NCERT Notes Class 8 Science Chapter 1 Crop Production and Management Till Science for Class 8 10,000 B.C. people were nomadic. They were wandering in groups from place to place in search of food and shelter. They ate raw fruits and vegetables and started hunting for animals for food. Later, they could cultivate land and produce rice, wheat and other food crops. Thus, was born ‘Agriculture’.
NCERT Notes Class 8 Science Chapter 1 Crop Production and Management | Science for Class 8
All living organisms require food. Plants can make their food themselves. Animals including humans can not make their own food. Human beings and all other animals directly or indirectly depend on plants for food.
India is a vast country. The climatic condition like temperature, humidity and rainfall vary from one region to another. Hence, different crops are grown in different regions depending on the region.
Today in this chapter we will know what are the steps involved in growing any crop? By which methods the crop is grown? How is it managed after the crop is ripe?
When plants of the same kind are grown and cultivated at one place on a large scale, it is called crop.
Example – The meaning of maize crop is that all the plants grown in that area are maize.
The wheat crop means that all the plants grown in the field are wheat.
Crops can be mainly divided into two categories, but here we will discuss three types of crops.
|1. Kharif Crops
|2. Rabi Crops
|3. Zaid Crops
1. Kharif Crops
The crops which are sown in the rainy season are called Kharif crops.
- The rainy season in India is generally from June to September. Therefore, the crops grown from June to September are Kharif crops.
Examples of Kharif Crops – Maize, Soyabean, Paddy, Groundnut, Cotton etc. are Kharif crops.
2. Rabi Crops
Crops grown in winter are called Rabi crops.
- The winter season in India is generally from October to March. Therefore, the crops grown from October to March are Rabi crops.
Examples of Rabi Crop – Wheat, peas, linseed, gram, mustard etc. are Rabi crops.
3. Zaid Crops
A crop grown in a relatively short period of time between two main crops of the year or before a major crop is called Zaid/interstitial crop.
- Sowing of Zaid crops is done in the month of February to March.
- It is harvested between April and May.
- It has the ability to tolerate drought.
Examples of Zaid Crops – Paddy, Millet, Jute, Cotton, Oilseeds, Melon, Watermelon, Cucumber etc. are examples of Zaid crops.
Basic Practices of Crop Production
The work done by the farmers from growing the crop till its complete preparation and storage is called basic cropping methods.
These activities or work farming methods are mainly of 7 types, which are being given in detail below.
- Preparation of soil
- Adding manure and fertilisers
- Protecting from weeds
(i) Preparation of Soil
The preparation of soil is the important and first step before growing a crop. In this step, to turn the soil and loosen it by dug up. The process of loosening and turning of the soil is called tilling or ploughing. This allows the roots to penetrate deep into the soil. Go deep into soil the roots of the plant helps them to breathe easily.
Tilling of the soil is done by ploughing. If the soil is too dry or hard, then water is added to it before plowing, so that the soil becomes soft.
Earthworms and micro-organisms, which are called farmer’s friends, also grow rapidly in loosen soil. which is necessary for the crop. Earthworms and micro-organisms keep the soil loose by overturning and forming humus.
Why Farmer Need to Preparation Soil – Reason
Since, we all know that soil consists of minerals, water, air and some living things. Apart from this, dead plants and animals are also decomposed by the organisms found in the soil. In this way, various nutrients held in the dead organisms are released back into the soil. These nutrients are again absorbed by plants.
Since, only a few cm in the top layer of soil is helpful in the growth of the plant. Therefore turning and loosening of soil brings the nutrient rich soil to the top so that plants can use these nutrients. So soil preparation is a very important step.
Tools used in soil preparation (Agricultural Implements) – Plough, plank, hoe and cultivator.
It is made of wood or iron. The plow is pulled with the help of bulls, horses or camels. The strong iron strip attached to it is called ploughshare. The long part made of wood is the main part, which is called plough-shaft. It has a handle on one end and the other end is attached to a beam. This end is placed on the neck of the bulls.
