Frans Kwaad, physical geographer
Soil erosion is the removal of soil from cultivated land at a rate that is (much) higher than the rate that would occur under the natural vegetation at the considered site. Besides the loss of fertile topsoil, soil erosion entails the dissection of cultivated land by rills and gullies and the deposition of eroded soil material on roads, in residential areas, rivers, ponds, lakes and reservoirs, and it can be accompanied by flooding.
Guly erosion is the formation of gullies that are too deep to be removed by normal tillage. Gullies are formed in unconsolidated soil material. Several types of gullies can be distinguished, a.o. valley side gullies, valley bottom gullies, V-shaped gullies, U-shaped gullies, continuous gullies, discontinuous gullies, arroyo’s, badlands. In the picture: gullies in Rif Mountains (Morocco, 40 km west of Al Hoceima).
So, soil erosion not only affects land owners and farmers but also the general public outside agriculture. Soil erosion research started in the 1920’s in the USA. Despite 90 years of research, soil erosion continues to be a serious problem, worldwide. According to Pimentel (2006) the yearly damage of soil erosion amounts to 400 billion US dollars worldwide.
Soil erosion may damage crops (by uprooting, or burial with colluvium). Location of the picture: Zuid-Limburg (The Netherlands).
According to Napier (2012) farmers today know very well which measures to take to combat erosion on their farms. The reasons that they don’t do this, are of an economic nature. Most conservation production systems are seldom profitable in the short-term and, often, not even in the long term, says Napier. We live in a time of economic crisis with reduced public conservation funding, the upcoming of grain-based energy, increased grain prices and an expected mass exodus from land set-aside programs in the USA. No longer can be relied on voluntary participation of farmers in conservation programs. Coercion will be required to achieve such participation. In several European countries mandatory measures are already in force, e.g. Austria, Belgium, Germany, Italy, Netherlands, United Kingdom.
Piping is the formation of pipes or tunnels by subsoil erosion. Location of the picture: Rif Mountaisn (Morocco, 40 km west of Al Hoceima).
As an aid to lessons and lectures on environmental issues at secondary schools, agricultural colleges and universities, a website was made with 12 series of images of the various forms and manifestations of soil erosion. The URL of the site is: http://www.kwaad.net/Erosion.htm.
References
- Napier, Ted L., 2012. US conservation achievements threatened by future prosperity of the agricultural sector. Guest Editorial, ESSC Newsletter, 1/2012, pp. 3-10.
- Pimentel, David, 2006. Soil erosion: a food and environmental threat. Environment, Development and Sustainability, 8, pp. 119-137.
