NCERT Textbook: Improvement in Food Resources Notes | Study Science Class 9 - Class 9

 Page 1


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?
15.1 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. 15.1).
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.
15
I I I I IMPROVEMENT MPROVEMENT MPROVEMENT MPROVEMENT MPROVEMENT     IN IN IN IN IN F F F F FOOD OOD OOD OOD OOD R R R R RESOURCES ESOURCES ESOURCES ESOURCES ESOURCES
Chapter
2020-21
Page 2


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?
15.1 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. 15.1).
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.
15
I I I I IMPROVEMENT MPROVEMENT MPROVEMENT MPROVEMENT MPROVEMENT     IN IN IN IN IN F F F F FOOD OOD OOD OOD OOD R R R R RESOURCES ESOURCES ESOURCES ESOURCES ESOURCES
Chapter
2020-21
SCIENCE 204
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.
15.1.1 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
Fig. 15.1: 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
Q
2020-21
Page 3


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?
15.1 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. 15.1).
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.
15
I I I I IMPROVEMENT MPROVEMENT MPROVEMENT MPROVEMENT MPROVEMENT     IN IN IN IN IN F F F F FOOD OOD OOD OOD OOD R R R R RESOURCES ESOURCES ESOURCES ESOURCES ESOURCES
Chapter
2020-21
SCIENCE 204
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.
15.1.1 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
Fig. 15.1: 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
Q
2020-21
IMPROVEMENT IN FOOD RESOURCES 205
all 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?
15.1.2 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.
15.1.2 (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 15.1).
Q
2020-21
Page 4


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?
15.1 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. 15.1).
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.
15
I I I I IMPROVEMENT MPROVEMENT MPROVEMENT MPROVEMENT MPROVEMENT     IN IN IN IN IN F F F F FOOD OOD OOD OOD OOD R R R R RESOURCES ESOURCES ESOURCES ESOURCES ESOURCES
Chapter
2020-21
SCIENCE 204
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.
15.1.1 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
Fig. 15.1: 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
Q
2020-21
IMPROVEMENT IN FOOD RESOURCES 205
all 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?
15.1.2 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.
15.1.2 (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 15.1).
Q
2020-21
SCIENCE 206
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
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 15.1: 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
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2020-21
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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?
15.1 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. 15.1).
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.
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I I I I IMPROVEMENT MPROVEMENT MPROVEMENT MPROVEMENT MPROVEMENT     IN IN IN IN IN F F F F FOOD OOD OOD OOD OOD R R R R RESOURCES ESOURCES ESOURCES ESOURCES ESOURCES
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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.
15.1.1 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
Fig. 15.1: 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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IMPROVEMENT IN FOOD RESOURCES 205
all 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?
15.1.2 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.
15.1.2 (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 15.1).
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SCIENCE 206
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
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 15.1: 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
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IMPROVEMENT IN FOOD RESOURCES 207
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 from 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.
15.1.2 (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.
using 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
15.1.2.(iii)]. These cropping systems are
beneficial in insect, pest and wheat control
besides providing nutrients.
15.1.2 (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.
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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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