Geography [3 Mark Question Answer]

(i) Contour ploughing reduces the speed of water and thus controls erosion, Contour bunding stops/prevents the flow of water and thus controls the erosion. It is helpful in more percolation of water and thus the quantity of water will also be reduced and thus erosion will be controlled.
(ii) Gullies are plugged by constructing bunds in the gullies. Contour bunding stops/ prevents the flow of water and thus controls the erosion. It is helpful in more percolation of water and thus the quantity of water will also be reduced and thus erosion will be controlled.

(i) Methods of Controlling Erosion:
(i) Erosion by water: Gully erosion can be stopped by plugging them, growing plants in gullies.
(ii) Terraced farming can be done on mountain slopes.
(ii) Erosion by wind:
(i) Planting more and more trees should along the edges of the field, the waste land and also on the steep slopes.
(ii) Carrying out strip cropping.

(i) Climate: If the climate is hot, rocks get disintegrated by exfoliation, granular disintegration whereas in cold climatic condition it's by block disintegration.
(ii) Vegetation: Plant roots penetrate rocks and break it down to form soil Their decay results into formation of organic acids which cause chemical disintegration and increase the rate of soil formation.
(iii) Microorganisms: They are responsible for bio-chemical processes in soil. Bacteria and fungi cause the decay of plants and animal remains whereas some transform the atmospheric nitrogen into nitrogen compounds needed by plants to grow.

(i) It is a process of growing leguminous crops such as soybean, chana, tur dal, etc. are grown first. These plants have nodules in which rhizobium bacteria grow which convert nitrogen into nitrogen compounds which are useful for the plants to make proteins.
(ii) After the harvesting, farmer grows non leguminous plant for which nitrogen is already available in the soil. During growth, these crops absorb nitrogen compounds and thus soil is devoid of them.
(iii) Hence the farmer grows leguminous plants again and thus the cycle continues. This is called as crop rotation.

(a) Gulley erosion can be controlled by:
(i) plugging the gullies,
(ii) growing trees or grass in the gullies.
(b) The sheet erosion is controlled by:
(i) growing trees.
(ii) controlling overgrazing and deforestation.

(i) Plants' roots hold the soil and thus prevent erosion.
(ii) Moreover, plants, their fallen leaves, fruits, etc. obstruct the flow of water and thus reduce erosion.
(iii) They also absorb the impact of rain on the soil.
(iv) The plants also absorb lot of water and thus control soil erosion.