CBSE Class 9 Science Chapter 15 Revision Notes

Chapter 15: Improvement in Food Resources Revision Notes

  • Food provides all of the essential nutrients needed for growth, development, and good health.
  • All nutrients, including carbs, lipids, proteins, vitamins, and minerals, are found in food.


  • Agriculture is the study or practise of farming, which includes soil cultivation for the growing of crops and the keeping of animals for the production of food, wool, and other items.

Carbohydrates sources

  • Sugars, fresh fruits, starch, vegetables, cereals, maize, potatoes, fibres, bread, pastries, milk, and milk products are all examples of carbohydrates.

Fats and their sources

  • Fats may be found in a variety of foods, including butter, cheese, and milk, as well as oilseeds such as soybeans and groundnuts.

Vitamins and minerals

  • Vitamins and minerals are mostly found in vegetables and fruits. Meat and fish can also provide some of the vitamins.

Protein-rich foods

  • Chicken, egg, fish, almond, chicken, oats, seafood, soybeans, pulses, cottage cheese, Greek yoghurt, milk, broccoli, and quinoa are the most prevalent foods high in protein.

Fodder crops

  • Forage crops such as berseem, oats, and sudangrass are grown as fodder for cattle.

Kharif crops

  • Kharif crops are those that are planted during the monsoon season (June to October).
  • Kharif crops include black gramme, cotton, green gramme, maize, paddy, pigeon pea, and soybean.

Rabi crops

  • Rabi crops are those that are cultivated throughout the winter months (October to March).
  • Rabi crops include wheat, gram, peas, mustard, and linseed.

Improvements in Crop Variety

  • Crop varieties or strains can be chosen for numerous valuable traits like as disease resistance, fertiliser responsiveness, product quality, and high yields via breeding.
  • Crop variety improvement is the term for this.


  • Crossing between genetically distinct plants is referred to as hybridisation.

Hybridization between varietals

  • It’s a cross between two separate species of the same species.

Hybridization between species

  • It is a hybrid of two separate species belonging to the same genus.

Hybridization between genera

  • It is the result of a cross between two intergeneric hybridizations from separate genera.

Genetically modified crops

  • We acquire genetically modified crops when a beneficial gene is inserted to the genome of a crop.
  • Bt cotton, Bt brinjal, golden rice, and other genetically modified crops are examples of GM crops.

Factors that influence variety improvement

  • Different enhanced types of crops are created for a variety of reasons. The following are some of the reasons:
  1. The yield is higher.
  2. Quality has improved.
  3. Duration of maturation.
  4. Increased adaptability.
  5. Resistance to biotic and abiotic factors.
  6. Agronomic traits that are desirable.


Crop production management is the process of cultivating and harvesting crops efficiently.

Nutrient management

  • Air, water, and soil are all sources of nutrients for plants.
  • There are sixteen nutrients that are required for plant growth.
  • Carbon and oxygen come from the air, hydrogen comes from water, and the other thirteen nutrients come from the soil.
  • Nutrient management involves applying fertilisers and manures to the soil to provide the necessary nutrients.


  • Six of the 13 essential nutrients are the most important for plant growth and development, and they must be present in large quantities.
  • Macronutrients are a term used to describe a group of vital nutrients.
  • The list of macronutrients required by plants includes nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sulphur (S), and magnesium.


  • Six of the 13 necessary nutrients are categorised as macronutrients, while the remaining seven are classified as micronutrients.
  • Iron (Fe), boron (B), chlorine (Cl), manganese (Mn), zinc (Zn), copper (Cu), and molybdenum (Mo) are examples of these nutrients (Mo).
  • They are also known as trace minerals since they are only required in tiny amounts.


  • Manure is an organic material made up of animal and human waste, sludge, sewage, household trash, decomposed dead plants and animals, and other plant wastes such as dried leaves, twigs, agricultural wastes, and weeds, among other things.
  • It has a high nutritional content, which helps to enhance soil quality and boost the yield of healthy crops.

Compost and vermicompost


  • Composting is a decomposition technique in which biological waste is degraded in pits.
  • Vermicompost is compost made with the help of earthworms to speed up the process.

Green manure

  • Some plants, such as sun hemp or guar, are cultivated and then ploughed into the soil as a mulch before the crop seeds are sown.
  • As a result, these green plants become green manure, which serves to increase the soil’s nutrients.


  • Fertilizers are plant nutrients that are manufactured commercially and are only needed in modest amounts.
  • This fertiliser is available in a variety of brands on the market. NPK fertiliser, which contains nitrogen, phosphorous, and potassium, is a common type of fertiliser.

