Class 8 Science Chapter 1

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.

6. The Differences Between ‘Manure’ And ‘Fertilizers’

Manure is an organic substance obtained from the decomposition of plant or animal wastes. The decomposed matter is used as organic manure. Moreover, fertilizers are chemical substances which are rich in a particular nutrient. Such as Urea, Potash, Ammonium sulphate etc. You are surprised to know that fertilizers have also become a source of water pollution. Hence, the other method of replenishing the soil with nutrients is through crop rotation. That means growing different crops alternately.

7. Irrigation

As you know, all living beings need water to live in. Water is essential for proper growth and development of flowers, fruits and seeds germination. And water is absorbed by the root of the plants. The supply of water to crops at different intervals is called ‘Irrigation’. Do you know, what are the sources of irrigations? Wells, ponds, dams, rivers, canals, and so many other water sources. In summer the plant needs more water. Do you know why? Generally, in the summer rate of evaporation of water is higher from the soil and the leaves.

8. Modern Methods Of Irrigation

Sprinkler systems are more useful than traditional systems on the uneven land where sufficient water is not available. It gets sprinkled on the crops as if it is raining. The sprinkler is very useful for sandy soil. In the other system, where the waterfalls drop by drop just at the position of the roots, called ‘Drip System’. It is a boon in that region where the availability of water is poor.

9. Protection From Weeds

You observed that, in many fields, undesirable plants grow along with the crop. These undesirable plants are called ‘Weeds’. Do you know why removing these weeds are necessary? Wedding is necessary because they compete with the crop plants for water, nutrient, space and light. Thus, they affect the growth of the crop.

10. Harvesting

The cutting of crop after its maturity called harvesting. It usually takes three to four months for a cereal crop to mature. In India, the period of harvest celebrated as Pongal, Baisakhi, Holi, Diwali and other festivals with great joy and happiness. In the harvested crop, the grain seeds need to be separated from the stalks. This process is known as ‘threshing’. And after that, the winnowing process is followed by the farmers.

11. Storage

The cutting of crop after its maturity called harvesting. It usually takes three to four months for a cereal crop to mature. In India, the period of harvest celebrated as Pongal, Baisakhi, Holi, Diwali and other festivals with great joy and happiness. In the harvested crop, the grain seeds need to be separated from the stalks. This process is known as ‘threshing’. And after that, the winnowing process is followed by the farmers.