Environmental and public health implications of soil erosion

Introduction

Soil erosion is one of the greatest problems of our time from the view point of agriculture as well as food supplies. It is a process whereby nature removes soil more quickly than it is replaced by soil forming processes. Ordinarily, soil erosion may be beneficial to man but when it is accelerated, agriculture loses its importance; rivers become choked up with large quantities of solid matter and are then prone to flooding and of cause less navigable.

However, various activities of man has led to the increase of erosion on soil which has led to the destruction o lives and properties in various parts of the world like for example, the construction of roads without damage system. Also, following the trends in urbanization, our environment has been greatly degraded which makes it unhealthy for habitation.

This menace of soil erosion also occurs in most cases in some areas as a natural phenomenon which makes the already unpleasant situation of the environment to become worse and this has resulted to the damage of roads and railway lines, loss of lives, loss of properties and also loss of farm lands. In fact, soil erosion has led to the pollution of water bodies meant for consumption and other domestic purposes and also the loss of aquatic lives (Umoru, 2001).

Pacifica (2009) opined that soil erosion has been a major environmental problem in the world and it is a natural process that has been increased dramatically by man’s activities. He went further to say that land used for industrial and agricultural purposes generally experience significantly greater level of erosion than lands that are still under natural vegetation.

Definition of soil erosion

Umeh (2007) defined soil erosion as the detachment and transferring of the top soil by water or wind or other agents to another place. Moseri (2004) defined soil erosion as the movement of water on the soil surface. He further explained that water which ought to sink (percolate) into the soil flow on the soil surface in the process valuable top soil is carried away by the water current and this leads to serious degradation.

Iwena (2008) defined erosion on soil as the gradual removal of the top layer of the soil through the action of wind, ice and water. Pacifica (2009) explains that soil erosion has been a major environmental problem in the world and that approximately 49% of the world’s agricultural land is seriously degraded.

Types of soil erosion

According to Umeh (2007) soil erosion is classified into four (4) which includes;

1. Splash erosion: this occurs as a result of displacement of soil particles by rain drops.
2. Sheet erosion: This occurs when there is slight displacement of the top soil by flowing water.
3. Rill erosion: This occurs when the current of the running water create furrows in the soil.
4. Gully erosion: This normally occurs when there is heavy rainfall and the flowing water down a steep slope cuts deep openings into the soil and when the openings or grooves are deeply cut and broad, gullies are formed.

Iwena (2008) described about another type of erosion which he termed “coastal erosion”, which is caused by the action of waves along coast lines resulting from the movement of water along the coasts and it leads to the gradual removal of soil along the coast.

Causes of erosion

According to Iwena (2008) the causes of soil erosion are classified as follows:

• Nature and composition of the soil.
• Excessive rainfall or wind
• Absence of vegetative cover
• Population pressure on land
• Cultivation along slopes
• Overgrazing
• Deforestation
• Mining and construction
• Bush burning or shifting cultivation

According to Pacifica (2009) the rate of erosion on soil depends on many climate factors which include;

• Seasonality
• Wind speed
• Storm frequency

He further said that geological factor is another factor that increases the rate of soil erosion and these factors includes,

• Sediments on rock type
• The porosity and permeability of the soil
• Slope gradient of the soil

While the biological factor is soil covered by vegetation (Pacifica, 2009).

According to Ajayi (2008) factors which has accelerated soil erosion in Nigeria include;

• Wrong crop cultivation
• Quarry and some other mining operations
• Construction of roads without the provision of drainage system
• Deforestation
• Use of footpaths
• Overgrazing
• Trampling by livestock’s
• Uncontrolled bush burning

Environmental and public health implications of soil erosion

Iwena (2008) state that soil erosion can pollute drinking water from rivers and lakes due to deposition of debris, create environmental imbalance, lead to loss of farmlands, lead to the damage of roads and railway lines, development of bad lands, loss of lives and properties and that it also causes the removal of the top fertile soil meant for crop cultivation.

According to Ichidi (2008) the environment health implications of soil erosion include;

• Flooding
• Disease infestation
• Physical disasters

Flooding

According to Iwena (2008) flooding is the occurrence of excessive volume of water in areas not usually water logged. It is also defined as a large amount of water covering an area that is usually dry.

Iwena (2008) further explained that flooding occurs mostly when there is heavy rainfall in an area and all the water refuse to sink into the soil but flows on the soils surface as flood.

