Soil erosion and conservation - class-IX

Answer: A- 3; B- 4; C- 1; D- 2

Land use: Land is used for different purposes such as agriculture, forestry, mining, building houses, roads and setting up of industries. This is known as land use.

Humus: Humus is defined as black organic matter formed in soil due to the decay of dead plant and animal matter.

Rock dams: These are the artificial embankments created by constructing mould of soil, clay, sand and rock. Main function is to prevent floods and soil erosion

Arable land: It is the land suitable for agriculture.

• Row of trees planted in the coastal areas to check the wind movement is called Shelter Belts.
  

The most appropriate method to verify soil erosion on steep slopes is terrace cultivation.Terrace farming is a method of farming whereby “steps” known as terraces are built onto the slopes of hills and mountains. When it rains, instead of rain carrying away the soil nutrients and plants down the slope, they flow to the next terrace. Every step has an outlet which channels water to the next step.

Over irrigation is main cause of land degradation in Punjab due to waterlogging leading to increase in salinity and alkalinity in the soil. Punjab, Haryana, Uttar Pradesh are the states facing issue of land degradation.

Afforestation is the most effective method for soil conservation on hill slopes because tree roots bind the soil together, preventing erosion caused by water runoff.

Terracing, contour cultivation, and afforestation are all well-established and effective methods of soil conservation. Therefore, none of the options listed are 'not' effective.

 Ploughing in a wrong way i.e. up and down the slope. It forms channels for the quick flow of water leading to soil erosion. 

1:The denudation of the soil cover and
subsequent washing down is described as soil
erosion. Wind blows
loose soil off flat or sloping land known as wind
erosion. It is very high in the state of Rajasthan.
2:It causes soil loss, dryness and deterioration of soil structure, nutrient and productivity losses and air pollution. Suspended dust and dirt is inevitably deposited over everything.

Steps can be cut out on the slopes making terraces. Terrace cultivation restricts erosion. Western and central Himalayas have well developed terrace farming. 

Soil erosion causes by water, mining, air.

Human activities like deforestation, overgrazing, construction and mining etc. lead to soil erosion. 

A terrace in agriculture is a piece of sloped plane that has been cut into a series of successively receding flat surfaces or platforms, which resemble steps, for the purposes of more effective farming. This method is called terracing. It is very useful in soil conservation in hilly or mountain areas.

Soil conservation is a method of protecting soil from getting eroded either by wind or by water.

• Few soil conservation methods include:
  
• Graduated terrace steps which are commonly used to farm on hilly or mountainous terrain. Terraced fields decrease both erosion and surface runoff.
  
• Wind breaks: Row of trees or a fence, wall, or screen that provides shelter or protection of soil from the wind.
  
• Conservation tillage is a method of preparing soil from getting eroded. This technique involves leaving the previous year crop residues until the next crop is planted.

Reforestation is the natural or intentional restocking of existing forests and woodlands that have been depleted, usually through deforestation. Reforestation activities promote the gradual depletion of CO2 from the atmosphere through absorption during photosynthesis.

Ploughing along the contour lines can decelerate the flow of water down the slopes. This is called contour ploughing. Contours act like bunds. Terraces are levelled into step-like small fields with even slope.

Dustbowl catastrophe is nothing but the dust storm that greatly damaged the ecology of US and Canadian prairies. The main reason for this storm was the wind erosion. Hence to prevent such catastrophes people should be taught well to prevent soil erosion. 

In the states of Punjab, Haryana, western Uttar Pradesh, over irrigation is responsible for land degradation due to waterlogging leading to increase in salinity and alkalinity in the soil. 

The running water cuts through the clayey soils and makes deep channels known as gullies. The land becomes unfit for cultivation and is known as bad land. In the Chambal basin, such lands are called ravines. Chambal is in the state of Madhya Pradesh.

Afforestation and proper management of grazing can help to some extent. 

The running water cuts through the
clayey soils and makes deep channels as
gullies. The land becomes unfit for cultivation
and is known as bad land. In the Chambal
basin such lands are called ravines.

In Punjab and Haryana, intensive agriculture and the use of canal systems have led to significant over-irrigation, which causes waterlogging and soil salinity, damaging the soil.

Ploughing along contours on a slope prevents soil being washed away by rainwater or by surface run off. Contours act like bunds. Terraces are levelled into step like small fields with even slope.

 Ploughing in a wrong way i.e. up and down the slope form channels for the quick flow of water leading to soil erosion. 

Wind erosion refers to the movement and deposition of soil particles by wind. It occurs when soil devoid of vegetation is exposed to high velocity of wind. Rajasthan is the region facing the highest levels of soil erosion due to the dry winds present in the region.

• Soil conservation is a method of protecting soil from getting eroded either by wind or by water.
  
