Crop Production Incredible science class 8 answer

Ch01 Crop Production and management Incredible science

A. Choose the correct option.

1.Which of the following machines is used for harvesting and threshing?

a. Harvestor  b. Cultivator c. Sickle  d. Combine

2.Field fallow is done

a. in the summer season only

b. so that farmers can grow other crops in the same field

c. to replenish the lost nutrients in the soil by natural means

d. to kill weeds

3. Which of the following is a cash crop?

a. Banana   b. Cereals   c. Pepper  d. Pulses

4. Apiculture is the rearing of

a. honey bees  b. freshwater fish   c. marine fish   d. fowls

5, Which of the following is a modern method of irrigation?

a. Moat  b. Rahat  e. Drip irrigation d. Dhekli

Ans: A. 1. d    2. c      3. c       4. a          5. c

B. Fill in the blanks using the words given in the box.

1. Loosening and turning of soil is known as ---------

2. ----- and ------- are examples of insecticides.

3. The process of removing unwanted plants from the field is called --------

4. Legumes have a bacteria called ------- their root nodules.

5. Milk producing animals are also known as ----- animals.

Ans: B. 1. ploughing 2. malathion, dimecron 3. weeding 4. Rhizobium 5. milch

C. State whether the following statements are true or false. Correct the false statement.

1. Manures add specific nutrients to the soil.

2. Cutting and gathering of crops is called harvesting

3. Cold storage is used to store vegetables and fruits.

4. Seed drill is a traditional device used for sowing seeds.

5. Fish farming on a large scale is known as pisciculture.

Ans: C. 1. False. Fertilizers add specific nutrients to the soil.

2. True

3. True

4. False. Seed drill is modern tool used for sowing seeds.

5. True

D. Give reasons for each of the following.

1. Drip irrigation system is the best technique to water fruit plants and vegetables.

2. Seeds should be sown at appropriate distances and at proper depths.

3. Weeds should be removed from plants.

4. Granaries should be fumigated before storing grains.

5. Grains should be dried before storage.

Ans: 1. It is the best technique to water fruit plants and vegetables as water is allowed to fall drop by drop only at the roots of the plants, thus avoiding wastage of water.

2. Seeds should be sown at proper depths and distances so that they get sufficient amounts of sunlight, nutrients and water and grow into healthy high-yielding plants.

3. Weeds should be removed as they compete with the crop plants for nutrients, water, sunlight and space. They reduce the yield of the crop plants. They grow very quickly and may be toxic for animals and human beings. They may also spread pests and diseases to the main crop.

4. The granaries should be fumigated to improve storage and avoid loss of grains due to pests, insects and rats.

5. The grains should be dried in the sun to avoid destruction and loss of grains by insects and pests.

E. Answer the following questions in one word or a sentence.

1. Define winnowing.

2. Why is levelling done?

3. What is green manure?

4. How is the cultivator useful for a farmer?

5. What is the advantage of transplantation?

Ans: 1. The process of separating the grain from the chaff is called winnowing.

2. Levelling is done to break the big lumps of soil and make the field even before sowing the seeds.

3. Crops such as legumes are cultivated on the land and then ploughed back into the soil. This is called green manure.

4. A cultivator is a modern farm implement that has many metallic blades and is attached to the tractor. It is used to plough the field. It saves time and is easy to operate.

5. Transplantation enables the farmer to select healthy saplings and plant them at correct distances.

F. Answer the following questions in brief.

1. What is broadcasting?

2. How does field fallow improve soil fertility?

3. What would happen if pesticides are used indiscriminately by farmers?

4. Name the tools used in the preparation of soil.

5. What are weeds? Give two examples.

Ans: F. 1. Broadcasting involves the scattering of seeds all over the field by hand. It is not efficient as it can neither ensure proper spacing between the seeds nor the correct depth.

