WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production Long Answer Type Questions

Chapter 8 Human Food And Food Production Long Answer Type Questions


Question 1. What are kharif and rabi crops? Write their differences.

Crop Production and Management

We know that the energy from food is utilized by organisms for carrying out their various bodily functions, such as digestion, respiration, and excretion.

We get our food from plants, animals, or both. Since we all need food, how can we provide food to a large number of people in our country? In order to provide food for a large population— regular production, proper management, and distribution of food are necessary.

Till 10,000 B.C. people were nomadic. They were wandering in groups from place to place in search of food and shelter. They ate raw fruits and vegetables and started hunting for animals for food.

Later, they could cultivate the land and produce rice, wheat, and other food crops. Thus, was born ‘Agriculture’. When plants of the same kind are grown and cultivated in one place on a large scale, they are collectively called a crop.

For example, a crop of wheat means that all the plants grown in a field are of wheat. We already know that crops are of different types like cereals, vegetables, and fruits.

These can be classified on the basis of the season in which they grow. India is a vast country. The climatic conditions like temperature, humidity, and rainfall vary from one region to another.

Accordingly, there is a rich variety of crops grown in different parts of the country. Despite this diversity, two broad cropping patterns can be identified. These are:

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Kharif Crops: The crops which are sown in the rainy season are called Kharif crops. The rainy season in India is generally from June to September. Paddy, maize, soybean, groundnut, cotton, etc., are Kharif crops.

Rabi Crops: The crops grown in the winter season are called rabi crops. Their time period is generally from October to March. Examples of rabi crops are wheat, gram, pea, mustard, and linseed.

Besides these, pulses and vegetables are grown during summer in many places. Basic Practices of Crop Production Cultivation of crops involves several activities undertaken by farmers over a period of time.


Kharif Rabi
Season of sowing Rainy season Winter season
Cultivation period June to September October to March
Examples of such crops Paddy, maize and soybeans, pulses, and vegetables are grown during summer Wheat, gram, pea, and mustard


You may find that these activities are similar to those carried out by a gardener or even by you when you grow ornamental plants in your house. These activities or tasks are referred to as agricultural practices. These activities are listed below-

  1. Preparation of soil
  2. Sowing
  3. Adding manure and fertilizers
  4. Irrigation
  5. Protection from weeds, pests, etc
  6. Harvesting
  7. Storage.

Question 2. Write about the preparation of soil for crop production.

Preparation of soil:

The preparation of the soil is the first step before growing a crop. This involves turning the soil and loosening it so that roots can penetrate deep into the soil and also allows the roots to breathe easily.

Loosening of soil helps in the growth of earthworms and microbes which further loosens the soil and also adds humus to it. Need for the soil to be loosened – Soil is rich in minerals, water, air & some living organisms.

The dead plants and animals when decomposed, release nutrients back into the soil making it nutrient-rich. Loosening of soil brings the nutrient, rich soil to the top for the plants to use for their growth.

The process of loosening and turning the soil is called Tilling or Ploughing. Tilling / Ploughing is done by using Ploughs made of wood & iron.

Big pieces of soil or crumbs left in the plowed field are broken with the help of a plank. Leveling of soil is done with the help of a leveler which is important for the purpose of Sowing and Irrigation.

Tilling also ensures proper mixing of manure with soil. A home is also sometimes used for removing weeds and for plowing.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production Preparation of soil


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

Plough: This is being used since ancient times for tilling the soil, adding fertilizers to the crop, removing the weeds, scraping of soil, etc. This implement is made of wood and is drawn by a pair of bulls or other animals (horses, camels, etc.).

It contains a strong triangular iron strip called plowshare. The main part of the plow is a long log of wood which is called a plow shaft.

WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production Plough


Removing the weeds, scraping off the soil, etc. This implement is made of wood and is drawn by a pair of bulls or other animals (horses, camels, etc.).

It contains a strong triangular iron strip called plowshare. The main part of the plow is a long log of wood which is called a plow shaft.

There is a handle at one end of the shaft. The other end is attached to a beam that is placed on the bulls’ necks. One pair of bulls and a man can easily operate the plow.

The indigenous wooden plow is increasingly being replaced by iron plows nowadays.

Hoe: It is a simple tool that is used for removing weeds and for loosening the soil. It has a long rod of wood or iron. A strong, broad, and bent plate of iron is fixed to one of its ends and works like a blade. It is pulled by animals.

Cultivator: Nowadays plowing is done by tractor-driven cultivators. The use of cultivators saves labor and time. For plowing small agricultural land or flower garden nowadays power tiller is used.

Question 3. What are manures and fertilizers? Write their difference.

Adding manure and fertilizers:

The substances which are added to the soil in the form of nutrients for the healthy growth of plants are called manure and fertilizers.

Soil supplies mineral nutrients to the crop. These nutrients are essential for the growth of plants. Continuous growing of crops makes the soil poorer in certain nutrients.

Therefore, farmers have to add manure to the fields to replenish the soil with nutrients. This process is called manuring. Improper or insufficient manuring results in weak plants.

Manure is an organic substance obtained from the decomposition of plant or animal wastes. Farmers dump plant and animal waste in pits in open places and allow it to decompose. The decomposition is caused by some microorganisms. The decomposed matter is used as organic manure.

Fertilizers are chemical substances that are rich in a particular nutrient. How are these different from manure? Fertilizers are produced in factories.

Some examples of fertilizers are- urea, ammonium sulfate, superphosphate, potash, and NPK (Nitrogen, Phosphorus, and Potassium). The use of fertilizers has helped farmers to get a better yield of crops such as wheat, paddy, and maize.

