Crop Production And Management Class 8 Science Chapter 1 Notes are available here. These notes were carefully prepared by our team of subject experts to make it easier for you to grasp the chapter. We hope you like these notes and have a great time studying with them.
Crop Production And Management Class 8 Science Chapter 1 Notes
Introduction
- Plants can make their own food, but animals cannot.
- Green plants synthesise their own food through a process called photosynthesis.
- Animals, including humans, get their food from plants or other animals.
- We need to eat food because it gives us energy for various body functions like digestion, respiration, and excretion.
- To provide food for a large population, regular production, proper management, and distribution are important.
Crop:
Definition:
- Plants of the same kind cultivated on a large scale
Example:
- Wheat, paddy, maize, barley, corn etc.
Types of crops:
- Cereals, pulses, vegetables, and fruits
Crop diversity in India:
- India is a vast country with varying climatic conditions (temperature, humidity, rainfall)
Cropping patterns
Kharif Crops:
- Sown in the rainy season (June to September)
- Examples: Paddy, maize, soybean, groundnut, cotton
Rabi Crops:
- Grown in the winter season (October to March)
- Examples: Wheat, gram, pea, mustard, linseed
Agricultural Practices:
Preparation of soil:
- Preparing the land for planting crops
- Clearing, ploughing, and levelling the soil
Sowing:
- Planting seeds or seedlings in the prepared soil
- Done manually or using machines
Adding manure and fertilisers:
- Adding organic or chemical substances to enrich the soil
- Provides essential nutrients for plant growth
Irrigation:
- Supplying water to the crops
- Ensuring proper moisture for plant growth
Protecting from weeds:
- Controlling and removing unwanted plants (weeds)
- Prevents competition for nutrients, sunlight, and space
Harvesting:
- Cutting or picking mature crops from the field
- Timing depends on the type of crop
Storage:
- Preserving harvested crops for future use
- Proper storage techniques to maintain quality and prevent spoilage
Preparation of Soil for Crop Cultivation:
Importance of turning and loosening the soil:
- First step before growing a crop
- Turning and loosening soil allows roots to penetrate deep and breathe easily
- Loose soil provides space for root expansion
Benefits of loosened soil:
- Promotes growth of earthworms and soil microbes
- These organisms further turn and loosen the soil, enhancing soil quality
- Addition of humus improves soil fertility
Reason for turning and loosening the soil:
- Soil contains minerals, water, air, and living organisms
- Decomposition of dead plants and animals by soil organisms
- Releases nutrients back into the soil for plant absorption
- Turning and loosening bring nutrient-rich soil to the surface
Process of turning and loosening the soil:
- Known as tilling or ploughing
- Ploughs made of wood or iron used
- Dry soil may require watering before ploughing
- Clumps of soil called crumbs are broken for finer texture
Levelling the field:
- Important for sowing and irrigation
- Achieved using a leveller tool
Addition of manure and soil moisture:
- Manure added to soil before tilling for nutrient enrichment
- Ensures proper mixing of manure with the soil
- Soil moistening before sowing supports germination and early growth
Agricultural Implements or Tools
Purpose:
- Breaking soil clumps for better yield before sowing seeds
Tools used:
- Plough, hoe, cultivator
Plough:
- Ancient tool for tilling soil, adding fertilisers, removing weeds, and turning soil
- Made of wood, drawn by animals (bulls, horses, camels)
- Contains a strong triangular iron strip called ploughshare
- Main part is a long wooden log called ploughshaft
- Handle at one end, attached to a beam placed on animals’ necks
- Indigenous wooden plough being replaced by iron ploughs
Hoe:
- Simple tool for removing weeds and loosening soil
- Consists of a long rod of wood or iron
- One end has a strong, broad, and bent iron plate acting as a blade
- Pulled by animals
Cultivator:
- Modern tool used for ploughing, driven by a tractor
- Saves labour and time compared to traditional ploughing methods
Sowing:
- Sowing is the process of planting seeds or seedlings in the soil to grow crops. It is a crucial step in agriculture that involves placing the seeds at a specific depth and spacing in prepared soil.
Selection of seeds:
- Good quality, clean, and healthy seeds chosen
- Preference for seeds that yield high productivity
- Farmers select seeds of good varieties
Floating seeds:
- Some seeds have the ability to float on water.
- These floating seeds are lighter than the seeds that sink.
- Damaged seeds often become hollow and lighter, which makes them float on water.
Importance of the floating test:
- The floating test is a useful method for separating good, healthy seeds from damaged ones.
- Floating seeds are more likely to be damaged or less viable.
- Sinking seeds, on the other hand, are generally healthier and more suitable for sowing.
