Kaushal Bodh Class 8 Chapter 1 Extra Questions MCQ Hydroponics Growing Plants without Soil

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Hydroponics Growing Plants without Soil Class 8 Extra Questions MCQ

Hydroponics Growing Plants without Soil Class 8 Extra Questions

Question 1.
What does the term ‘urban farming’ mean?
Answer:
Urban farming means growing crops in cities using methods like hydroponics, where soil is not required.

Question 2.
Name the three types of hydroponic systems described in this project.
Answer:
The three types of hydroponic systems that described in this project are
(i) Wick Method
(ii) Deep Water Culture (DWC)
(iii) Nutrient Film Technique (NFT)

Question 3.
What growth media can be used instead of soil in hydroponics?
Answer:
Coco peat, gravel, sand, clay pebbles and sawdust can be used as growth media in hydroponics to support plant roots.

Question 4.
What are microgreens?
Answer:
Microgreens are young seedlings of vegetables and herbs, harvested just after the emergence of the first 2-4 leaves, when they are about 1-3 inches tall.

Question 5.
What is compost tea?
Answer:
Compost tea is a liquid organic fertiliser made by soaking compost in water for 2-3 days often with aeration. It contains dissolved plant nutrients.

Question 6.
Name the app developed by ICAR that can identify plant diseases from photos.
Answer:
The app developed by ICAR that can identify plant disease from photos is ICAR AI-DISC (Artificial Intelligence for Disease Identification and Severity in Crops).

Question 7.
What is soil degradation?
Answer:
Soil degradation means the loss of natural nutrients and quality of soil over time, caused by repeated use, chemical fertilisers, erosion, pollution and mining.

Question 8.
What does a pH paper strip do?
Answer:
A pH paper strip changes colour when dipped in a liquid. The colour change indicates the pH value of the liquid — whether it is acidic, neutral or alkaline.

Question 9.
Why is vertical farming possible in hydroponics but not in traditional soil-based farming?
Answer:
Vertical farming is possible in hydroponics but not in traditional soil-based farming because hydroponics does not require soil and plants. Traditional farming needs flat land and soil for root support, so vertical stacking of crops is not possible.

Question 10.
What is sustainable farming? Why is hydroponics considered suitable for sustainable farming?
Answer:
Sustainable farming means producing food while minimising damage to the environment and preserving resources for future generations.

Hydroponics is considered sustainable because

• It uses significantly less water than traditional farming as water is recycled and reused.
• It does not require large areas of land as plants can be grown using vertical farming.
• It reduces the use of chemical fertilisers and pesticides.
• It can be practised in cities, reducing the need to transport food over long distances.

Question 11.
Compare the wick method and the DWC method of hydroponics.
Answer:
Comparison of the Wick method and the DWC method of hydroponics is as follows

Feature	Wick Method	DWC Method
Water supply	Via cotton wick (capillary action)	Roots submerged in water
Equipment	No pump needed	Aerator required
Container	Recycled PET bottles	Bucket/Tub (10-15 L)
Electricity	Not required	Required for aerator
Best suited for	Small plants, seedlings	Leafy vegetables

Question 12.
What are the conditions needed for plant growth and how does hydroponics fulfil them without soil?
Answer:
Plants need water, nutrients, sunlight, physical support, air and growth medium, and hydroponics fulfils them in the following ways
(i) Water: In hydroponics, the nutrient solution provides water directly to the roots.
(ii) Nutrients: Minerals are dissolved in the water and absorbed by roots.
(iii) Sunlight Natural sunlight or artificial LED/ tubelightisused.
(iv) Physical Support: Plants are held in net pots or on floating sheets.
(v) Air/Oxygen: An aerator (DWC) or flowing water (NFT) provides dissolved oxygen to the roots.
(vi) Growth Medium: Coco peat, gravel or sand replaces soil.

Question 13.
Describe the role of microbes in plant growth and in the compost tea preparation.
Answer:
The role of microbes in plant growth and compost tea preparation is as follows

In Plant Growth

• Microbes break down complex organic matter into simpler nutrients, which plants can easily absorb through their roots.
• Some beneficial microbes protect plants from diseases and help improve their overall growth and health.

In Compost Tea

• Microbes multiply rapidly when jaggery or sugar is added, as it acts as food for them.
• Aeration provides oxygen, helping beneficial microbes grow and release nutrients in a form that plants can easily use.

