02 Contents Frame
Land suitability in terms of use and services of the land
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40 2019 ND-CP 413905
- Điều hướng trang này:
- Comparison of benefits obtained and inputs needed
| Land suitability in terms of use and services of the land
The first principle of the 1976 Framework stipulates that land suitability is to be assessed and classified with respect to specified kinds of use. Depending on the objectives of the evaluation, the suitability classes are defined by economic criteria (five classes) or physical criteria (four classes). Physical evaluations are predominantly based on yield reductions, whereas economic evaluations are made on the basis of predicted economic value of the land use. The extended concept of land suitability requires analysis for the services delivered by the land that are valued by society. Such services may include carbon sequestration, biodiversity value and agricultural biodiversity, improved water quality due to reduced sediment transport and biocide use, and landscape value. These services need to be evaluated and monitored by agro-environmental indicators for each specified land use. Comparison of benefits obtained and inputs needed The evaluation of land requires estimates of the output of goods and services, for management methods and levels of inputs specified in the LUTs, and on each mapped land unit. For goods, these will be estimates of crop yields, forest production, or livestock output. For services and environmental consequences it may be difficult to put benefits in quantitative terms, although an effort should be made to do so. Quantitative estimates of crop yields or other types of output are essential to economic evaluation. If the surveyors do not supply them, then the economists will be forced to make estimates. It has been argued that linking soils with agronomic data should be an integral part of soil survey (Young 1973). The surveyor should, for example, make soil observations where agronomic results are available, e.g. at fertilizer trial sites; and when making any soil description, should question farmers on outputs from that land, thus building up a data bank on land performance under given management. Often, this is best carried out by collaboration between surveyor and agronomist or other technical expert. The second principle of the 1976 Framework indicates that productive potential is contingent on some kind of input, which might include factors such as labour, external inputs (e.g., fertilizer) or infrastructure (e.g., road construction). Thus evaluation of land for a land use requires a comparison between benefits obtained and inputs needed. The principle of comparing benefits and inputs to assess the productive potential of the land is essentially of an economic nature. In practice, however, the majority of land evaluations have taken quantitative physical land qualities as the basis for comparison. Chapter 4 – Revised principles and procedures 31 The comparison of benefits obtained and inputs needed should aim at assessing the productive potential, environmental services and social equity (e.g. rural development). Depending on the specific objectives of the evaluation, the comparison should be carried out in biophysical and more or less explicit and detailed socio-economic terms. tải về 0.57 Mb. Chia sẻ với bạn bè của bạn:
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