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CBSE NOTES CLASS 9 SCIENCE CHAPTER 15

IMPROVEMENT IN FOOD RESOURCES

Need to Improve Food Resources

Green Revolution

White Revolution

Food Security

Sustainable Practices

Food Sources

Types of Crops by Season

Activities in Improving Crop Yield

The Crop Variety Improvement

The Crop Production Management

Practices in Crop Production Management

Comparision of manure & fertilizers

Crop Protection Management

Storage of Grains

Animal Husbandry

Need for Animal Husbandry

Cattle Farming

Good management practices for caring of animals

Poultry Farming

Purpose of Poultry Farming

Good management practices for poultry farming

Disease Control in Poultry

Fish Production

Marine Fisheries

Inland Fisheries

Composite Fish Culture

Bee Keeping or Api Culture

Indian varieties of bees

Desired characteristics in bees

CBSE NOTES CLASS 9 SCIENCE CHAPTER 15

IMPROVEMENT IN FOOD RESOURCES

Need to Improve Food Resources

There is a need to improve production efficiency of crops and livestock because

1. We need to provide for the food requirements of rapidly increasing population.

2. There is no major scope of increasing area of land under cultivation.

3. Green revolution and white revolution have increased the production of crops and dairy products. These revolutions have caused damage to our natural resources to the point of destroying their balance completely.

4. Apart from the quantity of food, we need good quality food products.

Hence increase in food production without degrading our environment and disturbing the ecological balance i.e. sustainable practices are required in agriculture and animal husbandry.

Green Revolution

A large increase in crop production achieved by the use of artificial fertilizers, pesticides, and high-yield crop varieties.

White Revolution

It was the biggest dairy development program in the world. It transformed India from a milk-deficient nation into the world's largest milk producer and increased the milk available per person.

Food Security

Food security means both availability of food and access to it.

Simply increasing grain production for storage in warehouses cannot solve the problem of malnutrition and hunger.

People should have money to purchase food.

Increasing the incomes of people in the agricultural sector is necessary to combat the problem of hunger.

Sustainable Practices

Green revolution and white revolution have increased the production of crops and dairy products. These revolutions have caused damage to our natural resources to the point of destroying their balance completely.

To avoid harmful effects to the ecosystem, scientific management practices should be undertaken to obtain high yields from farms. For sustained livelihood mixed farming, intercropping, and integrated farming practices, for example, combine agriculture with livestock/poultry/fisheries/bee-keeping, etc. should be used.

Food Sources

Cereals (Wheat, rice, maize, millets and sorghum) provide us carbohydrates.

Pulses (Grams, pea and lentil) provide us proteins.

Oil seeds (Soya bean, ground nut, sesame, and castor) provide us fats.

Vegetables, spices and fruits provide us a range of minerals, nucleic acids and vitamins.

Animal Foods - Milk, Meet, Egg, Fish, Honey.

Types of Crops by Season

Kharif Crops

The crops grown in rainy season are called as Kharif crops. They are grown from June to October.

Examples - Paddy, Soya bean, pigeon pea and maize, bajra, cotton, green gram and black gram (urad).

Rabi Crops

The crops grown in winter season are called Rabi crops. They are grown November to April. Examples - Wheat, gram, peas, and mustard, linseed.

Why different crops are cultivated at different times?

Different crops require different climatic conditions, temperature and photoperiods for their growth and completion of their life cycle.

Photoperiod

Duration of availability of sunlight per day is called photoperiod.

Photosynthesis, growth, flowering etc. are all related to the duration of sunlight.

Hence different crops are cultivated at different times of the year.

Activities in Improving Crop Yield

The major groups of activities for improving crop yields can be classified as:

Crop Variety Improvement

The factors for which variety improvement is done are:

 S. No.

Type of Hybridization

Context

1

Intervarietal Hybridization

Between different varieties of same species, such as between Bengal tiger and Siberian tiger.

2

Interspecific Hybridization

Between different species, such as between lions and tigers

3

Intergeneric Hybridization

Between different genera, such as between sheep and goats

The Crop production improvement or Crop Production Management

Availability of money or financial conditions of the farmers decides different farming practices and agricultural technologies. There is a correlation between higher inputs and yields.

No cost production – no input cost, meager output

Low cost production – Some input cost, but not able to meet latest technologies and practices will result into low output.

High cost production – Latest technology, good quality seed and best practices leads to high yield.

Practices in Crop Production Management

They include nutrient management, irrigation and cropping patterns.

Nutrient Management

Plants require nutrients for growth. Nutrients are supplied to plants by air, water and soil. There are sixteen nutrients which are essential for plants.

