hand written question answers of chapter 1 of science class 8 from NCERT book
Answers
Answer:
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What are the two ways of sowing the seeds? [DAV2007]
Give any three advantages of ploughing.
Solution:
Seeds can be sown manually or by seed drills.
Ploughing has following advantages :
Loose soil has lot of air trapped which allows roots to breathe.
Loose soil allows the roots to penetrate deeper.
Loose soil helps the growth of microbes and other organisms.
Question 2.
What will happen if field is not ploughed before sowing the seeds? Give any two disadvantages. [DAV2006]
How are perishable food items stored on a commercial scale?
Why should excessive supply of water be avoided?
What are weeds?
Solution:
Disadvantages:
Seeds cannot be sown at proper depth.
Water and air holding capacity of soil will be poor.
Perishable food items can be stored in deep freezers and cold storages.
Roots get damaged and the plants die because of excessive supply of water.
They are unwanted plants which grow along with the cultivated plants.
Question 3.
(a) Why does farmer rotate crops in the field?
(b) Differentiate between manure and fertiliser. [DAV2005]
Solution:
(a) To replenish the nutrients of the soil.
(b)
Manure Fertiliser
(i) It is natural.
(ii) It is organic.
(iii) It adds humus to the soil.
(iv) It is not nutrient specific.
(v) It is cheap.
(vi) It is prepared in the fields. (i) It is man-made.
(ii) It is inorganic.
(iii) It does not add humus.
(iv) It is nutrient specific.
(v) It is costly.
(vi) It is prepared in factories.
or
(a) (i) While spraying pesticides, nose and mouth should be closed.
(ii) Position of the farmer should be such that the wind blows away from his face.
(iii) Immediately after spraying is done, hands should be washed, face and mouth should be cleaned with water.
Question 4.
Arrange the following boxes in proper order to make a flow chart of sugarcane crop production: [NCERT]
NCERT Solutions for Class 8 Science Chapter 1 Crop Production and Management 5 Marks Q4
Solution:
NCERT Solutions for Class 8 Science Chapter 1 Crop Production and Management 5 Marks Q4.1
Question 5.
List the steps involved in crop production in a flow chart.
Solution:
NCERT Solutions for Class 8 Science Chapter 1 Crop Production and Management 5 Marks Q5
NCERT Solutions for Class 8 Science Chapter 1 Crop Production and Management 5 Marks Q5.1
Question 6.
Explain the method used these days to sow seeds.
Solution:
These days the seed drill is used for sowing seeds with the help of a tractor. This sows the seed uniformly at a proper distance and depth. Seeds get covered by soil during sowing with a drill. This prevents damage caused by birds. Sowing by using seed drill saves time and labour.
Question 7.
What are the advantages of organic manure?
Solution:
The advantages of organic manure are :
It enhances the water holding capacity of the soil.
It makes the soil porous due to which exchange of gases takes place.
The number of friendly microbes is increased.
The organic manure improves the texture of the soil.
Question 8.
How does a plough work?
Solution:
A plough is an agricultural implement used for tilling and loosening of soil. It has a triangular iron strip called plough share. Plough shaft is the main part made of a long wooden log. The other end is hung on the bull’s necks. The plough can be with two bulls and one person.
Question 9.
Write a paragraph in your own words on each of the following : [NCERT]
Preparation of soil
Sowing
Weeding
Threshing
Solution:
Preparation of soil : Preparation of the soil involves loosening and turning the soil.
This process, known as ploughing, is done by using a wooden or iron plough which is pulled either by an animal or by tractors. Loose soil is then levelled by using a wooden or iron leveller.
Sowing : Seeds are sown after preparation of the soil. Seeds can be sown manually or by seed drills by the process called broadcasting. Seeds should be sown at the correct depth and at correct distance.
Weeding : The process of removing weeds from a field is called weeding. Weeding can be done manually by pulling the weeds out by hand or by using a harrow to uproot them. Weeding can also be done by spraying special chemicals called weedicides.
Threshing: Threshing is the process of separating the grain from the cut crop. Threshing can be done manually by making oxen or buffaloes trample over the cut crop or by using a machine called thresher.
NCERT Solutions for Class 8 Science Chapter 1 – Multiple Choice Questions
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Answer:
Explanation:
Important Terms On Class 8 Science Chapter 1
1. Agricultural Practices
In this part of the content focuses how agricultural practices provide food for us with the science needed for adaptation in agriculture systems as well as the impacts of climate change, on food production systems and to develop strategies. You have learnt that all living organisms require food. We get energy from food, and it is utilised by organisms for carrying out their various body functions. Such as digestion, respiration, excretion etc.
In order to provide food for a large population agriculture practices are needed. Generally, the ‘Crop’ refers, when the plants of the same kind are grown and cultivated at one place on a large scale, called crop. Cereals, vegetables and fruits are known as different types of crop. Remember, “wheat” was the first crop that the human started growing. Do you know that the climatic conditions like temperature, humidity and rainfall vary from one region to another? Despite this diversity, two broad cropping patterns can be identified as Kharif crops and Rabi crops.
2. Basic Practices Of Crop Production
In this part of chapter 1 of Class 8 Science, introduces the conventional agricultural practices with modern values that are adopted by the Indian farmers. Cultivation of crops involves several activities undertaken by farmers over a while. These activities or task are referred to as ‘Agriculture Practices’. Such as preparation of soil, sowing, it is adding manure and fertilisers, irrigation, protecting from weeds, harvesting and storage of food crops.
3. Preparation Of Soil
In this part of the content describes the system of agricultural practices which is essential for crop production and its growth. The preparation of the soil is the first step before growing a crop. One of the most critical tasks in agriculture is to turn the soil and loosen it, called ploughing or tilling. But why does the soil need to be turned and loosen?
You have learnt that soil contains minerals, water, air, dead plants and animals and some living microorganisms. And the living organisms help to decompose that dead plants and animals. As a result, various nutrients are released back into the soil. These nutrients are again absorbed by the plants. As you can see, the turning and loosening of soil are essential for the cultivation of crops.
4. Sowing
Remember, sometimes manure is added to the soil before tilling. You may know that, before sowing the seeds, it is necessary to break the soil to the size of grains to get better yield. Sowing is an essential part of crop production. But why? Without sowing any seed, we cannot get any plants, and without any plants, we never get food grains from them. Remember, before sowing; good quality seeds are selected. Farmers prefer to use seeds which gave a high yield. And the appropriate distance between the seeds is also important to avoid overcrowding of plants. In this way every seed can get proper food, air and light for growth.
5. Adding Manure And Fertilisers
In this part of the chapter focuses on the importance of adding manure in the field of crop. You may saw that healthy crop growing on some farm, but in the neighbouring farm, the plants were weak. What is the reason behind that some plants grow better than others? Your answer will be due to fertilisers or manure. The substances which are added to the soil in the form of nutrients for the healthy growth of plants are called ‘Manure’ and ‘Fertilizers’. You learnt that soil supplies many mineral nutrients to the crop. The continuous growing of crops makes the soil weaker in particular nutrients. Therefore, farmers added manure to the fields to replenish the soil with nutrients.