NIOS Class 12 Environmental Science Chapter 17 Conservation of Solid and Land

NIOS Class 12 Environmental Science Chapter 17 Conservation of Solid and Land Solutions to each chapter is provided in the list so that you can easily browse throughout different chapters NIOS Class 12 Environmental Science Chapter 17 Conservation of Solid and Land Notes and select need one. NIOS Class 12 Environmental Science Chapter 17 Conservation of Solid and Land Question Answers Download PDF. NIOS Study Material of Class 12 Environmental Science Paper Code 333.

NIOS Class 12 Environmental Science Chapter 17 Conservation of Solid and Land

Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 12 Environmental Science Chapter 17 Conservation of Solid and Land Solutions, NIOS Senior Secondary Course Environmental Science Solutions for All Chapter, You can practice these here.

Conservation of Solid and Land

Chapter: 17

Module 5: Environmental Conversation

Textual Question Answer

INTEXT QUESTIONS 17.1

1. Define soil.

Ans: Soil is the uppermost layer of earth’s crust in which plants grow. 

2. Name two natural agencies which cause soil erosion.

Ans: Water and wind. 

3. What is coastal erosion?

Ans: Erosion at sea shores.

4. What is surface creep?

Ans: Surface creep is the movement of large soil particles by rolling and sliding along the ground due to strong wind velocity.

5. How wind erosion is damaged roads and agricultural fields?

Ans: Deposits soil on roads. 

INTEXT QUESTIONS 17.2 

1. Nahin Maine three human activities which cause soil erosion.

Ans: Deforestation, agriculture or farming and mining.

2. What is monoculture?

Ans: Raising one plant variety only on a piece of land. 

3. Why monoculture may lead to soil erosion? State one reason.

Ans: Barren land left after harvest/rainfall does not seep into soil after harvest/ water or wind erodes soil of damaged by a pest. 

4. How does building construction soil erosion?

Ans: Large chunks of earth mass dug out. 

INTEXT QUESTIONS 17.3 

Give one to three words for the following:

1. The losing and displacement of top soil particles from land.

Ans: Soil erosion.

2. The deterioration in quality of land resulting in reducing of crops productivity.

Ans: Land degradation.

3. The first phase of soil formation which is a physio-chemical that leads to the breakdown of rocks into its mineral constituents.

Ans: Weathering.

4. The erosion of soil from banks of rivers due to flowing water. Stream bank erosion.

Ans: Stream bank erosion.

5. Man-made varieties of agriculture plants, fodder plants, forest trees, livestock and fishes that have been raised and modified by us by means of various breeding techniques in order to increase productivity.

Ans: High yielding varieties/ HYV.

6. Toxic chemicals used to kill organisms that are pests.

Ans: Biocides.

7. The progressively increased concentration of chemical in organisms through the food chain.

Ans: Biomagnification.

INTEXT QUESTIONS 17.4 

1. How does polyvarietal cultivation prevent soil erosion?

Ans: Entire field does not become bare as different varieties harvested at different times.

2. Out of the lady bird beetle and the cottony cushion scale (Icerya purcahsi), which is the best and which the predator?

Ans: Icerya purchasi- pest.

Ladybird beetle- predator. 

3. How do microbes resist soil erosion?

Ans: Microbes decompose organic matter to produce polysaccharides which bind soil particles together and thus prevent from erosion.

TERMINAL EXERCISE

1. Define soil erosion.

Ans: The removal of the uppermost top layer of the soil is called soil erosion.

2. State the difference between geological and accelerated erosion with respect to (i) rate and (ii) cause. 

Ans: 

Basis	Geological Erosion	Accelerated Erosion
Rate	A slow natural process that continues unnoticed and has been occurring for millions of years.	A rapid process; the rate and extent are much higher compared to natural geological erosion.
Cause	Caused by natural agents like wind, water, glaciers, and weathering of rocks into soil particles.	Caused mainly by human activities such as deforestation, overgrazing, faulty farming practices, and mining, which destroy protective vegetation cover.

3. What are the various ways by which water erosion takes place? Give details of any of three. 

Ans: Water erosion takes place in different ways:

(i) Raindrop erosion.

(ii) Sheet erosion.

(iii) Rill erosion.

(iv) Stream bank erosion.

(v) Erosion due to landslides.

(vi) Coastal erosion.

Details of three:

(i) Sheet erosion: The uniform removal of a thin layer of soil over a large area by flowing rainwater. It is a slow process and often goes unnoticed.

(ii) Coastal erosion: Occurs along seashores due to wave action and the inward movement of seawater into the land.

(iii) Stream bank erosion: The washing away of soil from the banks of rivers or streams by flowing water. It damages nearby agricultural lands, highways, and bridges.

