Land Resources
P.Anbukarasi
Land Resource, its importance let us discuss about it. Land makes up only about 30% of the
surface of the earth the rest is covered by oceans and seas .As you all know land provides us
the shelter not only for human beings but for so many living things depending on land and we all
are living on the land constructing houses, industries, roads etc. The major support system is
land.90% of the world population lives in just 30% of the land area. Plains and river valleys are
suitable living as well as for agriculture. Based on the topography land is divided into many
categories. Let us discuss about that. Most of the land is made of vast deserts, dense forests,
rugged mountains, rocky slopes, low-lying areas prone to flood, regions covered by mountain
glaciers, thick forested areas are generally sparsely populated or uninhabited. Let me explain
this .That is the availability of land is very less because majority of our land is covered by vast
desserts, very vast and sandy land with harsh climate when you don’t get sufficient water and
it’s not suitable for survival. Then dense forest is also not suitable for survival because of variety
of animals and insects which are available. Rugged mountains, where transportation and
communication will be a problem and agriculture then rocky slopes, even rocky slopes it is not
suitable for survival or residential purpose. Low lying areas that is close to the sea shores are
also not suitable because they are prone to floods .Then regions’ covered by mountain glaciers,
as we go higher and higher form the sea level the higher altitude where we have less
temperature .So naturally that area will be covered by ice or snow. So these are the places you
can find very less population. Then thick forested areas, again thick forest area is also difficult
for survival because, communication and transportation will be a major problem. The areas
where we find more population or moderate or heavy population is river valleys and plains.
People prefer living on plains because you can construct houses on plains. Transportation,
communication and all the commercials activities are very easy more over moderate climate.
We have suitable climate to live and water facilities. So these are the things that make plains
favorable place for settlements. Then river valleys, river valleys are the places where you get
ample water for agriculture and all the industrial activities these are the suitable place. The soil
develops on the top of earths land surface as a thin layer known as the pedosphere. That is
land is covered by soil layer. The thin layer that is covering the land is known as soils. It is also
known as peadoshpere. This thin layer is precious natural resource and so deeply affects every
part of the eco system and it is also called as the great integrator. It is known as great integrator
because it is only holding all the living organisms’ on the entire universe including human beings
from small protozoan onwards you can find any kind of organism surviving on the land. Soil
holds nutrients and water for plants and animals. Soil holds nutrients and water for plants and
animals. So on land soils plays very important role this is only supplying nutrients and water for
the plants as well as animals. Soil filters and cleans water that passes through it. As we get
rainfall most of the water gets into the land through the soil. The soil is acting as a filtering
agent, filtering the rain water passing it to the underground and reaching the underground water.
Then it also cleans the water .They can change the chemistry of water and the amount that
recharges the ground water are returned to the atmosphere to form the rain.
Wherever the rain water is falling, that particular areas land nature the rain water will represent.
If the land is filled with alluvial or soil rich in minerals naturally the water which enters into the
ground water will be rich in that particular mineral. It can be acidic in nature or basic in nature. It
also changes the physical as well as the chemical qualities of the water. That is if the land is
clean then ultimately the water which is entering into the ground will be clear. Whereas if the
land is filled with solid waste and liquid effluents and industrial effluents naturally the water
which is getting inside the earth will be impure and apart from that the land also holds the water
and in later same water is evaporated and it reaches the clouds in the evaporation process. So
soil plays very important role in water cycle and maintaining the water cycle.
The land is very important resource .The importance of land once again let us sum up. The food
we eat the minerals we use and the space to build shelter and clothing we get from land
resource. They provide shelter for all the living organisms. They store and transfer heat and
hence maintain the temperature balance on the earth. Let me explain this point. That is in the
day time land is heated up by the sun. In the night time land cools very fast .Land has the
tendency to become hot as well as become cool. So because for that the land breeze is
possible and sea breeze and land breeze play very important role in balancing the temperature.
