Another one of the five main factors is the climate in which the soil resides. Climate determines the type of soil at a global scale. The distribution of world soil types corresponds closely to patterns of climate and vegetation. This is because climate affects the rate of weathering to the parent rock. With break down of bedrock being faster within hot humid environments. Climate also affects the amount of humus in the soil this is because of the effects of temperature and moisture on the biological activity. It is a common misconception that tropical rainforest soils will have more humus than tundra soils because of the larger amount of vegetation. However tundra soils have more humus accumulation due to lower output, and rainforests soils may have less because of greater humus breakdown
Rainfall total and intensity are also important aspects that can change a quality of soil. Where rainfall is heavy, the downward movement of water through soil transports material silts with it, a process known as leaching. Where there is less rainfall or where evapotranspiration exceeds precipitation brings minerals upwards towards the surface by the process of capillary action. Temperature may affect the length of the growing season in a particular area it also affect the speed of decay of humus.
The relief of the land also know as topography is also a factor that can affect the properties of a particular soil. This links in with climate, because as the height of the land increase the amount of precipitation increases along with it where as temperature decrease thus a resulting shorter growing season and decaying material takes longer to fully decay. Aspect is an important factor in mid-latitudes, with south-facing slopes in the northern hemisphere being warmer and drier than those facing north, aspect affect the drainage and depth of a soil. Steep slopes soils are usually thin and dryer than soils that exist on more gentle slopes as the passage of water is a lot slower thus not much leaching, but a higher probability of water logging.
Plants, micro organisms, animals and fungi all interact in the nutrient cycle. Plants take up minerals from the soils and either the plant dies and returns the nutrients. Micro organisms help with the recycling of nutrients by decomposing dead organic material or biota which as the same time small organisms such as worms and termites mix and aerate the soil.
One of the more overlooked factors of soil creation is that of time, soil usually takes about 400 years fro 1 cm of soil to form and under extreme conditions 1000 years for mm it can take 3000 – 12,000 years to produce a sufficient depth of mature soil for farming. Newly formed soils tend to retain the characteristics of the parent material for which they are derived. With the addition of time soils gain new characteristics resulting from organic material, activity of organism and leaching on the soil. Horizons or layers reflect the balance between the soil processes and the time that have been available for their development.
