Crop Production and Management Class 8 Science Extra Questions and Answers

Crop Production and Management Class 8 Science Chapter 1 Extra Questions and Answers is provided here. We prepared these extra questions based on the latest NCERT Class 8 Science Book. CBSE Class 8 Science Chapter 1 Crop Production and Management Extra Questions will help you to properly understand a particular concept of the chapter.

Class 8 Science Chapter 1 Crop Production and Management Extra Questions

Very Short Answer Type Question

Question 1: Give few examples of weedicides.

Answer: 2, 4-D

Question 2: Name the bacteria which fix atmospheric nitrogen.

Answer: Rhizobium bacteria

Question 3: What is called weeding?

Answer: The removal of weeds is called weeding.

Question 4: Name the tool used for tilling of soil.

Answer: Tilling of soil is done by using a plough.

Question 5: How are crumbs broken?

Answer: Crumbs are broken with the help of plank.

Question 6: Write 2 natural methods of replenishing the soil with nutrients.

Answer: i. Use of manure
ii. Crop rotation

Question 7: How is levelling of soil done?

Answer: The levelling of soil is done with the help of a leveller.

Question 8: What are the two ways of sowing the seeds?

Answer: Seeds can be sown manually or by seed drills.

Question 9: How is ploughing done nowadays?

Answer: Nowadays ploughing is done by tractor driven cultivator.

Question 10: What is sowing?

Answer: Sowing is the process of planting seeds in the soil.

Question 11: Name two categories of crops based on season.

Answer: Two categories of crop based on season are kharif and rabi crops.

Question 12: What is threshing?

Answer: Separation of the grains from the chaff is called threshing.

Question 13: How are grains stored at home?

Answer: Dried neem leaves are used for storing food grains at home.

Question 14: What are called crumbs?

Answer: The ploughed field may have big pieces of soil called crumbs.

Question 15: Why is it important to level the field after ploughing?

Answer: The field is levelled for sowing as well as for irrigation purposes.

Question 16: What are good quality seeds?

Answer: Good quality seeds are clean and healthy seeds of a good variety.

Question 17: Give some examples of Rabi crop?

Answer: Examples of rabi crops are wheat, gram, pea, mustard and linseed.

Question 18: What is harvesting?

Answer: Harvesting is the cutting of the mature crop manually or by machines.

Question 19: Name the two modern methods of irrigation that help us to use water economically.

Answer: Sprinkler System and Drip system

Question 20: Why can paddy not be grown in the winter season?

Answer: Paddy requires a lot of water. Therefore, it is grown only in the rainy season.

Question 21: Why proper storage of crop products is important?

Answer: Proper storage of crop products is important to prevent them from spoilage.

Question 22: Give some examples of Kharif crop.

Ans. Examples of Kharif crops are Paddy, maize, soyabean, groundnut, cotton, etc.

Short Answer Type Questions

Question 1: What are the benefits of eating fish?

Answer: Fish is good for health. We get cod liver oil from fish which is rich in vitamin D.

Question 2: How do fertilisers help farmers?

Answer: The use of fertilisers has helped farmers to get better yield of crops such as wheat, paddy and maize.

Question 3: How are crops categorised in India?

Answer: In India, crops can be broadly categorised into two types based on seasons – rabi and kharif crops.

Question 4: How is harvesting done in India?

Answer: Harvesting in our country is either done manually by sickle or by a machine called harvester.

Question 5: What is winnowing?

Answer: After threshing, grains are separated from chaff with help of wind. This process is called winnowing.

Question 6: List some festivals that are associated with the harvest season.

Answer: Special festivals associated with the harvest season are Pongal, Baisakhi, Holi, Diwali, Nabanya and Bihu.

Question 7: What is crop rotation?

Answer: Crop rotation is a method of replenishing the soil with nutrients by growing different crops alternately.

Question 8: Why should excessive supply of water to plants be avoided?

Answer: Excessive supply of water to plants should be avoided because roots get damaged and the plants die.

Question 9: Why some seeds float on water?

Answer: Damaged seeds become hollow and are thus lighter. Therefore, they float on water.

Question 10: Why does farmer rotate crops in the field?

Answer: Farmer rotates crops in the field because crop rotation helps in the replenishment of the soil nutrients.

Question 11: What are the different sources of irrigation?

Answer: Sources of irrigation: The sources of irrigation are— wells, tube-wells, ponds, lakes, rivers, dams and canals.

Question 12: What is the right time to spray weedicides?

Answer: The weedicides are sprayed during the vegetative growth of weeds before flowering and seed formation.

Question 13: How is threshing carried out?

Answer: Threshing is carried out with the help of a machine called ‘combine’ which is in fact a combined harvester and thresher.

Question 14: What are the advantages of using manure in crop fields?