Land can be classified broadly on the basis relief. That is plateau, plains and mountains
.Plateau is an elevated land, plains is flat land and mountains are huge hills .So the earth is
filled with these major three categories of land forms. On the basis of soil fertility land is divided
in to fertile and barren. Fertile means on that particular land any crop can be grown or that
particular crop can be grown well. The land will have much nutritious value in the soil, this is
suitable for cultivation. Then barren land is ultimately a waste land where nothing can be grown
and it will be lying as a waste land. On the basis of development again the land is divided into
rural and urban. Rural land belongs to villages and small towns where as urban land belongs to
towns and cities. They come under this category. It depends on whether the particular area is
rural or urban it is based on infrastructure and the facilities available , educational institutions ,
hospital facility , industrial development then transportation and all these things are deciding
about the nature of the land , whether it is rural or belonging to urban in nature. On the basis of
ownership land can be divided into private or community owned or government owned. Any
individual or group of individuals can own land. They can buy a land or construct their own
houses, their own industries, institutions that belong to a particular individual or that particular
family. This is known as private land. Whereas the land which is belong to the community or
property of that particular area or belonging to the government it is known as a government
land. This is used by everyone and it is accessible for everyone, whereas the private land
cannot be accessible for others or outsiders. Land is again classified on the basis of the use. It
is again classified into arable (suitable for agriculture), pasture land, forest, fallow, Cultivable
and non –Agricultural land. Let me explain one by one, arable land is suitable for cultivation that
means it is agricultural land .Pasture land, pasture land is nothing but used for grazing by the
animals. So usually this land will be having grasses, grassland or small herbs and shrubs.
Usually this kind of land can be outskirts of the villages or peripheral area of the forest. Then
forest, forest is nothing but huge trees and different varieties of vegetation and wildlife you get.
Then fallow land, this land can be cultivable if it is used in a proper manner. So that kind of land
is known as fallow land which may not used for cultivation is a proper manner. Then cultivable
waste land, that means it can be cultivated but lying fallow for more than five years, that is
cultivable waste land means the land can be used for cultivation if proper nutrients and proper
irrigation is provided. But people may not use it .So that kind of land is known as cultivable
waste land. Then non-agricultural land that is land is not suitable for agriculture and not even
for pasture land. So that kind of land is known as non agricultural land. Then land use, how we
are making use is very important. All the land cannot be used for all purposes. The use of land
is determined by physical factors such as topography that means relief features and land forms
then soil, climate, minerals, and availability of water. These are the major factors determining
the nature of the land, where the land has more value or not. We will not buy land in an area
where it doesn’t have any market value. So we will see all such things, even if you are
constructing a house you will be seeing different factors definitely whether the area is accessible
, water facility and how far the place is from schools and all such things makes a lot of
difference. Human factors Such as population density, availability of capital and technology are
also important determinants of land use pattern.
In India how we are making use of the land? In India the pattern of land use is nett sown area
i.e. cultivable area or arable area is 46.6%, forest land is 22.6% once upon a time our forest
land was very high, that is before British period we had very huge forest land , British introduced
railways so that destroyed lot of our forest. That is why we are also not getting proper rainfall.
Then permanent pasture that means the land which are allotted only for pasture purpose and
grazing purpose where you cannot grow other crops because the land is suitable only for
grazing that is 3.6%.
Cultivable waste land that is 4.5%.Cultivable waste land is the land which may be lying waste at
present but proper irrigation and nutrition is given this land can be converted as cultivable land.
Land not available for cultivation is 13.5%.Maybe they are rugged mountains or they are under
snow covered area or they may be a desert , so these are the land which are totally 13.5%
.When we talk about land the major component of land is soil. Soil only is indirectly called land.
So we are going to learn about soil. It is the unconsolidated covering of fine rock particles that
covers the surface of the earth. The thin layer that covers the earth is soil. It consists of
weathered particles of rocks brought down by the age. That is, soil is nothing but the withered
particles of rock. This takes long time. The rocks are broken due to the various natural and
human activities and soil particles are formed, the major agents of weathering is water, wind
and glacier. It also consists of decaying organic matter known as humus and minerals. The soil,
the major part of soil which is holding the nutritious value in soil is humus. It is nothing but
decayed organic particles. When you take a soil in a glass and pour some water and you stir it
well and you allow the soil to settle down for five or ten minutes after sometime you will find
certain things floating on the soil. That is only humus; they are the decayed organic particles.
