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Essay on Land Degradation
Essay # 1. Introduction to Land Degradation:
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Land degradation threatens the livelihoods of Earth’s many inhabitants, the so called environmental refugees, including many of the world’s poorest and most marginalized populations. Degradation caused by over cultivation, overgrazing, deforestation and inefficient irrigation affects most of the world’s drylands. Desertification occurs in drylands, which span a third of the Earth’s land surface in over 110 countries.
All continents are under threat including 37 per cent of arid areas in Africa, 33 per cent in Asia, 14 per cent in Australia and some areas in America and the southern fringes in Europe. According to United Nations Convention to Combat Desertification (UNCCD), over 250 million people are directly affected by land degradation. In addition, some one billion people around world are at risk. Each year 12 million hectares are lost to deserts. That is enough land to grow 20 million metric tons of grain.
The land degradation issue for world food security and the quality of the environment assumes a major significance when one considers that only about 11 per cent of the global land surface can be considered as prime or Class-1 land, and this must feed the 6.5 billion people today and the 8.2 billion expected by the year 2020.
Hence land degradation will remain high on the international agenda in the 21st century. Desertification is often the result of human activity and can therefore be prevented or controlled by human effort. Because of its magnitude, desertification is a global issue, and such can only be addressed through a global partnership.
What is Land?
It is an area of the Earth’s surface including all reasonably stable or predictably cyclic attributes vertically above and below it. Land includes not only the soil resource but also the water, vegetation, landscape and microclimatic components of an ecosystem.
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Land Resources:
Land, a non-renewable resource, is central to all primary production system. Land is considered as the most important basic natural resource. It is a dynamic and complex combination of geology, topography, hydrology, soil, flora and fauna and influences every sphere of human activity. Different sectors including agriculture, industries, infrastructure and power projects put forth competing demand for land. Subsistence farming practices, accelerated soil and water erosion, erratic rainfall, increasing population and high density of livestock population have all contributed to unsustainable land use that has led to degradation of this valuable resource.
Land is classified into two categories viz. – arable and non-arable. Non-arable land comprises of area under forests, permanent pasture land, current fallow, cultivable wasteland and land put to non-agricultural use. Arable land includes area sown with crops (net sown area), area sown more than once and gross sown area.
i. Degraded Land:
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According to International Fund for Agricultural Development (IFAD), it is defined as the land which due to natural processes or human activity is no longer able to sustain properly an economic function and/or the original natural ecological function; or, the loss of the productive capacity of the land to sustain life.
ii. Land Degradation:
The definition of land degradation, under Article 1 of the UNCCD, is the reduction or loss, in arid, semi-arid and dry sub-arid areas, of the biological or economic productivity and complexity of rain fed cropland, irrigated cropland, or range, pasture, forest and woodlands resulting from land use or from a process or combination of processes, including processes arising from human activities and habitation patterns, such as:
(a) Soil erosion caused by wind and/or water
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(b) Deterioration of the physical, chemical, and biological or economic properties of soil and
(c) Long-term loss of natural vegetation
The Global Environment Facility (GEF) defines land degradation as any form of deterioration of the natural potential of land that affects ecosystem integrity either in terms of reducing its sustainable ecological productivity or in terms of its native biological richness and maintenance of resilience.
iii. Drought:
The UNCCD definition of drought is the naturally occurring phenomenon that exists when precipitation has been significantly below normal recorded levels, causing serious hydrological imbalances that adversely affect land resource production systems.
iv. Desertification:
The UNCCD definition of desertification is the land degradation in the arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities.
v. Land-Use Policy:
An expression or perception of the direction to be taken on major issues related to land use and the proposed allocation of the national land resources over a fixed period of time. It has a production and conservation components (FAO/UNEP).
vi. Sustainable Land Management:
It combines technologies, policies and activities that are aimed at integrating socio-economic principles with environmental concerns so as to simultaneously maintain or enhance production, reduce the level of production risk, protect the potential of natural resources and prevent (buffer against) soil and water degradation, be economically viable and be socially acceptable.
vii. Aridity Index:
Aridity, the characteristic nature of an arid climate, is measured using an aridity index (Al). Al is a numerical indicator of the degree of dryness of the climate at a given location. A number of aridity indices have been proposed to identify, locate or delimit regions that suffer from a deficit of available water, a condition that can severely affect the effective use of the land for such activities as agriculture or stock-farming.
