RBSE Class 8 Science Important Questions Chapter 1 Crop Production and Management

Rajasthan Board RBSE Class 8 Science Important Questions Chapter 1 Crop Production and Management Important Questions and Answers.

RBSE Class 8 Science Chapter 1 Important Questions Crop Production and Management

Objective Questions

Question 1.    
Usually mixed to maintain the nutrient level in the soil -
(a) Seed    
(b) Manure
(c) Insecticide    
(d) Water
Answer:
(b) Manure

Question 2.    
The amount of element which increases in the soil from the crop of leguminous plant is -
(a) Potash    
(b) Nitrogen
(c) Phosphorus    
(d) Ammonia
Answer:
(b) Nitrogen

Question 3.    
In the following which is not the traditional method of irrigation -
(a) Chain pump    
(b) Dhekli
(c) Drip system    
(d) Rahat
Answer:
(c) Drip system    

Question 4.    
Harvester machine is used -
(a) In cutting of crop
(b) Separation of crop grain from the chaff
(c) In removing weeds
(d) In sowing of seeds
Answer:
(a) In cutting of crop

Question 5.    
The supply of water in the field at different intervals is called -
(a) Irrigation    
(b) Threshing
(c) Weeding    
(d) Winnowing
Answer:
(a) Irrigation

Fill in the blanks
1. Earthworm and microbs turn and loosen the soil and add .................. to it.
Answer:
Humus 

2. The process of loosening and turning of the soil is called .................. 
 Answer:
Ploughing 

3. .................. provides the mineral matters to crop.
 Answer:
Soil 

4. Removal of weeds is called ..................    
Answer:
Weeding.

True/False
Mark true (T) or false (F) on the under - mentioned statements:
1.  The crops grown in the winter season are called kharif crops.
Answer:
False

2.  For good yield, before sowing it is necessary to loose the soil.
Answer:
True

3.  Soil texture is improved by fertilizers.
Answer:
False

4.  Removal of weeds is known as cutting.
Answer:
False

5.  Separation of grains from the chaff is known as threshing.
Answer:
True

6.  Fertiliser is an organic salt.
Answer:
False 

Match the words given in 'Column - A' with 'Column - B'

Question 1.

Column-A	Column-B
(i) Cultivator	(a) Cutting
(ii) Seed drill	(b) Irrigation
(iii) Rahat	(c) Sowing
(iv) Harvester	(d) Ploughing

Answer:

Column-A	Column-B
(i) Cultivator	(d) Ploughing
(ii) Seed drill	(c) Sowing
(iii) Rahat	(b) Irrigation
(iv) Harvester	(a) Cutting

Question 2.

Column-A	Column-B
(i) Threshing	(a) Loosening of soil
(ii) Weeding	(b) Removing weeds
(iii) Irrigation	(c) Watering in field
(iv) Tilling	(d) Grain seed separated from the chaff

Answer:

Column-A	Column-B
(i) Threshing	(d) Grain seed separated from the chaff
(ii) Weeding	(b) Removing weeds
(iii) Irrigation	(c) Watering in field
(iv) Tilling	(a) Loosening of soil

Question 3.

Column-A	Column-B
(i) Nitrogen	(a) Nutrients
(ii) Urea	(b) Manure
(iii) Vermi compost	(c) Weedicide
(iv) 2,4-D	(d) Fertilizer

Answer:

Column-A	Column-B
(i) Nitrogen	(a) Nutrients
(ii) Urea	(d) Fertilizer
(iii) Vermi compost	(b) Manure
(iv) 2,4-D	(c) Weedicide

Very Short Answer Type Questions

Question 1. 
What is meant by NPK ?
Answer:
NPK is a mixed fertilizer. It consists of Nitrogen, Phosphorus and Potassium, all the three nutrient elements.

Question 2. 
Write the name of a method which replenishes the nutrients in the soil.
Answer:
Crop rotation.

Question 3. 
Write the name of bacteria which is found in nodules of the roots of leguminous plants. 
Answer:
Rhizobium bacteria.

Question 4. 
Write the name of traditional methods used in irrigation.
Answer:

1. Moat (pulley - system) 
2. Chain pump
3. Dhekli 
4. Rahat (lever system).

Question 5. 
What do we get from cod liver oil obtained from fish?
Answer:
Vitamin 'D'.

Question 6. 
What is the best time for spraying of weedicides?
Answer:
The best time for the spraying of weedicides is before they produce flowers and seeds.

Question 7. 
What do you mean by winnowing? 
Answer:
Grains are separated from chaff is called winnowing.

Question 8. 
Where seeds are stored on a large scale? 
Answer:
In silos and granaries.

Question 9. 
Write the names of two crops which are harvested on the festival of Holi.
Answer:
Wheat and Gram crops are harvested on the festival of Holi.

Question 10. 
Write the names of any two festivals which come at harvesting season.
Answer:

• Diwali 
• Holi.

Short Answer Type Questions

Question 1. 
Write two methods each of traditional and modern method of irrigation.
Answer:
Two methods of traditional irrigation:

• Moat (pulley - system) 
• Chain pump.

Two methods of modem irrigation:

• Sprinkler system 
• Drip system.

