Improvement in Food Resources CBSE Class 9 Science Revision Notes Chapter 15

 

All living organisms need food because:

• It provides carbohydrates, fats vitamins and minerals

• It allows development of the organisms

• It is needed to gain energy for everyday tasks

Main sources of food:

• Plants – obtained from agriculture

• Animals – obtained from animal husbandry

The efficiency of crops and livestock is required in India because:

• The population of India is growing at a faster rate hence more amount of food is required to meet the rising demand.

• The agricultural land is limited as compared to the growing population.

Efforts made to meet the increase in food demands

• Green Revolution – The introduction of modern technology and equipment, usage of fertilizers and high-quality seeds

• White Revolution – Increasing the growth of milk production by introducing dairy development programs

The introduction of these revolutions has led to an increased use of natural resources hence now sustainable methods of increasing crops and livestock efficiency are also required.

Improvement in Crop Yields

Different types of crops and their Nutritional Value

Crop	Examples	Value
Cereals	Wheat, rice, maize, millets, sorghum	Carbohydrates
Pulses	Gram, black gram, green gram, pigeon pea, lentil	Proteins
Oilseeds	Soybean, groundnut, sesame, castor, mustard, sunflower	Fats
Vegetables, Spices and Fruits	Carrot, Cinnamon, orange, spinach	Minerals, vitamins and small amounts of Carbohydrates, fats and proteins
Fodder crops	Berseem, oats, sudan grass	Food for Livestock

 

Figure 1 Different types of Crops

Different crops grow in different Seasons because they require a particular climate temperature and photoperiod for their growth.

Crop	Season	Example
Kharif	Rainy (June to October)	Rice, maize, millets
Rabi	Winter (November to April)	Soybean, pigeon pea, wheat
Zaid	Summer (March to June)	Sugarcane, Watermelon, Cucumber

Activities that lead to improvement in the crop yield:

• Crop Variety Improvement

• Crop Production Improvement

• Crop Production Management

Crop Variety Improvement

In this approach, crops are selected on the basis of their characteristics. For instance, how well they can respond to fertilizers, can they produce high yield, how they resist diseases and so on.

Different methods of Crop Variety Improvement

1. Hybridisation - In this process, genetically different plants are crossbred.

They can be three types of crossing

• Intervarietal - Between two varieties of a plant

• Interspecific - Between two species belonging to same genus

• Inter Generic - Between species of different genus

2. Introduction of Gene - A gene that can provide the desirable characteristics to a crop are introduced in this process. As a result, we obtain genetically modified crops.

Factors on which Crop Yield Generally Depends

• The seeds used by the farmers - The seeds that are of similar variety are preferable.

• Climate or Weather Conditions - Crops that can sustain diverse climatic conditions are preferable.

• The duality of the Soil - Crops that can survive in a highly saline soil are preferable.

• Availability of Water - Crops should be grown as per the availability of water in the region.

Why do we need to perform a crop variety improvement?

• Increasing the yield of the crops

• Improving the quality of the crop. Different crops may have different qualities. For Example, pulses have high protein quality, oilseeds have oil quality fruits and vegetables must have preserving quality.

• Improving crop resistance to biotic and abiotic stresses. Biotic stresses referred to the diseases, insects and nematodes while abiotic stresses referred to floods, drought, heat and cold weather conditions.

• To shorten the maturity period of crops. This will allow farmers to grow a variety of crops in a year.

• It would also lead to an increase in the yield of the crop as it reduces the chances of losses during the harvesting and simplifies the harvesting period.

• Achieving the required agronomic characteristics of crops such as the right height, weight, lodging, resistance and high yield. In this way, they would consume the right nutrients and would produce a higher yield. 

Crop Production Management

Different farmers can have small or large farms on which they can use different farming practices. The choice of farming practices would depend upon the availability of financial resources money. Hence, production practices can be divided into different levels

1. No cost Production

2. Low-cost Production

3. High-cost Production

Nutrition Management

16 Essential Nutrients that plants need –

Figure 2 - 16 Essential nutrients for plants

The nutrients that are required in large quantities are called Macronutrients. The nutrients that are required in small quantities by the plants are called Micronutrients. 

Figure 3 Nutrients provided by air, water and soil

What happens if plants lack in these nutrients?

• The yield may be affected as plants won't be able to reproduce

• Plant growth can be affected plants can get diseases easily

How can we increase the yield by providing all nutrients to the plants?

Using Manure - Manure is prepared by using animal excreta and plant waste.

Functions or Features of Manure

• Manure mainly contains organic matter which increases the fertility of the soil.

• It also contains nutrients in small quantity which are then supplied to the soil on adding manure.

• The soil structure also enhance is due to manure. It tends to hold more amount of water.

