AP State Syllabus 9th Class Biology Solutions 10th Lesson Soil Pollution
9th Class Biology 10th Lesson Soil Pollution Textbook Questions and Answers
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Define soil pollution. (AS 1)
Soil or land pollution can be defined as the buildup in soils of persistent toxic compounds, chemicals, salts, radioactive materials, or disease causing agents, which have adverse effects on plant growth and animal health.
Why are plastic bags a big environmental nuisance? (AS 6)
- Plastics are so versatile in use that their impact on environment are extremely wide ranging.
- Careless disposal of plastic bags chokes drains, blocks the porosity of the soil, and causes problems for ground water recharge.
- Plastic disturbs the soil microbe activity, and once ingested can kill animals.
- Plastic bags can also contaminate food stuffs due to leaching of toxic dyes and transfer of pathogens.
- Plastic bags remains strewn on the ground, or in unmanaged garbage dumps.
- Though small percentage lies strewn, it is this portion that is of concern as it causes extensive damage to the environment.
Describe an environmental friendly method to profitably dispose of human waste and cattle waste. (AS 1)
- In recent years, an alternate and better method is used to obtain energy from not only from cattle waste but also from human waste.
- This is by anaerobic fermentation of the wastes to produce a gas which can be used as fuel.
- As this gas is produced from biological waste, this is called biogas.
- Biogas is a mixture of several gases : methane, carbondioxide, and small amounts of hydrogen, nitrogen, and hydrogen sulphide.
Chemical fertilizers are useful to crops. In which way they cause environmental pollution? (AS 1)
We often read in newspapers that environmentalists often show deep concern of threats posed by chemical fertilisers and pesticides, etc. What are those threats to environment?
- Fertilisers contaminate the soil with impurities, which come from the raw materials used for their manufacture.
- Due to excessive use of phosphate fertilizers soil becomes an indestructible poison for crops.
- Excessive use of fertilizers can endup polluting lakes, rivers and streams.
- This leads to promote the growth of algae in water bodies and is called eutropication.
- This abundant uncontrolled growth of plants blocks the flow of water and reduces oxygen content in the water.
- Other organisms living in the water do not get sufficient water, oxygen and ultimately die.
- Nitrogen fertilizer contribute to air pollution when it enters the atmosphere as ammonia and nitrogen oxide.
- This inturn cause acid rain and city smog associated health and environmental problems such as respiratory illness.
What steps can be taken to reduce pollution due to particulate matter from industries?
- Industrial wastes can be treated physically, chemically and biologically until they are less hazardous.
- Acidic and alkaline wastes should be first neutralized; the insoluble material if biodegradable should be allowed to degrade under controlled conditions before being disposed.
- Electrostatic precipitators are used to reduce the particulate matter in the factory smoke.
What is a medical waste? Why it is called hazardous waste? What is the safe way to dispose medical waste? (AS 1)
- Waste that is produced from hospitals is known as medical waste.
- Medical waste include needles, syringes, saline bottles, instruments used in surgeries, bandages soaked with blood and pus, used medicines, human excreta etc.
- Medical waste is called as hazardous waste because it containing toxic substances.
- Burying the medical waste in locations situated away from residential areas is the simplest method to dispose medical waste.
Prepare a flow chart to describe soil pollution, causes and methods of control. (AS 5)
Prepare a pamphlet of your own to create awareness on soil pollution among the people in your area.
What soil problems do you find in your area? Prepare a list of those problems and suggest a method for each of them to control those problems. (AS 7)
The soil problems identified by me in our area :
What farm practices impact soil? Do they impact soil in a positive or a negative way?
- Indiscriminate use of fertilizers, pesticides, insecticides, herbicides, no-till farming and growing same crop in all seasons are the farm practices impact soil.
- These farm practices may show positive or negative impact on the soil.
- By using chemical fertilizers we can get high yielding for only 20 to 30 years.
- After that soil becomes reluctant to plant growth. These chemicals damage fertility.
- Due to the extensive use of pesticides, insecticides, herbicides the salinity of the soil increases and it is not suitable for growing crops.
- Notill farming is a way of growing crops without disturbing the soil through tillage.
- Tillage activity can lead to compaction of soil, loss of organic matter in soil, loss of native vegetation, and death of the organisms in the soil.
- Growing the same crop in all seasons decreases the fertility.
