- s=surface of earth
- o=organic matter
- I=Inorganic matter
- l=living beings
Soil;unconsolidated/loose surface materials of the earth having organic and inorganic matters that provide support to the plant,supply nutrieents,water and air for their growth and has microorganisms that recycle minerals for the life.
A natural body of mineral and OM occuring in the surface of the earth that is the medium for plant growth and having ever-changing properties in response to many physical,chemical and biological processes going on over a geological period of time.(soil genesis)
Father of soil science( Russian scientist);Prof Dr.Vasily Vasilli’evich Dokuchaev
Definition of soil
Soils are applied solely to those superficial or nearby superficial horizons of rocks,that have been more or less modified naturally by the interaction of water,air and various kinds of organisms,either living or dead;this being reflected in a certain manner in composition,structurue and color of such formations.Where these formations are abssent,there are no natural soils but either artificial mixtures or rocks.’Dokuchaev’
Soil is the superficial part of the earth where lithosphere,atmosphere,hydrosphere and biosphere are in contact and interact with each other.Soil is the fundamental part of Ecosystem;The living systems occuring above or below the ground surface are determined by the properties of the soil.
Soil Formation factors?
Soil is the function of 5 soil formation factors;S=f(cl,O,R.P,T)
- Cl=climate
- O=Organisms(biotic activities)
- R=relief/topography
- P=parent materials
- T=Time
For the deep study of soil over time 2 approaches have evolved;Pedological and Edaphological
Pedological approach
Greek word Pedon;soil or earth
Pedologists study,examine and classify soil as it occurs in its natural environment.They do not relate soil with plant growth functions or production.The kind and composition of soil horizons depend on the combination of geological materials,nature of climate,biological influences, relief or topography and time it took for soil formation.
Edaphological approach
Greek word Edapohos;soil or ground
study of soil is done from the stand point of higher plants
Also considers approaches of soil conservation in order to improve soil productivity,and enhance food and fiber production to humanity.This recognizes the importance human have put on soil resource since centuries,eg;land classification a/c to land quality for taxation(china,India,Egypt)
Uses of soil
- Natural H2O Filter
- water reservoir
- Habitat for microorganisms
- Develop forest
- Detoxification of chemicals
- Habitat for wildlife
- Plant nutrient reservior
- Develop pasture
- A place to construct buildings, roads
- Waste dumping sites
- Construction materials
- Sources of mines
Functions of soil
- water purification and soil contaminant reduction
- Climate regulation
- Nutrient cycling
- Habitat for organisms
- Flood regulation
- Source of pharmaceuticals and genetic resources
- Foundation for human infrastructure
- Provision of construction materials
- cultural heritage
- Provision of food fiber and fuel
- Carbon sequestration
The soil vs A soil-concept
soil as a material and soil as a natural body. It is a material composed of minerals, gases, water, organic substances, and microorganisms. Soil is a three-dimensional natural body like mountains, lakes, and valleys.The soil is a collection of individually different \soilbodies often said to cover the orange.The soil>>>Vegetation,A soil>>>plant species.
Soil-The Natural dynamic body
Regolith, unconsolidated material above bedrock formed by the breakdown of bare exposed rock, varies in thickness.
Soil is a part of the regolith, through biochemical and physical effects, living organisms have altered the upper part of the regolith. Here, at the interface between rock, air, water, and living things, the soil is born. The soil is a result of both destructive and creative natural processes.
