Introduction

Mankind for their profit is continuously exploiting the natural resources. Natural resource management connotes their optimal utilization and also conservation of resources.Both are essential for development and achieving environmental sustainability and hence an assessment of land resources and land use pattern is essential and important. Remote sensing technology in association with Geographical Information System (GIS) and Global Positioning System (GPS) is able to address many such issues pertaining to the management of natural resources and environment. Global Positioning System has come as an important tool in land use/land cover study by Satellite Remote Sensing and GIS techniques. Geographic Information Systems (GIS) are also map based information systems which enable the planning and management of spatially distributed resources

The application of GIS are facilitating new avenues of exploratory spatial data analysis that were previously not feasible and also enables the integration of data collected by different media thereby substantially increasing the communications capabilities. GIS-based multi-temporal land use data provides a historical vehicle for determining and evaluating long term changes of land use due to urbanization Remote sensing (RS) provides the information of landscapes synoptically, repetitively and objectively. It is an important source of spatial information such as land use and land cover which effectively illustrates the interaction between natural and human components in any region. Satellite remote sensing technique is useful to map and monitor the natural resources in real time and in a cost effective and unbiased manner. Geographic Information System (GIS) is a powerful tool for geo-environmental analysis and appraisal of natural resources. It allows the user to integrate the data bases generated from various sources including RS on a single platform and analyze them efficiently in a spatio-temporal domain. GIS provides support in resource management and decision making.

What is Geographic Information Systems (GIS)?

A GIS has been defined as a computer assisted system for the acquisition, storage,analysis and display of geographic data according to user-defined specifications(Laurini and Thompson, 1992). It has a digital database management systemdesigned to accept large volumes of spatially distributed data from a variety ofsources (Jensen and Christensen, 1986). The most powerful characteristics of GIScentre on their ability to analyse spatial data based on descriptive attributes.

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Geographic information systems (GIS) combined with land evaluation and site assessment (LESA) enhances land-use planning by delivering a versatile and dynamic model to assist state policy and decision makers, county and local officials, landowners and interested citizens in making wise land management decisions.The introduction of GIS, whether top-down or bottom-up, has usually come fromoutside and so far GIS has been only marginal to the solution of developmentproblems. Hence Taylor (1991) argues that it is a necessary first step for indigenousScientists to gain a greater degree of knowledge and control of this technology.

What is land evaluation?

Land evaluation is defined as the process of assessing the potential production for various land uses (Beek, 1978). This approach is based on the matching of qualities of different land units in a specific area, with the requirements of actual or potential land use. The results of land evaluation should be useful for rational land use planning (FAO, 1993).

Land evaluation is a method applied to the assessment of land suitability for a specific use. Land evaluation is itself knowledge-based and requires an extensive knowledge and different conditions to be fulfilled. This can be done automatically by the use ALES, LECS and GIS systems. At present, the use of knowledge- !'"' based (expert) systems in the geo-related sciences is not anew the phenomenon. Different types of these systems have been and are )., being developed depending upon the structure of knowledge representation. Knowledge can be represented in the forms of semantic networks, object-attribute-value (O-A-V) triplets, frames, decision trees, production rules, etc. The characteristics of these techniques are discussed by Amarsaikhan (1994) .At present, in the field of geoinformatics the widely used structures of knowledge representation are the frame-based and rule-based types

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Description

Land evaluation/Assessment

Land evaluation provides essential information on land resources. However this information is often not used in the planning and implementation of better land use systems or land use practices, for a number of reasons. Firstly, the information produced is frequently incompatible both to government’s objectives and/or the preferences of the local people. Secondly, data processing is inadequate, resulting in low quality information. Thirdly, land evaluation is based on a top-down approach; such an approach does not take sufficiently into account the aspirations, capabilities and constraints of the local land users. Added to which, land use plans tend not to consider sufficiently the limitations of interventions (subsidies, policy prices, input supply, extension, credit etc.) (Bronsveld et al, 1994).