Tools for Sowing Seeds
Traditional tool:
- Funnel-shaped tool used for sowing seeds traditionally
- Seeds filled into the funnel and passed through sharp-ended pipes
- Pipes pierce the soil and place seeds in the ground
Seed drill:
- Modern tool used with tractors for sowing seeds
- Ensures uniform and equal distance and depth for seed placement
- Soil covers the seeds after sowing, protecting them from birds
- Saves time and labour compared to traditional methods
Importance of appropriate seed spacing:
- Proper distance between seeds to avoid overcrowding of plants
- Allows plants to receive sufficient sunlight, nutrients, and water from the soil
- Occasionally, some plants may need removal to prevent overcrowding
Adding Manure and Fertilisers:
Manure and fertilisers:
- Substances added to the soil for supplying nutrients to support healthy plant growth
Soil’s role in nutrient supply:
- Soil provides mineral nutrients necessary for plant growth
- Nutrients are essential for the overall development of plants
Nutrient depletion due to continuous cropping:
- Repeated cultivation without fallow periods depletes soil nutrients
- Continuous cropping makes the soil nutrient-poor over time
Importance of manure:
- Farmers add manure to replenish soil nutrients
- Manuring is the process of adding organic matter to the soil
- Insufficient or improper manuring leads to weak plant growth
Manure:
- Organic substance derived from the decomposition of plant or animal waste
- Plant and animal waste is dumped in open pits for decomposition
- Decomposition process facilitated by microorganisms
- Resulting decomposed matter used as organic manure
Fertilisers:
- Chemical substances rich in specific nutrients
- Produced in factories
- Examples of fertilisers: urea, ammonium sulphate, super phosphate, potash, NPK (Nitrogen, Phosphorus, Potassium)
Difference between manure and fertilisers:
- Manure is organic, derived from decomposed plant or animal waste
- Fertilisers are synthetic chemicals manufactured in factories
- Manure provides a range of nutrients along with organic matter, while fertilisers supply specific nutrients in concentrated forms
Benefits of fertilisers:
- Improved crop yield, especially for crops like wheat, paddy, and maize
- Increased nutrient availability for plants
Negative effects of excessive fertiliser use:
- Soil fertility decline due to nutrient imbalances
- Fertilisers contribute to water pollution
Strategies for maintaining soil fertility:
- Substituting fertilisers with organic manure to replenish nutrients naturally
- Allowing fields to remain uncultivated (fallow) between two crops
Effects of manure usage:
- Improves soil texture and structure
- Enhances water retention capacity of the soil
- Replenishes soil with essential nutrients
Replenishing Soil Nutrients:
Crop rotation as a method:
- Growing different crops alternately to replenish soil nutrients
- Example: In northern India, farmers used to rotate legumes as fodder and wheat in alternating seasons
- Legumes help replenish soil with nitrogen
Role of Rhizobium bacteria:
- Rhizobium bacteria reside in nodules of roots of leguminous plants
- These bacteria have the ability to fix atmospheric nitrogen
Advantages of Manure:
- Enhances soil’s water holding capacity
- Promotes soil porosity, facilitating gas exchange
- Increases the presence of beneficial microbes
- Improves soil texture
Irrigation:
Importance of water for all living beings:
- Water is vital for proper growth and development
- Plant roots absorb water along with minerals and fertilisers
- Plants contain approximately 90% water
- Water is essential for seed germination, nutrient transportation, and overall plant health
Protection and support provided by water:
- Water safeguards crops from frost and hot air currents
- Maintaining soil moisture through regular watering ensures healthy crop growth
Key aspects of irrigation:
- Irrigation refers to the supply of water to crops at regular intervals
- Regular watering is necessary to sustain soil moisture levels
- Dry conditions hinder seed germination
- Water dissolves and transports nutrients throughout the plant’s various parts
Definition of irrigation:
- The process of providing water to crops at regular intervals to meet their water requirements
Variation in irrigation needs:
- Irrigation timing and frequency vary depending on factors such as crop type, soil properties, and seasonal variations
Increased watering in summer:
- During the summer season, there is a higher demand for irrigation due to increased evaporation rates
- Water evaporates more rapidly from the soil and leaves, leading to faster water loss
- To compensate for this, the frequency of watering needs to be higher to maintain optimal soil moisture levels for crop growth
Traditional Methods of Irrigation
Water lifting methods:
- Various regions employ different techniques to lift water from wells, lakes, and canals for agricultural use.
- Traditional methods often rely on the labour of cattle or humans, making them cost-effective but less efficient compared to modern methods.
Traditional irrigation methods:
- Moat (pulley-system): Involves using a pulley system to lift water and transport it to the fields.
- Chain pump: Uses a continuous chain with buckets to lift water and transfer it to irrigation channels.