But excessive use of fertilizers has made the soil less fertile. Fertilizers have also become a source of water pollution. Therefore, in order to maintain the fertility of the soil,

we have to substitute fertilizers with organic manure or leave the field uncultivated (fallow) in between two crops.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production Adding manure and fertilisers


The use of manure improves soil texture as well as its water-retaining capacity. It replenishes the soil with all the nutrients.

Another method of replenishing the soil with nutrients is through crop rotation. This can be done by growing different crops alternately.

Farmers sometimes grow legumes as fodder in one season and wheat in the next season. This helps in the replenishment of the soil with nitrogen.

In the previous chapter, you learned about Rhizobium bacteria. These are present in the nodules of the roots of leguminous plants. They fix atmospheric nitrogen.

Differences between Fertiliser and Manure


Fertiliser Manure
(1) A fertilizer is an inorganic salt. (1) Manure is a natural substance obtained by the decomposition of cattle dung, human waste, and plant residues.
(2) A fertilizer is prepared in factories. (2) Manure can be prepared in the fields.
(3) A fertilizer does not provide any humus to the soil. (3) Manure provides a lot of humus to the soil.
(4) Fertilisers are very rich in plant nutrients like nitrogen, phosphorus, and potassium. (4) Manure is relatively less rich in plant nutrients.


Advantages of Manure: Organic manure is considered better than fertilizers. This is because It enhances the water-holding capacity of the soil. It makes the soil porous which exchange of gases becomes easy.

Question 4. What is irrigation? Describe the modern methods of irrigation of crop fields.


All living beings need water to live. Water is important for the proper growth and development of flowers, fruits, and seeds of plants. Water is absorbed by the plant roots.

Along with water, minerals, and fertilizers are also absorbed. Plants contain nearly 90% water. Water is essential because the germination of seeds does not take place under dry conditions.

Nutrients dissolved in the water get transported to each part of the plant. Water also protects the crop from both frost and hot air currents. To maintain the moisture of the soil for healthy crop growth, fields have to be watered regularly.

The supply of water to crops at different intervals is called irrigation. The time and frequency of irrigation vary from crop to crop, soil to soil, and season to season.

In summer, the frequency of watering is higher due to the increased rate of evaporation of water from the soil and the leaves.

Sources of irrigation: The sources of irrigation are— wells, tube wells, ponds, lakes, rivers, dams, and canals.

Traditional Methods of Irrigation

The water available in wells, lakes, and canals is lifted up by different methods in different regions, for taking it to the fields.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production Taditional methods o0f irrigation

Protection from Weeds

In a field, many other undesirable plants may be Cattle or human labor is used in these methods. So these methods are cheaper but less efficient. The various traditional ways are:

  1. Moat (pulley system)
  2. Chain pump
  3. Dhekli, and
  4. Rahat (Lever system)

Pumps are commonly used for lifting water. Diesel, biogas, electricity, and solar energy are used to run these pumps.
Modern Methods of Irrigation Modern methods of irrigation help us to use water economically. The main methods used are as follows:

Sprinkler System: This system is more useful on uneven land where sufficient water is not available. The perpendicular pipes, having rotating nozzles on top, are joined to the main pipeline at regular intervals.

When water is allowed to flow through the main pipe under pressure with the help of a pump, it escapes from the rotating nozzles. It gets sprinkled on the crop as if it is raining. The sprinkler is very useful for sandy soil.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production drip system


Drip system: In this system, the water falls drop by drop just at the position of the roots. So it is called a drip system. It is the best technique for watering fruit plants, gardens, and trees.

The system provides water to plants drop by drop. Water is not wasted at all. It is a boon in regions where the availability of water is poor and grows naturally along with the crop. These undesirable plants are called weeds.

The removal of weeds is called weeding. Weeding is necessary since weeds compete with crop plants for water, nutrients, space, and light.

Thus, they affect the growth of the crop. Some weeds interfere even in harvesting and may be poisonous for animals and human beings.

Question 5. Write about the process of propagation, planting, and storage of mango.


Mango (Mangifera indica) belonging to Family Anacardiaceae is the most important commercially grown fruit crop in the country. Mango is the leading fruit crop of India and is considered to be the king of fruits.

Besides the delicious taste, excellent flavor, and attractive fragrance, it is rich in vitamins A and C. The tree is hardy in nature and requires comparatively low maintenance costs.

Mango occupies 22% of the total under fruits comprising 1.2 million hectares, with a total production of 11 million tones. b

Uttar Pradesh and Andhra Pradesh are having the largest area under mango each with around 25% of the total area followed by Bihar, Karnataka, Kerala, and Tamil Nadu.

Mango fruit is utilized at all stages of its development both in its immature and mature state. Raw fruits are used for making chutney, pickles, and juices.

The ripe fruits besides being used for dessert are also utilized for preparing several products like squashes, syrups, nectars, jams, and jellies.

India is the largest mango-producing country, accounting for about 60% of world production, the export of fresh fruit is Limited to Alphonso and Dashehari varieties.

India’s share in the world mango market is about 15 percent. Mango accounts for 40 percent of the total fruit exports from the country. There is good scope for increasing the area and productivity of mango in the country.



Climate: Mango can be grown under both tropical and sub-tropical climates from sea level to 1400 m altitude, provided there is no high humidity, rain, or frost during the flowering period.

Places with good rainfall and dry summer are ideal for mango cultivation. It is better to avoid areas with winds and cyclones which may cause flower and fruit shedding and breaking of branches.