In 1948, C.W.Thornthwaite proposed and defined AI as,
(d = water deficiency which is calculated as the sum of monthly differences between precipitation and potential evapotranspiration for those months where normal precipitation is less than the normal evapotranspiration; n = sum of monthly values of potential evapotranspiration for the deficient months)
In the preparations leading to the UN Conference on Desertification (UNCOD), the UNEP issued a dryness map based on a different aridity index, proposed originally by M.I. Budyko in 1958 and defined as follows:
(where R is the mean annual net radiation (also known as the net radiation balance); P is the mean annual precipitation; L is the latent heat of vaporization for water)
More recently, the UNEP has adopted yet another index of aridity, defined as:
(where PET is the potential evapotranspiration; P is the average annual precipitation)
Essay # 2. Definition of Land Degradation:
Land degradation is recognized as the main outcome of desertification. Land degradation refers to a temporary or permanent decline in the productive capacity of the land or its potential for environmental management. Net Productivity change reflects both natural and human induced processes of degradation and improvement.
Some types of land degradation are, for all practical purposes, irreversible. Examples are severe gullying and advanced salinization. In these cases, the long-term biological and environment potential of the land has been compromised. Displacement of soil material (erosion) is also irreversible, although its long-term effects on productive capacity depend on the depth and quality of soil remaining.
Most types of land degradation, however, can be prevented or reversed viz. adding nutrients to nutrient-depleted soil, rebuilding topsoil through soil amendments, re-establishing vegetation (reforestation), buffering soil acidity.
The practicality of rehabilitating degraded landscapes depends on the costs relative to the value of output or environmental benefits expected. Where farmers wish to intensify agricultural production on a sustainable basis, it may be necessary to undertake such land-enhancing or land-protecting measures even in non- degraded landscapes.
Degradation is a process of change over time. From policy perspective, it is critical to distinguish those lands that are currently undergoing degradation, in order to assess the need for action to stabilize or reverse the process. Other lands may have reached a degraded state relative to their natural condition many decades or centuries ago, but are currently in a stable or improving condition. For practical purposes, the land degradation problem refers to the former areas.
India has a total geographical area of 328.2 million hectare with a cultivated area of 141 million hectare. The country is situated between 8°04′ to 37°06′ N latitudes and 68°07′ to 97°25′ E longitudes. Over the years, the country’s landmass has suffered from different types of land degradations. Land degradation is caused by biotic and abiotic pressures. An ever increasing population places enormous demands on the land resources.
This is particularly true in India, which has only 2.4 per cent of the world’s geographical area but supports over 16 per cent of the world’s population. It has 0.5 per cent of the world’s grazing area but has over 18 per cent of world’s cattle population. These pressures have led to drastic changes in the proportion of land utilized for agricultural activities, urbanization and industrial development.
Intensive agricultural practices that rely heavily on water, chemical fertilisers and pesticides have caused waterlogging and salinity in many parts of the country. The expansion of the irrigation system without adequate steps for treatment of the catchment areas has exacerbated this. The quest for increased agricultural productivity has led to intensive cultivation of marginal lands causing their degradation.
These pressures on land are compounded by the fact that over 69 per cent of our geological area falls within dry zone as per the Thorn Waite classification. Land degradation has a direct bearing on the productivity of soil, its vulnerability to rainfall variations, scarcity of drinking water, fodder and fuel wood. Given the inter-linkages of crop production, livestock economy and environment, land degradation has a major impact on the livelihoods of the people, especially in rural areas.
