Chapter 9 | Crop Production and Its Management | Class- 8 DAV Science Solutions

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DAV Class- 8 Science Crop Production and Its Management Question and Answer

Something To Know

A. Fill in the blanks.

1. Ploughing results in loosening and mixing of soil.

2. Weeds compete with crops for nutrients.

3. Rhizobium bacteria, present in the root nodules of leguminous plants, help in fixing atmospheric nitrogen.

4. Harvested grains are dried to reduce moisture content.

5. Removal of anthers, from the flowers, is known as emasculation .

B. Match the following.

Ans:

Column IColumn II
(1) Sickle(d) Harvesting
(2) Tractor(c) Ploughing
(3) Seed drill(e) Sowing
(4) Combine(a) Threshing
(5) Silo(b) Storage

C. Tick (✓) the correct option.

C. Tick the correct option:

1. The practice of growing leguminous plants between successive cereal crops is called—

Agriculture Crop rotation Cultivation Transplantation

Ans. Crop rotation

2. Which among the following is a Kharif crop?

A. Wheat B. Gram C. Barley D. Rice

Ans. Rice

3. The organic substance obtained from dead plants, animals and their wastes is known as—

A.Manure B.Crumb C.Fertilizer D.Chaff

Ans. Manure

4. The process of separating grain from chaff is known as—

A.Threshing B.Weeding C.Tilling D.Winnowing

Ans. Threshing

5. Crops, which are grown during the rainy season, are known as—

A.Rabi crops B. Leguminous crops C.Kharif crops D. Cereal crops

Ans. 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?

Ans. Seed drill helps in saving time and labour. Hence, seed drill is more advantageous than sowing seeds by broadcasting.

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.

Ans. Babu should grow pulses between two consecutive cereal crops.Pea (Rabi) and Groundnut (Kharif) crops can be used to replenish the nitrogen content of the soil.

3. If rice is sown in the month of November, how is the produce likely to be impacted? And why?

Ans. If rice is sown in the month of November, then it will not get adequate temperature, sunshine, and water. This will result in low productivity of rice crop.

4. What are crumbs? Why should they be broken?

Ans: Crumbs are small lumps of soil in a field after ploughing. They need to be broken down so that the soil becomes more airy and seeds can easily enter and germinate through the soil.

5. Define the term ‘transplantation’? List any two advantages it offers to the farmer.

Ans: Planting seedlings on different plot of land is called transplantation. This method is used for paddy.

Two advantages transplantation offers to the farmer are:

It helps farmers to select only the healthy plants for farming.

This also helps in maintaining adequate gap between consecutive plants so that the plants get proper amount of sunshine and other resources.

E. Answer the following questions.

1.State the advantages of ploughing the soil and also state the different ways through which it is done.

Ans. The advantages of ploughing the soil are:

  • It improves air circulation in soil.
  • Roots can penetrate deeper into the soil. Thus, plant can have better anchorage in soil.
  • It increases water retaining capacity of soil.
  • It helps in removing weeds.
  • It helps in growth of microbes in soil that is beneficial for farming.

2.Different Methods of Ploughing are: By cattle driven plough, and by tractor drawn cultivator. Both manures and fertilizers replenish soil fertility. Compare and contrast the advantages and disadvantages of using them.

Ans.

ManureFertilizer
Slow to act.Fast to act.
It does not help in providing specific nutrients to plants.It helps in providing specific nutrients to plants.
Improves soil composition.It degrades soil composition.
It has a positive impact on ecosystem.It may be harmful for ecosystem.

3. Explain how weeds are harmful for plants. State the different ways of weed removal practiced by farmers.

Ans. Weeds compete with plants for various resources like sunlight, air, temperature, water, nutrients, etc. Thus, weeds hamper the growth of crops. Some weeds are poisonous and can prove lethal for cattle and humans. Weeds are removed manually by sickle. Weedicides are also sprayed to get rid of weeds.

4. Give reasons for the following:

(a) Excess water supply can damage crops.

Ans. Excess water supply results in waterlogging in the field which obstructs air-supply to the roots thus damage the crops.

(b) Grains are not stored without sun-drying.

Ans. Grains contain moisture which promotes growth of microbes and pests. Sun-drying helps in removing excess moisture from grain. It helps in preventing the growth of microbes and pest during storage. Hence, grains are not stored without sundrying.

(c) Overuse of pesticides should be avoided.

Ans. Overuse of pesticides should be avoided because: • Pesticides are poisonous and can harm cattle and humans.

• Pesticides may destroy some useful insects and animals which help in pollination.

• Too much of pesticide goes to groundwater and contaminates it.

• Harmful chemicals from pesticides end up in food chain which is harmful for animals and humans.

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).

Ans. Bhola will take following steps before selling the grains: Harvesting: Cutting and gathering of mature crops is called harvesting. Vegetables and fruits are plucked by hand. Cereals and other crops are harvested by sickle. Threshing: Separating the grains from husk is called threshing. Small amount of harvest is threshed manually. Threshing machine is used for large amounts. Sometimes, combine harvester is used which does harvesting and threshing simultaneously. Storage: Grains are dried in sun to remove moisture. After that, grains are stored in silos. Perishable items like fruits and vegetables are sent to cold storage.

6. Define hybridization. List the steps to be followed for obtaining seeds of a hybrid variety.

Ans. Cross breeding between two varieties of an organism is called hybridization.

Steps for obtaining seeds of a hybrid variety are as follows:

• Two varieties of plants of desired characteristics are chosen, say A and B.

• Anthers from plant A are removed. This process is called emasculation.

• Anthers from plant B are taken and its pollen are dusted on stigmas of plant A. • After that, stigmas of plant A are covered with plastic bags. This process is called bagging.

VALUE BASED QUESTIONS

The biology teacher was quick to observe the careless and time-wasting attitude of some of her students. She explained to them the need and importance of proper management of time and all other resources in our life. She then told them about the steps that are taken to properly manage the crops after they have ‘grown up’. The students realized the importance of her advice through this interesting comparison.

1. State the values conveyed by the Biology teacher to her students. Ans. Importance of time management

2. Name the steps taken to manage the crops after they have ‘grown up’. Ans. Irrigation, Weeding, Harvesting, Storage

3. Let the students organise a ‘play’, highlighting the importance of proper management of time/our resources, in our life. Ans. Do it yourself

SOMETHING TO DO

1. Visit a field, or a park and collect (using protective gloves) around five types of weeds.

Ans. Do it yourself

2.Make a list of Kharif and Rabi crops which are grown in your area. Find out if there are any silos in your city.

Ans. Do it yourself

3. Frogs play an important role in the biological control of insects in the agricultural fields. The decrease in population of frogs results in the increase of the population of insects. Try to find out the role of lizards, owls and bats in the biological control of pests.

Ans. Lizards, owls and bats also feed on insects. Thus, these animals help in getting rid of many pests.

4. Find out about ‘Organic Farming’. Learn about the activities involved, and the characteristics of plants grown, in ‘organic farming’.

Ans. Farming without the use of synthetic fertilizers and synthetic pesticides/weedicides is called organic farming. Organic farming involves using manure, biological pest control and biological methods of weed control. The produce of organic farming is free of toxic materials. Organic farming is a sustainable method of farming.

5. Visit a nearby farm and observe the various agricultural practices being carried out there. Find out the names and uses of the various machines that are used on the farm.

Ans. Do it yourself

6. Try to find out the ‘changes that have come about’ between ‘modern’ and ‘traditional’ farming practices. Ans. Do it yourself ADDITIONAL

Ans. Do it yourself

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