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Class 8th-Science: Chapter 1-Crop Production and Management Ncert

Q1.   Select the correct word from the following list and fill in the blanks.

(a)   The same kind of plants grown and cultivated on a large scale at a place is called ________.

(b)   The first step before growing crops is ________ of the soil.

(c)   Damaged seeds would ________ on top of water.

(d)   For growing a crop. suffcient sunlight and _________ and ________ from the soil are essentila.

Ans. (a) Crop  (b)  preparation  (c)  float  (d)  water ,nutrients

Q2.   Match items in column A with those in column B.

                              A                                B
(i)  Kharif crops(a)  Food for cattle
(ii)  Rabi crops(b)  Urea and super phosphate 
(iii)  Chemical fertilisers(c)  Animal excreta. cow dung urine and plant waste
(iv)  Organic manure(d)  Wheat, gram, pea
(e)  Paddy and malze

Ans.  (i)(e), (ii)(d), (iii)(b), (iv)(c)

Q3.   Give two examples of each.

    (a) Kharif crop

    (b) Rabi crop

Ans.   (a)  Two examples of kharif crops are (i) Padddy (ii) Maize

           (b)   Two example of Rabi crops are (i) Wheat (ii) Gram

Q4.   Write a paragraph in your own words on each of the following.

    (a)  Preparation of soil

    (b)  Sowing

    (c)  Weeding

    (d)  Threshing

Ans.   (a)  It is the first step of growing crops in, this generally soil is turned and loosened.

    Activities that prepare soil are ploughing, watering and sometime manure is also added.

          (b)  Sowing is the process of planting seeds on prepared soil.

               for food production of crop it is necessary to have seeds of good quality because they are more immune to diseases and can produce healthy plants, so selection of seeds becomes important in sowing.

         (c)   Weeds are the unwanted plants that grow along with the crop.

   The removal of weeds is called weeding.

   We remove weeds because they compete with the crop plants for water, nutrients, space, sunlight etc. thus they affect the growth of crop, even some weeds may be poisonous for animals and humans.

 (d)  The process of separating seeds from the chaff is called threshing, it can done either by manual or with the help of machine.

Q5.   Explain how fertilisers are different from manure.

Ans.

        Fertilisers Manure 
(i)  Fertilisers are the chemicals which are rich in aparticular nutrient.(i)  Manure is an organic substance obtained from the decomposition of plant or animal waste.
(ii)  Fertilisers are prepared in factories.(ii) Can be prepared in fields.
(iii)  Do not provide humus.(iii)  Provide humus.
(iv)  Very rich in nutrients.(iv)  Relatively less rich in nutrients. 
(v)  Example are urea, ammonium sulphate etc.(v)  Example cow dung.

 Q6.   What is irrigation? Describe two mettods of irrigation which conserve water.

Ans.   The supply of water to crops at regular intervals is called irrigation.

Two mwthods of irrigation which conserve water are

(i)  Sprinkler method:  In this method of irrigation perpendicular pipes with rotating nozzles on top are joined to main pipeline at regular interval, when water comes out from rotating nozzles it gets sprinkled on crop as if it is raining.

(ii)   Drip irrigation:  Inthis system water falls drop by drop directly near the roots, thats why it is called drop irrigation.

Q7.   If wheat is sown in the Kharif season. what would happen? Discuss.

Ans.   We know wheat is a Rabi crop and it requires cold climate to grow, so if it is sown in Kharif season then complete crop would be destroyed due to unsuitable conditions.

Q8.   Explain how soil gets affected hy the continuous plantation of crops in a field.

Ans.   We know soil provide nutrients to crop so continuous plantation of same crop in a field makes soil poorer in certain nutrients, so soil can become infertile after sometime.

Q9.   What are weeda? How can we control them?

Ans.   Weeds are the unwanted plants that grow along with the crop.

We can control them

(i)   By using weedicides: weedicides are chemicals that can kill the weeds without klling crop plant.

(ii)   By removing them: The removal of weeds is called weeding.

Q10.   Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.

Sending crop to sugar factory, Irrigation, Harvesting, Sowing, Preparation of soil, Ploughing the field,Manuring

Ans.   Preparation of soil —-> Ploughing the field —> Sowing —> Manuring —> Irrigation —> Harvesting —> Sending crop to sugar factory

Q11.  Complete the following word puzzle with the help of clues given below.

Down

1. Providing water to the crops.

2. Keeping crop grains for a long time nuder proper conditions.

5. Certain plants of the same kind grown on a large scale.

Across

3. A machine used for cutting the matured crop.

4. A rabi crop that is also one of the pulses.

6. A process of separating the grain from chaff.

Ans.   1. Irrigation

          2. Storage

          3. Harvester

          4. Gram

          5. Crop

          6. Winnowing

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