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40 2019 ND-CP 413905
| Land degradation
Environmental degradation is of particular concern in many parts of the world. Prima facie, loss of sustainability seems linked to the attitude of rural people towards land resources. Villagers are often considered to be placing their own short-term survival ahead of long-term land resource sustainability (IFPRI 1994). The increased needs of a rising population are regarded as particularly disruptive for the environment since the level of resources per capita declines. These negative views are often based on an Land evaluation – towards a revised framework 22 abstraction of personal observations and judgements but do not necessarily reflect the complex reality. Land degradation is dealt with in the original Framework under environmental impact, and also forms part of the definition of land itself, since this includes the effects of past human action –including harmful action. Land degradation has local effects, such as the formation of erosion gullies or salinization, but may also cause damage elsewhere, for example by increased flooding or rapid sedimentation in reservoirs, shortening their lifespan. The term desertification is used for land degradation in arid, semiarid and dry subhumid areas. Land degradation can be one of the reasons for carrying out a land evaluation, in support of changing land-use practices or management and related efforts to check or reverse the land degradation processes. Since land degradation may appear in many forms –such as water or wind erosion, salinization or sodification, soil nutrient depletion, soil compaction or surface sealing, decline in vegetation cover or diversity–, its estimation, mapping or measurement is a complex undertaking. Global and broad regional assessments (GLASOD and ASSOD: Oldeman et al., 1991 and Van Lynden & Oldeman 1997) used expert judgement by a large number of local specialists within a common, qualitatively defined framework. The current LADA programme (http://www.fao.org/ag/agl/agll/lada/default.stm) aims to produce multi-scale assessments of land degradation in drylands, with quantitative indicators in so far as feasible. tải về 0.57 Mb. Chia sẻ với bạn bè của bạn:
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