Soil: Mango comes up on a wide range of soils from alluvial to laterite provided they are deep (minimum 6′) and well drained. It prefers slightly acidic soils.

Varieties: Though there are nearly 1000 varieties of mango in India, only the following varieties are grown in different states: Alphonso,

the simplest way is by pouring the paddy down from a height on a windy day to a large square mat on open Bangalore, Banganpalli, Bombai, Bombay Green, Dashehari, Fazli, Fernandin, Himsagar, Kesar, KishenBhog, Langra, Mankhurd, Mulgoa, Neelam, Samarbehist, Chausa, Suvarnarekha, Vanaraj, and Zardalu.

Recently some mango hybrids have been released for cultivation by different institutes/ universities. These are – mallika, amrapali, mangeera, ratna, arkaanmol, etc.


Farmers should always get vegetatively propagated, true-to-type plants from recognized nurseries. Inarching, veneer grafting, side grafting, and epicotyl grafting are the popular methods of propagation in mango.


Land should be prepared by deep plowing followed by harrowing and leveling with a gentle slope for good drainage.
Planting is usually done in the month of July- August in rainfed areas and during February- March in irrigated areas. In case of heavy rainfall zones, planting is taken up at the end of the rainy season.

One-year-old healthy, straight-growing grafts from reliable sources can be planted at the center of pits along with the ball of the earth intact during the rainy season in such a way that the roots are not expanded and the graft union is above the ground level. Plants should be irrigated immediately after planting.

Fertiliser Application: Fertilizers may be applied in two split doses, one half immediately after the harvesting of fruits in June/July and the other half in October, in both young and old orchards followed by irrigation if there are no rains. Foliar application of 3% urea in sandy soils is recommended before flowering.

Question 6. Write the geographical conditions necessary for tea plantations.


Tea is the dried leaf of a bush. It contains theine and when added to boiling water along with sugar and milk, it gives a very cheap and stimulating drink.

Thus it is the most important beverage crop in India. Tea bush is supposed to be indigenous to China but it was reported by Major Robert Bruce in 1823 that indigenous tea bushes grew wild on the hill slopes of upper Assam. In the year 1840, tea seeds were.

Irrigation: Young plants are watered frequently for proper establishment. In the case of grown-up trees, irrigation at 10 to 15 days intervals from fruit set to maturity is beneficial for improving yield.

Harvesting and yield: The yield of mango varies greatly, depending upon the variety and agro-climatic conditions prevailing in a region. Grafted mango trees start bearing from the fifth year onward. However, seedling trees may take 8-10 years.

Economic Importance: Raw fruits of local varieties of mango trees are used for preparing various traditional products like raw slices in brine, amchur, pickle, murabba, chutney, pane (sharbat), etc.

Presently, the raw fruit of local varieties of mango is used for preparing pickles and raw slices in brine on the commercial scale while fruits of the Alphonso variety are used for squash in the coastal western zone.

The wood is used as timber, and dried twigs are used for religious purposes. The mango kernel also contains about 8-10% good-quality fat which can be used for saponification. Its starch is used in the confectionery industry.

Weed control and Plant protection: The mango orchard should be completely free from weeds. In order to control weeds, shallow hoeing at quarterly intervals should be done. Black plastic mulch should be used to restrict the germination of weed seeds and suppression of weed growth.

Mango crop suffers seriously from pests: hopper, mealy bug, fruit fly, shoot and stem borer, and stone weevil. The Hoppers are most divesting during the flowering period as they suck the sap from tender shoots, leaves, and panicles.

Proper pesticides are recommended for the protection of trees imported from China and commercial tea plantations were set up in the Brahmaputra valley.

There are four main types of tea: green tea, black tea, oolong tea, and white tea. There are even more varieties, including flavored, scented, and “herbal infusions,” but for the sake of simplicity, we’ll focus on the big four right now.

What many people don’t know is that these four types of tea come from one plant, not four different species of plant.

All tea begins with the plant known as Camellia sinensis, it’s the way the tea leaves are processed that gives us the different teas and their specific taste, color, and scent.

Conditions of Growth

Tea bush is a tropical and sub-tropical plant and thrives well in a hot and humid climate. There is a very close relationship between climate, yield, and quality of tea. The ideal temperature for its growth is 208-30°C and temperatures above 35°C and below 10°C are harmful to the bush.

It requires 150-300 cm of annual rainfall which should be well distributed throughout the year. While the prolonged dry spell is harmful to tea, high humidity, and heavy demand morning fog favor the rapid development of young leaves.

Alternate waves of warm and cool winds are very helpful for tea leaves. Tea is a shade-loving plant and develops more vigorously when planted along with shady trees.

In order to increase the yield, the proper dose of nitrogenous fertilizers such; as ammonium sulfate should be given to the soil.
Although tea requires heavy rainfall for its growth, stagnant water is injurious to its roots.

It is, therefore, grown on hill slopes where water drains away easily and water-logging does not take place. However, it grows equally well in the valley if the drainage is good. Most of the tea plantations in India are found at elevations varying from 600 to 1,800 meters above sea level.

Tea is a labor-intensive crop and requires an abundant supply of cheap and skilled labor, especially at the time of plucking the tea leaves.

This is a tedious process that requires skilled manipulation of fingers for plucking two leaves and a bud at a time. For this purpose, women laborers are employed in large numbers.


Tea cultivation in India is highly concentrated in a few selected pockets. The following three areas of tea cultivation are identified according to their importance as tea producers and their location.

