🌾 Crop Production and Management

Class 8 Science Chapter 1 - Crop Production and Management Notes

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Chapter - 1: Crop Production and Management

Introduction

1. Visit to Uncle's House:
   • Paheli and Boojho visited their uncle’s house during summer vacation.
   • Their uncle is a farmer.
     
     
2. Observation of Farming Tools:
   • They saw tools like khurpi, sickle, shovel, plough, etc., in the field.
     
     
3. Curiosity about Tools:
   • Boojho's interest in knowing where and how these tools are used.
     
     
4. Food Requirements for Living Organisms:
   • All living organisms require food.
   • Plants can make their own food through photosynthesis.
   • Animals, including humans, cannot make their own food.
     
     
5. Source of Food for Animals:
   • Animals get their food from plants, animals, or both.
     
     
6. Importance of Eating Food:
   • Food provides energy for various body functions like digestion, respiration, and excretion.
     
     
7. Food Production and Supply:
   • The necessity of providing food to a large population.
   • Food needs to be produced on a large scale.
   • Regular production, proper management, and distribution are necessary to ensure food supply.

Agricultural Practices

1. Nomadic Lifestyle till 10,000 B.C.E.:
   • People were nomadic and wandered in groups in search of food and shelter.
   • They ate raw fruits and vegetables and hunted animals for food.
     
     
2. Beginning of Agriculture:
   • People learned to cultivate land and produce crops like rice and wheat.
   • The birth of agriculture.
     
     
3. Definition of Crop:
   
   • Cultivating plants of the same kind at one place on a large scale is called a crop.
   • Example: A crop of wheat means all plants grown in a field are wheat.
     
     
4. Types of Crops:
   • Different types of crops include cereals, vegetables, and fruits.
   • Classification based on the season in which they grow.
     
     
5. Climatic Diversity in India:
   • India has diverse climatic conditions, including variations in temperature, humidity, and rainfall.
   • This diversity leads to a rich variety of crops grown in different parts of the country.
     
     
6. Broad Cropping Patterns:
   • Two broad cropping patterns: Kharif and Rabi crops.
     
     
7. Kharif Crops:
   • Sown in the rainy season (June to September).
   • Examples: Paddy, maize, soybean, groundnut, cotton.
     
     
8. Rabi Crops:
   • Grown in the winter season (October to March).
   • Examples: Wheat, gram, pea, mustard, linseed.
     
     
9. Summer Crops:
   • Pulses and vegetables grown during summer at many places.

Basic Practices of Crop Production

1. Paddy Cultivation:
   • Question: Why can't paddy be grown in the winter season?
   • Answer: Paddy requires a lot of water, so it is grown only in the rainy season.
     
     
2. Agricultural Practices:
   • Cultivation of crops involves several activities undertaken by farmers over a period of time.
   • These activities are similar to those carried out by a gardener or even by individuals growing ornamental plants at home.
   • These activities are referred to as agricultural practices.
     
     
3. List of Agricultural Practices:
   1. Preparation of soil
   2. Sowing
   3. Adding manure and fertilisers
   4. Irrigation
   5. Protecting from weeds
   6. Harvesting
   7. Storage

1. Preparation of Soil

1. Definition and Importance:

• Preparation of Soil: The first step before growing a crop, involving turning and loosening the soil.
• This allows roots to penetrate deep into the soil and breathe easily.
  
  

• Loosened Soil: Soil that has been turned and loosened, helping roots grow deep and breathe.
• It helps the growth of earthworms and microbes, which are beneficial for the soil. These organisms further turn and loosen the soil and add humus (organic matter) to it.
  
  

• Soil Components: Soil contains minerals, water, air, and living organisms.
• Dead plants and animals decompose in the soil, releasing nutrients that are absorbed by plants.
  
  

• Nutrient Cycling: The process of decomposing dead plants and animals to release nutrients back into the soil.
• Turning and loosening the soil brings nutrient-rich soil to the top, which is essential for plant growth.
  
  

• Tilling/Ploughing: The process of loosening and turning the soil using a plough.
• Plough: A tool made of wood or iron used for tilling.
• If the soil is very dry, it may need watering before ploughing.
  
  

• Soil Clumps (Crumbs): Big clumps of soil that form after ploughing.
• These need to be broken for better sowing and irrigation.
• Levelling: The process of flattening the soil using a leveller to make it even.
  
  

• Manure: Organic matter added to the soil to provide nutrients.
• Sometimes added before tilling to mix well with the soil.
  
  

• Moistening: Adding water to the soil before sowing seeds to ensure it is not too dry.

Agricultural Implements

Before sowing seeds, it is necessary to break soil clumps to get a better yield. This is done with the help of various tools. The main tools used for this purpose are the plough, hoe, and cultivator.