• The organic matter avoids waterlogging and drainage in clayey soil.

• Manure is purely organic hence using more manure is completely healthy for the plant as well as the environment.

• Using manure is a way to recycle farm waste.

What is composting?

The process of recycling farm waste material by decomposing it is called Composting. The product formed on decomposition is called Compost. The composed has a high variety of nutrients and organic matter. The material used in the preparation of compost is animal excreta, sewage waste, vegetable waste and weeds.

Figure 4 Compost preparation

Classification of Manure

1. Compost and Vermicompost Manure

Compost	Vermicompost
A manure prepared from waste materials such as cow dung, sewage, vegetable wastes and domestic waste	A manure that is prepared by using Earthworms
Takes around 3 to 6 months in formation	Takes around 1 to 2 months in formation
The microbes decay the matter and manure is formed	Earth worms reduce the matter and compost is formed

2. Green Manure – sometimes specific plants are grown and then ploughed again in the soil. These plants decay and turn into manure which enriches the soil, mainly with nitrogen and phosphorus. Plants that are used in the production of green manure are hemp, clover, peas grass mixtures.

Figure 5 Green Manure Crops

Using Fertilizers

Fertilizers are artificial materials that are produced on a commercial basis or natural substances that ensure nutrient benefits to the soil.

• Organic fertilizers used by Farmers: Limestone, rock phosphate

• Artificial fertilizers used by Farmers: Ammonium nitrate, potassium sulfate

Features of Fertilizers

• Fertilizers provide important nutrients such as nitrogen, potassium and phosphorus to the soil.

• They help in the proper growth of the plants.

• They are responsible for high yields in the high-cost farming methods.

Figure 6 Using fertilizers in fields

Precautions with Fertilizers

• Fertilizers should be applied in a proper amount as an excess of fertilizers is not good for the plants.

• Proper precautions regarding the time of applying fertilizers should be taken.

• Excess use of fertilizers can lead to water pollution as the extra fertilizers get washed away during irrigation.

• Excess use of fertilizers can destroy the fertility of the soil as well.

How are fertilizers and manure different?

Manure	Fertilizers
Manure provides humus to the soil	Fertilizers do not provide humus to the soil
Manures are less rich in nutrients	Fertilizers are highly rich in nutrients
Long term usage of manure leads to increment in the fertility of the soil	Long term usage of fertilizers can lead to decrease in the soil fertility

What is organic farming?

A farming practice which involves no use of artificial chemicals, fertilizers and pesticides and completely relies upon organic matter is known as organic farming. Organic farming uses healthy cropping systems such as crop rotation, intercropping and mixed cropping. Organic matter used in organic farming:

• manure

• bioagents such as blue-green algae

• biofertilizers

• Neem leaves and turmeric as biopesticides 

Figure 7 Elements of Organic Farming

Irrigation

It is a process of application of water in controlled amounts at regular intervals to the crops. Irrigation methods are adopted at various places especially in areas of low rainfall to ensure the proper growth of crops. 

Figure 8 Irrigation of fields

Why do droughts occur?

The scarcity of water or low rainfall often results in drought conditions. If farmers do not use any irrigation methods and only rely on rainfalls, draught poses a serious threat to the crops. Areas with light soils also tend to face drought-like conditions as soils cannot retain water

Irrigation Methods

Wells: two types of wells are used for irrigation: Tubewell: tube wells are tube-like structures that are used to extract the underground water. Dug Wells: dug wells are the wells dug in the ground in order to extract the underground water. Water from dug well and tubewell both is lifted by using pumps.
Canals: A canal system is a network created to move water from one source of water such as a stream or reservoir. The main canal is divided into branches that spread by through the fields so that water can be distributed everywhere.
River Lift System: A river lift system is used to draw water from the rivers directly for irrigational purposes. This system is successful in areas where the canal system is not successful.
Tanks: farmers often use small storage reservoir that can store as well as supply water in the small fields.
Rainwater Harvesting: Instead of just letting the rainwater flow away farmers often store it in the reservoir tank. This water can we for the used for irrigational purposes.
Watershed Management: Small dams are built on the rivers and streams in order to increase the ground levels of the area. These check dams prevent water from flowing away and causing soil erosion.

Cropping Patterns

Different cropping patterns are used by farmers in order to increase the crop yield:

• Mixed Cropping

• Intercropping

• Crop Rotation

Mixed Cropping

• It is a cropping pattern in which two or more crops are grown together in the same field.

• The main aim of this cropping method is to ensure some healed even if one of the crops fails to grow properly.

• The seeds of different crops are combined and planted together.

• Same fertilizers are used for all the crops.

• For Example, wheat and gram, wheat and mustard, groundnut and sunflower.

