NCERT Solutions for Class 8 Science Chapter 1 Crop Production and Management

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Crop Production and Management NCERT Solutions for Class 8 Science Chapter 1

Class 8 Science Chapter 1 Crop Production and Management Exercise Questions and Answers

Question 1.
Select the correct word from the following list and fill in the blanks:
float, water, crop, nutrients, preparation

1. The same kind of plants grown and cultivated on a large scale at a place is called………..
2. The first step before growing crops is……..of the soil.
3. Damaged seeds would………… on top of the water.
4. For growing a crop, sufficient sunlight and……….and………from the soil are essential.

Answer.

1. crop
2. preparation
3. float
4. water, nutrients.

Question 2.
Match items in column A with those in column B.

A	B
Kharif crops	Paddy arid maize
Rabi Crops	Urea and superphosphate
Chemical fertilizers	Animal excreta, cow dung, urine, and plant waste
Organic manure	Wheat, gram, pea

Answer:

A	B
Kharif crops	Paddy arid maize
Rabi Crops	Wheat, gram, pea
Chemical fertilizers	Urea and superphosphate
Organic manure	Animal excreta, cow dung, urine, and plant waste

Question 3.
Give two examples of each :

(a) Kharif crop
Answer:

• Paddy
• Maize

(b) Rabi crop
Answer:

• Wheat
• Gram

Question 4.
Write a paragraph in your own words on each of the following.
Answer:

1. Preparation of soil: It is necessary to prepare the soil before growing a crop. It involves tilling and loosening the soil. This allows the roots to penetrate deep into the soil. The loose soil allows the roots to breathe easily even when they are deep. The process of loosening and tilling the soil is called tilling or ploughing. This is done by using a plough.
2. Sowing: Sowing is the process of putting seeds in the soil. The tool used traditionally for sowing seeds is shaped like a funnel. The seeds are filled into the funnel, passed down through two or three pipes having sharp ends. Nowadays a seed drill is used for sowing with the help of tractors. This tool sows the seeds uniformly at a proper distance and depth.
3. Weeding: The undesirable plants grown along with the crop are called weeds. The removal of weeds is called weeding. Weeding is necessary since weeds compete with the crop plants for water, nutrients, space, and light, thus affecting the growth of the crop.
4. Threshing: The process of separating the grain seeds from the chaff is called threshing. Traditionally it is done by winnowing. Nowadays this is carried out with the help of a machine called ‘combine’ which is a combination of harvester and thresher.

Question 5.
Explain how fertilizers are different from manure?
Answer:
The substances which are added to the soil in the form of nutrients for the healthy growth of plants are called manure and fertilizers.
Fertilizers are different from manure in the following ways :

S.No.	Fertilizer	Manure
1.	Fertilizers are prepared in the  fertilizers	Manure is prepared in the fields.
2.	Fertilizers do not provide any humus to the soil.	Manure provides a lot of humus to the soil.
3.	Fertilizers are very rich in plant nutrients like nitrogen, phos­phorus and potassium.	Manure is not very rich in plant nutrients.
4.	Fertilizer is an inorganic substance.	Manure is a natural substance obtained by the decomposition of cattle dung, human waste and plant residues.

Question 6.
What is irrigation? Describe two methods of irrigation which conserve water.
Answer:

Irrigation: The supply of water to crops at appropriate intervals is called irrigation.
Two methods which help us to use water economically are:

1. Sprinkler System: This system is more useful on uneven land where water is available in smaller quantities. The perpendicular pipes, having rotating nozzles on the top, are joined to the main pipeline at regular intervals. When the water is allowed to flow through the main pipe with the help of a pump, it escapes from the rotating nozzles. It is sprinkled on the crop as if it is raining. The sprinkler is very useful for sandy soil.
2. Drip System: In this system, the water falls drop by drop just at the position of the roots. So, it is called a drip system. It is the best technique of watering fruit plants, gardens, and trees. This_ system consists of the main pipe to which lateral pipes are joined. The specially prepared nozzles are attached to these lateral pipes. The nozzles are grounded just near the roots of the plants. It provides water to plants drop by drop. Water is not wasted at all. So, it is a boon in regions where the availability of water is poor.

Question 7.
If wheat is sown in Kharif season, what would happen? Discuss.
Answer:
In the Kharif season, we have a lot of rainfall, whereas wheat needs winter (cold) season and not heavy rainfall. So, if wheat were sown in Kharif season, the crop will damage due to heavy rainfall as well as water logging (collection of water in the field).