4. How can soil erosion by water be prevented? 

Ans: Soil erosion by water can be prevented by following these methods:

(i) Plant trees as they intercept rainfall and protect soil from the direct impact of raindrops. 

(ii) Control grazing of cattle.

(iii) Crop rotation has to be practiced giving land time to regain its fertility.

(iv) Increase soil organic matter through vegetation and soil management

(v) Construct dams to store runoff water and prevent stream bank erosion.

(vi) Maintain coastal vegetation like mangroves to coastal erosion.

5. What are the consequences of soil erosion due to wind? 

Ans: The effects of wind erosion are as follows:

(i) Wind erosion removes the finer soil material including organic matter, clay, and slit, in a colloidal form and leaving behind coarser, less fertile material.

(ii) The productive capacity of the soil is lost as most of the plant nutrients which remain attached to a smaller colloidal soil fraction is lost.

(iii) It damages roads and fertile agricultural fields by depositing large quantities of air blown soil particles.

6. Describe the several causes of soil erosion due to human activities. 

Ans: The human activities that cause soil erosion are:

(i) Deforestation: Deforestation is the cutting and felling of trees, removal of forest litter which leads to erosion. This further leads to land degradation, nutrient, and the disruption of the delicate soil-plant relationship. 

(ii) Farming: plowing, tilling, continuous cropping, cultivation on mountain slopes, monoculture, overgrazing, etc. are the agricultural practices that cause soil erosion.

(iii) Mining: The extraction of useful natural resources such as metals, minerals, and fossil fuels, etc., from the land causes serious disturbance to the land leading to soil erosion and drastic changes in the landscape. 

(iv) Developmental works: Developmental activities such as housing, transport, communication, recreation, etc. can lead to soil erosion.

7. In way does land get degraded by use of agrochemicals. 

Ans: The land gets degraded by the use of agrochemicals in the following ways:

(i) Widespread imbalance in the soil nutrients. 

(ii) Eutrophication of water bodies.

(iii) Health problems like methemoglobinemia due to contamination of food and water.

(iv) They disrupt the balance of the natural ecosystem by killing non-target often-useful organisms.

(v) Continuous use of agrochemicals makes the pest resistant. 

(vi) It can cause biomagnifications that are the accumulation of chemicals in subsequent trophic levels.

8. What are HYV? How do they degrade land. 

Ans: HYVs (High Yielding Varieties) are specially developed crop varieties that give high production of food grains.

They degrade land because:

(i) They require heavy irrigation.

(ii) They depend on excessive use of chemical fertilizers and pesticides.

(iii) This leads to loss of soil fertility, pollution, and long-term land degradation.

9. How can soil erosion and land degradation be prevented? 

Ans: Measures for preventing soil erosion and land degradation are:

(i) Planting trees: The trees not only cover soil from the sun, wind, and water, they also help to hold the soil particles with the help of their roots.

(ii) Cultivation and farming techniques reduce soil erosion. 

These include:

(a) Cultivation of land at the right angles to the direction of wind helps to reduce wind erosion.

(b) Plowing style reduces the amount of erosion. Contour plowing is a plowing style in which the field is tilled at right angles to the slope of the land to prevent soil erosion.

(c) Strip Farming: This is the planting of the major crops in widely spaced rows and filling in the spaces between with minor crops to ensure complete ground cover. As the ground is completely covered, it retards water flow which thus penetrates the soil, and reduces soil erosion. 

(d) Terracing: Terracing is done on slopes, by leveling off the land on the slope to prevent the downflow of water.

(e) The time of plowing can have an effect on soil erosion.

(f) No-till cultivation prevents soil erosion. Some can loosen the soil, plant seeds, and take care of weed control all at once with minimum disturbance to the soil. 

(g) Polyvarietal cultivation Is the method in which the field is planted with several varieties of the same crop. As the harvest time varies for different varieties of the crops, the entire field Is harvested at a different time, and the land does not become bare and is protected from erosion. 

(h) The addition of organic matter to the soil reduces soil erosion. Microbes in the soil decompose the organic matter and produce polysaccharides which are sticky and glue the soil particles together and thus help the soil to resist erosion.

10. Give an account of innovative agricultural techniques which prevent land degradation.

Ans: The innovative agriculture techniques are the following:

(i) organic farming or green manures: cow dung, agricultural wastes are used instead of chemical fertilizers for supplying nitrogen and other nutrients to the soil. 

(ii) Biofertilizers: Microorganisms are present in fertilisers that help to increase the nutrient content of the soil. 

(iii) Biological pest control: The natural predators and parasites of pests help to control plant pests and pathogens.