North-Eastern India: It is more or less a triangular area mainly in Assam and West Bengal. Assam is the largest producer of tea accounting for over 51 percent of the production and over 53 percent of the area under tea cultivation in India.

West Bengal is the second largest producer contributing over 22 percent of India’s tea from about one-fourth of the country’s total area under tea cultivation.

The entire tea of West Bengal is produced in three northern districts of Darjeeling, Jalpaiguri, and Coochbehar.
South India: In South India tea is produced in Nilgiri, Cardamom, Palni, and Anaimalai hills in Tamil Nadu, Kerala, and Karnataka states.

Northwest India: Some of the tea is produced in the Dehra Dun, Almora, and Garhwal districts of Uttaranchal and in Kangra Valley and Mandi district of Himachal Pradesh. Green tea is produced in the Kangra valley of Himachal Pradesh.


Planting: Planting is a crucial operation as it basically determines the development and productive level of tea throughout its economic life.

Wrong planting of good planting materials is doubly unproductive as an investment is lost both on account of producing the plants and in the failure to put them up for productivity. Therefore, care, planning, and refinement of techniques are essential for long-term benefits.

Pruning: It basically helps in maintaining the plant as a low bush in a phase of continuous vegetative growth. Pruning both stimulates and controls growth.

It removes dead, diseased, and overage wood, and thus helps rejuvenate bushes that have crossed the period of maximum productivity.

Fertilizer: The nutrients that are removed from the plant as yield and from the soil by the plant for its growth, should be replenished.

ideally, nutrient requirements should be related to local soil conditions in addition to yield and they must be monitored continuously to ensure an optimum balance of nutrients.

Weed control: Weeds affect tea by competing with it for moisture, nutrients, and sunlight. The ultimate effect is a considerable reduction in yield.

Thus, the timing of weed emergence relative to the growth stages of tea is an important parameter in weed management. Apart from directly causing crop losses, weeds in tea areas also act as secondary hosts for some important pests of tea.

Pest Management: The simultaneous presence of different species of mites and insects, each with their characteristic mode of feeding, diverse habitat, and seasonal cycles, call for optimal management of the pests which should be both ecologically and economically sound.

Crop duration and harvest: Plucking commences when the tea bush is 3 years old. The plucking of the extreme tip of the growing branch consists of an unopened bud together with two leaves popularly known as “Two leaves and a bud”, while fine plucking is anything less than this.

In South India, plucking continues throughout the year at weekly intervals during March-May and at intervals of 10 -14 days during the other months.

Processing of tea

Once workers gather enough quantities of tea leaves, their stash is quickly carried over to a tea factory located right on the plantation.

The factory is placed close to the source of the leaves because once the tea is plucked, oxidation immediately begins. The oxidation process is important in understanding tea — it must be closely monitored during production and is essential in determining the type and quality of the tea.

Oxidation is what happens when you cut up a piece of fruit and leave it out for too long — the color of the fruit changes, usually turning brown or black. Depending on the type of tea you want, oxidation can be a necessary part of processing tea leaves.

Tea tasting is the process in which a trained taster determines the quality of a particular tea. Due to climatic conditions, topography, manufacturing process, and different clones of the Camellia sinensis plant (tea), the final product may have vastly different flavors and appearances.

These differences can be tasted by a trained taster in order to ascertain the quality prior to the sale of possibly blended tea.

Question 7. What are the advantages of poultry farming? Describe in brief, the deep litter system of poultry farming.

Poultry farming:

Poultry farming is the raising of domesticated birds such as chickens, ducks, turkeys, and geese, for the purpose of farming meat or eggs for food. Poultry is farmed in great numbers with chickens being the most numerous.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production polutry farming


Advantages of Chicken farming

  1. The initial investment is a little lower than layer farming.
  2. The rearing period is 6-7 weeks only.
  3. More flocks can be taken in the same shed.
  4. Broilers have high feed conversion efficiency i.e. least amount of feed is required for unit body weight gain in comparison to other livestock.
  5. Faster return from the investment.
  6. Demand for poultry meat is more compared to sheep/goat meat.
  7. Important terminologies associated with poultry

Breed: Birds with a common origin, having specific characteristics, such as body shape, that distinguish them from other groups within the same species.

Strain: Chicks having specific characteristics, produced in specific farms by breeding.

Variety: The subdivisions of breeds based on specific characteristics, for example- white Leghorn, brown Leghorn, etc.

Chick: Young chicken of either sex from day 1 to about 5-6 weeks of age.

Grower: Chicken of either sex from 6 weeks to 6 months of age.

Cock: A mature male chicken.

Cockerel: A male chicken from day 1 to about 1 year of age.

Hen: A mature female chicken.

Pullet: A female chicken less than one year of age.

Fowl: Generally refers to larger birds.

Broiler/ Fryer: A young bird of either sex, usually of meat-type breeds up to 8-10 weeks of age and weighing 1.5-2.5 kg. The term broiler is applied to chicks that have especially been bred for rapid growth.

  1. Broiler strains are based on hybrid crosses between Cornish White, New Hampshire, and White Plymouth Rock.
  2. In broiler production there are two main production phases:
  3. keeping of parent stock and production of day-old-chicken and
  4. Growing and finishing of broilers.

Layers: Layers are efficient egg producers, breeds used for egg production in the industrial production system are almost entirely based on the White Leghorn and Rhode Island Red.