Out of these thirteen nutrients, six are required in large quantities and are therefore called macronutrients.

The other seven nutrients are used by plants in small quantities and are therefore called micro-nutrients.

Nutrients supplied by air, water and soil

Source

Nutrients

Air

carbon, oxygen

Water

hydrogen, oxygen

Soil

(i) Macronutrients

nitrogen, phosphorus,potassium, calcium, magnesium, sulphur

(ii) Micronutrients

iron, manganese, boron, zinc, copper, molybdenum, chlorine

Deficiency of any of the nutrients affects physiological processes in plants including reproduction, growth and susceptibility to diseases. To increase the yield, the soil can be enriched by supplying these nutrients in the form of manure and fertilizers.

Manure

Manure is prepared by the decomposition of animal excreta and plant waste. The manures need around 30 days for absorption by plants.

Advantages of Using Manure

Types of Manures

(i) Compost and vermi-compost

The process in which farm waste material like livestock excreta (cow dung etc.), vegetable waste, animal refuse, domestic waste, sewage waste, straw, eradicated weeds etc. is decomposed in pits is known as composting.

The compost is rich in organic matter and nutrients.

Compost is also prepared by using earthworms to hasten the process of decomposition of plant and animal refuse. This is called vermi-compost.

(ii) Green manure

Prior to the sowing of the crop seeds, some plants like sun hemp or guar are grown and then mulched by ploughing them into the soil. These green plants thus turn into green manure which helps in enriching the soil in nitrogen and phosphorus.

Fertilizers

Fertilizers are commercially produced plant nutrients. Fertilizers are a factor in the higher yields of high-cost farming.

Advantages of Fertilizers

Harmful Effects of Fertilizers

Comparison of Manure & Fertilizers

S. No.

Manure

Fertilizers

1

Manure is prepared by the decomposition of animal excreta and plant waste

Chemical fertilizers are commercially produced plant nutrients.

2

It is cheap and prepared in rural homes and fields

It is costly and is prepared in factories

3

It is voluminous and bulky. It is inconvenient to store, transport and handle.

It is compact and concentrated. It is easy to store, transport and handle.

4

It is not nutrient specific.

It is nuteient specific and can provide specifically nitrogen, phosphorus etc.

5

Adds humus to the soil.

Does not add humus to the soil.

Organic farming

Organic farming is a farming system with

Irrigation

Most agriculture in India is rain-fed.

The success of crops is dependent on timely monsoons and sufficient rainfall spread through most of the growing season. Hence, poor monsoons cause crop failure.

Ensuring that the crops get water at the right stages during their growing season can increase the expected yields of any crop.

Due to wide variety of water resources and a highly varied climate, several different kinds of irrigation systems are adopted to supply water to agricultural lands depending on the kinds of water resources available, i.e., wells, canals, rivers and tanks.

Cropping Patterns

Different ways of growing crops can be used to give maximum benefit.

1. Mixed cropping is growing two or more crops simultaneously on the same piece of land, for example, wheat + gram, or wheat + mustard, or groundnut + sunflower.

2. Inter-cropping is growing two or more crops simultaneously on the same field in a definite pattern. A few rows of one crop alternate with a few rows of a second crop, for example, soyabean + maize, or finger millet (bajra) + cowpea (lobia).

Advantages of Mixed cropping and Inter cropping

3. Crop Rotation - The growing of different crops on a piece of land in a pre-planned succession is known as crop rotation.

Depending upon the duration, availability of moisture and irrigation facilities crop rotation is done for different crop combinations.

Advantages of Crop Rotation

If crop rotation is done properly then two or three crops can be grown in a year with good harvests. It also increases soil fertility and reduces soil erosion. It also helps in growing more than one crop on the same piece of land during a year.

All these methods reduce the need for fertilizers. These methods also help in controlling weeds and the growth of pathogens and pests in crops.

Crop Protection Management

Field crops are infested by a large number of weeds, insect pests and diseases.

Need - If weeds and pests are not controlled at the appropriate time then they can damage the crops so much that most of the crop is lost.

1. Weeds are unwanted plants in the cultivated field, for example, Xanthium (gokhroo), Parthenium (gajar ghas), Cyperinus rotundus (motha). They compete for food, space and light. Weeds take up nutrients and reduce the growth of the crop. Therefore, removal of weeds from cultivated fields during the early stages of crop growth is essential for a good harvest.

2. Insect pests attack the plants in three ways:

(i) they cut the root, stem and leaf,

(ii) they suck the cell sap from various parts of the plant, and

(iii) they bore into stem and fruits.