Question 14.
Why is it important to control the pH of water in hydroponics? What happens if it goes out of range?
Answer:
It is important to control the pH of water in hydroponics because of the following reasons

• Proper pH (6.0-7.0) ensures maximum nutrient mobility and easy absorption by plant roots.
• It maintains a suitable environment for healthy root growth and overall plant development.

If pH goes out of range, nutrient absorption is affected. When pH falls below 6.0, nutrients become
less available and roots may get damaged. When pH rises above 7.0, nutrient uptake decreases, leading to deficiency symptoms such as yellowing of leaves and stunted plant growth.

Question 15.
What is the NFT system? How is it different from the DWC system?
Answer:
NFT (Nutrient Film Technique) is a hydroponic method in which plants stand in PVC pipes and a thin, shallow stream of nutrient-rich water continuously flows over their roots.

Key differences between NFT and DWC system are

NFT (Nutrient Film Technique)	DlillC (Deep Water Culture)
Nutrient-rich water flows as a thin film over roots in PVC pipes.	Plant roots are fully submerged in nutrient-rich still water.
Does not require an aerator.	Requires an aerator to supply oxygen to roots.
Uses PVC pipes and supports vertical stacking.	Uses buckets or tubs with floating sheets.
More space-efficient and suitable for continuous flow systems.	Suitable for simple setups and leafy vegetables.

Question 16.
Explain the challenges in modern agriculture that make sustainable farming methods like hydroponics necessary.
Answer:
The challenges in modern agriculture that make sustainable farming methods like hydroponics necessary are as follows

• A growing world population increases food demand, leading to the clearing of forests for more farmland.
• Farming the same land repeatedly wears out the soil, causing it to lose natural nutrients and fertility.
• Excessive use of chemical fertilisers to help poor soil causes harmful pollution in our rivers and lakes.
• Wind and rain wash away the healthy top layer of soil, while mining and construction damage the land permanently.
• Soil degradation affects a large part of agricultural land, reducing it productivity over time make hydroponics necessary.

Question 17.
Describe in detail the step-by-step method of building a DWC (Deep Water Culture) hydroponic system.
Answer:
The step-by-step method of building a DWC (Deep Water Culture) hydroponic system is

• First, take a 10-15 liter recycled bucket or tub and ensure it does not have any leaks.
• Create a lid using styrofoam or plastic to cover the bucket, which blocks sunlight and prevents algae growth.
• Cut holes in the lid to fit net pots or small cups that have slits for roots to grow through.
• Fill these cups with coco peat or sand and plant your seeds or seedlings inside them.
• Finally, fill the bucket with water until it touches the cups and add an aerator to provide oxygen.

Question 18.
Describe the method of growing microgreens and their nutritional importance.
Answer:
The method of growing microgreens is as follows

• Soak seeds such as mustard, fenugreek, or coriander for a few hours to help germination.
• Spread the soaked seeds evenly on a moist growing medium like coco peat, soil, or cotton.
• Keep the tray in sunlight or under artificial light for proper growth.
• Water regularly to maintain moisture in the medium.
• Harvest the microgreens when the first 2-4 leaves appear, usually when they are about 1-3 inches tall.

Nutritional Importance
Microgreens are highly nutritious as they are rich in vitamins C, E, K, and A, along with carotenoids and essential nutrients.
They support better health, improve immunity, and are commonly eaten fresh in salads and sandwiches.

Question 19.
Describe the process of making compost tea. Why is it a better choice for hydroponics than solid fertilisers?
Answer:
The process of making compost tea is as follows

• Take about 150 g of crumbly compost and place it in a muslin bag.
• Submerge the bag in 10 litres of water.
• Add 50 g of jaggery to feed beneficial microbes and stir well.
• Keep the mixture for about 2-3 days with aeration using an aerator.

It is a better choice for hydroponics than solid fertilisers because it is a liquid fertiliser that mixes easily in water-based systems.
It provides dissolved nutrients and beneficial microbes that help plants absorb nutrients quickly. It does not clog pipes or systems like solid fertilisers and ensures smooth nutrient flow, making it more suitable for hydroponic farming.

Question 20.
Write a detailed note on the importance of hydroponics for the future of food production in India. Mention at least five points.
Answer:
The importance of hydroponics for the future of food production in India is as follows

• It allows us to grow food on rooftops or in tall buildings, which is helpful as cities grow and farmland disappears.
• This method recycles water continuously, making it very important for Indian regions that do not have enough water.
• It uses no soil, helping completely solves the problem of farming on poor or damaged land.
• Crops can grow in any season or weather, which helps keep our food supply safe from droughts.
• It creates new types of jobs and is supported by the government through training and financial help.

