SCIENCE140

We know that all living organisms need food.

Food supplies proteins, carbohydrates, fats,

vitamins and minerals, all of which we require

for body development, growth and health.

Both plants and animals are major sources

of food for us. We obtain most of this food

from agriculture and animal husbandry.

We read in newspapers that efforts are

always being made to improve production

from agriculture and animal husbandry. Why

is this necessary? Why we cannot make do

with the current levels of production?

India is a very populous country. Our

population is more than one billion people,

and it is still growing. As food for this growing

population, we will soon need more than a

quarter of a billion tonnes of grain every year.

This can be done by farming on more land.

But India is already intensively cultivated. As

a result, we do not have any major scope for

increasing the area of land under cultivation.

Therefore, it is necessary to increase our

production efficiency for both crops and

livestock.

Efforts to meet the food demand by

increasing food production have led to some

successes so far. We have had the green

revolution, which contributed to increased

food-grain production. We have also had the

white revolution, which has led to better and

more efficient use as well as availability of milk.

However, these revolutions mean that our

natural resources are getting used more

intensively. As a result, there are more

chances of causing damage to our natural

resources to the point of destroying their

balance completely. Therefore, it is important

that we should increase food production

without degrading our environment and

disturbing the balances maintaining it. Hence,

there is a need for sustainable practices in

agriculture and animal husbandry.

Also, simply increasing grain production

for storage in warehouses cannot solve the

problem of malnutrition and hunger. People

should have money to purchase food. Food

security depends on both availability of food

and access to it. The majority of our

population depends on agriculture for their

livelihood. Increasing the incomes of people

working in agriculture is therefore necessary

to combat the problem of hunger. Scientific

management practices should be undertaken

to obtain high yields from farms. For

sustained livelihood, one should undertake

mixed farming, intercropping, and integrated

farming practices, for example, combine

agriculture with livestock/poultry/fisheries/

bee-keeping.

The question thus becomes – how do we

increase the yields of crops and livestock?

12.1 Improvement in Crop Yields

Cereals such as wheat, rice, maize, millets and

sorghum provide us carbohydrate for energy

requirement. Pulses like gram (chana), pea

(matar), black gram (urad), green gram (moong),

pigeon pea (arhar), lentil (masoor), provide us with

protein. And oil seeds including soyabean,

ground nut, sesame, castor, mustard, linseed and

sunflower provide us with necessary fats (Fig.

12.1). Vegetables, spices and fruits provide a

range of vitamins and minerals in addition to

small amounts of proteins, carbohydrates and

fats. In addition to these food crops, fodder crops

like berseem, oats or sudan grass are raised as

food for the livestock.

MPROVEMENTMPROVEMENT

MPROVEMENT

ININ

F F

OODOOD

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hapter

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IMPROVEMENT IN FOOD RESOURCES 141

the kharif season from the month of June to

October, and some of the crops are grown in

the winter season, called the rabi season from

November to April. Paddy, soyabean, pigeon

pea, maize, cotton, green gram and black

gram are kharif crops, whereas wheat, gram,

peas, mustard, linseed are rabi crops.

In India there has been a four times

increase in the production of food grains from

1952 to 2010 with only 25% increase in the

cultivable land area. How has this increase

in production been achieved? If we think of

the practices involved in farming, we can see

that we can divide it into three stages. The

first is the choice of seeds for planting. The

second is the nurturing of the crop plants.

The third is the protection of the growing and

harvested crops from loss. Thus, the major

groups of activities for improving crop yields

can be classified as:

• Crop variety improvement

• Crop production improvement

• Crop protection management.

12.1.1 CROP VARIETY IMPROVEMENT

This approach depends on finding a crop

variety that can give a good yield. Varieties or

strains of crops can be selected by breeding

for various useful characteristics such as

disease resistance, response to fertilisers,

product quality and high yields. One way of

incorporating desirable characters into crop

varieties is by hybridisation. Hybridisation

refers to crossing between genetically

dissimilar plants. This crossing may be

intervarietal (between different varieties),

interspecific (between two different species of

the same genus) or intergeneric (between

different genera). Another way of improving

the crop is by introducing a gene that would

provide the desired characteristic. This

results in genetically modified crops.

For new varieties of crops to be accepted,

it is necessary that the variety produces high

yields under different conditions that are

found in different areas. Farmers would need

to be provided with good quality seeds of a

particular variety, that is, the seeds should all

Fig. 12.1: Different types of crops

uestion

1. What do we get from cereals,

pulses, fruits and vegetables?