Answer: The use of manure improves soil texture as well as its water retaining capacity. It replenishes the soil with all the nutrients.

Question 15: In summer, the frequency of watering is higher. Why is it so?

Answer: In summer, the frequency of watering is higher due to the increased rate of evaporation of water from the soil and the leaves.

Question 16: Why does the loosening of soil allow the roots to breathe easily?

Answer: Loosening of soil allow the roots to breathe easily because air fill up the spaces between the soil particles and provides airy soil to the roots.

Question 17: How are grains stored in godowns?

Answer: For storing large quantities of grains in big godowns, specific chemical treatments are required to protect them from pests and microorganisms.

Question 18: Is it a good practice to burn the stubs left in the field? Give reasons.

Answer: No, it is not a good practice to burn the stubs left in the field because it causes pollution. It may also catch fire and damage the crops lying in the fields.

Question 19: How weeds are removed manually?

Answer: The manual removal includes physical removal of weeds by uprooting or cutting them close to the ground, from time to time. This is done with the help of a khurpi.

Question 20: What are the harmful effects of using fertilisers?

Answer: Harmful effects of using fertilisers

Excessive use of fertilizers has made the soil less fertile.
Fertilizers have also become a source of water pollution.

Question 21: What do you understand by agricultural practices?

Answer: Cultivation of crops involves several activities undertaken by farmers over a period of time. These activities or tasks are referred to as agricultural practices.

Question 22: What is animal husbandry?

Answer: Animals reared at home or in farms, have to be provided with proper food, shelter and care. When this is done on a large scale, it is called animal husbandry.

Long Answer Type Questions

Question 1: What precautions should be taken while spraying weedicides and why?

Answer: Spraying of weedicides may affect the health of farmers. So they should use these chemicals very carefully. They should cover their nose and mouth with a piece of cloth during spraying of these chemicals.

Question 2: Explain in detail the structure and use of hoe.

Answer: It is a simple tool which is used for removing weeds and for loosening the soil. It has a long rod of wood or iron. A strong, broad and bent plate of iron is fixed to one of its ends and works like a blade. It is pulled by animals.

Question 3: What are fertilisers? Give some examples.

Answer: Fertilisers are chemical substances which are rich in a particular nutrient. Some examples of fertilisers are— urea, ammonium sulphate, super phosphate, potash, NPK (Nitrogen, Phosphorus, Potassium).

Question 4: Why appropriate distance between the seeds is important?

Answer: An appropriate distance between the seeds is important to avoid overcrowding of plants. This allows plants to get sufficient sunlight, nutrients and water from the soil.

Question 5: Why earthworms and microbes are called friends of farmer?

Answer: The loosened soil helps in the growth of earthworms and microbes present in the soil. These organisms are friends of the farmer since they further turn and loosen the soil and add humus to it.

Question 6: What are kharif crops?

Answer: The crops which are sown in the rainy season are called kharif crops. The rainy season in India is generally from June to September. Paddy, maize, soyabean, groundnut, cotton, etc., are kharif crops.

Question 7: What are rabi crops?

Answer: The crops grown in the winter season are called rabi crops. Their time period is generally from October to March. Examples of rabi crops are wheat, gram, pea, mustard and linseed.

Question 8: Why do farmers add manure to the soil?

Answer: Continuous growing of crops makes the soil poorer in certain nutrients. Therefore, farmers have to add manure to the fields to replenish the soil with nutrients.

Question 9: What will happen if field is not ploughed before sowing the seeds?

Answer: Disadvantage of not ploughing the field are:

Seeds cannot be sown at proper depth.
Water and air holding capacity of soil will be poor.

Question 10: What is called a crop?

Answer: When plants of the same kind are grown and cultivated at one place on a large scale, it is called a crop. For example, crop of wheat means that all the plants grown in a field are that of wheat.

Question 11: What is seed drill?

Answer: This tool sows the seeds uniformly at proper distances and depths. It ensures that seeds get covered by the soil after sowing. This prevents damage caused by birds. Sowing by using a seed drill saves time and labour.

Question 12: Why traditional methods of irrigation are cheaper, but less efficient?

Answer: The water available in wells, lakes and canals is lifted up by different methods in different regions, for taking it to the fields. Cattle or human labour is used in these methods. So, these methods are cheaper, but less efficient.

Question 13: How can we separate good, healthy seeds from the damaged ones?

Answer: Take a beaker and fill half of it with water. Put a handful of wheat seeds and stir well. Wait for some time. Are there seeds which float on water? Seeds that float on water are the damaged ones. Damaged seeds become hollow and are thus lighter. Therefore, they float on water.

Question 14: What are the advantages of drip system of irrigation?

Answer: Advantages of drip system of irrigation are:

It is the best technique for watering fruit plants, gardens and trees.
The system provides water to plants drop by drop. Water is not wasted at all.
It is a boon in regions where availability of water is poor.

