plants and help to convert young soil into mature soil
Answers
Rock starts becoming soil the moment it is exposed to the environment. But it’s a long transformation process from exposed rock to a mature soil. Depending on the nature of the rock and other factors in its surroundings, that time period can range between tens to tens of thousands of years!
Rocks, plants and sand
The sandstone, top layer, is weathered by climate, organisms and time. Lichen – a mixture of fungi and bacteria – help break the rock down. Eventually plants can grow in the space, adding organic matter as they grow and die. Photo: SVFisk
Soil is not simply weathered rock. Soil is a dynamic natural resource. It is comprised of minerals, water, gases, organic material, and living creatures including soil microbes and tiny animals. Calling a soil “mature” doesn’t mean that soil formation has stopped. It means the changes in the soil have become practically imperceptible as the soil comes into dynamic equilibrium with its environment. That means the rate at which soil is forming is about equal to the rate at which the soil is breaking down or naturally eroding away.
Soil scientists look at five major factors in the soil-forming process. These factors are: climate (Cl), organisms (O), relief (R) or topography and drainage of the land, the rock or other parent (P) material that will become the soil, and how much time (T) has gone by. These can be combined into a “recipe” for soil known as ClORPT.1 Soil scientists can study each factor separately, or in combinations, to find out how a particular soil became what it is. They can even predict what kind of soil will eventually mature in that place.
Let’s look at what it takes to turn rock into a soil. Under the action of heat, cold, rain, wind, and other atmospheric factors, the rock breaks down physically into small fragments that become the parent material of the soil. The rock also chemically changes as the compounds in the rock dissolve in rain or react with air. Rock is also broken down biologically by living organisms in contact with the rock and its fragments. These processes are collectively called weathering.
Plants, soil and roots