Different crops require different climatic

conditions, temperature and photoperiods for

their growth and completion of their life cycle.

Photoperiods are related to the duration of

sunlight. Growth of plants and flowering are

dependent on sunlight. As we all know, plants

manufacture their food in sunlight by the

process of photosynthesis. There are some

crops, which are grown in rainy season, called

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be of the same variety and germinate under

the same conditions.

Cultivation practices and crop yield are

related to weather, soil quality and availability

of water. Since weather conditions such as

drought and flood situations are

unpredictable, varieties that can be grown in

diverse climatic conditions are useful.

Similarly, varieties tolerant to high soil salinity

have been developed. Some of the factors for

which variety improvement is done are:

• Higher yield: To increase the

productivity of the crop per acre.

• Improved quality: Quality

considerations of crop products vary

from crop to crop. Baking quality is

important in wheat, protein quality in

pulses, oil quality in oilseeds and

preserving quality in fruits and

vegetables.

• Biotic and abiotic resistance: Crops

production can go down due to biotic

(diseases, insects and nematodes) and

abiotic (drought, salinity, water

logging, heat, cold and frost) stresses

under different situations. Varieties

resistant to these stresses can improve

crop production.

• Change in maturity duration: The

shorter the duration of the crop from

sowing to harvesting, the more

economical is the variety. Such short

durations allow farmers to grow

multiple rounds of crops in a year.

Short duration also reduces the cost

of crop production. Uniform maturity

makes the harvesting process easy

and reduces losses during harvesting.

• Wider adaptability: Developing

varieties for wider adaptability will

help in stabilising the crop production

under different environmental

conditions. One variety can then be

grown under different climatic

conditions in different areas.

• Desirable agronomic characteristics:

Tallness and profuse branching are

desirable characters for fodder crops.

Dwarfness is desired in cereals, so that

less nutrients are consumed by these

crops. Thus developing varieties of

desired agronomic characters help give

higher productivity.

uestions

1. How do biotic and abiotic factors

affect crop production?

2. What are the desirable agronomic

characteristics for crop

improvements?

12.1.2 CROP PRODUCTION MANAGEMENT

In India, as in many other agriculture-based

countries, farming ranges from small to very

large farms. Different farmers thus have more

or less land, money and access to information

and technologies. In short, it is the money or

financial conditions that allow farmers to take

up different farming practices and agricultural

technologies. There is a correlation between

higher inputs and yields. Thus, the farmer’s

purchasing capacity for inputs decides

cropping system and production practices.

Therefore, production practices can be at

different levels. They include ‘no cost’

production, ‘low cost’ production and ‘high

cost’ production practices.

12.1.2 (i) NUTRIENT MANAGEMENT

Just as we need food for development, growth

and well-being, plants also require nutrients

for growth. Nutrients are supplied to plants

by air, water and soil. There are several

nutrients which are essential for plants. Air

supplies carbon and oxygen, hydrogen comes

from water, and soil supplies the other thirteen

nutrients to plants. Amongst these, some are

required in large quantities and are therefore

called macro-nutrients. The other nutrients are

used by plants in small quantities and are

therefore called micro-nutrients (Table 12.1).

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IMPROVEMENT IN FOOD RESOURCES 143

our environment from excessive use of

fertilizers. Using biological waste material is

also a way of recycling farm waste. Based on

the kind of biological material used, manure

can be classified as:

(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 supply nitrogen,

phosphorus and potassium. They are used

to ensure good vegetative growth (leaves,

branches and flowers), giving rise to healthy

plants. Fertilizers are a factor in the higher

yields of high-cost farming.

Fertilizers should be applied carefully in

terms of proper dose, time, and observing pre-

and post-application precautions for their

complete utilisation. For example, sometimes

fertilizers get washed away due to excessive

irrigation and are not fully absorbed by the

plants. This excess fertilizer then leads to

water pollution.

Also, as we have seen in the previous

chapter, continuous use of fertilizers in an

area can destroy soil fertility because the

organic matter in the soil is not replenished

and micro-organisms in the soil are harmed

by the fertilizers used. Short-term benefits of

using fertilizers and long-term benefits of using

Deficiency of these 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.

uestions

1. What are macro-nutrients and

why are they called macro-

nutrients?

2. How do plants get nutrients?

MANURE

Manure contains large quantities of organic

matter and also supplies small quantities of

nutrients to the soil. Manure is prepared by

the decomposition of animal excreta and plant

waste. Manure helps in enriching soil with

nutrients and organic matter and increasing

soil fertility. The bulk of organic matter in

manure helps in improving the soil structure.

