CBSE – 8th Standard Science

Crop Production & Management

  • In order to provide food to our growing population, we need to adopt certain agricultural practices.
  • Humans get their food from plants, or animals, or both.
  • Energy from food is utilized by organisms for carrying out their various body functions, such as digestion, respiration and excretion.
  • India is a vast country. The climatic conditions like temperature, humidity and rainfall vary from one region to another.

When plants of the same kind are grown  and cultivated at one place on a large scale, it is called a crop

 

The agricultural practices of India are as follows

  • Crops can be classified on the basis of the season in which they grow.
  • Rich variety of crops grown in different parts of the country.
  • The rainy season in India is generally from June to September.
  • Paddy, maize, soyabean, groundnut, cotton, etc., are kharif crops.
  • Pulses and vegetables are grown during summer at many places.
  • Cultivation of crops involves several activities undertaken by farmers over a period of time.
  • Earthworms and microbes are friends of the farmer since they further turn and loosen the soil and add humus to it.
  • Turning and loosening of soil is very important for cultivation of crops.

  • The loose soil allows the roots to breathe easily even when they go deep into the soil.
  • The ploughed field may have big pieces of soil called crumbs.
  • The levelling of soil is done with the help of a leveller.
  • Sometimes, manure is added to the soil before tilling. This helps in proper mixing of manure with soil.
  • One pair of bulls and a man can easily operate the plough.
  • Plough is made of wood and is drawn by a pair of bulls or other animals.
  • Hoe has a strong, broad and bent plate of iron is fixed to one of its ends and works like a blade. It is pulled by animals.

Modern agriculture

  • Farmers prefer to use seeds which give a high yield.
  • An appropriate distance between the seeds is important to avoid overcrowding of plants.
  • Sometimes a few plants have to be removed to prevent overcrowding.
  • Good quality seeds are clean and healthy seeds of a good variety. Farmers prefer to use seeds which give a high yield.
  • Continuous growing of crops makes the soil poorer in certain nutrients.
  • Improper or insufficient manuring results in weak plants.
  • Manure is an organic substance obtained from the decomposition of plant or animal wastes.
  • Fertilizers are chemical substances which are rich in a particular nutrient.

  • Fertilizers have also become a source of water pollution.
  • The time and frequency of irrigation varies from crop to crop,
  • Soil supplies mineral nutrients to the crop. These nutrients are essential for the growth of plants.
  • Continuous growing of crops makes the soil poorer in certain nutrients.
  • Water is important for proper growth and development of flowers, fruits and seeds of plants.
  • Plants contain nearly 90% water.
  • Nutrients dissolved in water get transported to each part of the plant.
  • The sources of irrigation are wells, tube wells, ponds, lakes, rivers, dams and canals.
  • Modern methods of irrigation help us to use water economically
  • They are sprinkler and drip system

  • The removal of weeds is called weeding.

  • Special festivals associated with the harvest season are Pongal, Baisakhi, Holi, Diwali, Nabanya and Bihu.

  • Threshing is carried out with the help of a machine called ‘combine’
  • Farmers with small holdings of land do the separation of grain and chaff by winnowing.
  • We get cod liver oil from fish which is rich in vitamin D.
  • Proper storage of grains is necessary to protect them from pests and microorganisms.
  •  Food is also obtained from animals for which animals are reared. This is called animal husbandry

CBSE 8th Standard Science

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CBSE 8th Standard Science Syllabus and Revision Notes

  • Crop Production & Management
  • Microorganisms – Friends & Foe
  • Synthetic, Fibers & Plastic
  • Materials – Metals & Non-Metals
  • Coal & Petroleum
  • Combustion & Flame
  • Conservation Of Plants And Animals
  • Cell Structure And Functions
  • Reproduction In Animals
  • Reaching The Age Of Adolescence
  • Force And Pressure
  • Friction
  • Sound
  • Chemical Effects Of Electric Current
  • Some Natural Phenomena
  • Light
  • Stars And The Solar System
  • Pollution Of Air And Water