Tag: soil - formation and profile

Decomposers are organisms that feed on plant and animal dead bodies. They convert their complex material into simpler materials. These simple materials are stored in the form of humus, which is a dark-coloured material present in the soil. 

• Water contains lots of impurities inside it. it includes fine sand, clay and many other materials present in it. These are carried away by the flow of running water. They are then deposited or sedimented at the bottom of the water reservoirs.
• This sedimentation forms silt. As it is present at the bottom, it is usually accumulated at the bed of the river. 
• So, option C "Silt" is the correct answer.

• The different types of loam soils each have slightly different characteristics, with some draining liquids more efficiently than others. The soil's texture, especially its ability to retain nutrients and water are crucial.
• Loam soil is a mixture of soil that is the ideal plant-growing medium. It is actually a combination soil, normally equal parts of clay, silt, and sand, which gives the benefits of each with few of the disadvantages.
  

Sandy soil is made up of constituent particles that are relatively larger in size. The larger size of sandy particles leads to their lesser absorptive surface area. As a result, their water holding capacity is less. Their particles are larger and their inter particular space is more. So, air can move easily between these particles leading to proper aeration.  

There are four major types of colloids present in soil :

Clay soil is soil that contains a high percentage of clay particles. It is slow to drain water and quick to harden leading to water logging. It blocks root absorption, which prevents plants from getting nutrients required for survival. Hence it is not suitable for plant growth. Thus the correct answer is option C.

A good soil needs to be deep, fine-textured, moist, free-draining, loamy, and have an organic-rich topsoil. These properties best enable plant roots to take up nutrients, water and oxygen, and get enough support for rapid growth. In clay soils with small pore spaces, water moves slowly and spreads outward from where it is applied due to capillary action. In sandy soil, irrigation water can penetrate to 72 inches below the surface within 24 hours of application. In soils with a heavy clay content, water only penetrates to roughly 36 inches in 24 hours.

Humus controls and regulates many soil functions, as well as plant growth. The better the humus count in the soil, the healthier and more productive soil will be. Regardless of the program one uses in farming operations, the higher the humus count, the better the crop is grown yield. Good humus count in the soil will hold soil moisture longer, thus less water is required for crop production. Also, good humus count reduces both water and wind erosion of soil.

(b) Top soil contains decomposed and amorphous organic matter composing of sand with humus.