Some of the most degraded lands in the country are the common property resources and these resources include community pastures, community forests, wastelands and common dumping and threshing grounds. In spite of concerted efforts to check deforestation and the various afforestation schemes taken up during successive Plan periods, large tracks of forest continue to be classified as degraded.
Of the total forest area, 31 million hectare suffers from some form of degradation and 14.06 million hectare suffers from extreme degradation and are part of 63.85 million hectare of wastelands reported by the NRSA. Desertification and Land Degradation Atlas of India has reported that total area under land degradation in India is 105.48 million ha (32.07 per cent) and total area under desertication is 81.45 million ha (24.78 per cent) (Space Application Centre 2007).
In addition to the wastelands identified by the NRSA, other areas such as deserts, drought-prone, flood-prone and tribal areas have been subjected to severe forms of degradation. The capacity of these lands is limited due to environmental factors. Pressures of human and livestock population have further compromised them.
National Commission on Agriculture made the first step for assessment of area affected by the land degradation and reported 148 million ha land area are affected in India. Other organizations have also taken up the assessment of land degradation in India viz. Ministry of Agriculture, ICAR’s National Bureau of Soil Survey and Land Use Planning (NBSS & LUP), National Wasteland Board, National Remote Sensing Agency-Hyderabad (NRSA), Space Application Centre of ISRO.
NBSS & LUP followed process based degradation mapping methodology in agriculture and non-agriculture areas, derived from 1:250,000 soil map prepared from the satellite data supported with soil profile studies. The NRSA followed remote sensing techniques, identifying land use and physical condition of the surface features for mapping non-agriculture areas (non-arable) on 1:50,000 scale using satellite image with adequate field checks.
Essay # 3. Global Scenario of Land Degradation:
The international community has long recognized that desertification and land degradation are major economic, social and environmental problems of concern to many countries in all regions of the world. In 1991, the United Nations Environment Programme (UNEP) concluded that the problem of land degradation in arid, semi-arid and dry sub-humid areas had intensified.
As a result, the United Nations Conference on Environment and Development (UNCED) supported a new integrated approach to the problem emphasizing action to promote sustainable development at the community level. As a result, the United Nations Convention to Combat Desertification (UNCCD) was launched in 1996 to tackle desertification and drought.
Land degradation imposes an important constraint in achieving sustainable development. The World Summit on Sustainable Development (WSSD) in 2002 reaffirmed land degradation as one of the major global environment and sustainable development challenges of the 21st century.
It called for action to address causes of desertification and land degradation in order to restore land and to address poverty resulting from land degradation. Addressing land degradation also contributes significantly to the Millennium Development Goal (MDG) of reducing by half the proportion of people in poverty by 2015 and ensuring environmental sustainability.
By taking into account and realizing the importance of preventing desertification through land rehabilitation measures and sustainable land management practices and noting that these concerns were critical, the UNCCD expanded its programme to encompass activities to combat land degradation by making land degradation a Global Environment Facility (GEF) Focal Area. The second assembly of the GEF in October 2002, designated land degradation, primarily desertification and deforestation, as a new focal area for the purposes of supporting the implementation of UNCCD.
Rio Conventions:
The three Rio conventions, which include UNCCD, Convention on Biological Diversity (CBD) and the United Nations Framework Convention on Climate Change (UNFCCC) are all relevant to the prevention and control of land degradation. The CBD recognizes the importance of addressing land degradation for the conservation and sustainable use of biodiversity.
Furthermore, the relationship between climate change and land degradation is also recognized. Climate change contributes to desertification and deforestation through changes in temperatures which in turn adversely affects the respiration rate of vegetation. Human created deforestation releases carbon dioxide to the atmosphere and the loss of sequestered carbon in biomass and soils, further contributing to greenhouse gases in the atmosphere.