Question 21.
Aarav is setting up a hydroponic system in his school garden. Since hydroponics does not use soil, he needs another material to support the roots of the plants while they receive nutrients through water. What growth media can be used instead of soil in hydroponics?
Answer:
Coco peat, gravel, sand, clay pebbles and sawdust can be used as growth media in hydroponics to support plant roots.

Question 22.
During a hydroponics activity in the school laboratory, some students are cutting PVC pipes, handling nutrient solutions, and connecting aerators and pumps. Before starting the-activity, the teacher reminds everyone to follow safety rules. List any four safety precautions that should be followed while working with hydroponic equipment.
Answer:
Four safety precautions to be followed while working with hydroponics are
(i) Always wear gloves when handling tools, materials, cutting instruments and chemical solutions.
(ii) Take special care when using sharp tools like cutters and paper knives for cutting PET bottles or PVC pipes. Always work under the supervision of a teacher.
(iii) Work with electrical equipment like aerators, submersible pumps and drill machines only under adult or teacher supervision.
(iv) Disconnect electrical devices from the power supply before handling them in or near water to avoid electric shock.

Question 23.
Study the diagram of the Wick Hydroponic System (a PET bottle cut in half) and answer the following.

(a) Which part of the bottle acts as the water reservoir?
(b) How does water reach the plant roots from the reservoir?
(c) What is the advantage of using a PET bottle in this system?
Answer:
(a) The bottom (larger) portion of the cut PET bottle acts as the water reservoir.
(b) Water travels from the reservoir to the plant roots through a cotton wick threaded through the bottle cap, using capillary action.
(c) Using a PET bottle makes the system low-cost and eco-friendly because it recycles plastic waste. No electricity or water pump is needed.

Question 24.
Study the pH scale used in the water pH activity and answer the following.

(a) If a pH paper dipped in tap water shows a pH of 7, what does this indicate?
(b) After adding 20-30 mL of vinegar, the pH changes to 4. Is this good for hydroponics? Why?
(c) What step would you take to adjust pH 4 water to the ideal pH of 6.5 for your hydroponic system?
Answer:
(a) A pH of 7 means the tap water is neutral — neither acidic nor alkaline.
(b) No, pH 4 is too acidic for hydroponics. The ideal range is” 6.0-7.0. At pH 4, nutrient mobility will be very low and plant roots may get damaged.
(c) The acidified water (pH 4) should be slowly added in small quantities to the larger volume of neutral water in the hydroponic system. The dilution effect will raise the overall pH of the system water toward the ideal 6.5-7.0 range. The pH should be checked with a pH paper strip after each addition.

Question 25.
Complete the following flow chart reLated to Growth Media.

Answer:
(a) Sand
(b) Retains Moisture

Question 26.
Complete the following flow chart related to DWC System.

Answer:
(a) Styrofoam Sheet
(b) Aerator

Question 27.
Create a concept map showing the main components of a Hydroponic System.
Answer:

Question 28.
Draw a concept map showing different Hydroponic Methods.
Answer:

Question 29.
Your school is organising a workshop on sustainable farming practices. You have been invited as an agricultural expert to demonstrate hydroponic farming to students. Assume the role of a hydroponics specialist and explain the need for sustainable agriculture, the concept and benefits of hydroponics, the different hydroponic systems (Wick, DWC and NFT), the tools and materials required, and the safety precautions to be followed while setting up and maintaining a hydroponic system.
Answer:
Do it yourself.

Question 30.
Discuss the challenges faced by traditional agriculture, the need for sustainable farming practices, the advantages of hydroponics over soil-based farming, and its potential role in ensuring food security while conserving natural resources.
Answer:
Do it yourself.

Hydroponics Growing Plants without Soil Class 8 MCQ

Question 1.
The word ‘Hydroponics’ comes from two Greek words. What do they mean?
(a) hydro = fire, ponos = earth
(b) hydro = water, ponos = labour
(c) hydro = soil, ponos = growth
(d) hydro = light, ponos = food
Answer:
(b) hydro = water, ponos = labour

Question 2.
In which country does approximately 33% of land (around 109 million hectares) suffer from soil degradation?
(a) China
(b) Brazil
(c) India
(d) Australia
Answer:
(c) India

Question 3.
What is the role of an aquarium aerator in a DWC hydroponic system?
(a) It removes algae from water
(b) It pumps nutrients into the water
(c) It dissolves oxygen into the water
(d) It adjusts the pH of water
Answer:
(c) It dissolves oxygen into the water

