Introduction
Soil erosion is a process whereby soil (mostly the top fertile soil) is transported or swept away from its natural environment then deposited to other places. This usually happens as a result of blowing wind, water flow, rainfall, by the force of gravity (down slope movement of soil) and human together with animal activities. Erosion is a natural process although it has been seen to rise due to extensive use of land and more so in the agricultural industry. The reduction of soil cover and the cutting down of trees also triggers soil eroison. Agricultural land that is used on the industrial scale is seen to be the most affected as it is subjected to greater rates of erosion. “This is evident especially when there is the use of tillage which clears vegetation covering the soil while disturbing soil structures together with roots holding these soil particles together” (Willett, p. 24).
Main body
Soil erosion triggers a number of impacts but the main area of concern in this report is soil degradation by erosion affecting the world’s food supply. Soil is taken to be the world’s most valued resource. “The loss of this resource, through land degradation processes such as wind and water erosion, is one of the most serious environmental problems we are faced with as it is destroying the means of producing food” (Willett, p. 89). This is a problem that affects the whole world as food is a basic need. Erosion, takes away the best organic matters, it tempers with the depth of the top rich soil, reduces the soils capacity to hold water, and affects the soil biota. “Rainfall’s beneficial impacts are reduced too due to increases in water runoff and reductions in the soil’s water holding capacity. Taken together or separately, these factors limit the soil’s productivity and, as a result, can reduce crop yields from 15 to 30 percent” (Pruski, p. 15).
A research carried out by the U.N showed that about 11% of the worlds best soils (which are as big as size India and China put together) have been spoiled by our activities from as early as 1935. “About 9 million hectares of arable land have been irreversibly damaged by erosion through overgrazing, deforestation and unsustainable agricultural practices. A further 1.25 billion hectares is considered to be seriously degraded and could be restored only at great costs” (Hinkel, p. 81).
There are many examples showing that erosion has really affected the world’s food supply. This one is explained by Lal who reveals that:
Erosion is very significant in land degradation that leads to decline in crop production which eventually leads to a drop in the world’s food supply. On a global scale, the annual loss of 75 billion tones of soil through deforestation as a major cause of soil erosion costs the world about US$400 billion in a year (at US$3/ton of soil for nutrients and US$2/ton of soil for water), or approximately US$70 per person a year. It is estimated that the total annual cost of erosion from agriculture in the US is about US$44 billion in a year or about US$247/ha of cropland and pasture. In Sub-Saharan Africa it is much larger; in some countries productivity has declined in over 40% of the cropland area in two decades while population has doubled. Overgrazing of vegetation by livestock and subsequent land degradation is a widespread problem in these regions (Lal, p. 157).
The production ability of most land that has been subjected to soil erosion is seen to decline up to 40% due to soil erosion brought about mainly by deforestation. The reduction of yields in Africa as a result of erosion is about ten to fifty percent. “The total mean loss for the whole continent stands at 9%. Africa is perhaps the continent most severely impacted by land degradation due to soil erosion, with the global average being lower, possibly in the range of 1–8%” (Baanante, 224). With increasing land degradation due to erosion and deforestation triggering erosion on a bigger scale, food productivity might actually drop up to 50% necessitating international aid which in turn affects the supply from wherever the food is coming from. With the current rate of population growth and soil erosion it is said that by 2050 there would be a humanitarian crisis as far as food supply is concerned.
Another good example is of an East African country (Kenya) which has had severe famine due to lack of enough produce. In Kenya agriculture is taken to be the backbone of the country. The country was initially self sufficient in terms of feeding its people. The famine that affected the country was attributed to soil erosion that occurred mainly by the use of unsustainable agricultural practices that exposed soil to erosion and deforestation. Kenya being a hilly country is highly prone to erosion by gravity. This issue is made worse by unsustainable agriculture that does not take care of the issue of soil erosion. Top fertile soil was extensively carried away leaving behind soil that was not good for agricultural food production. Due to lack of produce in the year 2007 and later rains were not sufficient in the year 2008 a great famine ensued leaving people to boil poisonous wild fruits for hours to extract the poison in order to fix a hot plate (Kamau, p.17). Research shows that lack of rain again was due to deforestation that is helping desertification in this nation. The country was forced to use all its food reserves to the extent of asking for emergency relief food from international organizations.
Generally soil erosion occurs where there is lack of adequate soil cover, putting this in consideration; the situation can only worsen when necessary measures are not taken on time. When erosion continues all fertile soils will be swept away leaving behind soils that are not good for crop production or farming activities. Because of the lack of vegetation on land, rainfall attraction does not take place then a famine may be realized. Many countries having this problem rely on other countries for food supply thus creating imbalance in the supply of food. All this is brought about by not tackling the initial problem that is soil erosion.