The work programme of the UNFCCC, therefore, emphasizes the role of conservation and sustainable management of forests and woodland in carbon sequestration and reducing carbon dioxide emissions. The UNFCCC also recognizes the need to develop strategies to adapt the impacts of climate change. Many of these adaptation strategies are linked to combating land degradation and drought.
Joint work programmes for the three Rio conventions are now starting to achieve multiple global benefits, such as poverty alleviation, sustainable ecosystems and minimising greenhouse gas emissions. Since all of the Rio conventions are closely linked to each other, consolidating the policy and planning work required to carry out the responsibilities of the conventions allows for maximum efficiency and synergy in planning.
UNCCD:
The United Nations Convention to Combat Desertification in countries experiencing serious drought and/or desertification, particularly in Africa (UNCCD), was adopted on 17 June 1994. The CCD aims to combat desertification and mitigate the effects of drought, particularly in Africa. The convention recognizes that the people of the dry lands themselves hold the keys to combating desertification, and that the eradication of poverty is a precondition for success.
The CCD entered into force in 26 December 1996; today 179 countries acknowledge it as a legally binding framework to tackle land degradation and promote sustainable development in fragile ecosystems. The global mechanism was established under CCD to promote actions leading to the mobilization and channeling of substantial financial resources, including for the transfer of technology, on a grant basis, and/or on concessional or other terms, to affected developing country parties.
Essay # 4. Types of Land Degradation:
The land degradation is classified according to specific phenomenon prevalent in the land with respect to physical, chemical and biological condition.
(i) Physical – compaction, crusting, sealing, loss of structure, accelerated erosion
(ii) Chemical – salinization, toxicities, nutrient depletion and imbalances, acidification
(iii) Biological – reduction in biodiversity, loss of ecological component
Various types of soil and land degradation have been explained by many authors including FAO/UNDP/UNEP. As only to be expected, authors differ in their approach to describing and classifying land degradation.
It is generally recognized that land degradation has five main components:
(i) Soil degradation,
(ii) Vegetation degradation,
(iii) Water degradation,
(iv) Climate deterioration
(v) Loss due to urban/industrial development.
Each of these major components could be subdivided into more specific types of degradation.
Fragile Ecosystems:
Fragile ecosystems are important ecosystems, with unique features and resources. Fragile ecosystems include deserts, semi-arid lands, mountains, wetlands, small islands and certain coastal areas. Most of these ecosystems are regional in scope, as they transcend national boundaries.
For Small Island States, these fragile ecosystems may encompass the entire nation. Comprehensive plan of action should be taken globally, nationally and locally by international communities of the UN Systems, Governments and major groups in every area in which human’s impact on their environment. It also addresses managing of fragile ecosystems: combating desertification, land degradation and drought.
Essay # 5. Causes of Land Degradation:
The causes of land degradation has been grouped into three categories viz. natural degradation hazards, direct causes of land degradation, underlying causes of land degradation
(i) Natural degradation hazards cyclones, drought, volcanic activities etc.
(ii) Direct causes of land degradation deforestation, overcutting of vegetation, shifting cultivation, overgrazing, non-adoption of soil conservation practices, extension of cultivation in the lands of lower potential and /or high natural hazards, improper crop rotation, unbalanced fertilizer and pesticide use
(iii) Underlying causes of land degradation population increase, attitude, economic pressure, land tenure, land shortage, poverty
Major Causes of Land Degradation:
i. Lack of Land Use Planning:
Road and dam construction projects have a number of significant environmental impacts. It results in destruction of vegetation, hence increasing vulnerable lands to soil erosion and degradation. The establishment of land use and management planning will reduce the land degradation.
ii. Sea Level Rise:
Sea level rise is a significant threat to many countries. In recent times, land has become subject to inundation and saltwater intrusion during tide events. Sea level rise degrades coastal areas including nearby vegetation. Inland vegetation is also affected as the sea water percolates up through the ground and forms large pools of saltwater on the land.