Question 4.
Microgreens are harvested when they are approximately how tall?
(a) 1-2 cm
(b) 5-7 cm
(c) 15-20 cm
(d) 30 cm
Answer:
(b) 5-7 cm

Question 5.
Which material is used as a float to hold plants above water in the DWC system?
(a) PVC pipe
(b) Bamboo sheet
(c) Styrofoam/Thermocol sheet
(d) Cotton cloth
Answer:
(c) Styrofoam/Thermocol sheet

Question 6.
In the Wick hydroponic method, how does water move from the reservoir to the plant roots?
(a) By gravity
(b) By a water pump
(c) By capillary action
(d) By evaporation
Answer:
(c) By capillary action

Question 7.
What is the ideal pH range for water in a hydroponic system for best nutrient absorption?
(a) 4.0-5.0
(b) 6.0-7.0
(c) 7.5-8.5
(d) 3.0-4.0
Answer:
(b) 6.0-7.0

Question 8.
Which government mission promotes technologies like hydroponics and aeroponics in India?
(a) Mission Green India
(b) Digital India Mission
(c) Mission for Integrated Development of Horticulture
(d) National Soil Health Mission
Answer:
(c) Mission for Integrated Development of Horticulture

Question 9.
What does the colour of roots in a DWC system indicate?
(a) White roots = poor health, brown roots = healthy
(b) White roots = healthy, brown roots = lack of dissolved oxygen
(c) Brown roots = excess nutrients
(d) Colour of roots has no significance
Answer:
(b) White roots = healthy, brown roots = lack of dissolved oxygen

Question 10.
A group of students is preparing a tray of microgreens for a school gardening project. They are selecting seeds that grow quickly and can be harvested within a few weeks. One student suggests using mango seeds. Which of the following is not a suitable crop for growing as microgreens?
(a) Mustard
(b) Spinach
(c) Coriander
(d) Mango
Answer:
(d) Mango

Question 11.
In the NFT (Nutrient Film Technique) system, water flows as a
(a) Thick flood of water
(b) Thin, shallow film
(c) Mist sprayed on roots
(d) Still pool in a bucket
Answer:
(b) Thin, shallow film

Question 12.
Why is the water surface in a DWC bucket covered with a styrofoam sheet?
(a) To keep the water warm
(b) To prevent sunlight from causing algae growth
(c) To reduce water evaporation only
(d) To add nutrients to the water
Answer:
(b) To prevent sunlight from causing algae growth

Question 13.
What is the purpose of jaggery in compost tea?
(a) To sweeten the water for plants
(b) To adjust the pH
(c) To feed beneficial microbes
(d) To change the colour of compost tea
Answer:
(c) To feed beneficial microbes

Question 14.
ISRO successfully sprouted cowpea seeds in which mission, taking a step toward space gardens?
(a) Chandrayaan-3
(b) PSLV-C60 POEM-4
(c) Mangalyaan-2
(d) Gaganyaan
Answer:
(b) PSLV-C60 POEM-4

Question 15.
Riya lives in a crowded city where there is very little open land for farming. She visits a farm where vegetables are grown indoors using nutrient-rich water instead of soil. Which of the following is an example of urban farming?
(a) Wheat cultivation in a large field
(b) Growing rice in paddy fields
(c) Growing crops in cities using hydroponics
(d) Planting trees in national parks
Answer:
(c) Growing crops in cities using hydroponics

Fill in the Blanks

1. Hydroponics is a method of growing plants in a ___________ instead of soil.
Answer:
Nutrient-rich water solution

2. The process by which liquid moves upward through narrow fibres without the help of gravity is called ___________
Answer:
Capillary action

3. Microgreens are harvested after the emergence of the first ___________ (1-3 inches tall).
Answer:
2-4 true leaves

4. In the DWC system, an ___________ is used to dissolve oxygen in the water to keep plant roots healthy.
Answer:
Aquarium aerator

Question 5.
If the pH of hydroponic water is above 7.0 (alkaline), we add a weak acid like ___________ or ___________ to bring it down.
Answer:
Acetic acid (vinegar)/citric acid (lime juice)

True or False

1. Hydroponics requires large amounts of soil for growing plants.
Answer:
False

2. Brown roots in a DWC system indicate a healthy plant.
Answer:
False

3. Microgreens are a rich source of vitamins C, E, K, A and carotenoids.
Answer:
True

4. In the NFT system, an aerator is required because water remains still in the pipes.
Answer:
False

5. A pH of 7 is considered neutral on the pH scale.
Answer:
True

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