Essay - Factors Affecting Both Soil Formation & Soil Characteristics

There are five factors which influence both soil formation and soil characteristics:

• Climate - The development of any soil is closely linked to the climate of that particular region. It is probably the main influence on soil types at a global scale, with the distribution and location of world soils closely related to climate patterns. Climate has the ability to dictate which processes are dominant in an area. Soils in wet climates tend to be leached, podzolised or gleyed. Soils in dry climates tend to be salinised or calcified. Soils in warm and moist climates tend to be humified or laterised. Climate also controls both the type and speed of weathering that takes place in an area. This will again determine whether deep & fertile or shallow & infertile soils develop.

• Relief/topography - This tends to influence both the depth and drainage of a soil. In general, sloping land is well-drained so soils in such locations tend to be dry. However, mass movement/mass wasting can easily affect these soils. Therefore some of them can be quite thin. In flat upland areas where the weather tends to be both cold and wet, waterlogging is common. Low temperatures, in conjunction with low levels of biological activity mean that the decaying process is slowed down, so organic matter builds up rather than being converted into humus. As a result, flat, upland regions tend to be infertile. Flat, lowlands tend to be warmer. As a result, biological activity is greater and organic matter is quickly converted into humus. Mostly, they tend to be well-drained, except in some particular zones where aspect (angle) may cause waterlogging.

• Parent material - The first stage in the formation of soil is generally the mechanical/physical weathering of parent rock/bedrock to produce a layer of loose, broken rock called regolith. Therefore, the type of rock that a soil develops from is one of the biggest influences on its characteristics. However, the parent material is not always rock; it can also be volcanic material, alluvium or glacial deposits. In Ireland, the majority of soils have developed on glacial deposits of boulder clay/till. As a result, the majority of our soils are deep, fertile and well-drained.

• Micro-organisms - Earthworms and beetles burrow through the soil, creating pore spaces for roots. Water then gathers inside these pore spaces, keeping the soil moist. When these creatures die, their bodies decompose and add further nutrients to the soil. Other micro-organisms such as bacteria and fungi also add nutrients by aiding in the decomposition or other organic matter.

• Time - This also plays a significant role in soil development. The longer the soil forming processes are in operation, the more fully developed a soil will be.