Disease infestation

Soil erosion and its associated pollution has been major factor in the spread of diseases. The pollution of water by soil erosion has consequently made water unfit for human consumption so that any attempt made by man in using the polluted water will result to disease infestation. Examples of such diseases are cholera, typhoid, diarrhea etc.

Physical disasters

Soil erosion in Nigeria and beyond has caused a lot of physical disasters. Major cited examples are the collapse of Damage Dam near Kano as reported in the national concord of august 19, 1988 in which 18,000 houses were destroyed and over 210,000 people displaced. Also in November 1999, it was reported by the Guardian Newspaper that erosion in Vietnam divested they central province of the region and that about 550 people lost their lives and that lives and that properties worth over 200 million dollars were also lost.

Control measures of soil erosion

According to Iwena (2008) the control of soil erosion includes;

1. Re-forestation: The replanting of trees in areas where trees were previously present but were cut down.
2. Controlled ploughing: Making of ridges across slopes in farming to control erosion.
3. Cover cropping: Planting of legumes and grasses to cover the soil so as to prevent erosion.
4. Terracing: This is the method of cutting steps on hill sides to reduce the current or speed of water running down the hill.
5. Shelter belts: Planting of trees in form of belt where wind erosion is dominant to serve as wind break and reduce wind erosion.
6. Improved farming methods: The practice of mixed farming, strip cropping and crop rotation will help to control erosion.
7. Enlightenment programmed: Enlightenment programmed should be organized by the government, non-governmental agencies (NGOs) and other groups or organizations where people should be educated on the effects of soil erosion and soil conservation measures.
8. Legislation: Laws made to combat erosion through soil conservation boards.

Conclusion

Soil erosion is one of the surface processes that sculptures the earth’s landscape and constitutes one of the global environmental problems. It is a menace in many parts of the world, especially places that have bad terrains and towns situated in valleys with poor or no drainage systems. The agents of soil erosion include water, ice and wind. Soil erosion occurs in four (4) forms which are splash, sheet rill and gully erosions and these forms of erosion could result to the damage of roads and railway lines, loss of loves and properties, pollution of water bodies and loss of farm lands. The control  measures of soil erosion includes, a forestation, proper town planning, enlightening/educating the people on the effects of soil erosion and soil conservation measures, cover cropping, improved farming methods and enforcement of soil conservation laws.

In order to check this problem/menace of soil erosion in man’s environment, efforts should be made using the available and affordable materials to study and assess the prevailing situation so as to provide a lasting solution to the menace of soil erosion thereby averting its health implication.

Recommendations

Soil erosion is a great mechanism of environmental degradation which its environmental health implications can be reduce or limited by the following measures.

1. There should be improvement of land use practice as the trend in urbanization and industrialization has led to the degradation of soil and the environment in general.
2. Farmers should avoid overgrazing of farm lands and should also embark on forestation to conserve the soil.
3. The government should intensity environmental education on soil conservation measures and other environmental issues.
4. The government should make provisions for sanitary waste disposal sites and adequate construction of roads with drainage systems.
5. The government should also provide adequate legal backing and enforcement of planning regulation, building regulation and should employ town planners and other necessary skilled and unskilled workers needed.

And if all these can be done, the problem of soil erosion and its associated health implications will be brought to the barest minimum.

References

Ajayi, P. O (2008). Comprehensive Geography for Senior Secondary Schools. Benin City: Johnson pp.156, 198.

Ichidi, I. (2004). Introduction to Environmental Health [Lecture Note] Ofuoma – Ughelli:  College of Health Technology (unpublished).

Iwena, O. (2008).  Essential Geography. Ibadan: Tonad

Moseri, S. (2014).  Agricultural Economics and Production. Benin City: Kris Bec

Hornby, A S. (2006). Oxford Advanced Learners’ Dictionary (7^th ed.). London: Oxford University Press.

Hornby, A S. (2000). Oxford Advanced Learners’ Dictionary (6^th ed.). London: Oxford University Press.

Pacifica, M. (2009). Protection of Environmental Pollution. United Kingdom: Cambridge University Press.

Umeh, I. (2007).  Modern Biology for Senior Secondary Schools (3^rd ed), Onitsha: Africana First

Umoru, H. (2013).  The Nigerian Environmental Problem Conversation and Sustainability. Benin City: Gite

World Health Organization (WHO) (1948). Definition of Health. Retrieved on 20^th September, 2015 from http://www.who.int.