Question 8.
Explain how soil gets affected by the continuous plantation of crops in a field.
Answer:
Since crops take up nutrients from the soil, continuous growing of crops makes the soil poorer in certain nutrients. The soil becomes infertile. It does not get enough time to replenish the nutrients.

Question 9.
What are weeds? How can we control them?
Answer:
In a field, many other undesirable or unwanted plants may grow naturally along with the crop. These plants are called weeds. We can adopt many ways to remove weeds and control their growth. Tilling before sowing of crops helps in uprooting and killing of weeds, which may then dry up and get mixed with the soil. The best time for the removal of weeds is before they produce flowers and seeds. The manual removal includes physical removal of weeds by uprooting or cutting them close to the ground, from time to time. This is done with the help of a khurpi or a harrow.

Weeds are also controlled by using certain chemicals called weedicides like 2, 4-D. These are sprayed in the fields to kill the weeds. They do not damage the crops. The weedicides are diluted with water to the extent required and sprayed in the fields with a sprayer.

Question 10.
Arrange the following boxes in the proper order to make a flow chart of sugarcane crop production :

Answer:
The boxes should be arranged as follows

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:

Class 8 Science Chapter 1 Crop Production and Management InText Questions and Answers

Question 1.
Where are the tools like khurpi, sickle, shovel, and plough used?
Answer:
These tools are used in various agricultural practices :

Tool	Agricultural practice
Khurpi	loosening of soil and weeds
Sickle	for harvesting
Shovel	for loosening of the soil and removing weeds
Plough	turning and loosening of soil

Question 2.
Can you recall how do green plants synthesise their own food?
Answer:
Green plants synthesise their own food by the process of photosynthesis. In this process, plants synthesise food in the presence of sunlight using CO₂ and water.

Question 3.
Where do animals get their food from?
Answer:
Animals get their food from plants and other animals.

1.3 Preparation of Soil

Question 4.
Why does the loosening of soil allow roots to breathe easily?
Answer:
Loosening of the soil allows air to reach up to the roots of the plants so that roots easily trap air and breathe.

Question 5.
Why does the soil need to be turned and loosened?
Answer:
Reasons for the soil need to be turned and loosened are as follows.

1. Roots can breathe easily.
2. Only a few cons of the top layer soil supports plant growth, turning and loosening brings the nutrient-rich soil to the top.
3. Turning and loosening of soil bring the nutrient-rich soil to the top so that plants can use these nutrients. That is why soil needs to be turned and loosened.

1.4 Sowing

Question 6.
Which type of seeds are called good quality seeds?
Answer:
Good quality seeds are clean and healthy seeds of a good variety.

Question 7.
How can we check whether the seeds are healthy or damaged?
Answer:
If we put the seeds in a container containing water, the damaged seeds float on the surface of the water while healthy seeds settle down at the bottom of the container.

Question 8.
Why do damaged seeds float on water?
Answer:
Damaged, seeds become hollow and are thus lighter. Therefore, they float on water.

1.5 Adding Manure and Fertilizers

Question 9.
I saw a healthy crop growing on a farm. In the neighbouring farm, the plants were weak. Why do some plants grow better than others?
Answer:
Plants that get proper nutrients and water grow better than the plants which do not get these sufficiently.

Activity 1.2

Question 1.
Did all the plants in all the glasses grow at the same pace?
Answer:
No.

Question 2.
Which glass showed better growth of plants?
Answer:
Glass A and glass B showed better growth of plants; because in addition to soil these glasses contain cow dung and urea respectively.

Question 3.
In which glass the growth was fastest?
Answer:
In glass B, because of the presence of urea in that glass.

1.6 irrigation

Question 10.
In summer, the frequency of watering is higher. Why is it so?
Answer:
This is because in summer, the rate of evaporation of water from the soil and leaves increased.

1.7 Protection from Weeds

Question 11.
In a field are all plants planted purposely?
Answer:
No, some of them may not have been purposely grown. In a crop field, many other undesirable plants may grow naturally along with the crops. These undesirable plants are called weeds.

1.9 Storage

Question 12.
Why do we use dried neem leaves for storing food grains at home?
Answer:
Dried neem leaves protect the grains from pests and microorganisms. That is why these are used for storing food grains.

1.10 Food from Animals

Activity 1.3

Question 13.
Make the following table in your notebook and complete it.
Answer:

S. No	Food	Sources
1.	Milk	Cow, buffalo, she-goat, she-camel
2.	Meat	Goat, chicken
3.	Egg	Hen, duck
4.	Oil	Fish