1. What is soil?
2. What are the factors that contribute to the formation of soil?
3. What is soil horizon?
4. State the different layers of soil.
5. Name the different types of soil found in India.
Answers
Answer:
Soil is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Earth's body of soil, called the pedosphere, has four important functions:
as a medium for plant growth
as a means of water storage, supply and purification
as a modifier of Earth's atmosphere
as a habitat for organisms
This is a diagram and related photograph of soil layers from bedrock to soil.
A, B, and C represent the soil profile, a notation firstly coined by Vasily Dokuchaev (1846–1903), the father of pedology; A is the topsoil; B is a regolith; C is a saprolite (a less-weathered regolith); the bottom-most layer represents the bedrock.
Surface-water-gley developed in glacial till, Northern Ireland.
All of these functions, in their turn, modify the soil and its properties.
The pedosphere interfaces with the lithosphere, the hydrosphere, the atmosphere, and the biosphere.[1] The term pedolith, used commonly to refer to the soil, translates to ground stone in the sense "fundamental stone."[2] Soil consists of a solid phase of minerals and organic matter (the soil matrix), as well as a porous phase that holds gases (the soil atmosphere) and water (the soil solution).[3][4][5] Accordingly, soil scientists can envisage soils as a three-state system of solids, liquids, and gases.[6]
Soil is a product of several factors: the influence of climate, relief (elevation, orientation, and slope of terrain), organisms, and the soil's parent materials (original minerals) interacting over time.[7] It continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness, soil ecologists regard soil as an ecosystem.[8]
Most soils have a dry bulk density (density of soil taking into account voids when dry) between 1.1 and 1.6 g/cm3, while the soil particle density is much higher, in the range of 2.6 to 2.7 g/cm3.[9] Little of the soil of planet Earth is older than the Pleistocene and none is older than the Cenozoic,[10] although fossilized soils are preserved from as far back as the Archean.[11]
Soil science has two basic branches of study: edaphology and pedology. Edaphology studies the influence of soils on living things.[12] Pedology focuses on the formation, description (morphology), and classification of soils in their natural environment.[13] In engineering terms, soil is included in the broader concept of regolith, which also includes other loose material that lies above the bedrock, as can be found on the Moon and on other celestial objects as well.[14] Soil is also commonly referred to as earth or dirt; some scientific definitions distinguish dirt from soil by restricting the former term specifically to displaced soil.
The soil is found in layers, which are arranged during the formation of soil. These layers called horizons, the sequence of layers is the soil profile. The layers of soil can easily be observed by their color and size of particles.
The main layers of the soil are topsoil, subsoil and the parent rock.