Soil Science

• Various environmental factors can be divided majorly into climatic factors, edaphic factors and biotic factors.
  
• The factors which relate to structure and composition of soil are called edaphic factors. Soil composition, organic matter, soil water, soil air and soil organisms are examples of edaphic factors.
• Humidity, rainfall and wind velocity are climatic factors.
• Examples of biotic components include animals, plants, fungi, and bacteria.
  
• So the correct option is B.

• Alluvial Soils are formed by the deposition of silt by the rivers. 
• The black soil is formed in the Deccan region on account of climatic conditions here and the basalt rock which is the parent rock for this soil is also an important factor for the formation of black soil. Black soil is sticky and possesses high moisture retention capacity. 
• The main reason for laterite soils formation is due to intense leaching. Leaching happens due to high tropical rains and high temperatures. As a result of high rainfall, lime and silica are leached away, and soils rich in iron oxide and aluminum compound are left behind.

They prefer marshy environment and utilize dead and decaying material as food. Oligotrophic soil ( in between layers) have the above mentioned requirements in good quantities.Thus, the fungi prefer the oligotrophic soil for their survival

• As the plough is drawn through the soil, it creates long trenches of fertile soil called furrows. In modern use, a ploughed field is typically left to dry out and is then harrowed before planting. Plowing and cultivating a soil homogenizes and modifies the upper 12 to 25 cm of the soil to form a plow layer. 

The topmost layer of the soil is called topsoil. This layer is usually fairly loose, porous, dark and rich in humus. The humus is derived from decomposed and partly decomposed organic matters of plant and animal origin in the soil. It plays important role in maintaining the fertility of the soil.

Dokur village, located in the Mahbubnagar district of Telangana, is characterized by red soils which cover a significant portion of the agricultural land.

• Humus particles are tiny pieces of organic matter and are known as Organic Colloids.
• Humus is important because it retains moisture in the soil, loosens the soil permitting better aeration and drainage, and encourages the increase of soil organisms which help make nutrients available to plants.
  
• Hence Humus is an example of organic colloids.
• So, the correct answer is 'Organic colloids'.

The soils of Western Rajasthan are typically arid and sandy, often containing high levels of calcium carbonate, which forms kankar nodules in the soil profile.

Black soil, also known as Regur soil, is primarily formed by the weathering of basaltic rocks found in the Deccan Plateau region. Other soil types like alluvial or red soil have different parent materials and formation processes.

Rajasthan is characterized by an arid climate, which leads to the formation of sandy, desert soil. This soil type is dominant in the western parts of the state.

Soil that has very little capacity to hold water is sandy soil. Sandy soils have low moisture storage. High evaporation and low capacity limit the availability of rainwater for plant use.

Ganganagar (SGNR) is a planned city and the northern-most city of the Indian state of Rajasthan, situated near borders of Rajasthan and Punjab states. The place consists of Alluvium. It is loose, unconsolidated (not cemented together into a solid rock) soil or sediments, which has been eroded, reshaped by water in some form. It is fertile and supports agriculture. 

Brown soils are found in desert areas of Rajasthan. The colour of soils ranges from greyish brown too yellowish brown. Major areas of these soils are in catchment of Banas River. Brown soils are rich in calcium but it has poor organic matter. As the ground water are saline, soils irrigated with these water have accumulated salts.