1. Plough:

• Definition: A tool used since ancient times for tilling the soil, adding fertilizers, removing weeds, and turning the soil.
• Materials: Made of wood, often drawn by a pair of bulls or other animals like horses and camels.
• Components:
  • Ploughshare: A strong triangular iron strip.
  • Ploughshaft: The main part of the plough, a long log of wood.
  • Handle: Located at one end of the ploughshaft.
  • Beam: Attached to the other end, placed on the bulls’ necks.
• Operation: One pair of bulls and a person can easily operate the plough.
• Modern Use: Wooden ploughs are increasingly being replaced by iron ploughs.
  
  

2. Hoe:

• Definition: A simple tool used for removing weeds and loosening the soil.
• Materials: Made of wood or iron.
• Components:
  • Rod: A long rod of wood or iron.
  • Blade: A strong, broad, and bent plate of iron fixed to one end, working like a blade.
• Operation: Pulled by animals.
  
  

3. Cultivator:

• Definition: A modern tool used for ploughing, driven by a tractor.
• Advantages: Saves labor and time.

2. Sowing

1. Importance of Sowing:

• Sowing is a crucial part of crop production.
• Before sowing, good quality, clean, and healthy seeds of a high-yielding variety are selected.
  
  

2. Selection of Seeds:

• Farmers prefer seeds that give high yields.
  
  

Activity 1.1: Why Some Seeds Float

• Observation: Some seeds float on water while others sink.
• Explanation: Damaged seeds become hollow and lighter, causing them to float.
• Method: A good method for separating healthy seeds from damaged ones.
  
  

3. Tools Used for Sowing:

• Before sowing, it's important to know about the tools used.
• Traditional Tool: Shaped like a funnel, seeds are filled into it and passed down through pipes with sharp ends that pierce into the soil to place seeds.

Seed Drill

Seed Drill

• Definition: A modern tool used for sowing with the help of tractors.
• Function: Sows seeds uniformly at equal distance and depth, covering them with soil to protect from birds.
• Advantages: Saves time and labor compared to traditional methods.
  
  

Boojho's Observation:

• Nursery Plants: Little plants kept in small bags at a nursery near Boojho's school.
• Explanation: Seeds of some plants like paddy are first grown in a nursery. When they grow into seedlings, they are transplanted to the field manually.
  
  

Importance of Appropriate Seed Spacing:

• Purpose: To avoid overcrowding of plants.
• Benefits: Ensures plants get sufficient sunlight, nutrients, and water from the soil.
• Management: Sometimes, a few plants may need to be removed to prevent overcrowding.

3. Adding Manure and Fertilizers

1. Definition:

• Manure and Fertilizers: Substances added to the soil as nutrients for healthy plant growth.

Boojho's Observation:

• Healthy vs Weak Plants: Boojho noticed healthy crop in one farm and weak plants in another.
• Question: Why do some plants grow better than others?
  
  

Nutrient Depletion in Soil:

• Continuous cultivation without fallow periods depletes soil nutrients.
• Solution: Farmers add manure to replenish nutrients, a process called manuring.
• Improper or insufficient manuring results in weak plants.
  
  

Manure:

• Organic substance from decomposed plant or animal waste.
• Decomposition is caused by microorganisms.
• Used to enrich soil with nutrients.
  
  

• Objective: To observe the effect of different nutrients on plant growth.
• Method:
  • Use moong or gram seeds and germinate them.
  • Place seedlings in three separate vessels.
  • Vessel A: Soil mixed with cow dung manure.
  • Vessel B: Soil mixed with urea.
  • Vessel C: Soil without additives.

Plant Growth Observation:

• Pace of Growth: Plants in all glasses may not grow at the same pace.
• Better Growth: The glass with soil mixed with cow dung manure (Glass A) may show better growth.
• Fastest Growth: The growth may be fastest in Glass A.
  
  

Manure vs. Fertilizers:

• Manure: Organic substance from decomposed plant or animal waste.
  • Improves soil texture and water retention.
  • Replenishes soil with nutrients.
• Fertilizers: Chemicals rich in specific nutrients.
  • Examples: urea, ammonium sulfate, super phosphate, potash, NPK (Nitrogen, Phosphorus, Potassium).
  • Produced in factories.
    
    

Impact of Fertilizer Use:

• Benefits: Helps farmers achieve better crop yields (e.g., wheat, paddy, maize).
• Drawbacks: Excessive use reduces soil fertility and causes water pollution.
• Solution: Substitute with organic manure or practice crop rotation.
  
  

Crop Rotation:

• Definition: Growing different crops alternately to replenish soil nutrients.
• Example: Farmers in northern India used to grow legumes as fodder in one season and wheat in the next to replenish soil nitrogen.
• Encouragement: Farmers are encouraged to adopt this practice for soil fertility.
  
  

Role of Rhizobium Bacteria:

• Location: Present in the nodules of roots of leguminous plants.
• Function: Fixes atmospheric nitrogen, helping in soil replenishment.

Differences between Fertilizer and Manure

Advantages of Manure over Fertilizers

1. Water Holding Capacity: Enhances the soil's ability to hold water.
2. Porosity: Makes the soil porous, facilitating the exchange of gases.
3. Microbial Activity: Increases the number of friendly microbes in the soil.
4. Soil Texture: Improves the texture of the soil.

