Land degradation has long been recognized as a major problem in rwanda, especially impacting the southwest of the country, but important everywhere. Land degradation download ebook pdf, epub, tuebl, mobi. Rill erosion is common in bare agricultural land, particularly overgrazed land, and in freshly cultivated soil where the soil structure has been loosened. This includes soil erosion by water and wind, deterioration in soil physical. It can be prevented by formation of ridge and furrow during irrigation which lessens run off. Soil erosion and the effects of soil erosion on crop productivity have become emotional issues and have attracted the attention of agriculturists, environmentalists, and the public in general. The health of soil is a primary concern to farmers and the global community whose livelihoods depend on well managed agriculture that starts with the dirt beneath our feet. Significant wind erosion occurs when strong winds blow over lighttextured soils that have been heavily grazed during periods of. Introduction soil erosion represents one of the most serious land degradation problems 1. Land degradation explores the substantial decrease in an areas biological productivity or usefulness to humans due to human activities. The present rate of land degradation is estimated at 5 to 7 million hectares per year, suggesting that 0. Water erosion aspects of land degradation neutrality to.
In spite of heavy investments in research and development, the global rates of accelerated erosion are now presumbly higher than ever before. Taking land out of production would allow soil carbon to rebuild and become stable. Soil on construction sites is also degraded by compaction. Grenada land degradation neutrality national report. An assessment of the global impact of 21st century land. Soil erosion is one of the factors responsible for lad degradation.
Click download or read online button to get land degradation book now. The second edition of johnson and lewiss wellreceived text thoroughly. Assessment of soil erosion by rusle model using remote. Soil erosion and degradation on mediterranean type ecosystems. Efficiency of four different seeded plants and native vegetation as cover crops in the control of soil and carbon losses by water erosion in olive orchards. Loss of vegetative cover has made land more susceptible to erosion. Soil erosion is the displacement of the upper layer of soil, it is one form of soil degradation. World overview of conservation approaches and technologies. The term land degradation involves both soil and vegetation degradation. This erosion is the dominant form of soil degradation troeh et al. This study takes the degradation of soil resources as its focus. The older agricultural areas of the northeast have long been particularly affected, but the highest soil erosion rates are currently being observed in the western parts of the high lands. Land degradation here mainly refers to the loss of lifesupporting land resource through soil erosion, desertification, salinization, acidification, etc.
Soil loss from conventionally tilled land exceeds the rate of soil formation by. Estimation of soil erosion risk using the universal soil loss. It is directly or indirectly developed from the mineral constituents of the rocks. Causes and impacts of land degradation and desertification. Trafficking by animals as well as by vehicles and cultivation are the primary causes of this form of soil degradation. Accelerated erosion by wind and water in drylands is one of many causes of desertification. Soil erosion is a natural process in mountainous areas, but is often made much worse by poor management practices. By giving the current land condition, the soil conservation status fits as an indicator of the land degradation status as defined in the ldn framework cowie et al. Deforestation causes fast degradation when the soil is steep sloppy or easily erodible. Rill erosion can be reduced by reducing the volume and speed of surface water with grassed. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice glaciers, snow, air wind, plants, animals, and humans. The human dimension of land degradation and forest degradation. Soil, degradation, salinization, land quality, land rehabilitation, food security introduction land degradation will remain an important global issue for the 21 st centur y because of its.
The decline in quantity and quality of soil it includes erosion by wind and water biological degradation loss of humus physical degradation loss of structure, permeability, compaction chemical degradation reduced fertility, salinisation, changing ph, toxicity if degradation is so severe that land becomes unusable it is termed desertification. By this, the land area affected by soil degradation due to erosion is estimated at 1100 mha by water erosion and 550 mha by wind erosion. Soil degradation is, in itself, an indicator of land degradation. Land degradation is the temporary or permanent lowering of the productive. Soil loss from conventionally tilled land exceeds the rate of soil formation by 2 orders of magnitude medium confidence. Soil degradation associated with poor soil fertility management practices is a major factor underlying poor agricultural productivity in subsaharan africa. Farmers perception of soil erosion and adoption of soil. Watershed degradation is the loss of value over time, including the productive potential of land and water, accompanied by marked changes in the hydrological behaviour of a river system resulting in inferior quality, quantity and timing of waterflow the protection, improvement and rehabilitation of mountain andor upland watersheds are of critical importance in the achievement of. Causes and features of watershed degradation related to. Degradation of the soil is caused by natural processes as well as by human activities. In a typical scenario, large equipment is used to remove topsoil from a construction site. Pollution of water resources from the contamination of.
