Environment, soil survey and land suitability assessment for conservation management - Coursework Example

? ENVIRONMENT, SOIL SURVEY AND LAND SUITABILITY ASSESSMENT FOR CONSERVATION MANAGEMENT XXXXX XXXXX XXXXX XXXXX Date: XXXXX In evaluating the land suitability for multiple land use which includes grassland production, forestry, footpaths and the potential/actual wildlife habitats within the specified area, the following are some of the questions that should be addressed. First, for the specified kind of land use, which particular areas of the land are best suited. Secondly for the given area what kind of use will it be best suited? The procedure followed in evaluating the land suitability hence is as follows: Description of the promising land-use types For the given land-use type, determine the requirements for water, nutrients, erosion avoidance etc Conduction of surveys necessary to map the land units as well as description of their physical properties. Comparing requirements for the given land-use types with the properties of the given land units Any given land cannot be graded from “best” to “worst” irrespective of the particular kind of use since each particular use has a special requirement. For instance a stony and rocky ground my not be suitable for grassland production but may be a suitable home for some particular wildlife habitats. Description of land-use types A land-use type is defined as a kind of land use which is described in terms of its products as well as management practices. For efficient reconnaissance surveys being conducted at the national levels, highly generalized descriptions may be adequate i.e. “wildlife habitat”, “forestry conservation”. At district as well as lower levels, it is vital to specify the use in more details. For example will forest conservation b managed by the government forestry service or by the local community? Will grassland production be mechanized or based on animal traction? Such descriptions usually serve two purposes. First they are the basis of determining the requirements for use. Secondly, the management specifications can be used as the basis for the extension services as well as the planning for the necessary inputs. Selection of land qualities and land characteristics The particular land use requirements are usually illustrated by the land qualities required for the sustained production. A land quality is a very complex attribute of land which usually has a direct effect on the land use. The various examples are the availability of water, nutrients, rooting conditions and erosion hazards. Most of the given lands qualities are determined by the interaction of the several land characteristics as well as measurable attributes of a land. For example, the quality “availability of water” is usually determined by the potential balance between the water demand as well as the water supply. The water demand is the potential evaporation from the surface of the crop as well as the soil whereas the water supply is determined by the rainfall, infiltration, water storage in the soil and the ability of the grassland to extract the stored water. After selection of the relevant land qualities, it is vital to decide which particular land characteristics are to be used for measuring them. For instance, the quality “erosion hazard” demands information on rainfall intensity, slope angle as well as soil properties. A compromise is then reached between the characteristics that most define the given land quality with those that are less precise. Land evaluation can also at times be conducted directly in terms of the land characteristics i.e. by using rainfall as opposed to water availability, slope angle instead of erosion hazards. Despite the above, the following are the land suitability constraints that are imposed by the interaction of the soil, climate, topographic, hydrological as well as the geological factors. Mapping of land units and their characteristics The land is first identified as a basis for diagnosis of problems. The given units are then mapped into more details i.e. by dividing the land systems into land facets or rather complex soil mapping units into soils series. The criterion for a given choice of land units is that they are expected to respond to the management in a similar manner at the scale of study. This therefore means that district-level planning will require at least a semi-detailed survey which is at scale of 1:50000. S SUITABLE The land can support the land use indefinitely and benefits justify inputs S1 Highly suitable Land without significant limitations. Include the best 20-30% of suitable land as S1. This land is not perfect but is the best that can be hoped for S2 Moderately suitable Land that is clearly suitable but which has limitations that either reduce productivity or increase the inputs needed to sustain productivity compared with those needed on S1 land S3 Marginally suitable Land with limitations so severe that benefits are reduced and/or the inputs needed to sustain production are increased so that this cost is only marginally justified N NOT SUITABLE Land that cannot support the land use on a sustained basis, or land on which benefits do not justify necessary inputs N1 Currently not suitable Land with limitations to sustained use that cannot be overcome at a currently acceptable cost N2 Permanently not suitable Land with limitations to sustained use that cannot be overcome Constraints for land use requirements The limiting values are the given values of a land quality or rather land characteristics that usually determine the class limits of land suitability for a particular use. The land should be able to support the land use on a sustained basis. This implies that progressive use should not degrade the land. Many land changes will cause an initial loss of land resources, for example when a forest is cleared for grassland, there is always a loss of forest habitat and wildlife as well as of soil and the accumulated plant nutrients The use should yield benefits to justify the inputs. The user has to make reasonable living from the land. Local experience can be the best guide; however a financial analysis can be of significant help. It is now possible to distinguish up to the given three classes of suitability. Land classified as highly suitable is the best land for the intended use; moderately suitable land is clearly fit for use but has limitations; while the marginally suitable land falls near to the limit of a given suitability. Land which is still not suitable may be subdivided into permanently not suitable, where there may be limitations to the sustained use that are clearly impractical to overcome or rather currently not suitable where such limitations could be overcome but are not at a currently acceptable cost. TABLE 2 Example of land requirements for a specified land-use type (grassland) Land qualities Land characteristics Limiting values for land characteristics S1 S2 S3 N Sufficiency of energy Mean annual temperature, (°C >24 21-24 18-21 1800 Sufficiency of water 75% probability rainfall (mm) >1300 900-1300 500-900 80 60-80 40-60 10 The elevation has been used to assess sufficiency of energy where the temperature data are not available. The values described above apply to Sri Lanka. The above construction of the table of limiting values for a given land suitability class (Table 2) is a central operation in land evaluation practice. For efficient performance of the above, information is needed on the performance of a land-use type over a range of sites. References Davidson, D.A 1992, The Evaluation of Land Resources. Longman, Harlow. Dent, D. and Young, A. 1981,Soil Survey and Land Evaluation. Chapman & Hall, London. FAO 1976, “ A Framework for Land Evaluation”. FAO Soils Bulletin 32, Food and Agriculture Organization, Rome. Jarvis, R.A. et al 1984, Soils and Their Use in Northern England. Soil Survey of Great Britain. Jarvis, M.G. & Mackney, D 1979, “Soil Survey Applications”. Soil Survey of England and Wales Technical Monograph No.13. Harpenden, England. Jones, R.J.A. and Thomasson, A.J. (1985). An Agroclimatic Databank for England and Wales. Soil Survey of England and Wales Technical Monograph No.16, Harpenden, England. The Meteorological Office (1989). Climatological Data for Agricultural Land Classification: Gridpoint datasets of climatic variables at 5 km intervals for England and Wales. HMSO, London. Payton, R.W. (1987). Soils of the Lingy Hill SSSI, Upper Teesdale. Soil Survey and Land Research Centre, Silsoe. Payton, R.W. (1988). Soils of the Rock Estate, Northumberland. Soil Survey and Land Research Centre, Silsoe. Payton, R.W. and Palmer, R. (1990). Soils of the Alnwick and Rothbury District. Sheet No.81. Memoir of Soil Survey of Great Britain. Soil Survey and Land Research Centre, Silsoe. Smith, L.P. (1976). The Agricultural Climate of England and Wales. Ministry of Agriculture, Fisheries and Food Reference Book 435 (formerly Technical Bulletin No.35, HMSO, London. Smith, L.P. and Trafford, B.D. (1976). Climate and Drainage. MAFF References Book 434 (formerly Technical Bulletin No.34), HMSO, London. Read More