• Soil erosion is also caused due to defective methods of farming. Ploughing in a wrong way i.e. up and down the slope form channels for the quick flow of water leading to soil erosion. 
  
• The rest of the methods help in soil conservation.
  

On hilly slopes, terraces act as bunds and prevent the soil from being washed away by running water. 

• Soil erosion is the loss of top fertile layer of soil either by wind or by water.
  
• India is facing this problem in many parts. The area affected by soil erosion is 5, 00,000 square kilometres. It adversely affects productivity and economy of the country.
  
• There are many techniques to prevent soil erosion. But important step is to increase planting of trees or afforestation.
  

Strip cropping is a method or farming in which more than one variety of crops are grown in different strips.

One of the important crop that is usually grown along with other crops is gram. This is because it has good soil holding capacity and prevents soil erosion.

Deforestation removes the protective cover of vegetation, leaving the soil exposed to wind and water, which is the primary driver of soil erosion.

Deforestation is a cause of soil erosion, not a result of it. The other options (siltation, reduced water percolation, and loss of fertility) are direct consequences of the erosion process.

Running water, wind, and the sea (waves) are natural agents that physically transport soil. Industries are a human activity, not a natural agent of erosion.

In the Kambam valley of Tamil Nadu, the specific climatic and geographical conditions make wind erosion a common and significant issue.

The eroded materials gets carried away by agents like running water, glaciers, wind, sea waves and groundwater. These all work on erosion, transportation and deposition of eroded materials.

The riverbed and the river banks get eroded because of the fast flow of water, sand particles, pebbles etc, and the various tributaries joining the main river. All these lead to the formation of gorges, V-shaped valleys and waterfalls.

Following are the factor responsible for erosional transportational and depositional work of a river:-

• Slope of land
• The type of rock
• Volume of water flowing in the river
• The length of flow
• Volume of sediments in the river

The movement of air is called wind. Wind is a gaseous agent of erosion. The erosional, transportational and depositional work of wind is more prominent in deserts and semi-arid region.

Wind carries small sand particles, small pebbles, etc. along with it. These particles cause erosion along rocks coming in the way due to friction. This leads to formation of mushroom rocks, deflation hollows, yardangs, etc.

Afforestation is the process of planting trees on a large scale, which helps to stabilize the soil and prevent erosion.

Ploughing along the contour lines can
decelerate the flow of water down the slopes.
This is called contour ploughing. This is the best method to reduce the soil erosion in the hilly areas.

• Ploughing along the contour lines can decelerate the flow of water down the slopes. This is called contour ploughing. 
• Steps can be cut out on the slopes making terraces. Terrace cultivation restricts erosion. 
• Large fields can be divided into strips. Strips of grass are left to grow between the crops. This breaks up the force of the wind. This method is known as strip cropping. Strip cropping method reduce the soil erosion
  

Contour ploughing, terracing, and crop rotation are all effective soil conservation techniques. Shifting cultivation is generally considered harmful to soil as it involves clearing and burning land.

In India, ravine erosion and gullies cause the most severe and widespread damage to land, followed by issues like alkalinity, salinity, and water-logging.

Gully erosion occurs when water flows in narrow channels during heavy rain, cutting deep trenches into the soil. This process is responsible for the formation of the extensive Chambal Ravines.

Mulching is the process of covering the topsoil with plant material such as leaves, grass, twigs, crop residues, straw etc. it helps in soil conservation.

As noted previously, over-irrigation in Punjab and Haryana has led to waterlogging and soil salinity, which are the primary causes of soil degradation in those regions.

Coastal erosion is a significant issue in many Indian states, but Kerala is widely cited in geographical studies for its severe and persistent coastal erosion problems due to its specific coastline characteristics and high population density along the shore. While other states also face erosion, Kerala's situation is often highlighted as particularly critical.

 The running water cuts through the clayey soils and makes deep channels known as gullies. The land becomes unfit for cultivation and is known as bad land. In the Chambal basin such lands are called ravines. 

• Soil erosion is the loss of top fertile layer of soil either by wind or by water.
  
• Sheet Erosion: Uniform removal of the top soil just like a sheet. It is resulted because of water flow.
  

A mulch is a layer of material applied to the surface of an area of soil. Its used for the following purposes:
1. to conserve moisture.
2. to improve the fertility of the soil.
3. to reduce weed growth.

A check dam is a small, often temporary, dam constructed across a swale, drainage ditch, or waterway to counteract erosion by reducing water flow velocity.

While deforestation and overgrazing contribute, rain (specifically heavy rainfall and runoff) is the primary natural agent causing soil erosion in many regions.

Deforestation removes the protective vegetation cover, which accelerates soil erosion rather than preventing it.

Soil erosion is defined as the displacement of the upper layer of soil, which is the most fertile part, by agents like water, wind, or ice.