For example, planting crops at a location with heavy rainfall and steep slopes would create scientific and environmental concern regarding the risk of soil erosion by water, yet farmers could view. It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable. While this is a dynamic process that is occurring naturally all the time on a small scale, the results of largescale soil movement can be devastating to soil health and productivity. Environmental degradation is the deterioration of the environment through depletion of resources such as air, water and soil. Pdf on apr 9, 2014, velibor spalevic and others published land degradation, land use and soil erosion. Careless agricultural practices, pollution and deforestation cause lots of soil degradation in the world. Soil degradation is a serious global environmental problem and may be exacerbated by climate change.
Sustainable land use can help to reduce the impacts of agriculture and livestock, preventing soil degradation and erosion and the loss of valuable land to desertification. Pdf land degradation, particularly soil erosion, is currently a major challenge for nepal. Land degradation as the land use section earlier in this chapter shows, demands on the land for economic development and pressures from a burgeoning population are leading to unprecedented land use change. Routing runoff and soil particles in a distributed model with gis. Compaction compaction is where soil particles pack together increasing soil density and reducing pore space. United nations convention to combat desertification. Watershed, evaluation, soil erosion, land degradation, soil and water conserva tion, community based watershed management subject areas. Destruction of natural vegetation cover is a major factor responsible for erosion of soils by water and wind. Wind erosion is a common cause of land degradation in the arid and semi arid grazing lands of inland queensland. Chapter 2 types of land degradation food and agriculture. Loss of topsoil by wind erosion et, defined as a uniform displacement of the. Soil degradation in subsaharan africa and crop production. Unlike previous studies that dealt with soil erosion as a static process, here we shed light on the impacts of 21st century global land use change on soil erosion.
Future approaches should continue to address these issues while creating a better information flow on the true costs of land degradation and in addition approaches. The world is losing 10 ha of arable land each minute5 ha to soil erosion, 3 ha from salinity, and 2 ha by other degradation processes. T value tolerable erosion equilibrium between soil gains and losses. A problem with defining land degradation is that what one group of people might view as degradation, others might view as a benefit or opportunity. Deforestation accounts for the major land degradation problem as it results in severe soil erosion, flood, and loss of fertile soil.
Land degradation is, usually, the result of complex interrelationships between biophysical and socioeconomic issues which affect many people and their land, specially in the tropics and developing countries. Soil erosion leads to losses in soil and crop productivity, pollution of land and water resources, and a loss of farm income. And degraded lands are also often less able to hold onto water, which can worsen flooding. Soil degradation is any type of problem that removes soil in an area or makes highquality soil become poor. For example, the land productivity classes include class i, extremely high. On land degradation environmental degradation erosion. Sustainable land use can help to reduce the impacts of agriculture and. It refers to a special form of soil degradation in arid, semiarid and dry. Soil is subject to a series of induced degradation processes, which humannamely are displacement of soil material, and internal soil deterioration dwivedi, 2002. The world is losing 10 ha of arable land each minute5 ha to soil erosion, 3 ha from salinity, and 2 ha by. Field research stations report soil losses 35 to 246 tons hayr, and farmers report declining productivity of their fields. This process is experimental and the keywords may be updated as the learning algorithm improves.
However, degradation has led to most arable soils having already lost 40 to 60% of their organic carbon. Leaving more land alone, despite the challenges of a growing population, would really help. Significant wind erosion occurs when strong winds blow over lighttextured soils that have been heavily grazed during periods of drought. Soil degradation results when the soil is left exposed to the forces of erosion.
