organic matter to get dissolve and when the water evaporates, it gives the surface a black color.

This sodic soil creates physical disintegration and due to high sodium and low salt concentration, slaking, swelling and dispersion occurs which caused coagulation of soil particles as Vander Vaal forces dominate due to deficiency of hydrated ions. 

Complete dispersion causes soil crusting and as a result of this germination problem due to clogs that restrict soil and air movement and makes soil infertile.

The solution is All of these

Concept

• Soil pollution- the presence of toxic chemicals (pollutants or contaminants) in soil, in high enough concentration to pose a risk to human health and/or the ecosystem.
•  It can be also defined as the addition of substances to the soil, which adversely affects the physical, chemical, and biological properties of soil and reduces its productivity.
  •           Negative Pollution- Deterioration in the productivity of soil due to a reduction in quality or quantity of topsoil is called negative soil pollution. It is caused by over-use and erosion.
  • Positive Pollution- It is a reduction in soil productivity and deterioration in the quality of plants.due to the addition of pollution from the air, faulty sanitation, industrial effluents, supra-optimum fertilizers, and pesticides.
  • Third Pollution- It is landscape pollution in which the land is so severely misused that it becomes filthy and odorous because of the dumping of garbage, rubbish, sludge, ash, industrial wastes, etc. over it.

Explanation

• The use of pesticides should be minimized. Biological control should be known and imple­mented.
• The use of fertilizers should be highly judicious.
• Cropping techniques should be improved so that weeds are unable to take a foothold in the fields. This would automatically reduce the use of weedicides or herbicides.
• Special pits or low-lying areas are selected for the dumping of industrial wastes.
• Improvement in mining techniques and transport of extracted materials so that spread of mine dust should be minimized. The area should not be left barren and dry. Instead, afforestation should be carried out as soon as it becomes feasible.
• Controlled grazing and proper forest management.
• Windbreaks and windshields in areas exposed to wind erosion.
• Planting of soil binding grasses and other perennials along the banks and slopes prone to rapid erosion.
• Afforestation and reforestation.

The correct answer is Phytoremediation.

Key Points

• Phytoremediation is a bioremediation process that uses various types of plants to remove, transfer, stabilize, and/or destroy contaminants in the soil and groundwater.
• There are several different types of phytoremediation mechanisms:
  • Rhizosphere biodegradation - In this process, the plant releases natural substances through its roots, supplying nutrients to microorganisms in the soil.
  • Phyto-stabilization - In this process, chemical compounds produced by the plant immobilize contaminants, rather than degrade them.
  • Phyto-accumulation - In this process, plant roots sorb the contaminants along with other nutrients and water. 
  • Rhizofiltration - It is similar to Phyto-accumulation, but the plants used for cleanup are raised in greenhouses with their roots in water
  • Phyto-volatilization - In this process, plants take up water containing organic contaminants and release the contaminants into the air through their leaves.
  • Phyto-degradation - In this process, plants actually metabolize and destroy contaminants within plant tissues.
  • Hydraulic Control - In this process, trees indirectly remediate by controlling groundwater movement.

Additional Information

• Bioremediation is a process used to treat contaminated media, including water, soil, and subsurface material, by altering environmental conditions to stimulate the growth of microorganisms and degrade the target pollutants. 

The A horizon is the top layer of the mineral soil horizons, often referred to as 'topsoil'. 

• This layer contains dark decomposed organic matter, which is called "humus".
• Layers of Soil
• The soil profile is composed of a series of horizons or layers of soil stacked one on top of the other.
• These layers or horizons are represented by letters O, A, E, C, B, and R.

Key Points

The A-Horizon or Topsoil

• This layer is rich in organic material and is known as the humus layer. This layer consists of both organic matter and other decomposed materials. The topsoil is soft and porous to hold enough air and water.
• In this layer, the seed germination takes place and new roots are produced which grows into a new plant.
• This layer consists of microorganisms such as earthworms, fungi, bacteria, etc.