Burroughs (1996) states that we need to look more at the interactions between how the various tools for land evaluation can be used in different circumstances, and how physical, economic and social factors can be combined. A demand driven approach to selecting a land evaluation method would help to reveal what predictions are really needed and at what level of certainty

The aims of land evaluation/Assessment

Land evaluation may be concerned with present land performance. Frequently, however, it involves change and its effects: change in the use of land and in some cases change in the land itself. Evaluation takes into consideration the economics of the proposed enterprises, the social consequences for the people of the area and the country concerned, and the consequences, beneficial or adverse, for the environment. Thus land evaluation should answer the following questions:

How is the land currently managed, and what will happen if present practices remain unchanged?

What improvements in management practices, within the present use, are possible? What other uses of land are physically possible and economically and socially relevant?

Which of these uses offer possibilities of sustained production or other benefits? What recurrent inputs are necessary to bring about the desired production and

minimize the adverse effects?

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What are the benefits of each form of use?

Principles

Certain principles are fundamental to the approach and methods employed in land evaluation. These basic principles are as follows:

i. Land suitability is assessed and classified with respect t o specified kinds of use This principle embodies recognition of the fact that different kinds of land use have different requirements. As an example, an alluvial floodplain with impeded drainage might be highly suitable for rice cultivation but not suitable for many forms of agriculture or for forestry. The concept of land suitability is only meaningful in terms of specific kinds of land use, each with their own requirements, e.g. for soil moisture, rooting depth etc.The qualities of each type of land, such as moisture availability or liability to flooding, are compared with the requirements of each use. Thus the land itself and the land use are equally fundamental to land suitability evaluation.

ii. Evaluation requires a comparison of the benefits obtained and the inputs needed on different types of landLand in itself, without inputs, rarely if ever possesses productive potential; even the collection of wild fruits requires labour,whilst the use of natural wilderness for nature conservation requires measures for its protection. Suitability for each use is assessed by comparing the required inputs, such as labour, fertilizers or road construction, with the goods produced or other benefits obtained.

iii. A multidisciplinary approach is requiredThe evaluation process requires contributions from the fields of natural science, the technology of land use, economics and sociology. In particular, suitability evaluation always incorporates economic considerations to a greater or lesser extent. In qualitative evaluation, economics may be employed in general terms only, without calculation of costs and returns. In quantitative evaluation the comparison of benefits and inputs in economic terms plays a major part in the determination of suitability. It follows that a team carrying out an evaluation requires a range of specialists. These will usually include natural scientists (e.g. geo-morphologists, soil surveyors, and ecologists), specialists in the technology of the forms of land use under consideration (e.g. agronomists, foresters, irrigation engineers, experts in livestock management), economists and sociologists. There may need to be some combining of these functions for practical reasons, but the principle of multidisciplinary activity, encompassing studies of land, land use, social aspects and economics, remains.

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iv. Evaluation is made in terms relevant to the physical, economic and social context of the area concernedSuch factors as the regional climate, levels of living of the population, availability and cost of labor, need for employment, the local or export markets, systems of land tenure which are socially and politically acceptable, and availability of capital, form the context within which evaluation takes place. It would, for example, be unrealistic to say that land was suitable for non-mechanized rice cultivation, requiring large amounts of low-cost labor, in a country with high labor costs. The assumptions underlying evaluation will differ from one country to another and, to some extent, between different areas of the same country. Many of these factors are often implicitly assumed; to avoid misunderstanding and to assist in comparisons between different areas, such assumptions should be explicitly stated.

v. Suitability refers to use on a sustained basisThe aspect of environmental degradation is taken into account when assessing suitability. There might, for example, be forms of land use which appeared to be highly profitable in the short run but were likely to lead to soil erosion, progressive pasture degradation, or adverse changes in river regimes downstream. Such consequences would outweigh the short-term profitability and cause the land to be classed as not suitable for such purposes. This principle by no means requires that the environment should be preserved in a completely unaltered state. Agriculture normally involves clearance of any natural vegetation present, and normally soil fertility under arable cropping is higher or lower, depending on management, but rarely at the same level as under the original vegetation. What is required is that for any proposed form of land use, the probable consequences for the environment should be assessed as accurately as possible and such assessments taken into consideration in determining suitability.

vi. Evaluation involves comparison of more than a single kind of useThis comparison could be, for example, between agriculture and forestry, between two or more different farming systems, or between individual crops. Often it will include comparing the existing uses with possible changes, either to new kinds of use or modifications to the existing uses. Occasionally a proposed form of use will be compared with non-use, i.e. leaving the land in its unaltered state, but the principle of comparison remains. Evaluation is only reliable if benefits and inputs from any given kind of use can be compared with at least one, and usually several different, alternatives. If only one use is considered there is the danger that, whilst the land may indeed be suitable for that use, some other and more beneficial use may be ignored.