Figure 15 (a) Mixed Cropping in same row

Intercropping

• It is a cropping method in which two or more crops are grown together in a field but in a specific pattern.

• The seeds of these crops are not combined before plantation.

• Both the crops used different kinds of fertilizers depending upon their own requirements.

• The main objective of this method is to ensure the maximum productivity of the crops.

• Since the crops have different nutrient requirements they would use maximum nutrients from the soil.

• Diseases and pest would also not easily spread to all the crops.

• For Example, soybean and maize, finger millets and cowpea.

Figure 15(b) Intercropping in specific rows

Crop Rotation

• In this cropping method, different types of crops are chosen and irrigated on the same piece of land sequentially.

• The rotation of crops depends upon the soil, climate and water retention of the soil.

How is crop rotation useful?

• If farmers grow the same crop on the land for long-term the same nutrients keep on depleting from the soil which leads to a decrease in the soil fertility.

• But when crops with different nutritional requirements are grown the soil nutrients get enriched and the fertility of the land is maintained.

• Different crops are not susceptible to all kinds of pests and diseases.

• Planting different crops on rotation can lead to a better yield.

• Crop rotation allows a reduction in the number of fertilizers and pesticides on the fields.

Figure 16 Crop Rotation

Crop Production Management

Factors that can affect the production of crops are weeds, pests and diseases.

• Weeds: Along with crops, sometimes some other plants also grow up which are not needed. These are called weeds. Weeds can affect the crop as they utilise the nutrients from the soil that are meant to be used by the crops.

Weed Control Methods:

• Weedicides are sprayed on the fields that can kill them as they do not harm any crops.

• Weeds can be uprooted manually by the farmers.

• The crop is sown timely are not affected by weeds.

• Using different methods of cropping suggest crop rotation and intercropping also reduce the chances of growing weeds.

Figure 17 Uprooting weeds manually

2. Pests: Several insects and pests can affect the crops in different ways:

• They can cut the parts of the crops like fruits, leaves and stems.

• They can get into the stems and roots of the plants.

• They suck the cell sap of the plants and hence destroy them.

Pest Controlling Methods:

• Pesticides and insecticides are sprayed on the fields to kill the germs.

• Crops should be checked timely to ensure safety against pests.

• Usage of effective cropping methods such as crop rotation ensures insect management in the fields.

• Sometimes summer ploughing is also used to destroy the weeds and pests.

Figure 18 Pest Management

Diseases: Microorganisms such as fungi, bacteria and viruses often attack the crops and affect them. These pathogens can be transmitted to the crops via soil, water or air.

Disease Management Methods

• Selecting the crop that suits the temperature and climatic conditions of the place.

• Planting the seeds on right time and in an environment that favours their growth.

• Using herbicides such as dicamba and glufosinate ammonium and fertilizers such as ammonium nitrate, potassium sulfate.

• Using crop rotation method and mixed cropping.

Storage of Grains

Factors that lead to storage losses of crops are:

• Biotic Factors: Like insects, fungi, bacteria, rodents and mites

• Abiotic Factors: Like excessive temperature and moisture.

How to prevent storage loss?

• Maintaining the storage houses properly

• Cleaning the grains properly before storage

• Drying the grains properly before storage in sunlight as well as in the shade

Animal Husbandry

In agriculture, animal husbandry is a special field that deals with rising of the livestock in a controlled, selective environment by providing them with the right care so that they can stay healthy and disease free.

There is a need to improve livestock production because the population of India is tremendously increasing. This means an increase in demand for eggs, milk and meat.

Animal husbandry includes the following:

1. Cattle Farming

Cattle are used for two reasons –

• They provide milk

• They work as draught labour in the fields

Milch Animals: Animals that provide milk are called Milch Animals.

Draught Animals: Animals that work in the fields for irrigation, carting and tiling are called Draught Animals.

Figure 19 Cattle Farming

Can we increase milk production in cattle?

• Milk production can be enhanced by increasing the lactation period in the cattle.

• Crossbreeding of foreign breeds and local breeds can provide cattle with qualities of increased lactation period and resistance to diseases.

• Shelters of the cattle should be kept neat and clean in order to keep the cattle healthy.

• The cattle should be kept clean and should be provided with a covered shelter that can protect them from harsh weathers.

• The floor of the shelters to be kept a dry and clean

Food requirements of dairy animals:

• Maintenance requirements: the food that is required to keep the animals healthy

• Milk production requirements: the food that is needed in the lactation period

• Animal feeds

  • Roughage – contains fibre

  • Concentrates – contains low fibre but high nutritional value

  • Feed Additives – includes food that contains micronutrients that can promote health and milk production

Protecting the Cattle from Diseases:

• Diseases can lead to a reduction in the production of milk and even the death of cattle.