This involves increasing the water holding

capacity in sandy soils. In clayey soils, the

large quantities of organic matter help in

drainage and in avoiding water logging.

In using manure we use biological waste

material, which is advantageous in protecting

Table 12.1: Nutrients supplied

by air, water and soil

Air carbon, oxygen

Water hydrogen, oxygen

Soil (i) Macronutrients:

nitrogen, phosphorus,

potassium, calcium,

magnesium, sulphur

(ii) Micronutrients:

iron, manganese, boron,

zinc, copper,

molybdenum, chlorine

Source Nutrients

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India has a wide variety of water resources

and a highly varied climate. Under such

conditions, several different kinds of irrigation

systems are adopted to supply water to

agricultural lands depending on the kinds of

water resources available. These include wells,

canals, rivers and tanks.

• Wells: There are two types of wells,

namely dug wells and tube wells. In a

dug well, water is collected from water

bearing strata. Tube wells can tap

water from the deeper strata. From

these wells, water is lifted by pumps

for irrigation.

• Canals: This is usually an elaborate

and extensive irrigation system. In this

system canals receive water fr

om one

or more reservoirs or from rivers. The

main canal is divided into branch

canals having further distributaries to

irrigate fields.

• River Lift Systems: In areas where

canal flow is insufficient or irregular

due to inadequate reservoir release,

the lift system is more rational. Water

is directly drawn from the rivers for

supplementing irrigation in areas

close to rivers.

• Tanks: These are small storage

reservoirs, which intercept and store

the run-off of smaller catchment

areas.

Fresh initiatives for increasing the water

available for agriculture include rainwater

harvesting and watershed management. This

involves building small check-dams which

lead to an increase in ground water levels.

The check-dams stop the rainwater from

flowing away and also reduce soil erosion.

12.1.2 (iii) CROPPING PATTERNS

Different ways of growing crops can be used

to give maximum benefit.

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. This

reduces risk and gives some insurance

against failure of one of the crops.

manure for maintaining soil fertility have to

be considered while aiming for optimum yields

in crop production.

uestion

1. Compare the use of manure and

fertilizers in maintaining soil

fertility.

Organic farming is a farming system with

minimal or no use of chemicals as fertilizers,

herbicides, pesticides, etc., and with a

maximum input of organic manures, recycled

farm-wastes (straw and livestock excreta), use

of bio-agents such as culture of blue green

algae in preparation of biofertilizers, neem

leaves or turmeric specifically in grain storage

as bio-pesticides, with healthy cropping

systems [mixed cropping, inter-cropping and

crop rotation as discussed below in 12.1.2.(iii)].

These cropping systems are beneficial in

insect, pest and wheat control besides

providing nutrients.

12.1.2 (ii) IRRIGATION

Most agriculture in India is rain-fed, that is,

the success of crops in most areas 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.

Therefore, many measures are used to bring

more and more agricultural land

under irrigation.

More to know

Droughts occur because of scarcity or

irregular distribution of rains. Drought

poses a threat to rain-fed farming

areas, where farmers do not use

irrigation for crop production and

depend only on rain. Light soils have

less water retention capacity. In areas

with light soils, crops get adversely

affected by drought conditions.

Scientists have developed some crop

varieties which can tolerate drought

conditions.

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IMPROVEMENT IN FOOD RESOURCES 145

Inter-cropping is growing two or more

crops simultaneously on the same field in a

definite pattern (Fig.12.2). 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). The crops are

selected such that their nutrient

requirements are different. This ensures

maximum utilisation of the nutrients

supplied, and also prevents pests and

diseases from spreading to all the plants

belonging to one crop in a field. This way,

both crops can give better returns.

(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.

Generally 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.

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.

Weeds, insects and diseases can be

controlled by various methods. One of the

most commonly used methods is the use of

pesticides, which include herbicides,

insecticides and fungicides. These chemicals

are sprayed on crop plants or used for treating

seeds and soil. However, excessive use of

these chemicals creates problems, since they

can be poisonous to many plant and animal

species and cause environmental pollution.

Weed control methods also include

mechanical removal. Preventive methods

such as proper seed bed preparation, timely

sowing of crops, intercropping and crop

rotation also help in weed control. Some other

preventive measures against pests are the use

of resistant varieties, and summer ploughing,

in which fields are ploughed deep in summers

to destroy weeds and pests.

uestion

1. Which of the following conditions

will give the most benefits? Why?