Sea level rise not only affects vegetation, but also affects ground water. The biotic component of the watershed depends on ground water. Intrusion of salt water into ground water is a problem that has been identified in many countries.
iii. Drought:
Drought causes damage to water supply, food security systems and the degradation of terrestrial ecosystems.
iv. Unsustainable Agricultural Practices:
The infertile nature of soils has led to an increase in the use of agricultural chemicals. Fertilizers and pesticides have been used in excess to enhance agricultural productivity. While higher crop yields have been gained from regular and intensive use of these chemicals, they have also caused problems. Overuse of chemicals causes land to become unsuitable for agriculture through changes in the physical and bio-chemical composition of the soil. Consequently farmers abandon their land.
v. Uncontrolled Waste Disposal:
Overpopulation and overcrowding contribute to the problem of solid and liquid waste disposal. When population exceeds the natural carrying capacity of the area, it puts severe pressure on the limited available resources. Uncontrolled waste disposal systems result in land degradation.
Essay # 6. Assessment of Land Degradation:
a. GLASOD:
The land degradation concept aims at covering a range of climatic and man induced processes that lead to a decline of the soil potential to sustain plant productivity. The first attempt to produce a global assessment occurred two decades before (1990), resulting in a ‘Global Assessment of Soil Degradation’ (GLASOD) by the International Soil Reference and Information Centre (ISRIC), currently World Soil Information.
GLASOD was a qualitative assessment, largely based on expert judgement that distinguished the main processes and drivers leading to soil degradation, such as water and wind erosion-sedimentation, soil and water salinization, loss of soil organic carbon and soil nutrients, loss of soil structure etc. GLASOD data were used in the preparation of World Atlas of Desertification, published by UNEP in collaboration with some national and international institutions.
b. ASSOD:
The Assessment of the Status of Human-induced Soil Degradation in South and South East Asia (ASSOD), which is also made by ISRIC, is a follow-up activity of GLASOD for regional studies. The same methodology, slightly refined, was used on a more detailed scale (1:5M) for South and South East Asia.
The study provides data for 17 countries and includes data on several degradation types including water and wind erosion and their subtypes (e.g. loss of topsoil and terrain deformation) and the dominant subtypes of chemical deterioration (including salinization).
c. LADA:
GLASOD approach was recently upgraded by a new worldwide project ‘Land Degradation Assessment in Drylands’ (LADA) in 2002 sponsored by UNEP, GEF and FAO.
While retaining the original GLASOD categories of soil degradation, LADA takes a step forward by:
(i) Attempting at delivering quantitative results,
(ii) Formally including socioeconomic drivers and
(iii) Enlarging its scope to carbon balances and biodiversity as components of the functional land system and its degradation process.
LADA aims at developing and testing an effective methodology to assess causes, status and impact of land degradation in dry lands.
d. MA:
A third global initiative with implications in land degradation assessment is the Millennium Ecosystem Assessment (MA). It evaluates the condition of desertification in dry lands, by asking pointed questions and providing answers based exclusively on the reports generated by the MA.
It provides a consistent picture of the links between land degradation, climate change and biodiversity loss. It also supplies guidelines for improving assessment and monitoring approaches taking into account the role of human actions and climate variability.
The three afore-mentioned projects reveal an historical trend of increasing complexity in land degradation assessment approaches. They go from soil to land, from considering effects to explicitly include drivers (climate variability and human activity) and to be more concerned with global interactions of desertification, climate change and biodiversity.
e. GLADA:
Another global project in land degradation assessment is the GEF-UNEP-FAO program Land Degradation in Dry lands, the Global Assessment of Land Degradation and Improvement (GLADA). GLADA will identify the state and trends of land degradation, areas suffering severe degradation or at severe risk and places where degradation has been arrested or reversed.