With a high rate of population growth, subsistencebased rural economy, and increasingly intense rainfall events in the monsoon season, nepal is prone to several forms of land degradation, such as. While losses are uneven this represents a loss of 4 mm of soil a year, twenty or more times. Soil is a complex body and forms the thin outer layer of the earth. The result is a loss of land productivity with impacts on livelihoods and the. Soil erosion occurs when soil is removed through the action of wind and water at a greater rate than it is formed soil the soil covering the surface of the earth has taken millions of years to form and we must learn to respect it. Soil degradation is a critical and growing global problem, with implications for a number of key policy areas, including food security, climate change, flood risk management, drought tolerance, drinking water quality, agricultural resilience in the face of new crop diseases, biodiversity and future genetic resources. Land degradation is the major consequences of direct interference of human activities in the natural phenomenon. With a high rate of population growth, subsistencebased rural economy, and increasingly intense rainfall events in the monsoon season, nepal is prone to several forms of land degradation, such as floods, landslides, and soil erosion. Introduction watershed is not simply the hydrological unit but also a sociopoliticalecological entity which plays decisive. Principal processes of land degradation include erosion by water and wind, chemical degradation comprising acidification, salinization, leaching etc. In accordance with these agents, erosion is sometimes divided into water erosion, glacial. Soil erosion is the movement of soil, via wind or water, from its original position in the landscape.
But, in the field, further variables are used as indicators of the occurrence of soil degradation. Soil science institute of athensnational agricultural. Photograph of a compacted zone of soil immediately below the plough layer in a cropping soil. An introduction towards one of the massive soil issues. A conceptual model of natural land degradation based on regressive pedogenesis in semiarid tropical. Ethiopia is known for its historic agriculture, but also for the associated, widespread, and ongoing land degradation. Indirect drivers of land degradation in grenada the indirect drivers of land degradation in grenada are the driving forces of the direct causes of land degradation. Here, we modify a physicallybased wind erosion sediment transport model to better represent the vegetation cover using land surface aerodynamic roughness. About 65% of the agricultural land is degraded, mainly due to low nutrient application, soil erosion and soil acidification. On land degradation free download as powerpoint presentation. Land degradation, particularly soil erosion, is currently a major challenge for nepal. The acceleration of soil erosion is generally a symptom of.
Loss of natural fertility of soil because of loss of nutrients. Experts suggest rotating pastured land used by the meat and dairy industries so less is being used at once. Eastern africa including ethiopia has experienced moderate to severe land degradation problems as shown in. May 01, 2019 land degradation soil degradation is the decline in soil quality caused by its improper use, usually for agricultural, pastoral, industrial or urban purposes. Erosion rate soil erosion soil loss sediment yield land degradation these keywords were added by machine and not by the authors.
Water erodes top soil to an extent of around 12,000 million tonnes mt per annum. Land and soil are important components of abu dhabi emirate desert ecosystems and of the wider environment in which all plants and animals live. It encompasses physical soil erosion, chemical salinity and alkalinity, pollution and biological deterioration pollution and. It is one of the processes leading to desertification.
Agents of erosion like wind and water have left vast tracts of land barren. Land degradation indicators and management options in. Uneps project global assessment of soil degradation glasod was. Land degradation is the temporary or permanent lowering of the productive capacity of land unep, 1992b. It thus covers the various forms of soil degradation, adverse human impacts on water resources, deforestation, and lowering of the productive capacity of rangelands. The human dimension of land degradation and forest degradation 414. Helping north coast landholders reduce soil erosion. Practical guide to soil erosion archive local land services. This is indeed the most visible effect of soil degradation, but does not cover all of its aspects. Similarly the devastating impacts of these disasters left a wave of soil erosion particularly on steep slopes with limited protection.
Land degradation indicators and management options. The rills can usually be removed with farm machinery. Pdf soil degradation is one of the major global threats. In turn, unsustainable land use is driving land degradation. Technical report on soil degradation european commission. Land degradation is a process in which the value of the biophysical environment is affected by a combination of humaninduced processes acting upon the land. Soil erosion is a common term that is often confused with soil degradation as a whole, but in fact refers only to absolute soil losses in terms of topsoil and nutrients. Productivity of cultivated land may decline from severe soil degradation. Soil physical damage is an increasingly serious problem for agriculture. According to global assessment of soil degradation glasod, deforestation is the main cause of soil erosion by wind in about 98% of the area. Desertification is accentuated by land misuse and soil mismanagement. Land degradation soil degradation is the decline in soil quality caused by its improper use, usually for agricultural, pastoral, industrial or urban purposes. The soil integrates a variety of important processes involving vegetation growth, overland flow of water, infiltration, land use and land management.
Land degradation, soil erosion and soil conservation pmf ias. Download land degradation or read online books in pdf, epub, tuebl, and mobi format. Several types of soil degradation exist and are a threat to natural forests and planted crops. This site is like a library, use search box in the widget to get ebook that you want.
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