This is a simple tool. It consists of a wooden or iron rod. On one end of which there is a wide and bent iron plate which acts like a blade and the animal pulls the other part.
The function of a hoe – to remove weeds, for loosening the soil.
It is a tractor-drawn iron machine. In which many plow-like shapes are attached. Its use saves both time and labor.
Sometimes large lumps of soil are formed at the time of plowing, which needs to be leveled. Therefore, the tool used to level the soil is called Plank.
This is also an important step of the crop production. Sowing seeds in prepared soil is called sowing.
Clean and healthy seeds of good quality are selected before sowing.
Selection of Good Quality Seeds
We’ll take a pot. Fill it halfway with water. Now put a handful of wheat in it. Shake it and leave it for some time. After some time we see that some seeds float in the water and some seeds settle at the bottom of the pot. The seeds that floated on the surface of the water were hollow, due to which they became light and came up in the water. On the contrary, the seeds which were good and healthy get deposited in the bottom of the water.
This is a good method of separating good and healthy seeds from damaged seeds.
(a) Funnel Tool – The traditional tool used for sowing seeds is funnel shaped. When the seeds are put inside the funnel, they pass through pipes having two or three pointed ends. These ends remove the soil and put the seed in the soil.
(b) Seed Drill
A seed drill is a tool for planting seeds with the help of a tractor. This tool sows the seeds uniformly at proper distances and depths. It ensures that seeds get covered by the soil after sowing. Due to this even birds are not able to eat the seeds. Seed-drill save both time and labor.
Why is it necessary to plant the plants at proper distance? (Spacing the Plants)
Proper spacing between seeds is very important to prevent the plants from becoming overly dense. Due to this the plants get sufficient amount of sunlight, nutrients and water. Some plants are pruned and removed to prevent overcrowding.
(iii) Adding Manure and Fertilisers
This is the third important step of crop production. Continuous growing of crops makes the soil poorer in certain nutrients. Therefore, farmers have to add manure to the fields to replenish the soil with nutrients. This process is called manuring.
Note: – Manure should be given only as required, neither too much nor less. Improper or insufficient manuring results in weak plants.
Manures and Fertilizers – The substances which maintain the nutrient level in the soil are called manures and fertilizers.
Manure – Manure is an organic substance obtained from the decomposition of plant and animal wastes.
Preparing of Manure
A pit is made to make manure. Farmers dump plant and animal waste into this pit and leave it in the open for decomposition. Decomposition takes place by some micro-organisms. The decomposed matter is used as organic manure.
Fertilizers – Fertilizers are chemical substances. They contain special nutrients. Fertilizer is produced in factories.
Examples of Fertilizers – Urea, Ammonium Sulphate, Super Phosphate, Potash, NPK (Nitrogen, Phosphorous, Potassium).
Disadvantages of Fertilizers
- Excessive use of fertilizers reduces the fertility of the soil.
- It also becomes the cause of water pollution.
Note:- Excessive use of fertilizers reduces the fertility of the soil. In place of fertilizers, we should use organic manure or leave the field without growing anything for some time between two crops.
Manure is better than fertilizer (Benefits of manure)
- The use of manure also increases soil formation and water absorption capacity.
- In this, all the nutrients of the soil are replenished.
- It makes the soil porous due to which exchange of gases becomes easy.
- This increases the number of friendly bacteria.
- Whereas excessive use of fertilizers reduces the fertility of the soil.
When after one crop another type of crop is grown in the field in an alternate sequence, then this type of rotation is called crop rotation.
Example of Crop Rotation
Earlier, farmers in northern India used to grow legumes as fodder in one season and wheat in the next season. This helped in the replenishment of the soil with nitrogen.
Difference between Fertiliser and Manure
|A fertiliser is an inorganic salt.
|Manure is a natural substance obtained by the decomposition of cattle dung, human waste and plant residues.
|A fertiliser is prepared in factories.
|Manure can be prepared in the field.
|A fertiliser does not provide any humus to the sail.
|Manure provides a lot of humus to the soil.
|Fertilisers are very rich in plant nutrients like nitrogen, phosphrous and potassium.
|Manure is relatively less rich in plan nutrients.