Then soil varies in color texture, fertility and content. So all t he soil are not in the same color.
These are different types of soil based on the rock bed that is below the earth that is below the
earth’s crust we have the rock beds, form this rock beds only we have the soil formations based
on that the soil color also changes. The type of land forms and the nature of the parent rock
determine the type of soil. The rock-bed only is known as the parent rock. Fertility of the soil
refers to its ability to produce vigorous growth in plants .How do you call a soil as a fertile soil? If
you have a good cultivation, that particular land or soil is called fertile land. If you don’t get good
yield, then that is not considered as a fertile soils. The factors that determine the fertility of the
soil are right mixture f minerals‘, organic matter, ability to retain correct amount of moisture .Soil
forms very slowly .It takes 200 to several thousand years .The factors involved in soil formation ,
The material from which the soil is formed is called parent materials. Suppose the parent
material is rich in iron ore then the soil will be rich in iron and the colors also changes. It may be
slightly red in color. Then this also changes the properties of the soil. As per the parent material
the soil nature also depends on it. It may be from bed rock, organic material, and construction
material, loose soil material deposited by wind, water, glaciers and volcanoes. So it cannot be
exactly from a any rocks which is rich in minerals , it can be from any parent material may be
decayed organic matter, may be construction materials, some places you must have seen the
construction material is abundant, from there also the soil can be formed. Naturally the soil
which is coming from the construction materials may not be rich in nutritious value. It may not be
suitable for cultivation and some loose soil , that is soil from desert , soil from arid area is
always loose because they don’t have any vegetation covers to bind them so these kinds of soil
also may not be rich in cultivation. The second factor which is deciding the soil formation is
climate , heat is temperature, natural temperature or it may be heat due to industries or due to
volcanic eruption so many other reasons rainfall then ice cover, snow fall, wind, sunshine
.These are the climatic factors which also increase the soil formation. And other environmental
forces break down other environmental forces that are parent material and also affect the rate of
soil forming process and soil properties. Then third one is organisms. The soil is home to a large
number of micro and macro organisms. The dead remains of soil organism become organic
matter that enriches the soil. Organisms in the soil contribute to the exchange of gasses eg:
Rhizobium or nitrogen fixing bacteria. See soil is the home of so many organisms that is you
can find small micro organisms like bacteria’s , virus then protozoan’s algae fungi etc. where as
it is also providing shelter for the huge animals like elephants including human beings. So what
happens one all this living things die they naturally go into the soil .This macro animals are
disintegrated by the micro organisms like bacteria , fungi etc and they are mixed with the soil
and again increasing the fertility of the soil. So the dead remains of all these organic matter
enrich the soil by providing sufficient nutrients. Apart from that bacteria’s which are living on the
leguminous plants and the roots of the leguminous plants and also fixing the atmospheric
nitrogen in the soil because some of the plants by nature they cannot have the nitrogen which
is very important for their growth so such plants will have a nitrogen fixing bacteria on their
nodules or their root nodules so these kind of bacteria’s are trapping the nitrogen from
atmosphere giving it to the soil, fixing it to the soil apart form that the micro organisms living in
the soil is also helping in the gaseous exchange. Definitely they respire even plants respire;
plant’s roots respire so there is a possibility for gaseous exchange that way the microorganisms
play very important role. They penetrate and help the roots to penetrate into the soil and they
make way for the rain water to enter into the soil. Then topography, topography is land from
only. The location of soil on a landscape also affects it formation and its properties. Soil at the
bottom of the hill will get more water than the soil on the hill side. Soil on slopes that get direct
sunlight will be drier than soil at the bottom. Topography, suppose the soil is from alluvial fan
and it is fertile , soil is from desert it is unfertile , it is loose and sandy where as soil is from
clayey area, that is alluvial fan the penetration of water getting into the soil is bit difficult.