Biomass is an integrated measure of productivity and its deviance from the norm may indicate land degradation or improvement. Biomass can be assessed by remote sensing of the Normalised Difference Vegetation Index (NDVI). Norms may be established by stratifying the land area according to climate, soils and terrain and land use/vegetation. The deviance may then be calculated regionally and then combined globally to allow universal comparisons.
f. De-Survey:
The De-Survey is the last newcomer of the efforts in this line. Its objective is to develop and implement a cost-efficient procedure for assessing and monitoring of land degradation status and trend over large areas in an appropriate format to provide a link to the ‘land suitability’ attribute that is used classically by economists to allocate land use changes in space.
Essay # 7. Effects of Land Degradation:
The most important on-farm effects of land degradation are declining potential yields. The threat of degradation may also be reflected in the need to use a higher level of inputs in order to maintain yields. Serious degradation sometimes lead to temporary or permanent abandonment of land.
In other cases, degradation induces the farmers to convert land to lower-value uses. FAO/UNDP/UNEP has grouped the effects of land degradation as effects upon production and consequences for the people.
Effects on Land Degradation upon Production:
i. Reduced vegetation cover to the soil and biodiversity loss
ii. Top soil loss
iii. Watershed destruction with subsequent water shortages
iv. Reduced return of organic matter and less biological activity in the soil
v. Increased pollution from increased use of agrochemicals
vi. Land is abandoned (where degradation is severe)
vii. Crop yields are reduced
viii. Inputs and costs of production are increased (where farmers attempt to combat reduced yields by increased inputs)
ix. Responses to inputs are decreased
x. Flexibility of land management is decreased
xi. Risk is increased
xi. Labour, technical and financial resources are diverted to reclamation
Consequences of Land Degradation for the People:
i. Landlessness is increased
ii. Food supplies are reduced or less reliable
iii. Labour requirements are increased
iv. Incomes are decreased
v. Migration of young people in search for employment opportunities
Essay # 8. National Action Programme to Combat Desertification:
India became a signatory to the UNCCD on 14 October 1994 and it came into effect on 17 March 1997. One of the obligations of all developing country parties to the convention, including India, is to prepare the National Action Programme to Combat Desertification and to mitigate the effects of drought.
The Ministry of Environment and Forests, as the National Focal Point for the implementation of the Convention, has prepared the National Action Programme to Combat Desertification (NAPCD) through the setting up of a High-level Inter- Sectoral National Steering Committee (NSC) in July 1999.
The NSC constituted four Working Groups (WG) on various relevant to desertification viz. Desertification Monitoring and Assessment, Sustainable Land Use Practices for Combating Desertification, Local Area Development Programme, Policy and Institutional Issues.
Similarly Desertification Cell has been established under Ministry of Environment and Forests comprising multi-disciplinary team including agriculture, forestry, environment science, geo-hydrology, rural development and social sciences. It would service on all matters like preparation of NAP, monitoring its implementation, organizing reviews, feasibility studies and evaluation and impact studies.
Features of NAPCD:
i. Water is a diacritical element for building people’s confidence and satisfaction level, reclamation of degraded lands for sustainable biomass production ultimately leading to a better quality of life and enabling conditions through empowerment of the local communities.
ii. Bottom up approach and project planning, evaluation and monitoring by Panchayat Raj Institutions (Grass root level elected local Self-Governments in which women have at least 30 per cent representation) on all aspects of land development including rehabilitation of degraded areas.
iii. Convergence of resources and services. All resources available under different schemes will be channelled through Panchayats through single window service to the communities.
iv. Gaps in all the on-going schemes of different departments will be identified and resources will be provided to fill them up for generating good impact at the ground level.
v. The first five-year period will be experimental and include pilot projects and activities.
vi. Concurrent and continuous monitoring will be done and mid-course correction will be effected as the experiences are gained.
vii. The problem faced by farmers will be reported to R&D institutions for finding solutions. Thus both lab-to-land and land-to-lab flow of information will be ensured.
Essay # 9. Multi-Faceted Actions to Combat Land Degradation:
The integrated approach is necessary to combat land degradation.