They thus affect the health of the crop and reduce yields.

3. Diseases in plants are caused by pathogens such as bacteria, fungi and viruses.

These pathogens can be present in and transmitted through the soil, water and air.

Methods of Crop Protection

(i) Use of pesticides namely,

These chemicals are sprayed on crop plants or used for treating seeds and soil.

Harmful effects of pesticides

Excessive use of these chemicals creates problems, since they can be poisonous to many plant and animal species and cause environmental pollution.

(ii) Weed control methods also include mechanical removal.

(iii) Preventive methods

Storage of Grains

Factors responsible for storage losses

These factors cause losses leading to poor marketability.

The damages include

These factors can be controlled by

Preventive and control measures are used before grains are stored.

Animal Husbandry

It is a scientific management of animal livestock.

The main aspects of animal husbandry are feeding, breeding and diseases control.

Animal-based farming includes Cattle farming, Poultry farming, Fish farming, and Bee keeping.

Need for Animal Husbandry

Thus, livestock production also needs to be improved.

Cattle Farming

Cattle husbandry is done for two purposes - milk and draught labour for agricultural work such as tilling, irrigation and carting.

Indian cattle belong to two different species, Bos indicus or cows, and Bos bubalis or buffaloes.

Milk-producing females are called milch animals (dairy animals), while the ones used for farm labour are called draught animals.

Milk production depends on the duration of the lactation period meaning the period of milk production after the birth of a calf. So, milk production can be increased by increasing the lactation period.

Exotic or foreign breeds (for example, Jersey, Brown Swiss) are selected for long lactation periods.

Local breeds (for example, Red Sindhi, Sahiwal) show excellent resistance to diseases.

The two can be cross-bred to get animals with both the desired qualities.

Good Management Practices in Care of Animals

Poultry Farming

Purpose of Poultry Farming

To raise domestic fowl for

Different types of poultry birds

Layers: The birds which are reared for laying eggs.

Broilers:The birds which are reared for meat.

Indian Pure Breeds: Aseel, Chittagong or Malay, Kadaknath, Busra

Exotic or Foreign Breeds: Leghorn, Minocra, Ancona etc.

The cross-breeding programmes between Indian and foreign breeds for variety improvement are done for the following desirable traits,

(i) number and quality of chicks;

(ii) dwarf broiler parent for commercial chick production;

(iii) summer adaptation capacity/tolerance to high temperature;

(iv) low maintenance requirements;

(v) reduction in the size of the egg-laying bird with ability to utilise more fibrous cheaper diets formulated using agricultural by-products.

Egg and Broiler Production

Good management practices for Poultry farming

Disease Control in Poultry

Fish Production

Fish is a cheap source of animal protein for our food.

Fish production includes

There are two ways of obtaining fish,

The water source of the fish can be

Marine Fisheries

As marine fish stocks get depleted, the demand for more fish can only be met by culture fisheries, called mariculture.

Inland Fisheries

Fresh water resources include canals, ponds, reservoirs and rivers.

Brackish water resources, where seawater and fresh water mix together, such as estuaries and lagoons are also important fish reservoirs.

Capture fishing in inland water bodies does not have high yield.

Rearing of aquatic animals like fish for food is called aquaculture.

Fish culture is sometimes done in combination with a rice crop, so that fish are grown in the water in the paddy field and the agricultural waste can be fed to fish.

Composite Fish Culture

Both local and imported fish species are used in such a system.

Combination of five or six fish species is are used in a single fishpond.

These species are selected so that they do not compete for food among them having different types of food habits. As a result, the food available in all the parts of the pond is used.

For example, Catlas are surface feeders, Rohus feed in the middle-zone of the pond, Mrigals and Common Carps are bottom feeders, and Grass Carps feed on the weeds.

Hence together these species can use all the food in the pond without competing with each other.

This increases the fish yield from the pond.

Problem of good quality seed

A major problem in fish farming is the lack of availability of good quality seed.

Many of the fish breed only during monsoon, hence it is difficult to collect the seed from the wild. Even if fish seed is collected from the wild, it can be mixed with that of other species as well.

To overcome this problem, ways have now been worked out to breed these fish in ponds using hormonal stimulation. This has ensured the supply of pure fish seed in desired quantities.

Bee-Keeping or Api-Culture

Advantages of beekeeping

Indian varieties of bees

An Italian bee variety, A. mellifera, is also used to increase yield of honey. This is the variety commonly used for commercial honey production.

Desired characteristics in bees

The bee farms are called apiaries.

The value or quality of honey depends upon