Suppose the soil from the hill slope sis loose and dry because they are exposed to this and so
the topography of land is helpful in deciding the soils nature. Another important factor for soil
formation is time; the amount of time affects the properties of the soil. As it is the soil takes long
time to form, the amount of time affects the properties of soil. Time is a very important factor in
deciding the formation of soils properties like temperature and moisture content will change very
fast. Mineral changes will occur in every soil, as the formation of soil takes very long time the
properties like color , moisture and temperature of the soil changes very fast where as the
mineral content and the quality of the soil also changes but it takes a little long time. And huge
rock only after weathering becomes soil so it takes as the rock and the stones exposed to the
water running water and rain water and fast blowing wind then that only becomes soil. So time
plays very important role to form a thin soil layer it takes millions of years to it is very important
to protect the soil. Soil profile, the main layers of soil horizons are top-soil, sub-soil, parent
material and bed-rock. A horizontal section of soil when we need to test the soil, it can be taken
by a horizontal section, that horizontal section is known as a soil profile. You have a different
layer that is top soil, sub soil parent material and bed rock. Let us discuss about top soil .It is
nothing but top most layer of the soil having humus and other decayed material .This is the zone
where you can find number of macro and micro nutrients available. Then sub soil, next to the
top soil you have sub soil made out of small rocks. Then parent material it is a bed rock from
here only that particular soil is formed. Parent material and bed rock is fourth layer. You can find
very huge rocks. In our country the soil is classified into different category based on its original
and texture, quality content etc. First one is alluvial soil , this is formed by the river deposition,
depositional action of river, it is very fertile ,it is about 25% in our country , you can find this kind
of soil in Gangetic plains and deltaic peninsular area and delta of Krishna , Kaveri, Govdaveri
etc. Suitable for cultivating rice, banana etc. It is common in Deccan plateau, it is black in
colour, and it is formed from lava. Once upon a time the place we had the Arabian sea we had a
volcano. We had a volcanic eruption , due to this volcanic eruption the lava was thrown out and
the Deccan plateau , so part of the Deccan plateau that is Maharashtra, parts of Madhya
Pradhesh , Karnataka, and Andhra Pradesh , Chota Nagpur , all these areas are filled with this
black soil. It is very much suitable for cotton cultivation. Then laterite soil, laterite soil is formed
out of leeching activity, where you have more rain fall, the fertility of the soil is washed away, the
humus of the soil is washed away, this may not be that suitable for cultivation. Then red soil, the
colour is due the presence of iron oxide, this is also suitable for cotton cultivation and millet,
some small cereals. Then peat and forest soil is rich in humus, very much suitable for
cultivation, this kind of soil you can find in every green forest, areas close to the ever green
forest. Then arid and sandy soil , this is very much common in desert area , lose and sandy soil
, if proper irrigation facilities are done , this soil can be used for cultivation .This you can find in
western Rajasthan. Problems leading to land degradation , Land is degraded due to mining
activities, over exploitation of land resources, landslides, soil erosion and desertification.So land
degradation is not only due to human activities, even nature also has its role to degrade land.
That is deforestation .The major reasons is deforestation which is manmade. Deforestation is
nothing but reckless cutting down of trees so the forest area after sometime will become a land
where this land can used for cultivation or construction. Then slash and burn agriculture. It is a
way of cultivation in these days and even now it is practiced in some interior parts that is close
to Amazon region and in Amazon forest. Even in India it was once upon a time very much in
practice, now it is banned. It is bad for the environment as well as land, Slash and burn
agriculture in India is known as ‘jhoom ‘agriculture or shifting cultivation. A piece of land is taken
and the trees and the vegetation is cleared in the particular area and those things are burnt
there itself and the ash is utilized a manure and the land will be used for cultivation. People
cultivate for three or four years an once they realize that the land has lost its fertility , they leave
the land as fallow land and shit their agricultural activities to some other area, The surface area,
mining , coal mines and gold mines, all these mining activities open cast mining and such
activities lead land into great damage to the land. Then toxicity of landfills in cities wherever
people find vacant land it is their tendency to dump just without thinking anything, they just
dump their garbage here. It has become the habit of everyone so that should be avoided. Even
peripheral areas of big towns and cities we can find people and municipalities are dumping their
garbage that naturally destroys the fertility of the land and the eco system of that particular area.