Water is life i.e. all living beings need water to survive. Similarly, water is of most importance for the growth and development of plants. Plants contain about 90% water.
The supply of water to crops at different intervals is called irrigation.
The time and frequency of irrigation varies from crop to crop. In summer, crops are given more water as more water is needed in summer.
Water is absorbed by the plant roots. Along with water, minerals and fertilisers are also absorbed. Water essential because germination of seeds does not take place under dry condition. Nutrients dissolved in water get transported to each part of the plant. Water also protects the crop from both frost and hot air currents. To maintain the moisture of the soil for healthy crop growth, fields have to be watered regularly.
Sources of irrigation – The sources of irrigation are wells, tube wells, ponds, lakes, rivers, dams and canals.
Traditional Methods of Irrigation
There are different ways of extracting water from irrigation sources and conveying it to the fields, which differ from region to region.
The various traditional ways are:
|(i) Moat (Pulley System)
|(ii) Chain Pump
|(iv) Rahat (Lever System)
Note:- Pump is generally used to lift the water up. The pump is run on diesel, petrol, biogas, electricity, or solar energy.
Modern Methods of Irrigation
Modern methods of irrigation are those by which we can save water.
The main modern methods of irrigation are as follows –
- Sprinkler System
- Drip System
(i) Sprinkler System
- For flat land
- In a place where water content is less
In this system, rotating nozzles are attached directly to the upper ends of the pipes. All the pipes are connected to the main pipe at regular intervals. When water is allowed to flow into the main pipe, it travels through smaller pipes to reach the nozzle and exit. This sprinkler system looks like rain.
This type of spraying is very important for lawn, and coffee cultivation.
(ii) Drip System
In this system, water goes drop by drop directly to the roots of the plant. Hence this method is called a drip system.
This type of method is used in fruit plants, gardens and trees. This is the best method of irrigation, in which not even a drop of water is wasted.
Many undesirable plants naturally grow along with the crops, which are called weeds.
Weeding – The removal of weeds is called weeding.
Weeding is necessary since weeds compete with the crop plants for water, nutrients, space and light. Thus they affect the growth of the crop. Some weeds interfere even in harvesting and may be poisonous for animals and human beings.
Protection from Weeds
Farmer removes weeds in many ways, some are as follows :-
- The manual removal includes physical removal of weeds by uprooting or cutting them close to the ground, from time to time.
- The best time for the removal of weeds is before they produce flowers and seeds.
- To remove weeds, the help of Khurpi or seed drill.
- Weeds are also removed with the help of chemicals, of which 2, 4-D is the main weedicide.
- While using weedicide, a cloth should be wrapped over the mouth and nose.
The cutting of crop after it is mature is called harvesting. Harvesting of a crop is an important task. In harvesting, crops are pulled out or cut close to the ground.
Sickle – Harvesting is done by hand with the help of sickle.
Harvester – Harvesting is also done with the help of a harvester machine. By this, harvesting is done in less time and effort.
clearing the crops
Threshing – In the harvested crop, the grain seeds need to be separated from the chaff. This process is called threshing.
Threshing is done by combine machine. A combine machine is a combination of harvester and thresher.
Note: – Small farmers separate the grains by winnowing.
Keeping the cleaned crop in a properly protected place is called storage. This is an important step. Failure to do so can ruin the whole hard work. If storage is to be done for a longer period, then they have to be protected from moisture, insects, rats and microorganisms.
Freshly harvested crop contains moisture. Therefore, the moisture is removed by drying the seeds before storage. So that the seeds do not get spoiled.
For storage, farmers collect their crop produce in jute bags, and large metallic bins.
Silos – Silos is the latest and modern technology of grain storage, through which a large quantity of grain can be stored easily.
Note: – Small farmers and people in their homes put dry neem leaves in the grain and store it.
Animal Husbandry – Keeping animals in large quantities is called animal husbandry.