Rank the negative impact practices in your area in the order in which you think they should be eliminated. (AS 1)
Negative impact practices in our area :
- Using chemical fertilizers
- Using pesticides
- Using insecticides
- Using herbicides
- Till farming
- Using weedicides
- Growing same crop in all seasons
- Using locally prepared seeds
Rank the positive impact practices in order in which you think they should be used for the most benefit on your farm. (AS 1)
- Hybridised seeds
- Organic manures
- Organic weedicides
- Predatory insects
- No-till farming
- Maintaining suitable pH value
- Crop rotation
- Salinity management
- Soil organisms
Ravi said soil health is important. How can you support him? (AS 7)
- I support Ravi’s statement.
- Healthy soil is fundamental to the quality of food it produces and to the health of those who eat the food produced from it.
- When the soil components are present in appropriate percentage, the productivity is high.
How would soil texture affect the nutrients in soil? What would be its impact on crop production? (AS 2)
- Soil with loose pores will allow water to collect and roots to expand. Loose soil is better than hard compact soil.
- Finer particles like clay increase surface area of the soil which allow nutrients to stay in the soil.
- Very porous soil, such as sand will allow nutrients to be leached more easily which can make less nutrients available to plants.
- Generally, a loose, airy soil structure is best for most plants.
- This can be accomplished by digging the bed and mixing together coarse and finer textures such as tilling compost into clay soil.
What are the three main physical properties of soil? What effects do this have on the plants? (AS 1)
- Colour texture, structure and porosity are the three main physical properties of soil.
- These properties regulate and affect air and water movement in the soil and thus, soil ability to function.
What is pH? What is its range? What are the negative impacts if the pH of soil is too low or too high? (AS 1)
- The term pH is used to indicate the level of acidity or alkalinity of a soil.
- The range of pH values of a good soil live from 5.5 to 7.5.
- Below pH 7 the soils are termed as acidic and above pH 7 alkaline.
Negative impacts of low pH value :
- The concentration of soluble metals especially aluminium and manganese may be toxic.
- Calcium may be deficient.
- Soil organisms responsible to transform N, S and P to plant available forms may be reduced.
- Symbiotic nitrogen fixation in legume crops is greatly impaired.
- Soils will be having low organic matter.
- The availability of mineral elements to plants may be effected.
Negative impacts of high pH value :
- If the pH is beyond 7, nutrient absorption and microbial activity will be affected which can be poisonous to plants.
- pH extremes are unhealthy for most plants because they close or open membranes of plant cells too much.
- This affects plant structure and their ability to uptake nutrients.
- pH extremes make minerals and nutrients either too available or not available enough.
What is soil fertility? What are the sources of soil fertility? (AS 1)
- Fertility of soil is closely associated with the properties of soil and is defined by its capacity to hold water and nutrients and supply them to plants when they need them, independent of direct application of nutrients.
- Soil organisms contribute to buildup soil organic matter, including humus, the soils most important nutrient reservoir.
- A major part of the soil microbial biomass is composed of fungi.
- Soil fertility is a complex process that involves the constant cycling of nutrients between organic and inorganic forms.
- As plant material and animal wastes decompose they release nutrients to the soil solution.
- Soil pH, its acidity or alkalinity is highly relevant to how readily nutrients become available in the soil.
Name 5 living things that live in soil. What do these things do to affect the soil?
- Viruses, earthworms, rats, ground squirrels, bacteria, fungi, algae, protozoa, dung beetle and different types of worms live in the soil.
- These organisms feed on plant residues burrow the soil and help in aeration and percolation of water.
- Soild microbes convert organic forms of elements to their inorganic forms.
- Soil bacteria also control the forms of ions in which these nutrients occurs.
What is organic matter? Why it is important to plants? (AS 1)
- Organic matter is the organic component of soil which includes the residues of dead plants and animals.
- Organic matter consists of nutrients necessary for plant growth such as nitrogen, phosphorus, and potassium.
- Soils which contain 30% or more organic matter are considered organic soil, all other soils are identified as mineral soils.
- Organic matter in soil improves water in filteration, decreases evaporation, and increases the water holding capacity.
- And also where there is organic matter, there will be numerous organisms present helping to convert it back to nutrients and these organisms help to create small pieces of nutrients, ideal for cultivation.
What are the factors affecting organic matter levels in soil? How this level of organic matter can be increased? (AS 1)
1. Temperature, rainfall, natural vegetation, texture, drainage, cropping and tillage and crop rotation are the factors affecting organic matter levels in soil.
2. Temperature :
The decomposition of organic matter is accelerated in warm climates as compared to cooler climates.
