Read more ; Ch 2 history, Ch 5 history class 8
Land
Land is most important Natural resources. it covers only about thirty per cent of the total area of the earth surface an all parts of this small percentage are not habitable.
uneven distribution of population in different parts of the world is mainly due to varied characteristics of land and climate.
The rugged topography, steep slopes of the mountains, low-lying areas susceptible to water 2024-2logging, desert areas, thick forested areas are normally sparsely populated or uninhabited.
Plains and river valleys offer suitable land for agriculture.
Land Use
• Land is used for different purposes such as agriculture, forestry, mining, building houses, roads and setting up of industries. This is commonly termed as Land use.
• Land can also be classified on the basis of ownership as – private land and community land.
• Private land is owned by individuals whereas, community land is owned by the community for common uses like collection of fodder, fruits, nuts or medicinal herbs. These community lands are also called common property resources.
• Land degradation, landslides, soil erosion, desertification are the major threats to the environment because of the expansion of agriculture and construction activities
Conservation Of Land Resource
Growing population and their ever-growing demand has led to a large-scale destruction of forest cover and arable land and has created a fear of losing this natural resource.
the present rate of degradation of land must be checked. Afforestation, land reclamation, regulated use of chemical pesticide and fertilisers and checks on overgrazing are common methods used to conserve land resources.
SOIL
The thin layer of grainy substance covering the surface of the earth is called soil.
Soil is made up of organic matter, minerals and weathered rocks found on the earth. This happens through the process of weathering. The right mix of minerals and organic matter make the soil fertile.
Landslides
Landslides are mass movement of rock, debris or earth down a slope. They often take place in conjunction with earthquakes, floods and volcanoes.
spell of rainfall can cause heavy landslide that can block the flow of river for quite some time. The formation of river blocks can cause havoc to the settlements downstream on its bursting.
Factors Of Soil Formation
The major factors of soil formation are the nature of the parent rock and climatic factors. Other factors are the topography, role of organic material and time taken for the composition of soil formation. All these differ from place to place.
Degradation Of Soil and Conservation Measures
Soil erosion and depletion are the major threats to soil as a resource.
Factors which lead to soil degradation are deforestation, overgrazing, overuse of chemical fertilisers or pesticides, rain wash, landslides and floods.
1. Mulching: The bare ground between plants is covered with a layer of organic matter like straw. It helps to retain soil moisture.
2. Contour barriers: Stones, grass, soil are used to build barriers along contours. Trenches are made in front of the barriers to collect water.
3. Rock dam: Rocks are piled up to slow down the flow of water. This prevents gullies and further soil loss.
4. Terrace farming: Broad flat steps or terraces are made on the steep slopes so that flat surfaces are available to grow crops. They reduce surface run off and soil erosion Contour ploughing: Ploughing parallel to the contours of a hill slope to form a natural barrier for water to flow down the slope
5. Shelter belts: In the coastal and dry regions, rows of trees are planted to check the wind movement to protect soil cover
Water
. Three fourth’s of the earth’s surface is covered with water. It is therefore appropriately called the ‘water planet’.
Ocean water is however saline and not fit for human consumption. Fresh water accounts for only about 2.7 per cent.
70 per cent of this occurs as ice sheets and glaciers in Antarctica, Greenland and mountain regions.
1 per cent of freshwater is available and fit for human use.
Its total volume remains constant. Its abundance only seems to vary because it is in constant motion, cycling through the oceans, the air, the land and back again, through the processes of evaporation, precipitation and run-off. This as you already know is referred to as the ‘water cycle’.
Problems of Water availability
Many regions of the world. Most of Africa, west Asia, south Asia, parts of western USA, north-west Mexico, parts of south America and entire Australia are facing shortages in fresh water supply.
Conservation of water resources
Access to clean and adequate water sources is a major problem facing the world today.
Natural vegetation and wildlife exist only in the narrow zone of contact between the lithosphere, hydrosphere and atmosphere that we call biosphere. Discharge of untreated or partially treated sewage, agricultural chemicals and industrial effluents in water bodies are major contaminants. They pollute water with nitrates, metals and pesticides.
These chemicals are non-biodegradable and reach human bodies through water. Water pollution can be controlled by treating these effluents suitably before releasing them in water bodies.
Sprinklers effectively irrigate the area by checking water losses through seepage and evaporation. In dry regions with high rates of evaporation, drip or trickle irrigation is very useful.
Rain water harvesting is the process of collecting rain water from roof tops and directing it to an appropriate location where it is stored for future use.
Natural Vegetation and Wildlife
the biosphere living beings are inter-related and interdependent on each other for survival. This life supporting system is known as the ecosystem.
Wildlife includes animals, birds, insects as well as the aquatic life forms. They provide us milk, meat, hides and wool. Insects like bees provide us honey, help in pollination of flowers
Vulture due to its ability to feed on dead livestock is a scavenger and considered a vital cleanser of the environment.
Distribution Of Natural Vegetation
Growth of vegetation depends primarily on temperature and moisture.
Areas of heavy rainfall, huge trees may thrive. The forests are thus associated with areas having abundant water supply.
Amount of moisture decreases the size of trees and their density reduces. Short stunted trees and grasses grow in the regions of moderate rainfall forming the grasslands of the world.
Scrubs grow in dry areas of low rainfall. In such areas plants have deep roots and leaves with thorny and waxy surface reduce loss of moisture through transpiration
Conservation Of Natural Vegetation
Deforestation, soil erosion, constructional activities, forest fires, tsunami and landslides are some of the human and natural factors which accelerate the process of extinction of these resources.
major concerns is the poaching which result in a sharp decline in the number of particular species.
animals are poached for collection and illegal trade of hides, skins, nails, teeth, horns as well as feathers. Some of these animals are tiger, lion, elephant, deer, black buck, crocodile, rhinoceros
National parks, wildlife sanctuaries, biosphere reserves are made to protect our natural vegetation and wildlife.
CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora)