Soil is one of the most important natural resources of man. Soils provides habitat for billions of organisms and acts as water filter and growing medium. Soils are also the basis of our nation’s agroecosystems which provide us with feed, fiber, food and fuel. Nowadays, soil erosion is one of the most sought issue in the world. Soil erosion is a gradual process that occurs when the actions of water, wind, and other factors eat away and wear down the land, causing the soil to deteriorate or disappear completely. Soil deterioration and low quality of water due to erosion and run off has often become a severe problem around the world. Many times the problems become so severe that the land can no longer be cultivated and is abandoned. Soil is simply a resource necessary for crop production and for building structures. We take it for granted and fail to notice it is disappearing. About 6 metric tons of soil coming off of 2.5 acres would reduce the topsoil level by only 1 millimeter. On the other hand, soil formation may take between 200 and 1,000 years to form one inch of topsoil. Under natural conditions, soil is virtually a non-renewable resource. (“Property Management”, 2007)

Source : http://www.fewresources.org/soil-science-and-society-were-running-out-of-dirt.html

From the figure above, it shows the 2008 report that entitled “Global soil degradation” which estimated that land degradation affects 38% of the world’s cropland and has reduced water and nutrient availability. The report also represents about 15 per cent of the Earth’s land area that has been degraded through human activities. The report was prepared by IAASTD – International assessment of agricultural science and technology for development, and authored by Philippe Rekacewicz, UNEP/GRID-Arendal. (“Madison Powers”, 2015)

Source : http://www.unibuc.ro/prof/scradeanu_d/docs/2014/mai/20_18_53_18LANDSLIDE_HAZARD.

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From the table above, we can see that soil erosion had caused landslides in our country. It occurred in every area, causing many people died in the accident, especially the area near slope.

There are many reasons which cause the soil erosion. For our opinion, deforestation is the major culprit of this problem. Deforestation is the permanent destruction of forests in order to make the land available for other uses. An estimated 18 million of forest are lost each year, according to the United Nations' Food and Agriculture Organization (FAO).The government cut the trees for other uses. For example, to make more land available for housing, to create commercial items such as paper with the timber and to create ingredients that are highly prized, such as palm oil. However, they lack of replantation practices. This affects the soil is free to wash or blow away as there is no tree root can anchor it. After a clear cutting, cash crops like coffee, soy and palm oil are planted. Planting these types of trees can cause further soil erosion because their roots cannot hold onto the soil. As a result, more extreme soil erosion, flooding and landslide issues will occur.

Source: http://news.mongabay.com/2012/0425-unilever_segregated_palm_oil.html

The table above shows the oil palm plantings and forest loss in Indonesia and Malaysia from 1990 to 2008. Palm oil is one of the high productive crops in Indonesia and Malaysia. It has come under fire because its production has taken a heavy toll on wildlife-rich rainforests (deforestation) and carbon-dense peat swamps in Indonesia and Malaysia, including key habitat for endangered animals. Some plantations have also been associated with forced displacement of communities, social conflict, and labour abuses.

Besides that, soils are exposed to the sun’s heat. Soil moisture is dried up, nutrients evaporate and bacteria that help break down organic matter are affected. The soil is eroded as layers from the hill slopes, sometimes slowly and sometimes rapidly. The particles in the soil loosened and shifted by the rain drops are carried down slope by a sheet of water which moves along the surface. Thus, more flow of water on the surface of the soil, greater the erosion.

Other than that, we think that wind is also an important mover of soil. Under certain condition it can move large amount. Wind erosion may not be as evident as water erosion, but it is still a serious environmental problem attracting the attention of many across the globe. It is most common phenomenon occurring mostly in flat, bare areas; dry, sandy soils; or anywhere the soil is loose, dry, and finely granulated. Wind erosion damages land and natural vegetation by removing soil from one place and depositing it in another. It causes soil loss, dryness and deterioration of soil. Suspended dust and dirt is inevitably deposited over everything. It blows on and inside homes, covers roads and highways, and smothers crops. Sediment transport and deposition are significant factors in the geological changes which occur on the land around us and over long periods of time are important in the soil formation process.

Source : http://www.environment.nsw.gov.au/soildegradation/winder.htm

The picture above shows the modes of transport of soil particles during wind erosion. First, creep is when wind rolls the soil particles or they are moved along the surface by bombardment by other moving particles.  Second, the major fraction of soil moved by the wind is through the process of saltation. In saltation, fine soil particles are lifted into the air by the wind and drift horizontally across the surface increasing in velocity as they go, s they hop or bounce across the surface. Soil particles moved in this process of saltation can cause severe damage to the soil surface and vegetation. Third, suspended particles cause abrasion of the soil surface when they fall back to the ground. Forth, they can also hit other particles and break into smaller particles, a process called attrition. Last, suspension occurs when very fine dirt and dust particles are lifted into the wind. They can be thrown into the air through impact with other particles or by the wind itself. Once in the atmosphere, these particles can be carried very high and be transported over extremely long

distances. Soil moved by suspension is the most spectacular and easiest to recognize of the three forms of movement.

After our research, we found that soil erosion impacts the agricultural industry as well as the natural environment. The effects of soil erosion can be felt both on-site, meaning at the site of soil disruption, or off-site, meaning the location where the eroded soil deposits. Let's start by building our understanding of the impact of soil erosion on-site. When the topsoil is eroded from an area, that area loses its most nutrient-rich layer, and therefore soil quality is reduced. Poor soil quality means smaller and lower crop yields, higher production costs and may even wash away seeds and small plants. This may call for more of a need for artificial fertilizers and pesticides, which can runoff of fields and contaminate waterways. Also, when the organic matter that is found within the top layer of soil is removed, it can weaken the soil's ability to hold water, leaving the field susceptible to weather conditions such as droughts. When top soil is gone, erosion can cause rills and gullies that make the cultivation of paddocks impossible. The impacts of erosion on cropping lands include exposure of subsoil which often has poor physical and chemical properties, loss of newly planted crops and also deposits of silt in low-lying areas.

Source : https://www.qld.gov.au/environment/land/soil/erosion/impacts/

The picture above shows the effect of soil erosion in Queensland Erosion has created a gully in this paddock, exposing the subsoil (lighter coloured soil), and making it difficult to cultivate. In Queensland, farmers have been cultivating the land since the 1850s. However, early farmers were not aware that some of their farming practices were causing erosion. By the 1950s, soil erosion was seriously threatening the productivity of fertile cropping areas such as the Darling Downs and the Inland Burnett. Around 3 million hectares or 2% of Queensland is now used for growing crops. Around 80% of the state’s cultivated area is vulnerable to soil erosion. If nothing is done to protect the soil, losses can be very high. Soil erosion has been so severe that some areas of Queensland are now unsuitable for cropping. Soil losses from unprotected cultivation in upland cropping areas of the Darling Downs can average between 20 and 60 tonnes per hectare per year. Steep, unprotected cropping lands in tropical areas can lose up to 400 tonnes of soil per hectare per year. (Queensland Government, 25 October 2013)

Eroded soil, which can contain nutrients, fertilisers and herbicides or pesticides, can be deposited where there is a reduction in the slope of the land. This can be in sediment traps, along contour banks, or in grassed waterways, dams or wetlands. Heavier soil particles are the first to be deposited, while finer colloidal clay particles may remain in suspension. Soil removed by gully erosion may be transported directly to creeks or rivers. This sedimentation and pollution can damage freshwater and marine habitats and the local communities that depend on them. Erosion will reduce the water quality of creeks, rivers and coastal areas.

Source : http://www.thestar.com.my/Metro/Community/2015/04/21/Soil-erosion-in-Sungai-Langat-causes-water-disruption/

The figure shows the local authorities at clogged river, Sungai Langat. This incident happened not long ago (April 2015). The soil erosion in Sungai Langat caused water disruption for 100,000 residents. The local authorities were engaged of clearing the soil as fast as possible. For me, I had experienced this too in my hometown few years ago. We didn’t receive any prior notice by our management on the water disruption as usual. It happened for few days. We had to buy water from the town far from us as all towns nearby experienced that too. For those few days, the price of the water increased as the demands increased. According to the press statement released by Syabas few days later, the river had serious pollution. The factory nearby released the toxic materials into the river, causing the fatal pollution. Finally, after a week, we had our water back.

A flood occurs when water overflows or inundates land that's normally dry. When raining, the soil that is carried away by the water has to go somewhere, and this leads to off-site problems. As mentioned, when soil is carried away from a farmer's field by water, it carries with it contaminants, such as fertilizers and pesticides. This runoff can cause water pollution that contaminates drinking water and disrupts ecosystems of lakes and wetlands. This negatively impacts the fish and wildlife that depend on these downstream waters for food and habitat. It may lead to the extinction of the aquatic animals. Sediments that accumulate down slope of the erosion can obstruct the flow of water in streams and drainage canals, leading to flooding. Flooding may cause the loss of house and even worse take the people’s life.