3. For each 10°C decline in mean annual temperature the total organic matter and nutrients increases by two to three times.
There is an increase in organic matter with an increase in rainfall.
5. Natural vegetation :
The total organic matter is higher in soils developed under grasslands than those under forests.
6. Texture :
Fine textured soils are generally higher in organic matter than coarse textured soils.
Poorly drained soils because of their high moisture content and relatively poor aeration are much higher in organic matter and nutrients than well drained soils.
8. Cropping and Tillage :
The cropped lands have much low nutrients and organic matter than comparable virgin soils.
9. Crop rotation :
Crop rotation of cereals with legumes results in higher soil organic matter.
What is solid waste? Explain best practices for solid waste management. (AS 1)
Solid waste may be defined as the organic and inorganic waste produced by various activities of the society which have lost their value to the first user.
Best practices for solid waste management:
- By practicising four R’s : Reduce, Reuse, Recycle and Recover we would get less solid waste.
- Materials such as glass containers, plastic bags, paper, cloth, etc., can be reused at domestic levels rather than being disposed, reducing solid waste pollution.
- Solid waste management involves activities including collection, transfer, and transport to suitable sites and safe disposal of wastes by methods which are environmentally friendly methods.
- Burying the waste in locations situated away from residential areas is the simplest and most widely used technique of solid waste management.
- Solid waste management can also be done by methods such as sanitary landfill, composting and incineration, etc.
What is bioremediation? How it helps in controlling soil pollution? (AS 1)
- Bioremediation means to use a biological remedy to reduce or clean up contamination.
- Microbes are often used to remedy environ¬mental problems found in soil, water and sediments.
- Plants have also been used to assist bio¬remediation processes. This is called phytoremediation.
- Biological processes have been used for some inorganic materials, like metals to lower radioactivity and to remediate organic contaminants.
Why soil conservation is important to us? What will happen if no preventive measures would be taken? (AS 2)
- Soil conservation is important to us because it forms the basis for habitats and plants, which act as source of food to both humans and animals.
- Soil conservation is also important because with the erosion of the top soil layer, valuable nutrients are lost and crop yield diminish, which means very less food is produced per acre.
- We have to conserve soil because it has organic material that is good for plant growth.
- If no preventive measures are taken for soil conservation, soil erosion takes place.
- And also soil will be over used and it has more chemicals leading to unproductive soil.
- Amount of nutrients present in the soil decreases.
Look at the following symbol, what does it mean?
1. It is the symbol of bioremediation.
2. Plants have been used to assist bioremediation.
9th Class Biology 10th Lesson Soil Pollution InText Questions and Answers
9th Class Biology Textbook Page No. 155
Today what are the pollutants produced from your school. How many of these are non-degradables?
Wastes produced from our school :
Peels of fruits, vegetables, rice, glass materials, pens, polythene bags, biscuit and chocolate covers, icecream sticks, rubber, plastic tea glasses, paper leaves twigs etc.
Non-degradable pollutants :
Glass materials, pens, polythene bags, biscuit and chocolate wrappers, rubber, plastic glasses.
9th Class Biology 10th Lesson Soil Pollution Activities
Activity – 1
1. During interval time Venu was eating a fruit.
2. He was about to throw the peel in corner of verandah.
3. His friend Ramu stopped him.
4. Ramu said you should not throw waste in the verandah. Drop it in the bin/basket given.
5. Prepare a list of waste materials we throw out in a day from morning to evening.
6. Classifying them as wet wastes and dry wastes with the help of the example given in the table.
|Wet waste||Dry waste|
|Vegetable peels||Biscuit wrapper|
|Banana peels||Polythene covers|
|Food materials||Used papers|
|Fruit peels||Plastic materials|
7. Weigh the wet wastes, which you have listed in the table for one day.
8. Divide the weight by number of people in your home.
9. The result will be the per capita wet waste we are producing in one day.
10. Suppose if a family containing four members throws 400 gms of wet wastes per day,
Multiply it by 30 = 100 × 30 = 3000 gms per month
Multiply it by 365 = 3000 × 365 = 10,95,000 gms = 1095 kgs per year.
Activity – 2
Dumping and decomposing,
1. Take a polythene bag / plastic bucket / or any container.
2. Fill half of it with soil.
3. Keep wet wastes and other wastes in it.
4. Wastes should include vegetable peels, rubber, plastic etc.
5. Add some more soil and sprinkle water regularly on it.
6. Dig it and observe in 15 days intervals.
7. Note your observations in the table.