Slide land evaluation

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LAND EVALUATION What is land evaluation? The assessment of land performance when used for a specified purpose, involving the execution and interpretation of surveys and studies of land forms, soils, vegetation, climate and other aspects of land in order to identify and make a comparison of promising kinds of land use in terms applicable to the objectives of the evaluation' (FAO, 1976) Principles Land suitability is assessed and classified with respect to specified kinds of use Evaluation requires a comparison of the benefits obtained and the inputs needed on different types of land A multidisciplinary approach is required Evaluation is made in terms relevant to the physical economic and social context of the area concerned Suitability refers to use on a sustained basis Evaluation involves comparison of more than a single kind of use Land comprises the physical environment ( including climate, relief, soils, hydrology and vegetation, to the extent that these influence potential for land uses It includes the results of past and present human activity Land evaluation ASSESS LAND SUITABILITY BASE ON  The requirements of specific land uses  A comparative analysis of input Vs benefit (Multi-disciplinary)  The physical, economic and social context  Potential environmental impact & suitability TWO-STAGE AND PARALLEL APPROACH TO LAND EVALUATION (FAO 1976) Land characteristics, land qualities and diagnostic criteria A land characteristic is an attribute of land that can be measured or estimated (Ex: slope angle, rainfall, soil texture, available water capacity, biomass of the vegetation, etc Land mapping units, as determined by resource surveys, are normally described in terms of land characteristics.) A land quality is a complex attribute of land which acts in a distinct manner in its influence on the suitability of land for a specific kind of use (Ex: are moisture availability, erosion resistance, flooding hazard) A diagnostic criterion is a variable which serves as a basis for assessing the suitability of a given area of land for that use This variable may be a land quality For every diagnostic criterion there will be a critical value which are used to define suitability class limits Structure of the suitability classification Land Suitability Orders: reflecting kinds of suitability Land Suitability Classes: reflecting degrees of suitability within Orders Land Suitability Subclasses: reflecting kinds of limitation, or main kinds of improvement measures required, within Classes Land Suitability Units: reflecting minor differences in required management within Subclasses Land Suitability Orders with code Land Suitability Orders S Suitable and N Not Suitable Land Suitability Classes: S1 Highly suitable S2 Moderately suitable S3 Marginally suitable N1 Currently not suitable N2 Permanently not suitable Land Suitability Subclasses: Land Suitability Units: S2n Moderately suitable , S3ne Marginally suitable N1m Currently not suitable S2n-1 Moderately suitable , S3ne-1 Marginally suitable [...]... classification 1 Land Suitability Orders: reflecting kinds of suitability 2 Land Suitability Classes: reflecting degrees of suitability within Orders 3 Land Suitability Subclasses: reflecting kinds of limitation, or main kinds of improvement measures required, within Classes 4 Land Suitability Units: reflecting minor differences in required management within Subclasses Land Suitability Orders with code Land Suitability... management within Subclasses Land Suitability Orders with code Land Suitability Orders S Suitable and N Not Suitable Land Suitability Classes: S1 Highly suitable S2 Moderately suitable S3 Marginally suitable N1 Currently not suitable N2 Permanently not suitable Land Suitability Subclasses: Land Suitability Units: S2n Moderately suitable , S3ne Marginally suitable N1m Currently not suitable S2n-1 Moderately
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