(a) Farmers use high-quality

seeds, do not adopt

irrigation or use fertilizers.

(b) Farmers use ordinary

seeds, adopt irrigation and

use fertilizer.

adopt irrigation, use

fertilizer and use crop

protection measures.

Fig. 12.2 : Intercropping

The growing of different crops on a piece

of land in a pre-planned succession is known

as crop rotation. Depending upon the

duration, crop rotation is done for differ

ent

crop combinations. The availability of moisture

and irrigation facilities decide the choice of the

crop to be cultivated after one harvest. If crop

rotation is done properly then two or three

crops can be grown in a year with

good harvests.

12.1.3 CROP PROTECTION MANAGEMENT

Field crops are infested by a large number of

weeds, insect pests and diseases. 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.

Weeds are unwanted plants in the

cultivated field, for example, Xanthium

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Activity _____________12.1

• Visit a nearby garden/agricultural

field and make a list of the weeds and

the flowers/crops found in the area.

Also, make a list of insect pests, if

any, infesting the flowers/crops.

STORAGE OF GRAINS

Storage losses in agricultural produce can be

very high. Factors responsible for such losses

are biotic— insects, rodents, fungi, mites and

bacteria, and abiotic— inappropriate moisture

and temperatures in the place of storage. These

factors cause degradation in quality, loss in

weight, poor germinability, discolouration of

produce, all leading to poor marketability.

These factors can be controlled by proper

treatment and by systematic management of

warehouses.

Preventive and control measures are used

before grains are stored for future use. They

include strict cleaning of the produce before

storage, proper drying of the produce first in

sunlight and then in shade, and fumigation

using chemicals that can kill pests.

uestions

1. Why should preventive measures

and biological control methods be

preferred for protecting crops?

2. What factors may be responsible

for losses of grains during

storage?

Activity _____________ 12.2

• Collect grains/seeds of cereals,

pulses and oil seeds and gather

information about the seasons in

which they are sown and harvested.

12.2 Animal Husbandry

Animal husbandry is the scientific

management of animal livestock. It includes

various aspects such as feeding, breeding and

disease control. Animal-based farming

includes cattle, goat, sheep, poultry and fish

farming. As the population increases and as

living standards increase, the demand for

milk, eggs and meat is also going up. Also,

the growing awareness of the need for

humane treatment of livestock has brought

in new limitations in livestock farming. Thus,

livestock production also needs to be improved.

12.2.1 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, cows, and Bos bubalis, buffaloes.

Milk-producing females are called milch

animals (dairy animals), while the ones used

for farm labour are called draught animals.

Milk production depends, to some extent,

on the duration of the lactation period,

meaning the period of milk production after

Table 12.2: Nutritional values of animal products

Animal

Products

Fat Protein Sugar Minerals Water Vitamins

Milk (Cow) 3.60 4.00 4.50

0.70 87.20 B1, B2, B12, D, E

Egg 12.00 13.00 * 1.00 74.00 B2, D

Meat 3.60 21.10 * 1.10 74.20 B2, B12

Fish 2.50 19.00 * 1.30 77.20 Niacin, D, A

*Present in very small amounts

Per cent (%) Nutrients

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IMPROVEMENT IN FOOD RESOURCES 147

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, while 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.

uestion

1. Which method is commonly used

for improving cattle breeds and

why?

Activity _____________12.3

• Visit a livestock farm. Note the

following:

(1) Number of cattle and number of

different breeds.

(2) The amount of daily milk production

from the different breeds.

Proper cleaning and shelter facilities for

cows and buffaloes are required for humane

farming, for the health of the animals and

for production of clean milk as well. Animals

require regular brushing to remove dirt and

loose hair. They should be sheltered under

well-ventilated roofed sheds that protect them

from rain, heat and cold. The floor of the cattle

shed needs to be sloping so as to stay dry

and to facilitate cleaning.

The food requirements of dairy animals

are of two types: (a) maintenance

requirement, which is the food required to

support the animal to live a healthy life, and

(b) milk producing requirement, which is the

type of food required during the lactation

period. Animal feed includes: (a) roughage,

which is largely fibre, and (b) concentrates,

which are low in fibre and contain relatively

high levels of proteins and other nutrients.

Cattle need balanced rations containing all

nutrients in proportionate amounts. Besides

such nutritious food material, certain feed

additives containing micronutrients promote

the health and milk output of dairy animals.

Cattle suffer from a number of diseases.