  1. Selection and crossbreeding techniques have resulted in productive laying hens producing 15 – 19 kg of eggs per year. In layer production,
  2. sometimes two phases of production are recognized:
  3. growing phase up to approximately 140 days; and
  4. productive phase from 140 – 560 days.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production eggs


Culling: The process of eliminating undesirable or non-reproductive animals.

Litter: The accumulation of materials, such as hay, sawdust, etc., to form the bed or floor of an animal farm.

Rooster: A young chick of meat type, weighing more than 1.5 kg.

Mash: A form of completely balanced feed that is finely ground and mixed so that birds can easily consume them and got proper nourishment.

Different Breeds Of Chicken

Different breeds are classified in different ways-

1. According to a place of origin

Mediterranean breeds: They originated in Europe, by the side of the Mediterranean Sea. They are small birds with lightweight but mature early and start egg laying. Examples- leghorn, Minorca, etc.

American breeds: The breeds originated in North America, due to hybridization with different Asiatic and Mediterranean breeds. They yield a considerable good amount of flesh and egg. Examples- are Rhode Island Red, New Hampshire, Plymouth Rock, etc.

English breeds: They are popular for their meat. Example- Sussex, Australia, etc.

Asiatic breeds: These breeds originated in Asia. A few important ones are – Brahma, Cochin, etc. Indian indigenous breeds are – Aseel, Chittagong, Ghagus, etc.

2. According To Utility

Laying breed: They lay about 220 or more eggs per year. Example- Leghorn.

Table breed or Meat breed: They produce a good amount of flesh. Examples- Aseel, Cochin, etc.

Dual breed: They produce both egg and flesh in moderately good amounts. Examples- Rhode Island Red, New Hampshire, etc.

3. According To Weight

Light breed: These breeds have body weights of about 2-3 kg. Example- Leghorn.

Heavy breed: These breeds have body weights of more than 3 kg. Example- Aseel, Brahma, etc

According to broodiness

Sitter: They sit on their eggs i.e., the mother incubates the eggs. Examples- Brahma, Aseel, etc.

1. According to a place of origin

Mediterranean breeds: They originated in Europe, by the side of the Mediterranean Sea. They are small birds with lightweight but mature early and start egg laying. Examples- leghorn, Minorca, etc.

American breeds: The breeds originated in North America, due to hybridization with different Asiatic and Mediterranean breeds. They yield a considerable good amount of flesh and egg. Examples- are Rhode Island Red, New Hampshire, Plymouth Rock, etc.

English breeds: They are popular for their meat. Examples- Sussex, Australia, etc.

Asiatic breeds: These breeds originated in Asia. A few important ones are – Brahma, Cochin, etc. Indian indigenous breeds are – Aseel, Chittagong, Ghagus, etc.

2. According to the utility

Laying breed: They lay about 220 or more eggs per year. Example- Leghorn.

Table breed or Meat breed: They produce a good amount of flesh. Examples- Aseel, Cochin, etc.

Dual breed: They produce both egg and flesh in moderately good amounts. Examples- Rhode Island Red, New Hampshire, etc.

According to weight

Light breed: These breeds have a body weight of about 2-3 kg. Example- Leghorn.

Heavy breed: These breeds have a body weight of more than 3 kg. Example- Aseel, Brahma, etc

4. According to broodiness

Sitter: They sit on their eggs i.e., the mother incubates the eggs. Examples- Brahma, Aseel, etc.

Non-sitter: The mothers do not sit on their eggs. Eggs are generally incubated in artificial incubator machines. Examples- Leghorn, Minorca, etc.

Different systems of fowl or chicken farming Generally different systems of farming are followed by poultry keepers. These may be-

  1. Free range or extensive system
  2. Semi-intensive system
  3. Intensive system:
  4. Battery cage system,
  5. Deep litter system.

1. Free range system

Free-range poultry farming consists of poultry permitted to roam freely instead of being contained in any manner. A free-range chicken must have daytime access to open-air runs for at least half of their life.

Free-range chickens grow slowly. Free-range poultry production requires that the poultry have access to the outside. The birds are to be protected from predatory animals and intruders. At present, due to several disadvantages and a shortage of space, this method is almost obsolete.

2. Semi-intensive system

This system is adopted where the amount of free space available is limited. It is necessary to allow 20-30 square yards per bird of outside run.

The birds are kept in a large enclosed area during the day time and are kept in adjacent farmhouses during the night and in unfavorable weather conditions.

3. Intensive system

This system is usually adopted where land is limited. In this system, the birds are confined to the house entirely with no access to the land outside.

The intensive system may be of the following types-

Battery cage system: Battery cages are a housing system used for various animal production methods, but primarily for egglaying hens.

The name arises from the arrangement of rows and columns of identical cages connected together, sharing common divider walls, as in the cells of a battery.

In a battery cage, the rate of food and water, and the duration and intensity of light are tightly controlled. There is no access to the natural environment, nor any opportunity to conduct natural behaviors such as perching, dust bathing, wing flapping or nesting.

Environmental conditions are automatically controlled, including light duration, which mimics summer day length. This stimulates the birds to continue to lay eggs all year round.


  1. A greater number of birds is reared per unit of area
  2. Facilitates correct maintenance of record
  3. Helps in identifying poor producers and prompt culling
  4. It helps in the production of clean eggs
  5. Easy control of parasitic disease
  6. Prompt steps to control feed wastage.

The cage method of housing is ideal for the area with moderate climate conditions where the day temperature in summer does not high and the temperature does not fall too low.

Egg production of the caged layer was reported to be more than those kept in a deep litter system.

Deep litter system: Deep litter system is commonly used all over the world. Litter is the substance that is used for farm animals to sleep on.

