Soil Science

Soil is formed by the breaking down of rocks by the action of wind, water and Climate. This process is called weathering.

The surface layer of the earth's crust is called soil. It forms by the process of weathering and erosion. It takes a long time to form the soil. There are several factors that affect the process of soil formation. These are climate, topography, parent material, organic material and time span. Rainfall influence the rate of weathering and humus formation. Parent rocks determine the texture, colour, chemical properties, mineral content and quality. Topography i.e. slope and altitude decide the accumulation of soil. Flora, fauna and microbes affect the rate of humus formation. Time span determines the thickness of soil layer. Water accumulation does not help in the formation of soil.

the presence and type of parent rock is the most determining factor in the formation of soil. This is because the parent decides what type of soil will be formed. The soil constituents, chemical nature, what type of crops it can grow is all determined by the type of parent rock.

Laterization is a prolonged process of chemical weathering of rocks leading to the formation of soil. It produces a variation in the thickness, grade, chemistry and ore mineralogy of the rock creating soil particles. Thus the correct answer is option C.

A soil profile is a vertical section of soil that displays its various layers, known as horizons. The primary horizons are typically classified as topsoil (A-horizon), subsoil (B-horizon), and parent material (C-horizon).

The soil is mainly formed by the process of pedogenesis. The abiotic factors constantly act on the rocks and lead to the formation of soil by weathering.

Weathering is the physical and chemical breakdown of rocks, while pedogenesis is the broader process of soil development. Both are integral to the creation of soil.

Rain, wind, ice and temperature changes break the tough, hard parent material or rocks. This process is very slow but it steadily continues. Such broken parts are further withered by same factors as well as some other factors as acids etc. Therefore, wind, water and the Sun are involved in soil formation. 

Polythene bags are not involved in soil formation. However, plastic bags are threat to environment, because these bags are non-degradable, i.e., do not decay and thus, do not lead to soil formation.

The percolation tanks are constructed in the land which is highly permeable. The water which gets collected in the tank is then percolated in the ground.  and helps to recharge the groundwater system. The nutrients which are present in the soil solution gets leached and migrate to the groundwater reserves. This causes loss of the nutrients of the soil.

Alluvium is loose, unconsolidated soil or sediment that has been eroded, reshaped by water in some form, and redeposited in a non-marine setting. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel. When this loose alluvial material is deposited or cemented into a lithological unit, or lithified, it is called an alluvial deposit.

Alluvial soils are formed mainly due to silt deposited by Indo-Gangetic-Brahmaputra rivers. They are the largest soil group covering about 15 lakh sq km or about 6 percent of the total area. They support more than 40% of India’s population by providing the most productive agricultural lands.

Black soils (regur) and alluvial soils are known for their high fertility and ability to sustain agriculture over long periods without intensive manuring.

Black soil is ideal for growing cotton and is also known as black cotton soil. These soils are made up of extremely fine i.e. clayey material. They are well-known for their capacity to hold moisture.