The percentage of desertification is very high in the world today. In deserts and arid areas very little crop production can take place. Deserts do occur because there is lack of vegetation which is responsible for rainfall attraction and soil cover for water preservation. When soil erosion takes place these areas lack the ability to have vegetation and thus there won’t be water retaining capabilities or factors influencing rainfall attraction. What will be left is the soil exposure to wind and other factors that influence soil erosion. The main factor influencing this is deforestation. After sometime these areas lose all agricultural relevancies thus having a negative impact on food supply.
Across the world research shows that after soil erosion (especially after over use of agricultural land or tillage erosion) has taken place the remaining soil is not good quality soil for food crops. What is normally done with this is the planting of other crops which can survive harsh conditions and the soils that are left behind. These crops are normally cash crops as food crops need more nutrients to grow. With the current rate of soil erosion most parts of the world lack the capacity to produce food crops and rely on other countries to produce food crops for them. This is also a negative factor to the worlds food supply since the initially food productive areas are unproductive at the time when the populations are high needing more food crops. This also has a negative effect on the worlds food supply.
Soil erosion does not only create unfavorable conditions for crop growth through land degradation but as shown by Matende:
The implications of soil erosion extend beyond the removal of valuable top soil. This is in regard to erosion brought about by water or rain. Crop emergence, growth and yield are directly affected through the loss of natural nutrients and applied fertilizers in the soil. Seeds and plants can be disturbed or completely removed from the eroded site by water erosion. Organic matter from the soil, residues and any applied manure is relatively light weight and can be readily transported off the field, particularly during spring thaw conditions. Pesticides may also be carried off the site with the eroded soil. This can effect negatively on the supply of food particularly when corrective measures are not taken on time or generally poor yields will be realized (Matende, p. 234).
“Wind erosion has also been seen to cause significant losses on food crops. The unavailability of lasting vegetation cover in a lot of areas has led to widespread wind erosion” (Bramson, p. 21). “Loose, dry, bare soil is the most susceptible; however, crops that produce low levels of residue also may not provide enough resistance. Wind erosion may also create adverse operating conditions in the field” (Mathews, p. 67). Food crops can be destroyed completely bringing about expensive delays and necessitating reseeding. If not the food crops could are sandblasted and destroyed with the end result being no yield, low yield and poor quality yields that impact negatively on food supply.
“Off-site impacts of soil erosion are not always as apparent as the on-site effects. Eroded soil, deposited down slope can inhibit or delay the emergence of seeds, bury small seedling and necessitate replanting in the affected areas” (Knight, p. 212). This kind of erosion is normally brought about by water or rainfall. When there are heavy rainfalls soils that are unprotected and do not have adequate cover or are loose due to tillage and human activities can easily be swept away. This type of erosion has its own share of negative effects as far as food supply is concerned as in the event of erosion taking place in wide areas crops will not only be buried but some will be left bare and thus germination will either not take place or the exposed seeds can be devoured by birds and other animals. If corrective measures are not taken on time there will be little or no production at all. This also affects the general food supply in the world today.
Conclusion
Therefore as shown in this report various types’ soil erosion has adverse impacts on the worlds food supply. “Nevertheless, enhanced land use practices if embraced can mitigate this situation, using techniques such as terrace building, conservation tillage practices, and tree planting can help reduce soil erosion” (Pruski, p. 14). When these practices are used properly soil erosion can not only be reduced significantly to about the same rate of soil reform but also the world will realize better food crop production and there will be sufficient food security. Using these methods again food crop yields could increase up to 20% this is in northern America and from about 4 to 17% in Africa.
Works cited
- Baanante, Amos. Deforestation, Erosion and Productivity. Kampala: East African Publishers, 2002. Print.
- Bramson, David. Wind erosion. Journal on water and wind erosion 21.1 (1998): 14-28. Print
- Hinkel, Jones. “Causes of soil Erosion.” Journal of soil and water conservation 53.6 (1995): 64-91. Print.
- Kamau, Samuel. Effects of Famine. Kampala: East African Publishers, 2009. Print.
- Knight, Carl. On sight and of sight effects of erosion. New York. Oxford university press, 2000. Print.
- Lal, Jones. “Effects of Soil Erosion.” International journal on soil erosion 82.9 (1989) 132-171. Print.
- Matende, Ronald. Effects of Soil Erosion on Crop Yields. Dodoma: Chacha and sons Publishers, 2004. Print.
- Mathews, Daniel. Effects of wind erosion. New York, NY: Oxford university press. 1992. Print.
- Pruski, Ferdinand. “Factors limiting soil productivity.” Journal of soil and water conservation 57.1 (1996): 7-16. Print.
- Willett, Sean. Soil Erosion and Land Degradation. Delhi: Kathak and sons publishers 1992. Print.