Soil is a mixture of organic matter with minerals and fluids and organisms that together support life. The body of soilof Earth called the Pedosphere has four important functions. Soil functions as a medium for plant growth. Soilfunctions as a means of water storage supply and purification. Soil is a modifier of Earth atmosphere. Soil is a habitatfor organisms. All of these functions in their turn modify the soil and its properties. Soil is also commonly referred toas earth or dirt. Some scientific definitions distinguish dirt from soil by restricting the former term specifically todisplaced soil. The Pedosphere interfaces with the whole biosphere which includes the lithosphere and the hydrosphereas well as the atmosphere. Soil consists of a solid phase of minerals and organic matter as well as a porous phase thatholds gases and water. Accordingly soil scientists can envisage soils as a three state system of solids and liquids alongwith gases. Soil is a product of several factors like the influence of climate relief or organisms and the soil parentmaterials interacting over time. It continually undergoes development by way of numerous physical and chemicalprocesses. This also includes biological processes which include weathering with associated erosion. Given itscomplexity and strong internal connectedness soil ecologists regard soil as an ecosystem. In engineering terms soil isincluded in the broader concept of regolith which also includes other loose material that lies above the bedrock as canbe found on the Moon and on the other celestial objects. Soil functions as a major component of the ecosystem of Earth.