Source : http://www.mastersoon.com/tag/anwar-ibrahim/

The figure shows the chart of flood-hit areas in Peninsular Malaysia in 2014. It was Malaysia’s worst flooding in decade, forced people to flee during storms. We have coursemate came from Pahang. He had told us about the situation at there. The houses were been destroyed by the flood. All their things were been washed away. They had to move to another place for safety. Some of them just walked through the floods, some of them leave by boat.

Source : http://www.thesundaily.my/news/1272390

The figure shows the floods happened in Terengganu in December 2014. Heavy seasonal rains and strong winds have affected most parts of Malaysia since mid-December 2014 and are expected to continue until early January 2015. The rains caused severe flooding in the East Coast – Terengganu, Pahang, and Kelantan states. In addition to the three most affected states, four other states in Peninsular Malaysia (Perak, Johor, Selangor and Perlis states) and one state in East Malaysia (Sabah) also are experiencing floods due to the heavy rainfalls (highest recorded at 255 mm). (IFRC, 28 Dec 2014) By 31 Dec, at least

21 people had been killed and almost a quarter of a million people had been displaced. Ketalan was the worst-hit state, with 14 deaths and more than 158,000 people displaced. (AFP, 31 Dec 2014). The IFRC is preparing a Disaster Relief Emergency Fund (DREF) amounting to CHF 82,964 (approximately USD 83,000) to support 25,000 (5,000 families) for a period of one month. (IFRC, 31 Dec 2014)

Landslides are the downward movement of a slope composed of earth materials such as rock, soil or artificial fills. Landslides are also called rock-slide, debris-slide, slump, earth-flow or soil-creep. Landslides may be slow tectonic movements, deep slides on mountainsides, earthquake-driven slide complexes, shallow slides following heavy rainfall, small slides on unstable roadcuts, or gradual hillside soil creep. Naturally-occurring landslides can be beneficial – creating features such as fresh rock escarpments, rubble piles, deep pockets of soil, small wetlands, and ponds. However, many ecological effects of landslides are negative. Landslides can release excess fine sediments into streams, creating major water quality impacts to listed species such as steelhead and coho salmon. Landslides are also caused by soil erosion. As the vegetation being removed from the land, the land become loosened and cannot hold the soil from being wash away by the water. When raining heavily, the soil will be washed down from the hill and cause landslides.

Source : http://www.snipview.com/q/Landslides_in_Malaysia

Landslides have occured in many areas around the globe including Malaysia, resulting in large numbers of casualties and huge economical loss in hilly or mountainous areas, especially during rainy seasons. As a result, not only many roads on constructions and terraces are destroyed, but also causing numerous fatalities. The figure above shows the landslides occurred on 6 December 2008, in Bukit Antarabangsa, Ulu Klang, Selangor,Malaysia. The landslide, which is believed to have buried 14 bungalows in Taman Bukit Mewah and Taman Bukit Utama, occurred at about 4 a.m.MST, causing 15 casualties and 4 deaths. The landslide tragedy occurred about 1.5 kilometers away from the Highland Towers landslide site which happened on 11 December 1993.  

Before the soil erosion issue become more serious, we think that our government need to have some ways to prevent this. There are ways to avoid and manage soil erosion. One of the best ways to prevent soil erosion is to increase vegetation reduce deforestation. Plants and trees grow above the surface, protecting soil from erosion, and their roots meander down through the soil and become like bars in a prison, locking the soil particles in

place, making it hard for them to escape and be carried away by water. Embankments and sloped land are most vulnerable to erosion due to gravity. So adding plants, shrubs and other vegetation to these areas is important. Vegetation not only locks in water, it can keep wind away. For example, if an area is vulnerable to damaging winds, a natural windbreaker created by trees planted across the wind’s direction acts like a wall, cutting down on wind erosion. Government can focus on preserve and protect wildlife and protected area. For example, Taman Negara preserves the habitats of the animals and avoids the extinction of the wildlife. Sustainable forest management should be done. Government should reserve some forest from being cut off. Punishment will be given for those who break the rules. We hope that these can help to prevent the soil erosion.

The other ways that we have thought is promoting sustainable agriculture. As farming is widely occurred in our country, our government should promote use and development of sustainable agriculture. In simplest terms, sustainable agriculture is the production of food, or other plant or animal products using farming techniques that protect the environment. Sustainable farms produce crops and raise animals without relying on toxic chemical pesticides, synthetic fertilizers or practices that degrade soil, water and other natural resources. By growing a variety of plants and using techniques such as crop rotation, sustainable farm protect biodiversity and foster the development and maintenance of healthy ecosystems.