Question 15: How is turning and loosening of soil important for cultivation of crops?

Answer: Since only a few centimetres of the top layer of soil supports plant growth, turning and loosening of soil brings the nutrient-rich soil to the top so that plants can use these nutrients. Thus, turning and loosening of soil is very important for cultivation of crops.

Question 16: Explain how soil gets affected by the continuous plantation of crops in a field.

Answer: Continuous plantation of crops in a field makes the soil deficient in certain nutrients such as nitrogen, phosphorus, potassium, etc. These nutrients are essential for the growth of plants. As such soil does not get time to replenish the lost nutrients, the crop yield decreases automatically.

Question 17: What are the traditional methods of irrigation?

Answer: The various traditional ways are:

moat (pulley-system)
chain pump
dhekli, and
rahat (Lever system)

Question 18: Why it is necessary to remove weeds?
Or
Why is weeding necessary?

Answer: The removal of weeds is called weeding. Weeding is necessary since weeds compete with the crop plants for water, nutrients, space and light. Thus, they affect the growth of the crop. Some weeds interfere even in harvesting and may be poisonous for animals and human beings.

Question 19: What is manure and how is it prepared?
Or
How is organic manure obtained?

Answer: Manure is an organic substance obtained from the decomposition of plant or animal wastes. Farmers dump plant and animal waste in pits at open places and allow it to decompose. The decomposition is caused by some microorganisms. The decomposed matter is used as organic manure.

Question 20: Why is water essential for plant? Discuss.

Answer: Water is essential because germination of seeds does not take place under dry conditions. Nutrients dissolved in water get transported to each part of the plant. Water also protects the crop from both frost and hot air currents. To maintain the moisture of the soil for healthy crop growth, fields have to be watered regularly.

Question 21: What are the characteristics of good quality seeds?

Answer: Following are the characteristics of a good quality seed:

It should be clean.
It should be healthy and of good variety.
It should have high yield.
It should be disease resistant.

Question 22: Why is it necessary to dry the harvested food grains before storage?

Answer: The fresh crop has more moisture. If freshly harvested grains (seeds) are stored without drying, they may get spoilt or attacked by organisms, losing their germination capacity. Hence, before storing them, the grains are properly dried in the sun to reduce the moisture in them. This prevents the attack by insect pests, bacteria and fungi.

Question 23: Why drilling is the best method for sowing of seeds?
Or
Explain the method used these days to sow seeds.

Answer: Nowadays the seed drill is used for sowing with the help of tractors. Seed drill sows the seeds uniformly at proper distances and depths. It ensures that seeds get covered by the soil after sowing. This prevents damage caused by birds. Sowing by using a seed drill saves time and labour. Hence, it is considered as the best method for sowing of seeds.

Question 24: What are the advantages of sprinkler system of irrigation?

Answer: Advantages of sprinkler system of irrigation

This system is more useful on the uneven land where sufficient water is not available.
Water gets sprinkled on the crop as if it is raining.
Sprinkler is very useful for sandy soil.
Water is also distributed more evenly across crops helping to avoid wastage.

Question 25: What are the steps involved in agricultural practices?

Answer: Steps involved in agricultural practices are:

Preparation of soil
Sowing
Adding manure and fertilisers
Irrigation
Protecting from weeds
Harvesting
Storage

Question 26: Why organic manure is considered better than fertilisers?
Or
What are the advantages of organic manure?

Answer: The organic manure is considered better than fertilisers. This is because

It enhances the water holding capacity of the soil.
It makes the soil porous due to which exchange of gases becomes easy.
It increases the number of friendly microbes.
It improves the texture of the soil.

Question 27: If wheat is sown in the kharif season, what would happen? Discuss.

Answer: Wheat is a rabi crop and grown in the winter season. Their time period is generally from October to March. It needs a cool, dry, and clear climate for better growth and yield. Kharif season is generally from June to September. Kharif crops require a huge amount of water and hot weather to grow. If wheat is grown in Kharif season it will be affected adversely as hot and humid climate is not ideal for the cultivation of wheat.

Question 25: Name the three tools used for ploughing. Write function of each.

Answer: Tools used for ploughing are:

Plough: This is being used since ancient times for tilling the soil, adding fertilisers to the crop, removing the weeds, scraping of soil, etc.

Hoe: It is a simple tool that is used for removing weeds and for loosening the soil.

Cultivator: Nowadays ploughing is done by tractor driven cultivator. The use of cultivators saves labour and time.

Question 26: Explain how fertilisers are different from manure.