2. Field fallow is a method where the land is left uncultivated for one or more seasons. The microorganisms in the soil, such as bacteria, decompose the dead and decaying organic matter, and add humus to the soil. It is a natural method to recover the lost nutrients.

3. pesticides can easily pollute the soil and water bodies and gradually enter into our body through the food chain. It can cause various health related issues.

4. Plough, hoe, cultivator and leveller are some tools used for preparation of the soil.

5. Weeds are the undesirable plants that grow along with the main crop plants in the field. These weeds share nutrients, water, sunlight and space with main crops. They reduce the yield of the crop plants.

Grass, amaranthus and wild oats are some common weeds.

G. Answer the following questions in detail.

1. Differentiate between:

a. Manures and fertilizers

ans. Manures are natural substances obtained by decomposition of vegetable and animal waste by the action of microorganisms.

Fertilizers are chemical substances commercially produced in factories. They add specific nutrients to the soil to replace the lost minerals

b. Pesticides and weedicides

Ans:  Pesticides are chemicals that kill only the pests and do not harm the crop plants.

Weedicides are chemicals that kill only the weeds and do not affect the crop plants.

c. Winnowing and threshing

Ans: The process of separating the grains from the stalk is known as threshing. This can be done manually by beating the harvested crops on a hard surface.

The process of separating the grain from the chaff is known as winnowing.

This can be done manually by dropping grain from height.

2.Explain the various ways to control pests in a farm.

Ans: Various ways to control pests in a farm:

• The diseased crops can be burned in field

• Deep ploughing can kill the eggs of various insects and pests.

• Sowing disease-resistant variety of seeds

• Pesticides can be sprayed on the plants.

3. Write the advantages of ploughing.

Ans: Some advantages of ploughing:

• ploughing loosen soil and allows the roots to penetrate and breathe deeper into the soil.

• ploughing helps in bringing the nutrient-rich soil to the top and in mixing the fertilizers properly so that the plants can absorb these nutrients more easily.

• It helps to retain moisture for a longer period.

• It helps to remove unwanted plants and destroys the eggs of insects or pests that can damage the crop in the future.

4. Explain how crop rotation improves soil fertility.

Ans: The practice of growing different crops alternately on the same piece of land is called crop rotation.

For example, legumes are grown between two cereal crops in crop rotation. Cereal crops use up a lot of nutrients where Leguminous plants can fix atmospheric nitrogen into usable nitrates in the soil, thus improving the soil fertility

5.Explain two methods by which farmers can avoid wastage of water in their fields.

Ans Farmers should follow the given methods to avoid wastage of water.

Sprinkler irrigation system: In this system, a main pipe is linked to a network of smaller pipes. Rotating nozzle are attached on their tops. Water flows like rain and save wastage of water. It is more useful on uneven dry lands where there is insufficient water supply

Drip irrigation system:  In this method, water is allowed to fall drop by drop only at the roots of the fruits and vegetables plants. This method is excellent for regions with severe scarcity of water. : It is the best technique to water fruit plants and vegetables.

H. Out of the box!

1. Why do people prefer organically grown fruits and vegetables?

2. Arjun's mother told him to wash apple and grapes thoroughly with water before eating them as they were brought from a wholesale market. Why?

3. Why can't paddy be grown in the winter season?

4. Why are earthworms called farmer's friend?

Ans: H. 1. Organic farming is the agricultural practice that includes growing crops using environmentally safe pesticides, weedicides and fertilizers. Fruits and vegetables grown organically are chemical-free and are safe for human beings.

2. Fruits bought from the wholesale market must be thoroughly washed with water as they can contain chemicals such as pesticides, dust and dirt on the surface, which can cause harm to the body.

3. Paddy (rice) is a kharif crop and grows well in places when there is plenty of water. So, it cannot grow well in winter season.

4. Earthworm is known as farmer’s friend as it makes the soil porous by turning the soil. This increases the water holding capacity of the soil. The earthworm also converts the biodegradable waste into manure.

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