• Mainly parasites can affect the health of the cattle. These parasites can be found in the animals or they may attack them externally.

• The internal parasites generally damage the liver and stomach of these animals. For example, worms and flukes.

• The external parasites cause skin diseases in cattle.

• Sometimes bacteria and virus also called several diseases in the cattle.

• A good way to prevent diseases is vaccination.

2. Poultry Farming

Poultry farming includes different kinds of domesticated birds. Different types of poultry are:

• Chicken

• Duck

• Goose

• Pigeon

• Turkey

It is mainly done for:

1. getting eggs through layers

2. getting chicken meat through broilers

Examples of Poultry Birds:

• Indigenous breeds: Aseel, Burosa

• Foreign breeds: Leghorn, Black Minorca

Figure 20 Poultry Animals

Crossbreeding is a way to achieve this. Generally, foreign breeds of chicken are crossed with Indian breeds to achieve high quality. It thus has better traits such as:

• Increase in a number of chicks.

• They can tolerate high temperatures.

• They do not require much maintenance

• They can survive cheap diets

Egg and broiler production

Broiler Chicken

• They need a diet with a high quality of Vitamins A and K, proteins and fats.

• They need special care to maintain feathering and avoiding death.

• Proper hygiene and temperature conditions should be provided to the broiler chicken.

Layers

• They do not require such nutrient-rich diet.

• They just need a controlled diet.

• The layers require more space and lightning as compared to the broilers.

Disease Control methods should also be adopted against the diseases that are generally caused by bacteria, fungi and parasites in broilers and layers. Disinfectants can be sprayed regularly to avoid such diseases. Sometimes deficiency of nutrition can also need to diseases. Vaccination is a good way to protect the poultry fowl from diseases.

3. Fish Production

Fish can be obtained in two ways:

• From Natural Resources - Capture Fishing

• From Fish Farming - Culture Fishing

Marine Fisheries

• Marine fishes are caught using fishnets and mechanical capturing techniques.

• The main source of marine fishes is marine water or salt water.

• Generally, large numbers of fishes can be captured at a time through mariculture.

• For Example, tuna, Bombay duck, prawns

Inland Fisheries

• Fishes found in lakes, ponds, lagoons and rivers are captured.

• The main source of Inland fisheries is freshwater and brackish water.

• The yield is not as high in these sources hence large numbers of fishes are captured through aquaculture.

• For Example, silver carp, common carp

Figure 21 Inland Fisheries

Aquaculture: It is a method of farming aquatic animals under controlled circumstances. It is performed in both freshwater and saltwater bodies.

Mariculture: It is a branch of aquaculture hence a method of fish farming under control environment. Mariculture is often performed in the ocean, a particular section of the ocean or in the tanks that are filled with seawater only.

Composite fish culture

• In a composite fish culture, fishes are grown along with rice crop in the paddy fields.

• In this method, a combination of 5 - 6 local as well as foreign fishes is grown in a single pond.

• Such species are selected because they have different food habits and would not compete for the food with each other.

• Some of them are surface feeders; some are middle zone feeders while others are bottom feeders.

• They would rather eat all the food in the pond.

• As a result, the fish yield in the pond increases

For Example, Catlas (surface feeders), Rohu (middle feeders), Mrigal (bottom feeders), Common Carps (bottom feeders), Grass Craps (aquatic weed eaters) are often grown together in composite fish culture. 

4.  Beekeeping

Bee farming is performed in bee farms or apiaries. Many farmers perform beekeeping as a means of generating additional income because:

• Honey is a widely used product

• Bee farming is not very expensive

• They also generate wax along with honey

 

Figure 22 Bee Farming

Bees used for commercial and honey production

• Apis Cerana Indica - Indian bee

• A. Dorsata - The rock bee

• A. Florae - The little bee

• A. Mellifera – Italian variety of bee

Figure 23 Honey Bee examples

Castes in Honey Bee

The honey bees build a nest which is called as a bee-hive. A hive contains almost 10,000 to 60,000 bees. The bees live together in a colony and divide themselves into 3 different castes.

• Queen bee: the fertile, functional female of all is the queen bee. It is the supreme bee in the colony.

• Drone bees: they are the smaller male bees of the colony. Their main task is to maintain the hive.

• Worker bees: they are the smallest in size but the most active members of the hive. They perform different functions such as collecting pollens and nectar, constructing the comb, cleaning the cells of the hive. 

Why Italian bees are popular in bee farming?

• They produce large amounts of honey.

• They do not sting much.

• The breeding period in Italian bees is long.

Factors that determine the quality of honey

• Along with the choice of selection of the bee species, the flowers decide the quality quantity and taste of the honey produced.

• There should also be enough pasturage or availability of flowers to the bees so that they can collect enough nectar and pollen.