Answer: Difference between fertilisers and manure

Fertiliser	Manure
1. A fertiliser is an inorganic salt.	1. Manure is a natural substance obtained by the decomposition of cattle dung, human waste and plant residues.
2. A fertiliser is prepared in factories.	2. Manure can be prepared in the fields.
3. A fertiliser does not provide any humus to the soil.	3. Manure provides a lot of humus to the soil.
4. Fertilisers are very rich in plant nutrients like nitrogen, phosphorus and potassium.	4. Manure is relatively less rich in plant nutrients.

Question 27: How a plough works?

Answer: Plough is used for tilling the soil, adding fertilisers to the crop, removing the weeds, scraping of soil, etc. This implement is made of wood and is drawn by a pair of bulls or other animals (horses, camels, etc.). It contains a strong triangular iron strip called ploughshare. The main part of the plough is a long log of wood which is called a ploughshaft. There is a handle at one end of the shaft. The other end is attached to a beam which is placed on the bulls’ necks. One pair of bulls and a man can easily operate the plough.

Question 28: What are weeds? How can we control them?

Answer: In a field many other undesirable plants may grow naturally along with the crop. These undesirable plants are called weeds. Weeds can be controlled in the following ways:

Tilling before sowing of crops helps in uprooting and killing of weeds.
The manual removal of weeds by uprooting or cutting them close to the ground, from time to time. This is done with the help of a khurpi. A seed drill is also used to uproot weeds.
Weeds are also controlled by using certain chemicals, called weedicides, like 2,4-D. These are sprayed in the fields to kill the weeds.

Question 28: What is irrigation? Describe two methods of irrigation which conserve water.

Answer: The supply of water to crops at different intervals is called irrigation.

Sprinkler System: This system is more useful on the uneven land where sufficient water is not available. The perpendicular pipes, having rotating nozzles on top, are joined to the main pipeline at regular intervals. When water is allowed to flow through the main pipe under pressure with the help of a pump, it escapes from the rotating nozzles. It gets sprinkled on the crop as if it is raining. Sprinkler is very useful for sandy soil.

Drip system: In this system, the water falls drop by drop just at the position of the roots. So, it is called drip system. It is the best technique for watering fruit plants, gardens and trees. The system provides water to plants drop by drop. Water is not wasted at all.

Question 29: Why is tilling of soil important?
Or
Why is turning and loosening of soil important?
Or
Give any three advantages of ploughing.

Answer: Importance of tilling are as follows:

This allows the roots to penetrate deep into the soil. The loose soil allows the roots to breathe easily even when they go deep into the soil.
The loosened soil helps in the growth of earthworms and microbes present in the soil. They further turn and loosen the soil and add humus to it.
This brings the nutrient-rich soil to the top so that plants can use these nutrients.
Tilling before sowing of crops helps in uprooting and killing of weeds.

Question 30: Write a paragraph in your own words on each of the following.

(a) Preparation of soil (b) Sowing (c) Weeding (d) Threshing

Answer: (a) Preparation of soil

The preparation of soil is the first step before growing a crop.
One of the most important tasks in agriculture is to turn the soil and loosen it. This allows the roots to penetrate deep into the soil. The process of loosening and turning of the soil is called tilling or ploughing. This is done by using a plough.
The ploughed field may have big pieces of soil called crumbs. It is necessary to break these crumbs with a plank.
The field is levelled for sowing as well as for irrigation purposes. The levelling of soil is done with the help of a leveller.
Sometimes, manure is added to the soil before tilling. This helps in proper mixing of manure with soil. The soil is watered before sowing.

(b) Sowing

Sowing is the most important part of crop production. Before sowing, good quality seeds are selected.
The tool used traditionally for sowing seeds is shaped like a funnel. The seeds are filled into the funnel, passed down through two or three pipes having sharp ends. These ends pierce into the soil and place seeds there.
Nowadays the seed drill is used for sowing with the help of tractors. This tool sows the seeds uniformly at proper distances and depths. It ensures that seeds get covered by the soil after sowing. This prevents damage caused by birds. Sowing by using a seed drill saves time and labour.

The removal of weeds is called weeding. Weeding is necessary since weeds compete with the crop plants for water, nutrients, space and light.
Farmers adopt many ways to remove weeds and control their growth. Tilling before sowing of crops helps in uprooting and killing of weeds, which may then dry up and get mixed with the soil.
The best time for the removal of weeds is before they produce flowers and seeds.
The manual removal includes physical removal of weeds by uprooting or cutting them close to the ground, from time to time. This is done with the help of a khurpi. A seed drill is also used to uproot weeds.
Weeds are also controlled by using certain chemicals, called weedicides, like 2,4-D. These are sprayed in the fields to kill the weeds.

(d) Threshing

In the harvested crop, the grain seeds need to be separated from the chaff. This process is called threshing. This is carried out with the help of a machine called ‘combine’ which is in fact a combined harvester and thresher.

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