The following approaches are considered necessary for the land improvement:
i. Integrated management of natural resources
ii. Soil conservation and restoration
iii. Improving agricultural production and stock-farming systems
iv. Agricultural water management
v. Sustainable forest management
vi. Agroforestry
vii. Watershed management
viii. Environmental monitoring, drought early warning and forecasting/response system
ix. Promotion of sustainable land management techniques geared to climate change adaptation
x. Biodiversity preservation
xi. Adding value to agricultural, forest, farmed products
xii. Diversifying activities so as to relieve pressure on resources
xiii. Increasing land and labour productivity with available technology
xiv. Developing technology to overcome agricultural production constraints
Table 33.4: Types of Land Degradation and Improvement
Essay # 10. Processes of Land Degradation in India (Space Application Centre 2007):
i. Vegetal Degradation:
It is observed as deforestation, forest blanks, shifting cultivation area and also degradation in grazing area/grassland as well as in scrubland. At places, agriculture is observed within forest land, this has been classified under vegetal degradation within forest area. Vegetal degradation processes are found in both cold and hot regions.
ii. Water Erosion:
It is observed in both hot and cold areas, in various land covers and with varying severity levels. The sheet erosion, rill erosion and shallow gullies mostly within agricultural lands are categorized as low category of severity. While deep & wide gullies and ravines are categorized as high category.
iii. Wind Erosion:
It pertains to the Aeolian activities. It denotes the spread of sand by virtue of lift and drift effect of wind, even up to lofty altitudes of Himalayas. Various categories of sand cover and their severity are classified based on the depth and spread of sand sheet, sand dunes and barchans.
iv. Salinization and Alkalinization:
It is fundamentally the chemical property of soils. It occurs mostly in cultivated lands, especially in the irrigated areas. At places salinity is clearly observed on satellite images, while the alkalinization is not seen and mostly inferred based on ground truth data and published maps.
v. Waterlogging:
The undrained land areas tend to accumulate standing water for longer duration of time on the surface, this condition is called waterlogging. The severity of waterlogging is determined based on the period for which the water remains stagnant.
vi. Mass Movement or Mass Wasting:
It is predominantly observed in mountainous areas, especially in cold dry land regions and it is defined as the process of desertification which leads to the down slope movement of rock, regolith and debris through the action of gravity viz. landslides, scree slopes.
vii. Frost Heaving:
It is defined as the process of intense frost and freezing of water operating in glacial and per glacial environment and evolves peculiar forms of rock, regolith and soil, for example, a typical irregular pattern ground is seen.
viii. Frost Shattering:
It is defined as the freeze and thaw action operating mostly in periglacial environment. When water, passing through the crevices and pores within the rock freezes, it expands by almost ten times. This puts enormous pressure on the surrounding rocks which shatters them.
ix. Man Made:
All those land degradation processes which are included directly or indirectly by human intervention and are not natural, are categorized as man-made desertification processes. It includes mining/quarrying, brick kiln, industrial effluents, city waste, excess use of fertilizers and pesticides. It occurs across various land use/land cover classes.
Essay # 11. Examples of Land Degradation in India:
i. Mining sites are abandoned after excavation work is complete leaving deep scars and traces of over-burdening.
ii. In states like Jharkhand, Chhattisgarh, Madhya Pradesh and Orissa, deforestation due to mining have caused severe land degradation.
iii. In states like Gujarat, Rajasthan, Madhya Pradesh and Maharashtra, overgrazing is one of the main reasons for land degradation.
iv. In the states of Punjab, Haryana, Western Uttar Pradesh, over irrigation is responsible for land degradation due to water logging leading to increase in salinity and alkalinity in the soil.
v. The mineral processing like grinding of limestone for cement industry and calcite and soapstone for ceramic industry generate huge quantity of dust in the atmosphere. It retards the process of infiltration of water into the soil after it settles down on the land.
vi. In recent years, industrial effluents as waste have become a major source of land and water pollution in many parts of the country.