Factors in Soil Formation

-

Factors in Soil Formation

1.      Climate: The two most important climatic variables influencing soil formation are temperature and moisture. 

·         Temperature has a direct influence on the weathering of bedrock to produce mineral particles. Rates of bedrock weathering generally increase with higher temperatures. Temperature also influences the activity of soil microorganisms, the frequency and magnitude of soil chemical reactions, and the rate of plant growth.

·         Moisture levels in most soils are primarily controlled by the addition of water via precipitation minus the losses due to evapotranspiration. High moisture availability in a soil promotes the weathering of bedrock and sediments, chemical reactions, and plant growth. The availability of moisture also has an influence on soil pH and the decomposition of organic matter.

2.      Topography: This refers to the landscape position and the slopes it has. Steep, long slopes mean water will run down faster and potentially erode the surfaces of slopes. The effect will be poor soils on the slopes, and richer deposits at the foot of the slopes. Also, slopes may be exposed to more direct sunlight, which may dry out soil moisture and render it less fertile. The steeper the surface slope, the more likely any eroded material is to be transported out of the system.

                       

Topographical Factor of Soil Formation

3.      Parent Material: Parent Material refers to the rock and mineral materials from which the soils develop. These materials can be derived from residual sediment due to the weathering of bedrock or from sediment transported into an area by way of the erosive forces of wind, water, or ice. Granites are more resistant to weathering than gabbros.  Sandstones are more resistant to weathering than limestones in humid climates, but limestones are more resistant than sandstones in arid climates.

4.      Plant and Animal activity: Plant and animal activity produces humic acids that are powerful erosion agents.  Plants can physically erode as well as chemically erode.  Plants stabilize soil profiles, Animals (including man) tend to destabilize the soil profile, increasing erosion.

5.      Time: Time influences the temporal consequences of all of the factors described above . Reaction rates are slow, the longer a rock unit has been exposed, the more likely it is to be weathered.

           

                       

Factors of Soil Formation

 

Most Viewed Posts

Planetary Winds: Their Types and Definition

-
Image
Planetary winds : These winds being controlled by the pressure belts, blow towards the same direction throughout the whole year. The planetary wind is of three types such as : the trade wind, the westerlies and the polar wind. So, in short, the characteristics of planetary winds are as follows: These winds being controlled by the pressure belts blow towards the same direction throughout the whole year.  Planetary winds are also known as permanent or prevailing winds  Blow from high to low pressure, over the earth surface & oceans throughout the year & in a particular direction  These winds are divided into 3 categories viz. Trade Winds (Tropical Easterlies) Westerlies Polar winds (Polar Easterlies) https://www.affairscloud.com/assets/uploads/2016/04/wind.png 1. Trade Winds (Tropical Easterlies) The sun’s rays fall vertically over the equatorial region, so the air becomes hot and goes upwards. Since the pressure is less upward, the rising air gets r
Read more

The Vance Model of Transport Development

-
Image
Based on his work on the eastern seaboard of America, Vance (1970) developed a five-stage ‘mercantile’ model to illustrate the development of transport links and the growth of the urban hierarchy in North America (Figure 3.6). Although primarily concerned with trade, his model is important in that it stresses the impact of exogenous forces on the evolution of transport networks and their associated spatial patterns. The Vance Model of Transport Development In the initial stage, an accumulating of wealth in Europe prompted overseas expansion of an exploratory nature. Stage 2 sees the beginnings of the transatlantic trade routes based on the one-way trade in staple products such a fish, furs and timber. From 1620, permanent settlement occurs in North America; this results in Atlantic trade in both directions as settlers begin to produce commodities for export and consume manufactured products from a rapidly industrialising Europe (stage 3). Internal transport links are limited
Read more