Soil Forming factor

Climate

• At low temperatures, the rate of soil formation is slower. This is because the organisms that break down and incorporate dead matter are less active. Precipitation (rain, snow, mist) influences both chemical and physical breakdown of parent material. Rain water is very important in washing organic matter another substances down through the soil.

Landscape

• The shape of the land controls factors such as soil depth and drainage. On slopes, soils tend to be thinner and material move downslope. Deeper soils are found on valley floors and in hollows. Altitude acts together with temperature to influence rate of soil development.

Vegetation

• Different plants are made up of many different chemical compounds. When the plants die and decay, these are released into the soil. The physical action of plant roots and earthworms pushing through the soil is also important.

Organisms

• Micro-organisms are essential to a healthy soil. They break down and incorporate dead plants and animals, eventually forming a black, crumbly substance called humus. Larger creatures, like moles and earthworms, help to improve soil structure.

Geology

• Usually, the chemical composition of the soil is very similar to the parent material it develops on. Few soils in Scotland have formed directly from underlying rocks. At the end of the last period of Ice cover (around 11,500 years ago), the retreating glaciers deposited a layer of material over the original land surface. It is this material - known as glacial till - that forms the basis for most Scottish soils.

Time

• Scottish soils are quite 'young', being at most around 11,500 years old. In other parts of the world, like the tropics where soil formation has not been interrupted by glaciation, the soils are often far older - millions of years in some cases - and deeper.