In the deep litter system, the poultry birds are kept in large pens of up to 250 birds each, on the floor covered with litter like straw, sawdust, or dried leaves up to a depth of 6-8 inches.

Deep litter is a method of chicken waste management that calls for droppings and bedding material to compost inside the chicken coop instead of being cleaned out and replaced regularly.

With the deep litter method, a carbon-based litter absorbs nitrogen from chicken droppings, which ferments in an odor-free process to produce rich, valuable humus just as in a traditional compost pile.

WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production different system of fowl or chicken farming..


  1. It is economical, hygienic, comfortable, and safe for birds
  2. Controls diseases and vices
  3. It increases the efficiency of production
  4. Materials such as paddy husks, sawdust, dried leaves, chopped straw, and groundnut kernels depending upon the availability can be used as litter materials.
  5. Nutritional value of chicken
  6. Naturally low in sodium.
  7. 100 grams of skinless boneless chicken has 31 grams of protein, or more than half the recommended daily allowance.

A good source of niacin, which aids in metabolism; vitamin B6, important to the immune system and blood sugar; biotin, which aids in cell growth; vitamin Bu, involved in nerve and red blood cell maintenance.

  1. Nutritional value of egg
  2. Contain one of the highest quality proteins of any food.
  3. A large egg contains about 70 calories and 6 grams of protein.
  4. A single egg contains 13 essential nutrients.
  5. Egg proteins contain time-release energy which helps maintain blood glucose levels and makes people feel full and energized longer.

Question 8. Mention the benefits of plowing. What is sowing? What are the factors that affect the irrigation requirements of crops?

Benefits of plowing:

Ploughing is beneficial because of the following reasons:

  1. The loose soil allows the plant roots to penetrate freely deeper into the soil and to breathe easily since loose soil can hold a lot of dirt in its spaces.
  2. The loose soil helps in the growth of worms and microbes which in turn adds humus to the soil.
  3. Plowing uproots the weeds and brings the nutrient-rich soil to the top so that the plants can use the nutrients easily.
  4. The process of scattering seeds in the ground soil for growing the crop plants is called sowing.

Factors affecting Irrigation requirements are-

  1. Nature of crop
  2. Nature of soil
  3. Season

Question 9. The figure shows yields of two crop fields (Plot A and Plot B) that have been treated with manure and chemical fertilizers :

WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production plot a and b


Question 10. What is the reason for the different patterns of the two graphs? What is a wedding? Name two harvest festivals.

Reason for the different patterns of the two graphs:

Plot B shows a sudden increase in yield due to the quick absorption of chemical fertilizers. Further gradual decline happens due to the nonreplenishment of organic matter in the soil, due to the death of microbes, etc.

Thus chemical fertilizers may be beneficial for a short time but it quickly turns fertile soil into infertile one. Manures maintain the sustainability of soil fertility.

It is beneficial for the long run and maintains durable crop yielding as is reflected in plot A.


The process of removing unwanted plants or weeds from a crop field is called weeding.

Harvest Festivals :Baisakhi and Pongal are two harvest festivals.

Question 10. How is honey prepared? Why is the honey bee called a social insect?

Preparation Of Honey:

Worker bees gather nectar from flowers and carry nectar within their honey sac, where it undergoes mixing with a specialized enzyme.

After returning to the hive, the worker bee vomits the nectar in the honey chamber and moves its wings very rapidly. Then the liquid from the nectar gets evaporated by the flowing air and the stuff becomes honey.

A highly organized division of labor is found in the colony of honey bees. A good and well-developed colony of bees has 40 to 50 thousand individuals consisting of 3 casts: queen, drone, and worker.

The queen, after fertilization, lays both fertilized and unfertilized eggs. From unfertilized eggs, males emerge which are called drones whereas from % the fertilized eggs worker bees are produced.

The workers when fed on royal jelly, develop into queens. The total indoor and outdoor duties of the colony are performed by the workers only. The sole duty of the drone is to fertilize the virgin queen. This is why honey bees are known as social insects.

Question 11. Mention the nutritional values of fish. How is induced breeding of carp carried out?

Fish Culture or Pisciculture

Fish is one of the most delicious and widely eaten aquatic animals and it is enriched with omega-3- fatty acid, a necessary constituent of a balanced diet.

As fish is a beloved food item all over the world, so its cultivation and harvesting are done on a larger scale in different parts of the globe.

Some branches of cultivation and harvesting fish are known as Fisheries, Pisciculture, Aquaculture, and Mariculture. Let us see the difference between these different ways of producing fish a larger scale.


Fisheries- It deals with all the aspects of harvesting or raising economically important

Weight Loss: Though honey has more calories than sugar, when honey is consumed with warm water, it helps in digesting the fat stored in your body. Similarly, honey and lemon juice as well as honey and cinnamon help in reducing weight.

Energy Source: Honey contains about 64 calories per tablespoon. Therefore, honey is used by many people as a source of energy. On the other hand, aquatic (freshwater and marine) organisms like fish, prawns, crabs, pearls, etc.

Pisciculture- This is the method of fish farming in which fishes are raised in artificial way for breeding and transportation.

Aquaculture- Aquaculture though simply means fish farming, in a broader sense, it is farming of aquatic organisms like fish, prawns, etc., and plants for breeding and rearing.

Mariculture- Mariculture involves the cultivation of only marine organisms, unlike any aquatic organism. This is the method of fish farming which is done usually on a very broader scale means by forming an enclosed section of the ocean.