4. Irrigation

1. Importance of Water:

• All living beings need water for growth and development.
• Water, along with minerals and fertilizers, is absorbed by plant roots.
• Plants contain nearly 90% water.
• Water is essential for seed germination and nutrient transport in plants.

• Water protects crops from frost and hot air currents.

• Fields need regular watering to maintain soil moisture for healthy crop growth.
• Supplying water to crops at regular intervals is called irrigation.

• The time and frequency of irrigation vary based on the crop, soil, and season.
• In summer, the frequency of watering is higher due to increased evaporation rates.

• Boojho learned the importance of watering plants from his previous experience of plants drying up and dying in summer.

• Wells, tubewells, ponds, lakes, rivers, dams, and canals are sources of water for irrigation.

Traditional Methods of Irrigation

1. Importance of Traditional Methods:

• Water from wells, lakes, and canals is lifted using traditional methods for irrigation.
• These methods are cheaper but less efficient as they require cattle or human labor.

• Moat (Pulley-System):
  • Water is lifted using a pulley system.
• Chain Pump:
  • A chain with containers lifts water and pours it into a trough.
• Dhekli:
  • A wooden contraption with a rope and bucket used for lifting water.
• Rahat (Lever System):
  • A lever system used to lift water from a water source.

• Pumps:
  • Commonly used for lifting water.
  • Powered by diesel, biogas, electricity, or solar energy.

Modern Methods of Irrigation

5. Protection from Weeds

1. Definition:

• Weeds: Undesirable plants that grow along with crop plants.

• Boojho and Paheli observed other plants growing along with wheat in a field.
• Question: Have these other plants been planted purposely?

• Weeds compete with crop plants for water, nutrients, space, and light.
• They affect the growth of crops and interfere with harvesting.
• Some weeds may be poisonous to animals and humans.

• Tilling:
  • Helps in uprooting and killing weeds before sowing crops.
• Manual Removal:
  • Involves physically uprooting or cutting weeds close to the ground using a khurpi.
• Chemical Control:
  • Use of weedicides like 2,4-D.
  • Sprayed in fields to kill weeds without damaging crops.
  • Diluted with water and sprayed using a sprayer.

• Best time for weed removal is before they produce flowers and seeds.

Effects of Weedicides on Handlers

• Question: Do weedicides have any effect on the person handling the weedicide sprayer?
• Effect on Health:
  • Weedicides may affect the health of farmers.
  • These chemicals should be used very carefully.
• Precautions for Handlers:
  • Farmers should cover their nose and mouth with a piece of cloth during spraying of these chemicals.

6. Harvesting

1. Definition:

• Harvesting: The cutting of a crop after it is mature.

• Manual harvesting:
  • Done using a sickle.
• Mechanized harvesting:
  • Done using a machine called a harvester.

• Separation of grain seeds from the chaff.
• Done using a machine called a 'combine', which acts as both a harvester and a thresher.

• Sometimes, stubs are left in the field after harvesting.
• These stubs are burnt by farmers, causing pollution and risk of fire damage to crops.

• Farmers with small land holdings separate grain and chaff by winnowing.

Harvest Festivals

1. Description:

• After three or four months of hard work, farmers celebrate the harvest.
• Golden fields of standing crop, laden with grain, bring joy and a sense of well-being to farmers.
• Efforts of the past season have borne fruit, and it is time to relax and enjoy.
  
  2. Celebrations:

• The period of harvest is a time of great joy and happiness in all parts of India.
• Men and women celebrate it with great enthusiasm.
  
  3. Special Festivals:
• Pongal: Celebrated in Tamil Nadu to mark the end of the harvest season.
• Baisakhi: Celebrated in Punjab to mark the beginning of the harvest season.
• Holi, Diwali, Nabanya, and Bihu: Also associated with the harvest season in various parts of India.

Storage

1. Importance of Storage:

• Storage of produce is crucial to prevent spoilage.

• Harvested grains should be safe from moisture, insects, rats, and microorganisms.
• Freshly harvested grains have more moisture and may spoil if not dried properly.
• Grains are dried in the sun before storage to reduce moisture content and prevent spoilage.

• Drying grains prevents attacks by insect pests, bacteria, and fungi.

Methods of Grain Storage

1. Storage Containers:

• Farmers use jute bags or metallic bins for storing grains.
• Large-scale storage is done in silos and granaries to protect grains from pests.

• Dried neem leaves are used for storing food grains at home.

• Chemical treatments are required for storing large quantities of grains in big godowns to protect them from pests and microorganisms.

Animal Husbandry

• Definition: Animal husbandry is the practice of breeding and raising livestock for meat, milk, wool, or other products.
• Importance:
  • Like plants, animals provide us with different kinds of food.
  • Many people living in coastal areas consume fish as a major part of their diet.
• Care of Animals:
  • Animals reared at home or in farms need to be provided with proper food, shelter, and care.
• Fish as Food:
  • Fish is good for health and is a major part of the diet in coastal areas.
  • Cod liver oil, obtained from fish, is rich in vitamin D.