Natural Resource Degradation - Land Degradation/Soil Erosion/Deforestation December 21, 2017 Land Degradation Land degradation is the process of deterioration of soil or loss of fertility of soil. The causes of land degradation can be divided into natural hazards, direct causes, and underlying causes. Natural hazards are the conditions of the physical environment which lead to the existence of a high degradation hazard, for example steep slopes as a hazard for water erosion. Direct causes are unsuitable land use and inappropriate land management practices, for example the cultivation of steep slopes without measures for soil conservation. Underlying causes are the reasons why these inappropriate types of land use and management are practised; for example,-the slopes may be cultivated because the landless poor need food, and conservation measures not adopted because these farmers lack security of tenure. There is a distinction, although with overlap, between unsuitable land use and inappropriate land management practices. Unsuitable land use is the use of land for purposes for which it is environmentally unsuited for sustainable use. For example- forest clearance and arable use of steeply sloping upper watershed areas which would have more value to the community as water sources, managed under a protective forest cover. Inappropriate land management practices refer to the use of land in ways which could be sustainable if properly managed, but where the necessary practices are not adopted. For example- the failure to adopt soil conservation measures where these are needed. It can also refer to land use which is ecologically sustainable under low intensity of use but in which the management becomes inappropriate at higher intensifies (shifting cultivation and the grazing of semi-arid rangelands). Causes of land degradation • Population: The indirect activities included pressure on agricultural intensification and population growth. About 220 million hectares of tropical forest have been degraded 1975 and 1990 mainly for food production. With the increase in population, more land is needed for producing food, fibre, and fuel wood leading to increasing pressure on the limited land resources. Therefore the land gets degraded due to over exploitation. • Human Activities: Human induced causes many human activities are leads to land degradation directly or indirectly include deforestation, overgrazing by livestock, wrong irrigation practices, urban sprawl and commercial development, pollution from industries, quarrying, and mining activities, Problems arising from planning and management of canal irrigation etc. • Urbanization: Increased urbanization due to population growth reduces the agricultural land. To compensate for loss of agricultural land, new lands comprising of natural ecosystems such as forests are cleared. Therefore, urbanization leads to deforestation which in-turn affects millions of plant and animal species. • Fertilizers and Pesticides: Increased application of fertilizers and pesticides are needed to increase farm output in new lands thereby leading to pollution of land, water and soil degradation. • Damage to top soil: Increase in food production generally leads to damage of top soil through nutrient depletion. Some specific causes are: a) Soil erosion: • It is wearing away of the land surface by physical forces such as rainfall, flowing water, wind, ice, temperature change, gravity or other natural or anthropogenic agents. b) Soil contamination: • It includes contamination by heavy metals, acidification, nutrient surplus (eutrophication), etc. c) Soil salinisation: • The salts which accumulate include chlorides, sulphates, carbonates and bicarbonates of sodium, potassium, magnesium and calcium. d) Soil sealing: • The covering of the soil surface with impervious materials as a result of urban development and infrastructure construction. e) Overgrazing: • Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. f) Acidification of Soil: • Acid soils are toxic to plants because they can release toxic levels of aluminium and other mineral elements. g) Mining and quarrying activities: • Due to this excavation process alter the structure of the land, stacking of top soil, loss of soil due to dumping of the mine wastes. h) Improper crop rotations: • It decreases fertility of soil. Impact of land degradation • Loss of soil organic matter and nutrients. • Loss of soil structure. • Loss of soil biodiversity. • Loss of water holding capacity and water infiltration. • Soil pollution. • Reduced yields of crops. • Reduced land value and resilience to future events. • Impact on food security. • Reduces ability to adapt to climate change. Sustainable Land Management Thus Sustainable Land Management (SLM) is crucial to minimizing land degradation, rehabilitating degraded areas and ensuring the optimal use of land resources for the benefit of present and future generations. SLM is based on four common principles: • land-user-driven and participatory approaches; • Integrated use of natural resources at ecosystem and farming systems levels • Multilevel and multi-stakeholder involvement; and • Targeted policy and institutional support, including development of incentive mechanisms for SLM adoption and income generation at the local level. Some of the methods for sustainable management of land are: • Management on overgrazing: Management practices like water development, placement of salt and supplements, fertilizer application, fencing, burning can control the overgrazing. • Managing irrigation: Irrigation system can be controlled like drip irrigation to reduce soil erosion. Using high and low salt water was most effective in maintaining the productive capacity of the clay soil. • Managing urban sprawl: The urban planning is the most important factor, to control the urban sprawl. Fertile field near by the urbane area need to be protected by the local government rules. There should be a proper waste management system dumping of these waste generated as part of urban sprawling will degrade the land, can cause soil salinity, acidity and loss of it vegetative properties. • Managing mining and quarrying: The impact can be reduced by proper management of mining process, using advanced technologies rather than conventional methods. After mining by proper back filling, spreading the soil back over the top, the land can be reclaimed. • Managing agricultural intensification: Agricultural intensification need to be managed properly to reduce the environmental effect. This can be done through education of the farmers.