Type of fisheries

Depending on the type of resources, it may be of the following types-
Capture fisheries: The process of obtaining fish from natural resources like lakes, rivers, ponds, etc. is called capture fishing. Capture fisheries are the exploitation of aquatic organisms without stocking the seed.

Recruitment of the species occurs naturally. This is carried out in the sea, rivers, reservoirs, etc. Fish yield decreases gradually in capture fisheries due to indiscriminate catching of fish including brooders and juveniles.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production winnowing type of fisheers


Culture fisheries: It is the production of fish in a given body of water such as ponds, lakes, or reservoirs using scientific methods of feeding, breeding, etc.

so as to enhance the output is called culture fishing-A culture fishery is the cultivation of selected fishes in confined areas with utmost care to get maximum yield.

The seed is stocked, nursed, and reared in confined waters, and then the crop is harvested. Culture takes place in ponds, which are fertilized, and supplementary feeds are provided to fish to get maximum yield.

In order to overcome the problems found in capture fisheries to increase production, considerable attention is being given to the culture fisheries.

Fishing in India: Fishing in India is a major industry in its coastal states, employing over 14 million people. Fish production in India has increased more than tenfold since its independence in 1947.

According to the Food and Agriculture Organization (FAO) of the United Nations, fish output in India doubled between 1990 and 2010.

India is endowed with vast and varied aquatic resources (Marine and Inland) amenable for capture fisheries. India is the third-largest producer of fish and the second-largest producer of inland fish in the world.

The fisheries sector provides employment to over 11 million people engaged fully, partially, or in subsidiary activities pertaining to the sector, with an equally impressive segment of the population engaged in ancillary activities.

The potential of fish production from marine and inland sources has been estimated at 3.9 million tonnes and 4.5 million tonnes, respectively.

Inland Fisheries: Inland waters are aquatic-influenced environments located within land boundaries. This includes those located in coastal areas, even where adjacent to marine environments.

Inland water systems can be fresh, saline, or a mix of the two (brackish water). Inland resources comprise of rivers and canals, estuaries, floodplains, wetlands, lagoons, and reservoirs.

While the marine water bodies are used mainly for capturing fisheries resources, the inland water bodies are widely used both for culture and capture fisheries.

Inland capture fisheries of India have an important place; it contributes to about 30% of the total fish production.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production winnowing marine fisheers


Marine Fisheries: The captured marine fishery resource of India comprises a long coastline (8118 km.) and an Exclusive Economic Zone (EEZ) (2.025 sq. km).

Marine capture fisheries play a vital role in India’s economy, providing employment and income to nearly two million people. Out of the total fish production in India, about 70% is obtained from the sea.

This gives the idea that how important is the marine fishery with its great economic and commercial values.

There are two main coastlines in India i.e., the East coast and the West coast. Out of these two the west coast is more productive because of better circulation and more oceanic character of its water.

Several exploratory surveys of fish wealth in the deep water on both coasts have been done which indicates that like coastal fisheries, deep sea fisheries can also be of much commercial and economic value.

Carp Culture

Carp are various species of oily freshwater fish of the family Cyprinidae, a very large group of fish native to Europe and Asia. Carp is a large freshwater fish native to central Asia.

Introductions in many countries have helped to make carp the most widely distributed freshwater fish in the world. They are highly cultured and domesticated in aquaculture for food and ornamental purpose.

Freshwater fishes cultured in India are mainly major carp, minor carp, exotic carp, and other fishes. Fishes like Katla, mrigal, and rohu (rui) are 3 major carps of India. A lot of research, hybridization, reduce breeding have been carried out with carps distressfully.

Indian major carp grow fast and can reproduce even in artificial ponds. v. Minor carps are smaller in size than major carp. They do not produce as many eggs as major carp.

Kalbasu, bata,punti, etc., are minor carps. minor carp fishes grow to a size of 30- 100 2cm. with an average weight of 1 to 1.5 kg. The rate of egg production is very low in these fishes.

When the indigenous fishes are not favored for culture due to economic viability, exotic breeds are selected and cultured. These fishes yield nutritious food and earn foreign exchange.

Examples of exotic carp are silver carp, grass carp, and common carp. Other common freshwater fishes are – lata, maguro, single, koi, Tangra, Boal, tilapia, panda, bhetki, etc. However, these fishes are not carp.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production crap fish


Indian Carp culture: Indian aquaculture has been,n growing at a fast pace over the last two d^cpdes, with freshwater aquaculture contributing over 95% of the production.

The three major carps cultured in India, namely, Katla (Catla catla), rohu (Labeo rohita), and mrigal (Cirrhinus mrigala), contribute as much as 87 percent of the total Indian aquaculture production.

Three exotic carp were also introduced, namely, silver carp (Hypophthalmichthys molitrix); grass carp (Ctenopharyngodon idyllic), and common carp (Cyprinus carpio).

There are also several other medium and minor carp species, namely kalbos(Labeo calabash) bata (L. bata), and Puntif Puntius sarana), which are important in aquaculture.

Among catfishes, major (Ciarias batrachus) is the only species that is widely cultured, while the catfish, Singh (Heteropneustes fossilis) is cultured to some extent in the eastern states.

The finfish species of importance include climbing perch koi (Anabas testudineus), lata (Channa striata), and tilapia (Oreochromis mossambicus).

Preparation of pond

Pond preparation involves making the ponds weed and predator-free and generating adequate natural food for the survival and growth of fish.

Spawning: Because of constant temperature and favorable weather conditions, carps spawn all year round in India. Spawning takes place early in the morning when the water surface cools down to about 18 degrees.