Organic Farming

  • Organic farming is a type of farming that uses little or no chemicals as fertilisers and relies heavily on organic manures.
  • To achieve the most chemical-free output, all resources are exploited to their full potential.


  • Irrigation is the technique of applying water to crops artificially in order to meet their water needs. Irrigation may be used in a variety of ways to increase agricultural productivity.
  • This procedure ensures that the crops receive water at the appropriate times.
  • During their growth season, for example, which aids in improving agricultural yields. Canals, wells, river lift systems, tanks, rainwater gathering, and watersheds are used for irrigation.

Pattern for cropping

  • The proportion of land under various crops is referred to as the cropping pattern. The following are the three types of cropping patterns:
  1. Intercropping is a cropping practise in which two or more crops are grown in the same plot of land in a certain row pattern at the same time. Crop production is improved by using this sort of cropping pattern. As a result, small farmers who are fully reliant on rains for a higher return follow it.
  2. Crop Rotation is a farming practise that involves planting many crops on the same piece of land in a predetermined order. Crops are chosen for one-year rotations, two-year rotations, and three-year rotations based on their duration.
  3. Mixed cropping is a cropping method in which two or more crops are grown on the same piece of land at the same time. Farmers choose this method because it decreases the danger of total crop loss due to insufficient rainfall or unfavourable weather conditions.

Management of Crop Protection

  • Field crops are plagued with a variety of weeds, insects, pests, and illnesses, all of which must be avoided.
  • Weeds are undesired plants in farmed fields that use all of the soil nutrients, lowering crop yields.

Weed control techniques

The following strategies are used to protect the crop from weeds.

  1. Getting a decent seedbed ready.
  2. Weeds are removed mechanically.
  3. Plants the seeds as soon as possible.
  4. Click here to learn more about Crop Protection.

Viruses and Fungi

  • Fungi and viruses are microorganism-causing illnesses that impact both plants and newly yielded crops. These infections are devastating, since they wipe out entire agricultural fields.
  • Tobacco mosaic virus, cauliflower mosaic virus, cucumber mosaic virus, and other plant viruses are examples.
  • Leaf rust, stem rust, powdery mildew, and other disease-causing fungus are examples.

Losses in storage

  • The newly harvested food grains are kept in large storage facilities such as silos after harvesting.
  • The food grains, on the other hand, are destroyed by pests or waterlogging. This is referred to as storage loss.


  • Animal husbandry is the raising and keeping of animals for a profit. Animals are raised for the purpose of producing milk, meat, and eggs.


  • Cattle are raised by nearly every farmer.
  • Cattle are raised for milk and draught labor is used for agricultural work in India.
  • Bos indicus (cow) and Bos bubalis (buffalo) are the two most common species of reared castles.
  • Cows of exotic breeds, such as Jersey and Brown Swiss, are bred to have long lactations.
  • Indian breeds such as the Red Sindhi and the Sahiwal are bred for disease resistance and drought resilience.
  • India also raises a lot of hybrids.

Poultry Farming

  • Poultry farming is a type of animal husbandry that involves raising domestic fowl for the purpose of producing eggs and chicken meat.
  • Indian poultry types include the Aseel, Busra Chittagong, and Ghagus.
  • American breeds include the Plymouth rock Wyandotte, Rhode Island red, and New Hampshire.
  • Here are some more examples:
  • Sussex, Cornish, red caps, and other English breeds are examples.
  • White leghorns, Minorca, are more often bred in the Mediterranean Class.
  • Layers are egg-laying birds, whereas broilers are meat-producing birds.


  • Fishery is the business of obtaining fish for human use. People that live near the seaside eat a lot of fish since it’s a fantastic source of protein.
  • Fish may be found in the sea, freshwater lakes, and even estuaries.
  • Aquaculture is the term for the process of catching fish. The following are the many sorts of fisheries:
  • Marine fisheries — Fishing in the oceans and seas is referred to as marine fisheries. It also deals with other seafood such as prawns, lobsters, and crabs, in addition to fish.
  • Inland fisheries – This type of fishing takes place in rivers, lakes, and tanks. Freshwater fish such as Rohu, Catla, Mrigal, Grass carp, and others are particularly popular.


  • Beekeeping, also known as apiculture, is the practice of raising bees for the purpose of producing honey and wax.
  • This has evolved into a significant agro-based and financially lucrative enterprise. Apis mellifera and Apis adamsoni are two exotic kinds cultivated in India.
  • A famous indigenous type is Apis cerena indica, sometimes known as Indian bee. Apis dorsata, popularly known as the Rock bee, is an indigenous species.

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