- Dhekli: Utilises a lever system operated manually to raise water from a well or a source and distribute it to the fields.
- Rahat (Lever system): Involves a lever mechanism to lift water and irrigate the fields.
Modern Methods of Irrigation
Purpose of modern irrigation methods:
- Efficient utilisation of water resources for irrigation
Sprinkler System:
- Suitable for uneven land and areas with limited water availability
- Perpendicular pipes with rotating nozzles connected to the main pipeline at regular intervals
- Water flows under pressure through the main pipe, escaping from rotating nozzles
- Water is distributed over the crops like rainfall
- Widely used for lawns, coffee plantations, and various crops
Drip System:
- Water is delivered drop by drop directly to the roots of plants
- Ideal for watering fruit plants, gardens, and trees
- Minimises water wastage by targeting the root zone
- Particularly beneficial in regions with poor water availability
Protection from Weeds
Definition of weeds:
- Undesirable plants that naturally grow alongside crops in the field
- Weeds compete with crop plants for essential resources such as water, nutrients, space, and light
- They negatively impact crop growth, yield, and quality
- Some weeds may even pose risks to animals and humans if consumed
Importance of weeding:
- Weeding involves the removal of weeds from the field
- Essential to minimise weed competition with crops
- Promotes healthy crop growth by ensuring adequate access to resources
- Helps prevent yield reduction and ensures better crop quality
Additional challenges caused by weeds:
- Weeds can interfere with harvesting operations
- Some weeds may have toxic properties, posing risks to animals and humans
Weed Removal and Control:
- Tilling the soil before sowing crops helps uproot and kill weeds, allowing them to dry up and mix with the soil
- Effective weed removal is best done before weeds produce flowers and seeds
- Manual removal involves physically uprooting or cutting weeds close to the ground using tools like a khurpi
- Seed drill can be utilised for uprooting weeds during the sowing process
Weed Control Using Weedicides:
- Weedicides: Chemical substances used to control weeds without harming crops
- Example: 2,4-D is a commonly used weedicide
- Application: Weedicides are sprayed in fields to kill weeds effectively
- Dilution and spraying: Weedicides are diluted with water as required and applied using a sprayer
- Timing of application: Weedicides are most effective when sprayed during the vegetative growth stage of weeds, before flowering and seed formation
Caution for farmers:
- Proper handling and careful use of weedicides are essential
- Covering the nose and mouth with a cloth during spraying
- Following recommended safety practices and guidelines
Harvesting:
Definition:
- Harvesting refers to the process of cutting or pulling out mature crops from the field.
Methods of harvesting
Manual harvesting:
- Done using a sickle or cutting tool, typically used by farmers.
Mechanised harvesting:
- Involves the use of a harvester machine, which enables efficient and rapid crop collection.
Time required for maturity:
- Cereal crops generally take around 3 to 4 months to reach maturity.
Post-harvest process:
- After harvesting, the separation of grain seeds from the chaff is necessary, a step known as threshing.
Threshing methods:
Mechanised threshing:
- Utilises a machine called a combine, which performs both harvesting and threshing.
Manual threshing:
- Farmers with small land holdings may opt for manual separation of grain and chaff through the traditional method of winnowing.
Winnowing:
- The process of tossing harvested crop material in the air to separate the grain from the chaff based on their weight and wind currents.
Storage:
Importance of storage:
- Proper storage is essential to preserve the quality of harvested produce and protect it from moisture, insects, rats, and microorganisms.
Moisture control:
- Harvested grains typically have higher moisture levels, making them susceptible to spoilage and attacks by organisms.
Drying process:
- To reduce moisture content and prevent spoilage, grains are dried before storage. Sun drying is a common method used for this purpose.
Benefits of drying:
- Prevents the growth of insect pests, bacteria, and fungi that can damage the grains.
- Ensures the grains remain usable and suitable for germination or consumption.
Sun drying:
- Grains are spread out in the sun to allow natural evaporation of moisture, making them more resistant to spoilage during storage.
Grain storage methods:
- Farmers commonly use jute bags or metallic bins for storing grains.
- Large-scale storage is done in specialised facilities such as silos and granaries to protect grains from pests like rats and insects.
Home storage:
- Dried neem leaves are employed for storing food grains at home due to their natural insect-repellent properties.
Chemical treatments:
- When storing substantial quantities of grains in large warehouses or godowns, specific chemical treatments are employed to safeguard them from pests and microorganisms.
Importance of animal husbandry:
- Animals also contribute to our food supply, as seen in coastal areas where fish is a significant part of the diet.
Animal husbandry:
- The practice of rearing animals at home or on farms involves providing them with proper food, shelter, and care on a larger scale.