Tag: soil profile

Explanation: These burrows create pores through which oxygen and water can enter and carbondioxide can leave the soil. Earthworm casts (their faeces) are also very important in soils and are responsible for some of the fine crumb structure of soils.

Chernozem is the black colored soil which is known for being rich in humus. This is the richest soil in the world and used for the cultivation of the cereals. Black soil is rich in calcium carbonate and iron. This soil also contains the lime, potash, aluminum, etc. Laterite soil contains the bauxite which is the ore of the aluminum. Terra Rossa is the red clayey soil. the soil formed from the limestone and is used for the production of the vine plants. 

While a nearly infinite variety of substances may be found in soils, they are categorized into four basic components: minerals, organic matter, air and water. Most introductory soil textbooks describe the ideal soil (ideal for the growth of most plants) as being composed of 45% minerals, 25% water, 25% air, and 5% organic matter. In reality, these percentages of the four components vary tremendously. Soil air and water are found in the pore spaces between the solid soil particles. The ratio of air-filled pore space to water-filled pore space often changes seasonally, weekly, and even daily, depending on water additions through precipitation, throughflow, groundwater discharge, and flooding. The volume of the pore space itself can be altered, one way or the other, by several processes. Organic matter content is usually much lower than 5% . Some wetland soils, however, have considerably more organic matter in them (greater than 50% of the solid portion of the soil in some cases).

Leaching is the process by which soluble nutrients are lost from the soil. The A horizon of the soil is the surface layer that consists largely of minerals. The A$ _2$ horizon of this layer shows the maximum leaching. 

Top soil contains detritus micro-organisms  that decompose dead plant and animals and add to the organic content of the soil. The decomposed organic matter is called humus.

• Climate affects soil formation because it determines the amount of water that is available for processes such as the weathering of minerals, the transportation of minerals and the release of elements. Climate also influences the temperature of the soil, which determines the rate of chemical weathering.
• Temperature and rainfall are the two main climatic factors responsible for soil formation. 
• Hence, Climatic factors affect soil profile and bring changes in soil structure.

Humus is dark brown amorphous gummy substance formed by partial decomposition of plant and animal matter. It constitutes the organic component of soil and is rich in lignin and cellulose. Humus is formed from organic remains through the activity of decomposer microorganism. The process of formation of humus from raw organic remains is called humification. Humus is quite resistant to microbial action. It is a reservoir of nutrients and is helpful in the maintenance of soil moisture as well as aeration. It is colloidal in nature. Nutrients are released slowly as the humus is decomposed slowly. Humus is further degraded by some microbes and release of inorganic nutrients occur by the process of mineralization.