2. Food comes from the three
sources
CROPLANDS : that
provide 76 % of the
total , mostly
grains.
RANGELANDS : that
produce meat mostly
from grazing livestock,
accounting for about
17% of the total food.
FISHERIES : That
supply the remaining
7 per cent
3. World Food Problem
1) NATURAL DISASTERS : Climate change is having an increased impact on food production
as droughts and flooding become more frequent and more severe. Shrinking access to fertile
land and water may trigger refugee crises and conflicts.
2) POVERTY : Ultimately, the main reason why most people are unable to feed themselves is
not that food is unavailable but they cannot afford it.
But poverty also reduces food output. Many African farmers produce small harvests because
they lack irrigation and fertilisers.
3) Example : Africa has the lowest fertiliser usage in the world – a measure of how its farmers
are simply unable to afford the inputs used by their developed world counterparts.
4) GLOBAL FOOD PRICES : Rising global food prices affect people's ability to buy enough to
feed their families., especially the urban poor, who can spend as much as 80 percent of their
income on food.
In 2007 and 2008, the global price of basics like rice, wheat and maize soared, triggering
riots in many countries.
5) Uncontrolled Population : “the balance of production and consumption” of foodstuffs is
also a problem. On Oct 31st 2011, the world population grows up to 7 billion.
So, if the world population grows up in current pace, the amount of production of cereal crops
is said to be unable to catch up with the population in the future.
4. 6) Example : Population growth demand for more varied diets in countries like China and
India, and a growing market for biofuels are putting pressure on limited resources like
land and water.
7) Foreign Companies : Foreign companies are taking over vast swathes
of fertile farmland in poor countries to grow food for export, potentially
diminishing local farmers' access to land and food.
8) Undernourishment : It is the lack of sufficient calories in food.
According to FAO estimate, the average minimum daily requirement
over the whole world is about 2,500 calories per day. People who
receive less than this calorie requirement are said to be
undernourished.
9) In the developing countries , one child in four dies of one disease or the
due to undernourishment and suffer from deafness, anaemia, thyroid
etc.
10) Malnourishment : It relates to the deficiency of such nutrients in food
as proteins, vitamins or essential chemical elements.
In poorer countries , people get malnourished because they cannot afford
a healthy diet like meat, fruit , milk and milk products and such lead to a
variety of health problem like goitre, anaemia etc.
11) Overnutrition : An intake of excessive calories and this problem
afflicts the rich , developed countries of the world. Consumption of
5. 12 ) Indian Scenario : Although India is the third largest
producer of staple crops , an estimated 300 million
Indians are still undernourished.Our food problems
are directly related to population.
“Every year our food problem is killing as many
people as were killed by the atomic bomb
dropped on Hiroshima during World War II”
13) World Food Summit , 1996 set the target to reduce
the number of undernourished to just half by 2015,
which still means 410 million undernourished people
on the earth.
6. Impacts of Over-Grazing
Overgrazing : India leads in livestock population in the world. The
huge population of livestock needs to be fed and the grazing
lands or pasture areas are not adequate.
1) Soil erosion : Due to overgrazing by cattle, the cover of
vegetation almost gets removed from the land. When the grasses
are removed , the soil becomes loose and susceptible to the
aviation of wind and water.
2) Land Degradation : Overgrazing leads to multiple actions
resulting in loss of soil structure, hydraulic conductivity and soil
fertility as explained below :
2.1) The humus content of soil decreases and overgrazing leads to
organically poor, dry, compacted soil.
2.2) Overgrazing removes the vegetal cover over the soil and the
exposed soil gets compacted due to which the operate soil depth
decline.
2.3) Due to trampling by cattle the soil loses infiltration capacity ,
which reduces percolation of water into the soil and more water
7. 2.4) Organic recycling also declines in the ecosystem
because not enough detritus or litter remains on the soil to
be decomposed.
3) Loss of useful species : Overgrazing adversely affects the
composition of plant population and their regeneration
capacity.
When the livestock graze upon them heavily, even the root
stocks which carry the reserve food for regeneration get
destroyed.