See this toxicity dumping on n the land leads to the killing of microorganism which is very
essential for the lands fertility, because these are the ones which act upon the decayed
substances or decayed organic matter converting them into nutritious substances enriching the
soil. The number of insects and worms which live in the land through their gaseous exchange,
throughout their activities and their life cycle they enrich the land for example earth worms
considered as the friends of the farmers they play very important role in our cultivation activity.
Then untreated industrial effluents, without thinking about our land resource or anything people
just let their industrial waste on the land and sometimes you can find overflowing drainage man
holes and then people also let out their domestic waste water in the road and streets so
naturally they pollute the soil as well as they pollute the entire area. Apart from this the soil is
also facing its own problem, on is pH of soil that is acidity and basic nature of soil. If it increases
whether acidity or basic nature if soil increase or decrease that is reflected on the soil, in turn
you can find out the yield is also reduced. Then this leads to acid soil syndrome, pH of less
than5.6 leads to acid soil syndrome and then salinity of the soil is caused due to the excess
irrigation or excess making use of ground water level. If you extract more ground water naturally
the soil salinity increases and making use of this fertilizers ,pesticides, insecticides, fungicides,
herbicide all these things are also increasing the salinity of the soils. So in that kind of soil plants
won’t grow. It may not be suitable for agriculture. Then soil pH is nothing but the acidity if the
soil which cause a lot of problems from the macro organisms living in the soil and especially the
bacteria which are living in the nodules are affect very badly and lot of dieses are also occurring
because of this. Then soil organisms, when the soil nature changes, the quality of the soul also
changes. If salinity increases or pH level increases it kills the organism which are living in the
soil as it is, I have discussed about this. Then soil contamination, soil contamination is mainly
human activity. We contaminate soil by dumping unwanted hospital waste then domestic waste,
industrial waste etc w hic affects the soil quality. Next major problem of the soil is soil erosion;
the removal of top soil is called soil erosion. The top soil can be removed by flowing water, rain
water or run odd water or fast blowing wind .These are the agents of soil erosion. If unchecked it
can lead to the depletion of soil. Soil erosion has to be checked then and there otherwise it will
become a disaster very fast. Soil erosion is a natural process. Even though it is natural process
if it goes beyond limit it has to be controlled. It becomes a problem when human activity causes
it to occur much faster that under natural conditions. The agents of soil erosion are water and
wind. Around 15% of the world’s ice free land surface is affected by all forms of land
degradation. Of this accelerated soil erosion by water is responsible for about 56%. Wind
erosion is responsible for about 28 %. It means roughly around 11 million square kilometer is
affected by water erosion. And 5.5 million square kilometer area is affected by wind. So wind
and water play a very important role in soil erosion. The factors that influence that amount of soil
erosion are speed that is speed of the water flowing and wind. The plant cover means even the
grass can bind the soil tightly , the trees are able to hold the soil so the y prevent the soil
erosion then erosion by water , sheet erosion , rill erosion and gully erosion .Sheet erosion is
accomplished by a thin layer of water moving over a land surface. This is very common and
further in rainy season we can find runoff water, surface runoff water flowing as a sheet; this is
only known as sheet erosion. Rill erosion is nothing but the water moves in small channels
when the rain increase and rain flow is increasing the rill erosion is common. Rill Erosion occurs
when the over flow of water is concentrated into small channels called rills .then Gullies, bigger
rills are known as gullies. When rain fall increases we can find gully erosion. Gullies are
enlarged rills created as the water from several rills flow together eroding a large channel. The
rate and magnitude of soil erosion The rate and magnitude of soil erosion influenced by the
following factors, one is rainfall intensity and run off, soil erodibility, slope gradient and length of
vegetation, stream and ditch bank erosion .Rain fall intensity and run off .Soil erosion definitely
depends on the rain fall. If the rain fall is very heavy naturally the run off also will be more. The
soil surface that is the top most layer of the soil will be washed away by the rain water, fast
moving rain water. It is the capacity of the soil if the soil is very fine it can be easily eroded.
