8 Science PPT
Chapter - 1, Crop Production and Management, Science
Class 8 Science Notes
Chapter - 1, Crop Production and Management, Science,
- Introduction
- ★ All the living organisms require food for their life processes like digestion, respiration,excretion etc.
- ★ Plants can make their own food by the process of photosynthesis and animals including humans cannot make their food so they are dependent on plants and other animals.
- ★ In order to provide food for a large population - regular production,proper management and distribution of food is necessary.
- Crop
- ★ When the same kinds of plants are grown at one place on a large scale, it is called a crop.
- ★ Different type crops like cereals, vegetables and fruits etc, can be classified on the basis of the season in which they grow.
- 1. Kharif Crops 2. Rabi Crops
- Kharif Crops
- ★ The crops which are sown in the rainy season are called kharif crops.
- ★ The rainy season in India is generally from June month to September month.
- ★ Paddy,maize, soya-bean,groundnut, cotton,etc., are the examples of kharif crops.
- Rabi Crops
- ★ The crops which are grown in the winter season are called Rabi crops.
- ★ Their time period is generally from October month to March month.
- ★ Wheat, gram, pea, mustard and linseed are the examples of Rabi crops.
- Basic Practice Of Crop Production
- ★ Preparation of Soil
- ★ Sowing
- ★ Adding manure and fertilizers
- ★ Irrigation
- ★ Protecting from weeds
- ★ Harvesting
- ★ Storage
- Preparation of Soil
- ★ One of the most important tasks in agriculture is to turn the soil and loosen it.
- ★ The loose soil allows the roots to penetrate and breathe easily even when they go deep into the soil.
- ★ The loosened soil helps in the growth of earthworms and microbes present in the soil.
- ★ The process of loosening and turning of the soil is called tilling or ploughing. This is done by using a plough which is made of wood or iron.
Sowing and quality of seeds- ★ Sowing is the process of planting the seeds in the soil.
- ★ The seeds are sowed in the soil that is loosened by cultivator or plough.
- ★ Quality of the seed is an important factor that determines the crop yield. Selection of good seeds is done by putting the seeds in water.
- ★ The dead and damaged seeds become hollow and float on water whereas the good seeds sink.
Traditional tools (sowing)- ★ Before the advent of modern agricultural machinery, traditional tools were used by farmers.
- ★ The traditional tool used to sow the seeds is like a funnel.
- ★ Once seeds put into this funnel, they would go to 2-3 tubes having sharp ends. The ends will pierce into the soil and place the seeds there.
- Seed drill (sowing)
- ★ Seed drills are used for sowing with the help of tractors.
- ★ It ensures that seeds are sown uniformly, at a particular depth and are covered by soil after sowing.
Manure / Fertilizers
- ★ Manures and fertilizers are the substances that are added to the soil to increase their fertility.
- ★ While manures are made by decomposition of organic substances, fertilizer is made of inorganic chemicals.
- Manure
- ★ Easily made using animal and plant waste.
- ★ No harmful effect as fully natural.
- ★ Good for long term soil fertility.
- ★ Not effective as fertilisers.
- ★ It is very cheap.
- fertilizers
- ★ Made in factories in well defined way.
- ★ Side effects as it is a chemicals.
- ★ Not good for long term soil fertility, If uses in excessive amount.
- ★ Very effective in obtaining fast result.
- ★ It is very costly.
Irrigation- ★ Water is important for proper growth and development of plants.
- ★ Water is essential because germination of seeds does not take place under dry conditions.
- ★ Nutrients dissolved in water get transported to each part of the plant.
- ★ Sources of Irrigation: Wells,Tube wells, Ponds, Lakes, Rivers, Dams and Canals are the sources of Irrigation.
- Traditional methods of irrigation
- The water available in wells, lakes and canals is lifted up by different methods in different regions, for taking it to the fields.
Modern methods of irrigation
- Sprinkler System : In this system, 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 sprinkles from the rotating nozzles.
- Drip system : In this system,the water falls drop by drop just at the position of the roots.So it is called drip system.
- Weeds
- ★ Weeds are undesirable plants that may grow naturally along with the crop.
- ★ Weeds compete with the crops by absorbing all the water, nutrients, space and light.
Protecting from weeds - tilling / manual removal / weedicides
- ★ Tilling is a process done before sowing of crops that helps in uprooting and killing of weeds.
- ★ Manual removal includes physical removal of weeds by uprooting them from the soil or chopping them off to ground level periodically.
- ★ Chemicals used to kill the weeds are known as weedicides.They usually don’t damage the crop.
- Harvesting
- The cutting of crop after it is mature is called harvesting.In harvesting,crops are pulled out or cut close to the ground. Harvesting is also done manually by sickle or by a machine. Manual Harvesting Harvesting (Machine)
- Threshing
- ★ Threshing is the process of loosening the grains from the chaff.
- ★ While it can be done manually, these days a machine is used that separates all the grain seeds. Manually Machine (Combine)
- Winnowing
- ★ Winnowing is the process of separation of grain seeds from the chaff using the help of the wind.
- ★ Due to the wind, the lighter chaff flies away and the heavier grains fall down.
- Storage
- ★ Storage of the grains is an important step in agriculture.
- ★ After harvesting steps, the ready grains are stored in granaries or silos.
- ★ The grains have to be stored in a dry place that does not have a rodent or fungal infestation.
- ★ Granaries are the place where the freshly obtained food grains are stored.
- ★ Animal husbandry is the management and care of farm animals for milk, egg or meat.
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