DAV Class 8 Science Solution Chapter 9 Crop Production and Its Management
DAV School Books Class 8 Science Solution Chapter 9 Crop Production and Its Management all Question Answer. DAV Class 8 9th Chapter Crop Production and Its Management full Chapter explanation by expert teacher.
DAV School Books Class 8 Science Solution Chapter 9 Crop Production and Its Management
A.) Fill in the blanks.
1.) ___________ results in loosening and mixing of soil.
2.) ___________ compete with crops for nutrients.
3.) ___________ bacteria, present in the root nodules of ___________ plants, help in fixing atmospheric nitrogen.
4.) Harvested grains are ___________ to reduce moisture content.
5.) Removal of anthers, from the flowers, is known as ___________.
Answer: (1) Ploughing (2) Weeds (3) Rhizobium, leguminous (4) dried (5) emasculation.
B.) Match the following.
1. sickle | a. threshing |
2. Tractor | b. storage |
3. Seed drill | c. ploughing |
4. Combine | d. harvesting |
5. Silo | e. sowing |
Answer: (1) d (2) c (3) e (4) a (5) b
C.) Tick the correct option.
1.) The practice, of growing leguminous plants between successive cereal crops, is called-
Answer: crop rotation
2.) Which among the following is a Kharif crop?
Answer: rice
3.) The organic substance, obtained from dead plants, animals and their wastes is known as-
Answer: manure
4.) The process of separating grain from chaff is known as-
Answer: winnowing
5.) Crops, which are grown during the rainy season, are known as-
Answer: kharif crops
D.) Answer the following questions in brief.
1.) Why is the use of a seed drill more advantageous as compared to sowing seeds by broadcasting?
Answer: The seed drill reduces labour costs and saves much more time as well as resources. Therefore, sowing seeds with a seed drill is preferred than broadcast sowing.
2.) Babu wants to practice crop rotation. Help him by suggesting what kind of crops can be grown between two consecutive cereal crops? Also, provide him names of one Rabi and one Kharif crop that can be used to replenish the nitrogen content of the soil.
Answer: Pulses should be grown by Babu in between two successive cereal crops. Kharif and Rabi crops such as groundnut or pea can be sown so that the rhizobium bacteria from the plant’s nodules can help in nitrogen fixation.
3.) If rice is sown in the month of November, how is the produce likely to be impacted? And why?
Answer: Rice will not receive enough temperature, sunlight, or water if it is sown in November because light winter prevails during this time and rainfall is almost absent and less in winters. Low rice crop productivity will be the ultimate result.
4.) What are crumbs? Why should they be broken?
Answer: In ploughed fields chunks of soil particles are found these are known as crumbs.They should be immediately ground into finer particles since they restrict the airflow into the soil.
5.) Define the term ‘transplantation’? List any two advantages it offers to the farmer.
Answer: It Is a process by means of which a small piece of land known as nursery the seeds are soon and upon germination ceilings are planted in the field this is known as transplantation
The major advantages of transplantation are that it helps in planting crops that are disease free and it make sure that each plants gets enough of resources such as water and sunlight and can grow properly
E.) Answer the following questions.
1.) State the advantages of ploughing the soil. State the different ways through which it is done.
Answer: Ploughing helps the soil to get more air and helps the plants to get sufficient air as well as the roots it also increases the water retention capacity of the soil and removes weeds from the field and keep sit microorganisms free usually wooden and iron clouds are used that are pulled by OX or a tractor in order to plough the field.
2.) Both manures and fertilisers replenish soil fertility. Compare and contrast the advantages and disadvatages of using them.
Answer: Manures are used to increase the soils capacity to hold water however the soil becomes infected by more microorganisms that are harmful for it it has an advantage that it is very cheap other than that that can be transported easily and shows quick action manures when compared to other fertilizers give the plant lesser nutrients fertilizers are expensive and over use of them may lead to chemical poisoning of the plants
3.) Explain how weeds are harmful for plants. State the different ways of weed removal practiced by farmers.
Answer: Weeds are unnecessary plants growing around the crops in a field they should be immediately removed because they take away all the nutrients that are intended for the crops. farmers use different processes such as manual removal techniques by using any sharp instrument to approve the unwanted weed. Other than this farmers also use weedicides that only kill such weeds but do not affect the crops.
4.) Give reasons for the following:
(a) Excess water supply can damage crops.
Answer: Excess water can cause problems such as water logging and fill up the spaces feel by a and thereby stop a circulation within the soil this will affect the plant as well as its root and eventually kill it
(b) Grains are not stored without sun-drying.
Answer: Food grains usually contain moisture in them hence they might result in microbial growth that might destroy it as a result they are Sun Dried in order to dry them and make them free from moisture.
(c) Overuse of pesticides should be avoided.
Answer: Over use of pesticide should be avoided because pesticides in a certain proportion can cause harm to the plants also frequent use of pesticide can also decrease the fertility of the soil
5.) Bhola’s field is ready with a mature wheat crop. List and explain the steps he would have to undertake before selling the grains to the FCI (Food Corporation of India).
Answer: At first Bhola will have to harvest the crops until their fully ready for for selling .the next step has to be threshing which means that the grain is separated from the crop. it can either be done by devices or by bhola him self. After threshing the grains should be winnowed , next it needs to be stored in a dry place to keep it free from microbes. They are then stored in silos to keep it away from being eaten and destroyed by pests.
6.) Define hybridisation. List the steps to be followed for obtaining seeds of a hybrid variety.
Answer:To obtain seeds of a hybrid variety, the steps listed below must be taken:
Step 1: Selecting two plant varieties with the desired characteristics, such as 1 and 2.
The second step would require taking the anthers off of plant 1. This process is known as emasculation.
Step 3: Plant 1 stigmas are coated with pollen from the anthers of plant 2.
Step 4 : The plant 1’s stigmas are then covered with paper bags in step four.
Step 5: By such cross-breeding of two desired varieties, hybrid seeds can be produced.