Geography [3 Mark Question Answer]

Methods of Controlling Erosion:
(i) Erosion by water: During heavy downpours deep ‘gullies’ are made on account of water run
off. Gully erosion can be stopped by plugging it with stones and pebbles or quick growing grasses can be grown in gullies to stop its expansion.
(ii) Erosion by wind: Wind erosion reduces the productive capacity of the soil by removing the loose particles of soil with the high velocity wind. The nutrients required by the plants are taken away by the wind. Therefore more and more trees should be planted along the edges of the field, the waste land and also on the steep slopes. If it is difficult to grow trees, grass should be grown but no land should be left devoid of plants.

(i) Laterite Soils are leached Soils because alternating dry and wet spells cause the soluble silica to be removed.
(ii) These Soils are acidic in nature and coarse and crumbly in texture.
(iii) The proportion of lime and silica is reduced when leaching takes place.
(iv) In the upper layers, the compounds of iron and aluminium become higher giving a reddish colour to the Soil.
(v) Lack of nitrogen, potassium and organic elements make these Soils unsuitable for cultivation. These Soils support pastures and scrub forests.
(vi) With the use of manures, coffee, rubber, cashew, etc., can be grown on these Soils.

(i) Red Soils are formed in situ by weathering of the ancient crystalline and metamorphic rocks.
(ii) They are rich in iron content, hence, they are red in colour.
(iii) The productivity of the Red Soil increases with regular use of fertilizers.
(iv) Red Soils are porous in nature but not retentive to moisture.
(v) They are suited for dry farming as it does not require much moisture.

(i) Silica: The main constituent of sand, it is present as small crystalline grains. It is mainly derived from the weathering of rocks.
(ii) Clay: It is a mixture of silicates and contains many minerals like iron, potassium, calcium, sodium and aluminium. Particles of clay absorb water and swell.
(iii) Chalk: It consists of calcium carbonate which provides the important element calcium.
(iv) Humus: It is the organic matter present in the Soil formed by the decomposition of plants and animal remains and animal manure. It is the most important element that determines the fertility of the Soil.