Source : http://permaculturenews.org/2013/11/22/making-terrace-garden/

The picture above shows terracing. Terracing is also one of the ways of soil conservation. Terracing is the practice of creating nearly level areas in a hillside area. The terraces form a series of steps, each at a higher level than the previous. Terraces are protected from erosion by soil other barriers. It can use to prevent the rainfall runoff on sloping land from causing the soil erosion. With rain and irrigation on the steep slope soil, everything will run off with the water as if no soil to hold. Terracing keeps everything in place so the water will run down in the soil, this also keeps plants healthy. Terraces reduce both the amount and velocity of water moving across the soil surface, which greatly reduces soil erosion. Terracing thus permits more intensive cropping than would otherwise be possible.

We also think that reduce tillage can help to reduce soil erosion. Deep, frequent tillage creates a layer of compact soil vulnerable to water erosion, topped by loose soil easily removed by wind. Consider a zero-tillage approach using a coulter or other deep planting device. Reduce tillage can reduce the effect of raindrop impact on the soil, reduce the rapid breakdown of soil structure and provide a better soil environment for crop growth.

Source : http://www.putrajaya.gov.my/tourist/green_city

For our opinion, green city or a sustainable city should be promoted by the government. A sustainable city, or eco-city is a city designed of environmental impact, inhabited by people dedicated to minimalization of required inputs of energy, water and food, and waste output of heat, air pollution and water pollution. In Malaysia, Putrajaya was designed to be the nation’s pride, an ‘intelligent garden city’ that is well-planned, aesthetically pleasing, environmentally friendly, and with many green, open areas and to nurture a sense of Malaysian and Islamic heritage and identity. It has promoted the “Green City” idea of buildings that use grayscale water management systems, efficient lighting (Energy Commission Building as main model), and Gas District Cooling, all within a ‘low carbon cities framework’. Putrajaya’s wetlands (200 hectares) are a bird breeding ground and a natural filtration system that will absorb pollutants from upstream river water, filter it, such that the water is Class 2B quality (suitable for body contact) upon entering the lake. (“New Cities Foundation”, 2015)

Soil erosion is one of the most important issues in the world. We have known what causes the issue occurred. We have to learn to prevent it. As we are future architects, we will learn to design buildings that won’t cause soil erosion and preserve the nature. Human activities contribute much in this issue. Hence, in built environment we have to give more concern on this.

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Reference

Property Management. (2007, December 9). Erosion Control. Retrieved from http://www.farminfo.org/property/erosion.htm

Madison Powers. (2015, March 28). Losing ground. Retrieved from http://www.fewresources.org/soil-science-and-society-were-running-out-of-dirt.html

Soil Science Society of America. (2002). Why is soil important? Retrieved fromhttp://www.envirothon.org/pdf/CG/Why_Soil_is_Important.pdf

Preserve articles. (2012). Short essay on the soil erosion and its conservation. Retrieved from http://www.preservearticles.com/2011110116378/short-essay-on-the-soil-erosion-a-its-conservation.html

NSW Government. (2014). Wind Erosion. Retrieved from http://www.environment.nsw.gov.au/soildegradation/winder.htm

Study.com. (2015). Soil erosion : Effects & Prevention. Retrieved form http://study.com/academy/lesson/soil-erosion-effects-prevention.html

Relief Web. (n.d.). Malaysia : Floods and Landslides – Dec 2014. Retrieved from http://reliefweb.int/disaster/fl-2014-000168-mys

Snipview. (n.d.). Landslides in Malaysia. Retrieved from http://www.snipview.com/q/Landslides_in_Malaysia

Grace Communication Foundation. (2015). Sustainable Agriculture – The basics. Retrieved from http://www.sustainabletable.org/246/sustainable-agriculture-the-basics

Study Mode. (2015). Ways to prevent soil erosion. Retrieved from http://www.studymode.com/essays/Ways-To-Prevent-Soil-Erosion-1664131.html

Buzzle. (2015). Soil erosion prevention. Retrieved from http://www.buzzle.com/articles/soil-erosion-prevention.html

Kibin. (n.d). Soil erosion is not one of the most sought after conservation movements today.Retrieved from https://www.kibin.com/essay-examples/soil-erosion-is-not-one-of-the-most-sought-after-conservation-movements-today-LNVoQ4lu

New Cities Foundation. (2015). Putrajaya, Malaysia: designed as an intelligent garden city. Retrieved from http://www.newcitiesfoundation.org/cityquest-putrajaya-malaysia-designed-intelligent-garden-city/

Group Members :

Liong Shun Qi 0315942

Lo Jia Woei 0318585

Yvonne Chin Yun Miin 0315662

Topic : Soil Erosion

Tutor : Ms Suja