Integration of information in a Geographical Information Systems (GIS)

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GIS was introduced into developing countries during the 1980’s, the key agents of delivery being various UN agencies. The approach adopted in the use of GIS was essentially top-down, with ARC/INFO used on mini-computers as the principal schema. As GIS developed, however, more inexpensive systems were introduced using micro-computers, e.g. ILWIS from ITC and IDRISI from Clark University. As these various GIS systems were taken up by both universities and research centres, so a change took place in the application of GIS, with bottom-up approaches being developed, (Taylor, 1991).

The introduction of GIS, whether top-down or bottom-up, has usually come from outside and so far GIS has been only marginal to the solution of development problems. Hence Taylor (1991) argues that it is a necessary first step for indigenous scientists to gain a greater degree of knowledge and control of this technology.

Yeh (1991) added that in developing countries it is necessary to improve the institutional arrangements and the application of GIS rather than the technology, and that successful implementation of GIS will depend upon a clear understanding of the functions and needs of planning that are translated to system applications. (Enrique Ojeda-Trejo)

Figure: General procedure for inputting raw data into the database and the modules of the GIS for generating, displaying and analysis of information.

GIS is a significant and useful mapping system which comprises not only comprehensive data base but also understandable visual appearance. The GIS mapping system consists of three stages of production. The first is situation analysis including irrigation facility assessment, land use investigation, soil investigation and topographic survey. The second is production of irrigation facility map, command area map, land use map, soil classification map and land ownership and tenure map. The third is GIS main component production which is composed by Land Use Planning, Farm Management Planning, Canal Rehabilitation Planning and Water Management Planning.

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Setup process of GIS system

Premised condition of GIS system Paddy field includes various kind of information not only agronomical data (yield, variety, soil, crop, fertilizer, agrochemical, etc) but irrigation related data (Irrigation water management, operation and maintenance, irrigation facility), therefore, detail attribute data collection is important step for achievement of this GIS system purpose. The setup process is composed by 2 parts, the first is system component setup process and the second is data component setup process, both processes is very critical for analysis of each model site.

System component setup

System component production is implemented for creating source map of GIS system

a. Source map

Acquirement Source map is a basic and indispensable information resource map which facilitates easy understanding of the model site. Generally, high accuracy source map is more costly than low accuracy map.

b. Topographic survey

Aerial photo is not always latest photo, therefore, through additional topographic survey; resource map should be added or adjusted due to the present condition.

c. Command area survey (Irrigation issue survey)

Aerial photo also does not always indicate small scale irrigation and drainage canal, so command area survey should be in indispensable for supplemental information.

Data component setup

Date component setup process is implemented in order to acquire data base for the field condition and farm management analysis and consensus.

a. Walk through survey (Irrigation facility and water management survey)

Walk through survey is investigation and evaluation of present condition of irrigation facilities such as canal, road, weir, gate, concrete structures, etc, and apply this condition to GIS system in order to evaluate and prioritize of rehabilitation plan.

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b. Base line survey (Farm management survey)

Base line survey is questionnaire survey to all cultivating farmers in the model site. In this survey, many farming elements should be investigated such as land ownership, kind of crop, variety, yield, amount of fertilizer, chemical, irrigation scarcity, etc, in order to analyze field condition and farm management.

c. Soil survey

Soil survey is composed by 2 components, one is physical property such as permeability, percolation and another is chemical property such as soil fertility (Nitrogen, Phosphorus, Potassium PH, Electric conductivity, Organic matter, etc). Through this step, Agronomical recommendation becomes possible through GIS mapping system in order to improve the yield and crop diversification and introduce collective harvesting for market trend and demand.