Additional Information

The O-Horizon

• The O horizon is the upper layer of the topsoil which is mainly composed of organic materials such as dried leaves, grasses, dead leaves, small rocks, twigs, surface organisms, fallen trees, and other decomposed organic matter.
• This horizon of soil is often black brown or dark brown in color and this is mainly because of the presence of organic content.

The E-Horizon

• This layer is composed of nutrients leached from the O and A horizons.
• This layer is more common in forested areas and has lower clay content.
• The B-Horizon or Subsoil
• It is the subsurface horizon, present just below the topsoil and above the bedrock.
• It is comparatively harder and more compact than topsoil. It contains less humus, soluble minerals, and organic matter.
• It is a site of deposition of certain minerals and metal salts such as iron oxide.
• This layer holds enough water than the topsoil and is lighter brown due to the presence of clay soil.
• The soil of horizon-A and horizon-B is often mixed while ploughing the fields.

The C-Horizon or Saprolite

• This layer is devoid of any organic matter and is made up of broken bedrock. This layer is also known as saprolite.
• The geological material present in this zone is cemented.

The R-Horizon

• It is a compacted and cemented layer.
• Different types of rocks such as granite, basalt, and limestone are found here.

The correct answer is soil conservation.

Key PointsMulching

• A layer of organic matter like straw covers the bare ground between plants and helps to maintain soil moisture.
• Mulching is a layer of organic material of hay and grass particles that is placed on the surface of the soil to conserve moisture in the soil. It is used to improve the soil around the plants.
• It reduces evaporation rates and conserves soil moisture. It protects the soil from erosion.
• It holds down weeds which helps to improve the soil structure and fertility.

Some soil conservation methods  

• Mulching
  • A layer of organic matter like straw covers the bare ground between plants and helps to maintain soil moisture.
• Contour barriers
  • To create barriers along contours, stones, grass, the soil is being used.
  • Trenches are made to collect water in front of the barriers.
• Rock dam
  • Rocks are stacked up to slow down water flow and also help to stop gullies and further erosion of soil.
• Terrace farming
  • On steep slopes, wide flat steps or terraces are designed so that flat surfaces are used for cultivation.
  • Thus minimizing surface run-off and soil erosion.
• Intercropping
  • Various crops can be grown in alternating rows and are planted at varying times to protect the soil from rain washing.
• Ploughing of contours
  • Ploughing parallel to the contours of a hill slope creates a natural obstacle for fluid to drain down the slope.
• Shelterbelts
  • In the coastal and dry areas, rows of trees are cultivated to track the passage of air and preserve the cover of the soil.

The correct answer is Adding Lime.

• Soil pH of acidic soil can be improved by adding Lime.

Key Points

• The pH of highly acidic soils can be raised by incorporating limestone into the soil.
• Hydrated lime works quicker, but over liming is more likely.
• pH is measured on a logarithmic scale from 1 to 14, with 7 being neutral.
• A soil with a pH of 4 has 10 times more acid than soil with a pH of 5 and 100 times more acid than soil with a pH of 6.

​Additional Information

• Soil pH is a measure of the concentration of hydrogen ions in the soil solution.
• The lower the pH of the soil, the greater the acidity.
• pH should be maintained at above 5.5 in the topsoil and 4.8 in the subsurface.
• A well-maintained soil pH will maintain the value of the soil resource, maximize crop and pasture choice, and avoid production losses due to low pH.

The correct answer is Saline soils.

• Reclamation of saline soil:
• Flooding or leaching of soluble salts by good irrigation water.
• Keep soil moist or frequent irrigation of the field.
• Use of FYM for the reclamation of saline soil.
   

Additional Information

• Saline soil: 
• The white crust of soil formed over land hence called white alkali or soon chalk
• Soluble salt i.e. Cl and SO4 ions of sodium and calcium in root zones of soil.

The correct answer is Clay.