The diseases, besides causing death, reduce

milk production. A healthy animal feeds

regularly and has a normal posture. The

parasites of cattle may be both external

parasites and internal parasites. The external

parasites live on the skin and mainly cause

skin diseases. The internal parasites like

worms, affect stomach and intestine while

flukes damage the liver. Infectious diseases

are also caused by bacteria and viruses.

Vaccinations are given to farm animals

against many major viral and bacterial

diseases.

12.2.2 POULTRY FARMING

Poultry farming is undertaken to raise

domestic fowl for egg production and chicken

meat. Therefore, improved poultry breeds are

developed and farmed to produce layers for

eggs and broilers for meat.

The cross-breeding programmes between

Indian (indigenous, for example, Aseel) and

foreign (exotic, for example, Leghorn) breeds

for variety improvement are focused on to

develop new varieties for the following

desirable traits—

(i) number and quality of chicks;

Fig. 12.3: Indigenous milch breed of cattle

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SCIENCE148

(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.

The ration (daily food requirement) for broilers

is protein rich with adequate fat. The level of

vitamins A and K is kept high in the poultry

feeds.

Poultry fowl suffer from a number of

diseases caused by virus, bacteria, fungi,

parasites, as well as from nutritional

deficiencies. These necessitate proper

cleaning, sanitation, and spraying of

disinfectants at regular intervals. Appropriate

vaccination can prevent the occurrence of

infectious diseases and reduce loss of poultry

during an outbreak of disease.

uestions

1. What management practices are

common in dairy and poultry

farming?

2. What are the differences between

broilers and layers and in their

management?

Activity _____________ 12.4

• Visit a local poultry farm. Observe

types of breeds and note the type of

ration, housing and lighting facilities

given to them. Identify the growers,

layers and broilers.

12.2.3 FISH PRODUCTION

Fish is a cheap source of animal protein for

our food. Fish production includes the finned

true fish as well as shellfish such as prawns

and molluscs. There are two ways of obtaining

fish. One is from natural resources, which is

called capture fishing. The other way is by

fish farming, which is called culture fishery.

The water source of the fish can be either

seawater or fresh water, such as in rivers and

ponds. Fishing can thus be done both by

capture and culture of fish in marine and

freshwater ecosystems.

12.2.3 (i) MARINE

FISHERIES

India’s marine fishery resources include

7500 km of coastline and the deep seas

Fig. 12.4

Aseel Leghorn

uestion

1. Discuss the implications of the

following statement:

“It is interesting to note that

poultry is India’s most efficient

converter of low fibre food stuff

(which is unfit for human

consumption) into highly

nutritious animal protein food.”

EGG AND BROILER PRODUCTION

Broiler chickens are fed with vitamin-rich

supplementary feed for good growth rate and

better feed efficiency. Care is taken to avoid

mortality and to maintain feathering and

carcass quality. They are produced as broilers

and sent to market for meat purposes.

For good production of poultry birds, good

management practices are important. These

include maintenance of temperature and

hygienic conditions in housing and poultry

feed, as well as prevention and control of

diseases and pests.

The housing, nutritional and

environmental requirements of broilers are

somewhat different from those of egg layers.

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IMPROVEMENT IN FOOD RESOURCES 149

beyond it. Popular marine fish varieties

include pomphret, mackerel, tuna, sardines,

and Bombay duck. Marine fish are caught

using many kinds of fishing nets from fishing

boats. Yields are increased by locating large

schools of fish in the open sea using satellites

and echo-sounders.

Some marine fish of high economic value

are also farmed in seawater. This includes

finned fishes like mullets, bhetki, and pearl

spots, shellfish such as prawns (Fig. 12.5),

mussels and oysters as well as seaweed.

Oysters are also cultivated for the pearls

they make.

Macrobrachium rosenbergii

(fresh water)

Peneaus monodon

(marine)

Fig. 12.5 : Fresh water and marine prawns

As marine fish stocks get further depleted,

the demand for more fish can only be met by

such culture fisheries, a practice called

mariculture.

12.2.3 (ii) INLAND FISHERIES

Fresh water resources include canals, ponds,

reservoirs and rivers. Brackish water

resour

ces, where seawater and fresh water

mix together, such as estuaries and lagoons

are also important fish reservoirs. While

capture fishing is also done in such inland

water bodies, the yield is not high. Most fish

production from these resources is through

aquaculture.

Fish culture is sometimes done in

combination with a rice crop, so that fish are

grown in the water in the paddy field. More

intensive fish farming can be done in

composite fish culture systems. Both local

and imported fish species are used in such

systems.