Output of GIS

After completion of above survey, several outputs have been producing on GIS mapping system as layer, polygon, line, point and attribute data for visual expression of site. The output map is shown below:

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Land Capability

Land Capability Classification (LCC) method developed by the United States Department of Agriculture (USDA) was used in the study to estimate different land capability classes in the watershed. This method provides information to farmers on the most appropriate use of the farm lands to obtain maximum benefits. The first four classes are arable lands with some limitations in soil conservation and crop management practices. Different soil mapping units in the watershed were evaluated for three levels of land capability classification such as order, class and sub-class for different land qualities such as soil texture, slope, drainage, depth, erosion hazard, and flooding hazard.

The deterministic land qualities like soil texture, soil depth, drainage, erosion, coarse fragments and flooding could be evaluated by using the FAO framework of land evaluation.

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Land suitability

Land Suitability means the fitness of a given Land Mapping Unit (LMU) for a Land Utilization Type (LUT), or the degree to which it satisfies the land user. In a more operational sense, suitability expresses how well the LMU matches the requirements of the LUT. It may be expressed on a continuous scale of ‘goodness’ (e.g. 0 to 100) or, more commonly, as a set of discrete classes, which are conventionally numbered from class 1 meaning ‘completely suited’ upwards to some maximum meaning ‘completely unsuited’.

To select the most suitable land utilization type (LUT) for each LU, the weighted linear

combination (WLC) formula (Voogd, 1983) is used:

In which S is the suitability score of a land use alternative for a defined LUP goal. This score is based on the standardized criterion score x and the priority weight W assigned to that criterion on basis of the chosen LUP goal. The alternative i will be judged better than alternative j’ if Si > Sj’. A land use scenario can be defined on the basis of one or more development targets. When multiple development targets are used to define a land use scenario, priority weights are assigned to the development targets (e.g. 25% weight for economic development, 75% weight for environmental conservation), and then the WLC can be applied for the alternative LUTs. For a given set of priority

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weights, the best alternative LUT for an LMU is the one with the highest final evaluation score.

Figure: Using GIS in Multi Criteria Evaluation for land use planning

Figure: Soil and land suitability for each LUT based on FAO land evaluation model.

Problems to be considered continuously

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Save cost and time

This GIS system is composed by many investigations and survey, consequently its setting up cost is increasing and taking time, and this cost might disturb dissemination to other site in Sri Lanka. Therefore, the contents of necessary investigations should be simplified and it needs collaboration work with many government organizations in order to acquire data resource effectively.

Local resource

Local resources should be utilized as much as possible in order to reduce cost and time.

Necessary accuracy

GIS itself, is precise and accurate tool, but in case of paddy field, it does not always need high allowable accuracy on the GIS map. Therefore, this concept should be kept in mind and look for local or conventional source map which can be utilized and combined with additional topographic survey.

The results demonstrate that the available RS satellite data in collaboration with soil survey data can be best utilized for agricultural development of an area with special reference to the mountainous areas, where acquiring the soil and land-use/land-cover data remains a difficult task. Multiple integration options in GIS are of immense use for data integration and overlay analysis to obtain better and faster results in judicious utilization and allocation of natural resources. It has been also found that the present land-use options can be changed to profitable ones for better economic returns and sustainable resource management of the given land, which could not have been possible through conventional land evaluation methods.

The process of land evaluation could be improved in several ways.

By involving local users in the plan formulation, so that their preferences and constraints are taken into account. This would include both the assessment of the impact of interventions by market or government, for example, and of inputs (input supply, extension, credit), as well as the economic, social and environmental outputs of the implementation of the land use plans.

Using existing data but changing the methods of data processing by the use of more flexible data processing methods.

By the optimal use and better integration of the existing data like remote sensed data and field data.

By a clear presentation of land evaluation and land use plans in non-technical terms (Bronsveld et al, 1994).

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CASE STUDY

In order to solve rapid population growth and urban expansion are turning land into a relatively scarce commodity problem, land evaluation and land use planning is necessary for the whole country in general, and for provinces and districts in detail. Geographic Information Systems (GIS) is one effective tool for land evaluation and land use planning. Geographic Information Systems (GIS) deal with information related to spatial distribution of features on the earth’s surface, and is designed to efficiently capture, store, update, manipulate, analyze and display all forms of geographically referenced information. Thus, nowadays, GIS is used widely as an effective tool for land evaluation throughout the world – including in Vietnam. In order to evaluate lands of district, the following maps have been compiled: soil map, present land use map, land unit map and land suitability map.. Compiling soil map are using for conduct a planned land evaluation, Present land use map was compiled using the land use map of 1995 as well as satellite images and aerial photos, Land unit map The following land characteristics have been used for compiling the land use map: Soil Types, Slope angle, Irrigation, Soil effective depth, Soil texture, Rainfall (mm/yr.), Land suitability map. In order to assess suitabilities, seven land use types have been used: Two rice crops, Rice crops +subsicrops, Subsidiarycrops, Noneirrigated Tea; none irrigated Coffee, Fruit tree, Forests. All maps at scale 1: 25,000 have been digitized and printed using computer and plotter in the Doan Hung district the obtained research results in land suitabilities of crops in Doan Hung district are summarized

