Tag: soil profile

Soil is the upper weathered humus containing part of earth's surface, which can sustain terrestrial plant life. Soil is composed of inorganic mineral particles (45 percent), water (25 percent), air (25 percent), humus (5 percent) and variable number of living organisms. Mineral particles are of four types- (i) gravel or fine pebbles, (ii) sand or silica or quartz, (iii) silt or very fine quartz, (iv) clay or hydrated silicates of aluminium. 

While soil composition varies, the organic matter content in typical mineral soils is generally low, usually around 5% by volume, with the rest being minerals, water, and air.

Sulphur is widely distributed as native deposits near volcanoes and hot springs, is a component of sulphide minerals. E.g., galena, pyrite, sphalerite, etc., and is also found in meteorites. Significant deposits exist in salt domes along the Gulf coast of the USA, and in large evaporite deposits in eastern Europe and western Asia, and are most likely the result of bacterial breakdown of sulphate minerals. The weathering of rocks will result in the production of major source of sulphur.

All living organisms have a definite life cycle.

The dark black upper layer of soil is known as humus. It is actually the dead matter of plants and animals that have been decomposed by bacteria and fungi. This humus rich soil increases the aeration capacity of soil and also helps in the penetration of roots of plants. The decomposition of organic matter helps in bringing the plant and animal residues back to soil. The soil organisms use the organic matter its food and in the process convert in into nutrient rich humus for plant growth. 

Humus is a type of organic material. It is present inside the soil in the form of a dark-coloured substance. Humus is formed by breaking down of plant litter that includes dried and fallen leaves, branches twigs etc. along with dead bodies of animals and insects. Over a period of time, all these decompose and cause break down of their complex substances into simple ones. It contains some of the important chemicals required for the soil for its nutrient maintenance. 

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.