The female carp swims near the water’s surface followed by the male carp in nuptial swimming and rubbing each other’s bodies. The female lays an egg and the male releases its milt and the eggs are fertilized.

Three days after fertilization, the eggs begin to hatch. The newly hatched larva (seedling) is about 5.5 mm long, delicate, and transparent, with a yolk sac attached to the belly.

It rarely swims but settles on the bottom or on some floating object. On the second day, the larva starts swimming, and on the third-day swims actively from surface to bottom.

During these stages, the larva or fry gets its nourishment from the yolk sac, which disappears on the third day and the fry now must search for food and eat.

Supplementary fry- feed in the form of hard-boiled egg yolk or powdered milk can be applied on the water surface at this time. When the fry grows slightly larger, about the size of a finger, it is called a fingerling.

Nursery ponds are constructed to rear carp fry or larvae. A normal-sized nursery pond measures 5 x 10 m, with a depth of 0.5 m. Before filling up the water the pond should be cleaned thoroughly to get rid of predators and parasites that may be destructive to the larvae. About 1,500 to 3,000 fries can be stocked in the nursery pond.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production winnowing prepation of pond


Rearing ponds where adult carp are cultured until they reach marketable size, are needed, which have dimensions of 15 x 50 m and depth of 1.5 to 2 m.

Rearing ponds should also be thoroughly cleaned before filling them with water. This is done by exposing the bottom and letting it dry thoroughly.

The next step involves the application of fertilizers, which encourages the growth of aquatic plants, moss, and algae, which are important natural food and also lead to the growth of microfauna.

Manure in the form of chicken dropping is the most commonly used being cheaper and more readily available in large quantities. When carp fry reaches a length of about 5 to 7 cm, they are transferred from the nursery pond to the rearing pond and allowed to grow to the adult stage.

Stocking ponds: Ponds are stocked with fish fries of the appropriate size. Fingerlings over 10 cm in size are recommended for stocking in culture ponds.

In composite fish farming, a combination of six species is cultured, namely, Katla, rohu, mrigal, and exotic carp like silver carp, grass carp, and common carp.

Supplementary feeds like groundnut oil cake and rice bran are fed to fishes during culture. At the end of the culture period of say 12 months, the fish will reach the marketable size and fetch attractive prices.

Aeration may be done mechanically to increase the concentration of dissolved oxygen in ponds, by paddle wheel aerators, aspirator aerators, and submersible pond aerators. It is also necessary to replace a certain amount of water at regular intervals.


Harvesting of fish is usually done after a culture period of 10 months to one year. However, fish attaining the marketable size can be harvested periodically depending on several factors,

which also reduces the pressure of density in the ponds and thereby provides sufficient space for the growth of fish.

Induced breeding of carps: Induced fish farming has allowed farmers to breed and raise species that do not naturally reproduce in captivity,

manipulate the timing of reproduction to suit production cycles, get fish to spawn on a predetermined date, and fertilize and incubate eggs under hatchery conditions.

The strategy is to inject the fish with one or more naturally occurring reproductive hormones or synthetic analogs to manipulate the maturation of gonads and ovulation.

Sewage-fed fishery: Increasing population, industrialization, and urbanization have created problems in the form of waste disposal.

Wastes arise from virtually all forms of human activities. The common means of disposal of these materials is to dump them outside the village or city limits, to burn them, or to discharge them into ponds and rivers.

But in recent times things have changed. The use of waste for productive purposes has generated a new idea of waste management. Sewage is a rich nutrient resource, cheaply available around big towns and cities.

It can be well-utilized: for fertilizing paddies, fishponds, and horticulture crops. Waste recycling also helps in maintaining a clean environment.

For fish cult urn sewage water from stabilizing tank well as the water after dilution can be utilized. Air-breathing fishes are more suitable to be cultured In sewage treatment ponds as they can survive In water with lesser dissolved oxygen content.

Fish like maguro, single, lata, tilapia, grass carp, etc., are the species of choice to be considered for culture in sewage-treated ponds.

Numerous species of fish are farmed in the sewage-fed ponds called burls In the East Kolkata wetlands.


WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production induced breeding of craps


Nutritional value of fish

Fish Is a food of excellent nutritional value, providing high-quality protein and a wide variety of vitamins and minerals, including vitamins A and D, phosphorus, magnesium, selenium, and Iodine in marine fish.

Its protein – like that of meat – is easily digestible and favorably complements dietary protein provided by cereals and legumes that are typically consumed in many developing countries.

Fishes may be classed as either whitefish or oily fish. Whlteflsh, such as rohu, Katla, mrigal, etc, contain very little fat (usually less than 1%) whereas oily fish, such as English, panda, etc, contain between 10-25%.

The latter, as a result of Its high-fat content, contains a range of fat-soluble vitamins (A, D, E, and K) and essential fatty acids, all of which are vital for the healthy functioning of the body.

Experts agree that, even in small quantities, fish can have a significant positive impact on improving the quality of dietary protein by complementing the essential amino acids that are often present in low quantities in vegetable-based diets.

But recent research shows that fish is much more than just an alternative source of animal protein. Fish oils in fatty fish are the richest source of a type of fat that is vital to normal brain development in unborn babies and infants. Without adequate amounts of these fatty acids, normal brain development does not take place.

Question 12. Mention the types of fisheries. Name two exotic carp.

Types of fisheries:

On the basis of location, fisheries are classified as:

WBBSE Solutions For Class 8 School Science Chapter 8 Human Food And Food Production location fishers




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