Key Points

• The particles that makeup soil are categorized into three groups by size – sand, silt, and clay.
  • Single clay particles cannot be seen with a naked eye.
  • Size is less than 0.002 mm in diameter.
  • ​​Sand particles are the largest and clay particles the smallest. 

Additional Information

• The particles in clay are tightly packed together with each other with very little or no airspace.
• This clay has very good water storage qualities and makes it hard for moisture and air to penetrate into it.
  • It is very sticky to the touch when wet, but smooth when dried.
  • It is the densest and heaviest type of soil that does not drain well or provide space for plant roots to flourish.

The correct answer is soil composition.

Key Points

• Soil composition is not a factor in soil formation.
• The soil is a mixture that contains minerals, organic matter, and living organisms.
• Soil is one of the most important elements of an ecosystem, and it contains both biotic and abiotic factors.
• The composition of abiotic factors is particularly important as it can impact the biotic factors, such as what kinds of plants can grow in an ecosystem.

Additional Information Factors responsible of soil formations

• Soils are formed through the interaction of five major factors: time, climate, parent material, topography and relief, and organisms.
• The relative influence of each factor varies from place to place, but the combination of all five factors normally determines the kind of soil developing in any given place
• Time-The formation of soils is a continuing process and generally takes several thousand years for significant changes to take place.
• Climate, particularly temperature, precipitation and frost action have a profound influence on the soil forming processes which occur within a region.
• Parent material is the unconsolidated mineral and organic deposits in which soils are developing.
• It determines the mineralogical composition and contributes largely to the physical and chemical characteristics of the soil.
• Topography-The shape of the land surface, its slope and position on the landscape, greatly influence the kinds of soils formed.

Moisture content is the ratio of mass of water to mass of soil solids. It may be greater than 100 %.

Permeability of soil  is the property of the soil with how much ease water can flow through the soil mass. Higher the easiness of flowing the water, higher the permeability of soil sample. Generally, coarse grained soils like sand have higher permeability than that of fine grained soils like clay.

Capillarity is the phenomena due to which water can rise and filled the air voids of partially or fully dried soil mass due the action of surface tension forces. The smaller the air void size, the higher the water rises in the soil.

This means that clay soil allows water to raise more as compared to sand.

Percolation is defined as the slow movement of water through the pores in soil or permeable rock.

Soil

• Plants obtain inorganic elements from the soil, which serves as a natural medium for land plants. 
• Soil is the outer loose layer that covers the surface of Earth.
• Soil quality is a major determinant, along with climate, of plant distribution and growth.
• Soil quality depends not only on the chemical composition of the soil but also on the topography (regional surface features) and the presence of living organisms.
• In agriculture, the history of the soil, such as the cultivating practices and previous crops, modify the characteristics and fertility of that soil.
• Soil develops very slowly over long periods of time, and its formation results from natural and environmental forces acting on minerals, rock, and organic compounds.

Soils can be divided into two groups: 

• organic soils are those that are formed from sedimentation and primarily composed of organic matter, while those that are formed from the weathering of rocks and are primarily composed of inorganic material are called mineral soils.

Black soil is also called as Regur soil or black cotton soil.

Black cotton soil:

• It is the third major group of soil in India and forms the top part of the earth's surface, that includes disintegrated rock, humus, inorganic, and organic materials.
• The soil is in black color and is formed by the weathering of igneous rock.
• Most states of India which includes Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh and some parts of Tamil Nadu are covered by the black soil.
• Black cotton soil is clayey in nature and is widely used for the purpose of agriculture. It has high water retention capacity as it is deep and impermeable in nature.

The black color of the black soil is due to the presence of aluminum compounds, iron, and humus. Crops such as cotton, pulses, millets, linseed, tobacco, sugarcane, vegetables and citrus fruits are cultivated in the black soil for high productivity.

Additional Information

Bhangar:

• Old alluvial soil composed of lime nodules or Kankar is called Bhangar.
• It has a clayey composition.​

Humus:

• Decayed remains of plants, animal manures and dead animals is called humus.
• It is an essential element in determining the fertility of soil.