Question 2. 
How many categories are of the crops? Explain.
Answer:
Usually crops may be divided in two categories:

1. Kharif crops:
These crops are sown in the rainy season, generally from June to September. Paddy, maize, soyabean, ground nut, cotton, etc. are kharif crops.

2. Rabi crops:
These crops are grown in the winter season. Examples of rabi crops are wheat, gram, pea, mustard and linseed etc.

Question 3. 
What is soil? Why is it essential for plants?
Answer:
The top layer of the earth in which plants grow is called soil. The functions of soil in agriculture are as under:

1. Soil provides essential nutritive elements for plant growth.
2. Soil provides water for growing plants.
3. Soil also provides oxygen by aeration to the plant roots.
4. Soil fixes the roots of the plant so that the crop plants rcitiain standing.

Question 4. 
How are the seeds of crop selected? 
Answer:
Before sowing, good quality of seeds are to be selected. To select the seeds, take them in a vessel and pour some water. After some time' damaged seeds being hollow and lighter float on top. This is a good method for separating good, healthy seeds from the damaged one. Good quality of seeds increase high yield and better qualitative crop.

Question 5. 
What are fertilisers? What are the different types of fertiliser? What are the advantages of them?
Answer:
Fertilisers:
These are chemical substances which are rich in nutrients. They are produced in factories. Fertilisers are usually of following types:

1. Urea 
2. Ammonium sulphate 
3. Super phosphate 
4. Potash and
5. NPK (Nitrogen, Phosphorus, Potassium). 

Advantage:
The use of fertilisers has helped us get better yield of crops such as wheat, paddy and maize.

Question 6. 
What are the disadvantages of excessive use of fertilisers?
Answer:
Disadvantages of excessive use of fertiliser:

1. It makes the soil less fertile.
2. It also produces water pollution.
3. It does not provide humus to the soil.

Question 7. 
What is manure? What is the advantage of it?
Or
Why is organic manure better than fertilizers? Write any three reasons.
Answer:
Manure:
It is a natural substance obtained by the decomposition of cattle dung, human waste and plant residues.
Advantages of Manure:
The organic manure is considered better than fertiliser. This is because

1. it enhances the water holding capacity of the soil.
2. it makes the soil porous due to which exchange of gases become easy.
3. it increases die number of friendly microbes.
4. it improves the texture of the soil.

Question 8. 
What is crop rotation? Explain.
Answer:
Crop rotation:
In this process after one crop the other variety of crop is grown alternately. For example, a former used to grow legume in one season and wheat in the next season. By this, deficiency of nitrogen does not develop. This helps in the replenishment of the soil with nutrients.

Question 9. 
Why is water essential to the plants? Explain.
Answer:
Significance of water to the plants:
Water is very significant for plants. Plant contains nearly 90% of water. The importance of water in plants is explained as follows:

1. Water is important for proper growth and development of flowers, fruits and seed of plants.
2. Water is absorbed by the plant by roots. Along with water, minerals and fertilisers are also absorbed.
3. Germination of seeds does not take place under dry conditions, germination is only possible in water medium.
4. In plants, transportation of nutrients takes place by water.
5. Water protects the crop from both frost and hot air currents.
6. So, for good crops we should regularly water to the plants.

Question 10. 
Which is the more useful method of irrigation in uneven land? Describe this method.
Answer:
More useful method of irrigation on uneven land is the sprinkler system.
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 it is raining.

Question 11. 
What do you mean by harvesting? Which type of equipments (tools) are used for this?
Answer:
The cutting of crop after it is mature is called harvesting. In harvesting, crops are pulled out or cut close to the ground.
The apparatus used for harvesting are - sickle and harvester. Even today in our country most of the cutting of crop is done by sickle. Now a days, formers are using the harvester machine. 

Question 12. 
What will happen if 'Rhizobium' is removed from the root nodules of the leguminous plants?
Answer:
Rhizobium bacteria fix the atomospheric nitrogen in the nodules. If they are removed than there will be deficiency of nitrogen element in the plants and will also retard plant growth.

Essay Type Questions

Question 1. 
How are agricultural products stored? 
Answer:
Storage of crop:
Crop grains are to be kept for longer time, they should be safe from moisture, insects, rats and micro organisms. Before storing the grains (seeds) are properly dried in the sun to reduce the moisture from them. This prevents the attack by insect pests, bacteria and fungi. Farmers store the agricultural products in jute bags or in laige metallic bins.

However, large scale storage of grains is done in silos and granaries to protect them from pests like rats and insects. Dried neem leaves are used for storing food grains at home. For storing large quantities of grains in big godowns, specific chemical treatments is done to protect them from pests and microorganisms.

Question 2. 
Describe the following tools used in agriculture work:
(i) Plough 
(ii) Hoe
(iii) Cultivator.
Answer:
(i) Plough:
Plough is an important tool used in agriculture work. Plough is used for tilling the land, adding manure/fertilisers to the crop, removing the weeds and scraping of soil etc. This instrument is made of wood and is drawn by a pair of bulls or horse, camel 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 ploghshaft. 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.

(ii) Hoe:
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.

(iii) Cultivator:
Cultivator is the modem tool of tilling. Nowadays ploughing is done by tractor driven cultivator. The use of cultivator saves labour and time.