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Crop Production And Management

Class 8th Science CBSE Solution

Exercises
Question 1.

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

float, water, crop, nutrients, preparation

(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, sufficient sunlight and________________ and ________________ from the soil are essential.


Answer:

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

Same kind of plants grown in fields on large scale to obtain cereals, pulses fruits and vegetables.

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

⇒Soil provides with minerals, water, air and anchorage to plants and needs to be prepared for crop production by ploughing, levelling and manuring.


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

⇒ Damaged seeds are those seeds which are eaten by yeast hence they become hollow and float in water


(d) For growing a crop, sufficient sunlight and water and nutrients from the soil are essential

⇒ Water and Nutrients from soil are essential as crops are grown in soil and the crops take up nutrients from them


Question 2.

Match items in column A with those in column B.



Answer:



Question 3.

Give two examples of each.

(a) Kharif crop

(b) Rabi crop


Answer:

(a) Kharif crops are those which are grown in rainy season. For example – Cotton, groundnut.

(b) Rabi crops are those which are grown in winter season. For example – Wheat, mustard.



Question 4.

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

(a) Preparation of soil

(b) Sowing

(c) Weeding

(d) Threshing


Answer:

(a) The Preparation of soil is the very first step before growing any crop. It consists of many methods such as turning and breaking the soil so, the roots of the crops are able to breathe it helps in the growth of microbes, earthworms etc, in the soil which provides essential nutrients to the soil. These methods are done using a plough, hoe and cultivators.


(b) Sowing is the most important step in crop production. It is the process of putting the seeds into the soil for growing crops. It can be easily done by a Seed Drill as it saves time and labour. The picture shows seed drilling using a tractor.



(c) Weeds are the unwanted plants that grow along with the crops, which compete with the crops for sunlight, nutrients and water. So, the process of removing these unwanted is called weeding. There are many ways to control adopted the growth of weeds, such as turning of the soil before sowing of crops, physical removal of weeds by uprooting or cutting them close to the ground, using certain chemicals called weedicides etc.


(d) Threshing is the process of separating grains or seeds from chaff. Chaff is the undesirable thing other than the seed or grain. It is done after harvesting the crop. It is usually carried out with the help of a machine known as 'Combine'. This machine is a combined harvester and thresher.


Question 5.

Explain how fertilizers are different from manure.


Answer:

The difference between fertilizers and manure is shown below in the following 4 points:


Question 6.

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


Answer:

Irrigation is a process in which water is given to crops at different time intervals.The sources of irrigation can be lakes, underground reservoirs, rivers, dams, ponds, canals and wells.

There are two methods of irrigation which conserve water:


(i) Sprinkler System: Under this method, 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. This system is more useful on uneven land, having fewer water supplies


(ii) Drip system: In this system, the water falls drop by drop just at the position of the roots. It is the best technique for watering fruit plants, gardens and trees. Water is not wasted at all. It is a boon in regions where availability of water is poor.


Question 7.

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


Answer:

Wheat is a Rabi crop, hence it requires cold climatic conditions to be grown properly. If it is sown in the Kharif season (June- October), it will not grow or may get destroyed due to excessive rains in the Kharif season because of many factors such as lack of optimum temperature, adaptability, availability of pests, etc.The Wheat crop wouldn't be able to tolerate the amount of water hence would not grow


Question 8.

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


Answer:

Soil supplies mineral and nutrients to the crop. These nutrients like nitrogen, phosphorus, potassium, etc. are essential for the growth of plants. The continuous growing of crops in the same field makes the soil poorer in certain nutrients as the growing crops take up the nutrients from the soil. Hence, the nutrients get depleted. This makes the soil infertile and with lack of nutrients. In order to replenish the soil with nutrients, farmers need to add manures or fertilizers to the soil which provide the soil with important nutrients and make the soil suitable for growing crops.


Question 9.

What are weeds? How can we control them?


Answer:

The undesirable plants may grow naturally along with the crops. These are called weeds. There are many ways to remove weeds and control their growth. Weeds can be removed by uprooting or cutting them close to the ground from time to time. This is done with the help of a khurpi. Weeds are also controlled using certain chemicals called weedicides. These are sprayed in the fields to kill the weeds.


Question 10.

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



Answer:

The correct order is 5, 6, 4, 7, 2, 3 and 1



Question 11.

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 under 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.



Answer:

DOWN ACROSS

1. IRRIGATION


3. HARVESTOR


2. STORGAE


4. GRAM


5. CROP


6. WINNOWING