In such a system, a combination of five or

six fish species is 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. As 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, together these

species (Fig. 12.6) can use all the food in the

pond without competing with each other. This

increases the fish yield from the pond.

(a)

(b)

(c)

(d)

Fig. 12.6: (a) Catla (b) Silver carp (c) Rohu (d) Grass

Carp (e) Mrigal (f) Common Carp

(e)

(f)

One problem with such composite fish

culture is that many of these fish breed only

during monsoon. Even if fish seed is collected

from the wild, it can be mixed with that of

other species as well. So, a major problem in

fish farming is the lack of availability of good-

quality seed. 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

desir

ed quantities.

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SCIENCE150

uestions

1. How are fish obtained?

2. What are the advantages of

composite fish culture?

Activity _____________12.5

• Visit a fish farm in fish breeding

season and note the following:

(1) Varieties of fish in fish farm

(2) Types of ponds

(3) Feed ingredients used

(4) Production capacity of the farm

If there are no fish farms close to your

locality, gather the above information from

Internet, by referring books or talking to

people who are engaged in fishery.

12.2.4 BEE-KEEPING

Honey is widely used and therefore bee-

keeping for making honey has become an

agricultural enterprise. Since bee-keeping

needs low investments, farmers use it as an

additional income generating activity. In

addition to honey, the beehives are a source

of wax which is used in various medicinal

preparations.

The local varieties of bees used for

commercial honey production are Apis cerana

indica, commonly known as the Indian bee,

A. dorsata, the rock bee and A. florae, the little

bee. An Italian bee variety, A. mellifera, has

also been brought in to increase yield of honey.

This is the variety commonly used for

commercial honey production.

The Italian bees have high honey collection

capacity. They sting somewhat less. They stay

in a given beehive for long periods, and breed

very well. For commercial honey production,

bee farms or apiaries are established.

The value or quality of honey depends

upon the pasturage, or the flowers available

to the bees for nectar and pollen collection.

In addition to adequate quantity of pasturage,

the kind of flowers available will determine

the taste of the honey.

uestions

1. What are the desirable

characters of bee varieties

suitable for honey production?

2. What is pasturage and how is it

related to honey production?

(a) (b)

Fig. 12.7: (a) Arrangement of beehive in an apiary

(b) honey extractor

What

you have

learnt

• There are several nutrients essential for crops. Of these,

some are required in large quantities and are known as

macro-nutrients whereas rest of the nutrients are required

in small quantities and are known as micro-nutrients.

• Manure and fertilizers are the main sources of nutrient

supply to crops.

• Organic farming is a farming system with minimal or no use

of chemicals as fertilizers, herbicides, pesticides etc. and

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IMPROVEMENT IN FOOD RESOURCES 151

with a maximum input of organic manures, recyled farm wastes, and

bio-agents, with healthy cropping systems.

• Mixed farming is a system of farming on a particular farm which

includes crop production, raising of livestock etc.

• Mixed cropping is growing of two or more crops simultaneously on the

same piece of land.

• Growing two or more crops in definite row patterns is known as inter-

cropping.

• The growing of different crops on a piece of land in pre-planned

succession is called crop rotation.

• Varietal improvement is required for higher yield, good quality, biotic

and abiotic resistance, shortening the maturity duration, wider

adaptability and desirable agronomic characteristics.

• Farm animals r

equire proper care and management such as shelter,

feeding, breeding and disease control. This is called animal husbandry.

• Poultry farming is done to raise domestic fowls. Poultry production

includes egg production and broiler production for poultry meat.

• To enhance poultry production, cross breeding is done between Indian

and exotic breeds for variety improvement.

• Fish may be obtained from marine resources as well as inland

resources.

• To increase production of fish, they can be cultured in marine and

inland ecosystems.

• Marine fish capture is done by fishing nets guided by echo-sounders

and satellites.

• Composite fish culture system is commonly used for

fish farming.

• Bee-keeping is done to get honey and wax.

Exercises

1. Explain any one method of crop production which ensures high yield.

2. Why are manure and fertilizers used in fields?

3. What are the advantages of inter-cropping and crop rotation?

4. What is genetic manipulation? How is it useful in agricultural practices?

5. How do storage grain losses occur?

6. How do good animal husbandry practices benefit farmers?

7. What are the benefits of cattle farming?

8. For increasing production, what is common in poultry, fisheries and

bee-keeping?

9. How do you differentiate between capture fishing, mariculture and

aquaculture?

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