and expressed in table1 (National Institute For Soils And Fertilizers, Hanoi)

Table 1. Recommended land suit abilities of Doan hung District

In Vietnam, land evaluation for land use planning and decision making in sustainable agriculture has benefited considerably from the effective use of GIS. Together with the adoption of FAO’s methodology and approaches of land evaluation, Vietnam’s land evaluation process in Vietnam has

progressively improved and developed. The set of maps, notably the land suitability map, completed for

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  Sum Area of suitability rating (ha)

Land use types (ha) S1 S2 S3

 87878  87878  87878  8787  778

1. Two rice crops 7,005.64 257.25 5,569.87 1,178.52

2. Rice crops + subsidiary crops

219.63 186.35 33.28 -

3. Subsidiary crops 1,163.69 915.74 224.59 23.36

4. Tea 5,236.52 1,342.70 2,480.94 1,412.88

5. Coffee 3,804.51

78-

1,071.39 2,733.12

6. Fruit trees 2,504.74 1,023.80 1,461.81 19.13

7. Forest 10,967.52

10,967.52

   

the Doan Hung District are proving a helpful database not only for decision-makers but also for farmers to help select the best crops for their lands.

Conclusion

GIS is capable of providing fast alternative solutions with relative ease. GIS not only enables a decision-maker to analyze a given situation but also provides opportunity to generate scenario pertaining to resource mobilizations of various management options. GIS is a common tool for land assessment, land use or land suitability assessment using several data layers such as land cover, topography, roads, weather, satellite imagery, soil, population etc.For a sustainable land use plan, land use planning (LUP) approachand data integration, multi-disciplinary and complex analysis, need faster or more precise information, Certainly, Geographic Information System (GIS), which is strong capacity in data integration, analysis, visualization,and becoming the main tool to land evaluation. Applications of a GIS-based information system shown the potential to make decisions with respect to natural resources more efficient and transparent. number of barriers that hamper GIS implementation, like lack of training in GIS and limited software and hardware resources in local institutions need to be overcome. However, lack of interest among key decision-makers to understand and use available information appeared to be the most limiting factor in establishing an operational GIS-based information system as an integral part of the natural resource management planning activities at the local level. The low response of the local institutions reveals and confirms the need to pay sufficient attention to issues of utilization of GIS in actual government in addition to issues of implementation.

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References

Trej- Enrique Ojeda,1995,Land Evaluation and GeographicalInformation Systems for Land UsePlanning, A Case Study of the Municipality of Texcoco, Mexico.

Land information bulletin,2000, Farmland Protection and GIS, Chesapeake, Pennsylvania State University.

N.H. Trung, L.Q. Tri, M.E.F. van Mensvoort and A.K. Bregt, 2006, Application of GIS IN LAND-USE PLANNING,2006, College of Agriculture, Can Tho University, Can Tho City, Vietnam.

Atesmachew Bizuwerk, Don Peden Girma Taddese andYasin Getahun ,2005,

GIS Application for analysis of Land Suitability and Determination ofGrazing Pressure in Upland of the Awash River Basin, Ethiopia, International Livestock Research Institute (ILRI), P.o.Box 5689. Addis Ababa, Ethiopia.

Eng.H.M.Jayatillake and Eng. Kenji YASUDA, 2006, SOME APPLICATIONS OF GIS IN TECHNOLOGY INFUSION AND PROMOTIONOF FARMERS PARTICIPATION IN IRRIGATION AND FARM MANAGEMENT

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Dr. Suwit Ongsomwang ,1995, Application of GIS in Forestry,in Geneva, Switzerland.

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