Five Major Factors Involved in Soil Formation

Organic Material and Minerals

• The organic material and minerals present in an area are known as the parent materials for soil formation. The soil is initially made up of partially weathered rock, ash from volcanoes and dust and sediment dropped by water and wind. Streams and rivers overflow and deposit additional sediment; gravity causes the sliding of other parent material down slopes to the ground where all of the gathered mass of material eventually becomes soil.

The Climate

• The climate is a major factor in determining the type of soil that will form in an area. The temperature alone will dictate the amount of chemical weathering that can take place in the area. The climate also determines if an area is suitable for certain plants or animal life. This affects the organic makeup of the soil. Warm and moist climates produce more plants and therefore the organic plant content is high.

Biota

• Biota describes the plants that live upon the soil as well as the animals that are present and the microorganisms that inhabit it. The diversity in soil is equal to the diversity of the plants, insects and animals that live in the area. This means soil that forms in the plains is vastly different than the soil that forms in the rainforest. Some of the difference in composition can be contributed to the decomposition of animal droppings and plant material. Both affect the way the soil forms.

Topography

• Steep or flat land can affect how the soil forms in an area. The topography affects water drainage and therefore affects the final soil product. Soil in a flat basin may be poorly drained soil, while soil on a steep slope will have excessive drainage. Upland soils often have better drainage because the water has somewhere to go. The lay of the land may also affect the amount of sunlight and heat an area gets, which will also play a role in soil formation.

Time

• Over many years. the earth undergoes changes. Changes in the soil range from depletion of mineral content to addition of new minerals. Soil can become more compact or change organic composition based on several factors that change slowly over time but ultimately have a major impact on the soil.