Then slope, if it is the land is sloppy naturally the erosion will be very fast, then vegetation. The
land is covered with more vegetation naturally the erosion will be very less if the land is not
covered with much vegetation then the erosion is very much higher. Then stream and ditch
bank erosion, this is very common , wherever you have ditches or the potholes there erosion is
very much common in these areas .It is accumulation and again erosion from that area. Wind
erosion, another important reason of soil erosion is wind, Wind erosion may create adverse
operation conditions in the field .Corps can be totally ruined because of wind erosion. Even big
trees will lose their branches because of the wind, and then we can see easily if is very common
sight, the fast blowing wind can uproot even electrical poles and huge trees. Then re seeding
may be necessary, the plants may be sand blasted. Soil Drifting is a fertility depleting process
that can lead to poor crop growth and poor yields. See soil drifting is another important problem
of the soil erosion is due to wind erosion. The soil will lose its fertility and then the soil will not
have any economical or agricultural value. Soil conservation, conservation of soil and land is
very essential because the methods and small tips what we are share however is very much
useful one is Conservation of land resources. Aforestation , it is nothing but planting lot of trees
and sapling, that will increase the soil conservation .Then land reclamation Then Regulated use
of chemical pesticides and fertilizers, we should avoid unnecessary the fertilizers or the artificial
insecticides , pesticides etc. Then planting of shelter belts, shelter belts are nothing but row of
trees grown on the coastal area or on the boundaries of the farms just to protect the crops form
the fast blowing winds. Controlled mining activities also should be very much checked. Then
Check over grazing , over grazing should also be checked because this will lead to
desertification .Overgrazing definitely leads that area into desertification .Then creating
awareness among people about land use and misuse is another important step. What we can
do is talk about land and the uses of soil, etc to the people. Creating awareness especially
among young minds, that works wonders. Then soil conservation, some more important
technical tips are mulching, mulching is nothing but retaining the soil moisture by putting wet
straw in-between the plants or the area in between the plants. The process of conserving soil
by retaining the moisture in the soil is mulching. Then contour barrier, on hill slides stones are
used to build across the slope following contours.
Contours are imaginary lines connecting places that lie at the same altitudes. Trenches are
made in front of the barriers to collect water this is also known as contour bunding. Contour
bunding is usually practised mostly in hill slopes just to protect soil from soil erosion. Then
plugging, rocks are piled up to slow down the flow of water this prevents gully erosion. Then one
more technique that we follow is terrace farming, this is also done on the hill slopes. Terraces
are made on steep slopes so that flat surfaces are available to grow crops. This reduces run off
and soil erosion in hill slopes. Then the technique we see in conserving soil is inter cropping and
crop rotation. Inter cropping is nothing but to growing different crops in alternative rows and
sown at different times to protect the soil from rain-wash. You must have seen around then
paddy fields or the greens or the vegetables you can find water melon or some of the cereals or
small plants are cultivated. Then crop rotation is growing different crops in the same field’s one
after the other and helps top conserve soil. That is same kind of crop is not cultivated on after
the other, See one season they may cultivate wheat , another season that same land is used for
cultivation potatoes that is only known as crop rotation so this shelter belts play very important
role in coastal region in fact it protects people from storm and cyclone. In the coastal and dry
regions rows of trees are planted which check the wind erosion. Increased use of organic
manure also will conserve the soil. Sprinkle and drip irrigation, also can be followed in irrigation
methods instead of flood irrigation we can use sprinkle and drip irrigation where the water will
not be wasted as well as the soil will not be washed away by the flowing water. In this entire
lecture we have discussed about land , soil etc let us sun it up .Land supports all living
organisms, it’s the basic support for every living thing in the world.
It supports Primary, Secondary and tertiary activities, storage for groudn water mieral s etc.
etc.The soil prvides all the nutrients for the e cultivation , and it is alo very importat for socis
economi development of the country .
Supports all living organisms, it’s the baseic suport for evey liinv thisn in the wolrd.
It supports Primary, Secondary and tertiary activities, storage for groudn water mieral s etc.
etc.The soil prvides all the nutrients for the e cultivation , and it is alo very importat for socis
economi development of the country .