Example : As a result of overgrazing vast areas in Arunachal
Pradesh and Meghalaya are getting invaded by thorny
bushes, weeds etc. of low fodder value.
Thorny plants like Lantana, Xanthium etc.
4) Floods : Soil erosion leads to floods. The soil cannot check
the flow of rain water and that causes floods.
5) Reduction in plant diversity : The cattle like to eat certain
plants, and leave the others results of destruction of certain
plant species.
8. Impact Of Agriculture
Changes brought about by agriculture on environment can broadly be divided into three
classes :
1) Local Changes : are also known as on-site effects which occur at o near the site of farming.
1.1) Soil erosion : wind or water action
1.2) Pollution of rivers: chemicals and fertilizers flown by wind and irrigation water.
1.3) Poisoning of fish: Due to water pollution, fish eating get toxic to human.
1.4) Depletion of nutrients : During slash and burn the organic matter in soil
destroyed the nutrient and taken up by crops within short period .Such cropping get
destroyed and supply becomes low .
2) Regional changes :refers to changes in region of farming
2.1) Deforestation
2.2) Desertification
2.3) Soil infertility
2.4) large pollution
3) Global changes : refers to changes in the world at large
3.1) Climatic changes : Change in Oxygen & Change in carbon and nitrogen dioxide
cycle
3.2) Global warming : Due to concentration of CO2 which results in the increasing of
temperature of earth which is very hazardous to human beings.
9. Effects of Modern Agriculture
1.) Impacts related to high yielding varieties(HYVs) :
1.1) The uses of HYVs encourages monoculture i.e. the same
genotype is grown over vast areas.
1.2) Attack of pathogens, leads to total devastation of crop by
disease due to uniform condition which results in rapid spread
of disease.
2) Water-logging : In punjab and Haryana , extensive areas
have become water-logged where adequate canal water
supply or tube –well water encouraged the farmers to use it
over enthusiastically leading to water-logging problem.
3) Salinity problem : At present one third of the total cultivable
land area of the world is affected by salts.
In India about 7 million hectares of land are estimated to be salt
affected which may be saline or sodic.
Salinization of soil is caused by excessive irrigation and sodic
soil have carbonate and bicarbonate of sodium, the pH
Exceeds 8.0.
10. 4) Fertilizers related problems :
4.1) Micronutrient Imbalance : Most of the chemical fertilizers used in
modern agriculture have nitrogen(N) , phosphorus(P) and potassium
(K) which are essential macronutrients .Excessive use of fertilizers
cause micronutrient imbalance.
Example :Excessive fertilizer use in Punjab and Haryana has caused
deficiency of micronutrient Zinc in soil which affecting productivity of
the soil.
4.2) Nitrate pollution : Nitrogenous fertilizers applied in the field often
leach deep into soil and ultimately contaminate the ground water.
If it excess 25 mg/L , cause “Blue Baby Syndrome”
methaemoglobinemia which even lead to death of infant.
Example : India, France, Germany and Netherlands
4.3) Eutrophication : A large proportion of N & P used in crop fields is
washed off and along with runoff water reach the water bodies
causing over nourishment of lakes a process known as
eutrophication.
Due to this, lakes get invaded by algal blooms and often produce toxins
and badly affect food chain.
Thus excessive use of fertilizer in agriculture field that lake ecosystem
gets degraded.
11. 5) Pesticide related problem :
Although DDT and chemicals as sulphur, arsenic etc. pesticides
have gone a long way in protecting our crops from huge
losses occurring due to pest , yet they have number of side-effects
:
5.1) Creating resistance in pests and producing new pests :
About 20 species of pests are now known which have become
immune to all types of pesticides and are known as “Super
pests”.
5.2) Biological Magnification : Many of pesticides are non-biodegradable
and keep on accumulating in food chain, a
process called biological magnification.
As human beings occupy a high trophic level in food chain get
pesticides in bio-magnified form which is very harmful.
5.3) Death of non-target organisms : Many insecticides are
broad spectrum poisons which not only kill the target species
but also several non-target species that are useful to us.