Causes of Land Erosion

            The factors contributing to soil erosion are classified into two major categories viz;

1.      Physical and Natural Factors

2.      Anthropogene (Man-made cause)

1

.    Physical and Natural Factors

a)   Climatic Factors: According to Henderson (2006), the various climate factors that can expose soil to erosion include the amount and intensity of precipitation, the average temperature as well as seasonality, wind speed, storm frequency, Carter (2005) opined that heavy rainfall/runoff are natural phenomenon that cause soil erosion. Heavy rainfall breaks down soil aggregates materials into smaller particles. Runoff occurs when there is excessive rainfall causing soil erosion.

b)   Geological Factors: Carla (2008), states that the geologic factors that predisposes soil to erosion include the sediment or rock type, its porosity and permeability, the slope (gradient) of the land and whether the rock are tilted, faulted, folded or weathered.

Soil or resistibility is an establishment of the ability of soil to resist erosion on the physical nature of each soil. Moreover, the natural geological type of soil (either clay or loamy sand) can also affect erodability of the soil. 

c    Biological Factors:  Ojebor (2006), the physical biological factors that exposes a soil to erosion include ground cover from vegetation or lack thereof, the type of organism inhabiting the area and the land use.

2          Man-Made Factors that Cause Erosion.

            The continuous cultivation of crops on a piece of land, grazing by cattle, deforestation, mining operation, logging render the land to the effects of erosion, Birkeland (2006), logging can cause increased erosion rates due to soil compaction, exposure of mineral. Heavy grazing can reduce vegetation enough to increase erosion. Vegetation can also change the speed of surface runoff flows, so grasses and shrubs can also be instrumental in this aspect.

            Henderson (2006), one of the main causes of erosive soil loss in the year 2006 is the result of splash and burn treatment of tropical forest. When the total ground surface is stripped of vegetation and then seared of all living organism, the upper soils are vulnerable to both wind and water.

References

Birkeland, P. W. (2005): Soil and Geomorphology. New York: Oxford University Press. Pp 52, 70.

Carla, W. (2008): Environmental Geology 5^th ed, McGraw-Hill Inc. USA pp 20-22.

Carta, W. (2005): Coastal Environment, New York Academy Press. Pp 20-19.

Henderson, (2006): “Causes and Effects of Soil Erosion” Omaff Fact Sheet Index 573.

Ojobor (2006): Comprehensive Geography for Senior Secondary School; Johnson A. Publishers, Benin. Pp 155, 188.