There is today a high demand worldwide for information on the suitability of land for a wide range of land uses. This demand comes from farmers and other rural land users, farmer cooperatives, banks and other lending agencies, planning offices, government ministries, and rural and urban development officers. The intent of the individual land user is to optimize the use of their land. The intent of the agencies is to plan or recommend the uses of land in a rational and equitable way, using the techniques of land use planning, primarily for agricultural development. Recommendations and plans must usually be made quickly, in response to actual needs and current conditions.
Land use planning has as its basic purpose to ensure that each area of land will be used so as to provide maximum social benefits, especially including food production, without degradation of the land resource. Planning has two aspects: the politicaland the rational. The political process is necessary to initiate and carry out land use planning, to set its objectives, and to arbitrate among competing interests. The rational, or technical, part of planning ensures that plans are feasible, that cost and return estimates are accurate, and that sufficient data have been collected and collated to ensure these. While the political aspect of land use planning is outside the scope of the land evaluator, clearly the expert knowledge of the agronomist, the production agriculture specialist, and other agriculturalists, must form the basis of correct land use planning in its technical aspect.
There are many sources of knowledge about land and land use. Even in less developed countries, there is often adequate information, such as soil surveys, about land resources, and much of this information is of high quality. Also, there is often a lot of information about the relation between land and land use. Much of this information is local, acquired over years of experience by local agriculturalists as well as farmers. Often there has been relevant work at local experiment stations, or in other areas with similar environments. Each of these sources of knowledge is expressed differently, published (or not) in diverse locations, and held by different people.
The aim of ALES is to allow agricultural scientists to present natural resource information in a form that is directly useful to land use planners. Our method was to write a computer program to be used by agriculturalists, with the results of the program to be presented to land use planners. The program is designed to allow contributions from all relevant sources of knowledge.
A further objective is to use the large quantity of information that has been recorded to date in soil surveys and other land resource inventories, much of which is sitting unused on office shelves. There are a variety of reasons for this disuse, primary of which is that the surveys are not interpreted for various land uses, and secondly that surveys have widely different definitions of map units and land characteristics. So a major design objective of ALES is to allow the use of land data in almost any format, as well as easy interchange of computer-readable data with national soils databases and similar repositories of land data.
This work is especially intended for application in less developed countries, since the opportunities for planning are greater there than in the developed countries. Planning implies a willingness to change, and in countries with developed agriculture, change is usually at the farm level, not involving larger-scale planning. Further, the need for change in agriculture is greater in those countries that can not feed themselves, provide meaningful occupations to their rural populations, or generate sufficient exports to stimulate their economic development.
However, ALES is certainly applicable to many problems in developed countries. Examples are defining prime farmland for agricultural land preservation laws or other rural zoning, arriving at assessments of agricultural potential for taxation or land valuation, and performing soil survey interpretations. These countries usually have well-established soils databases, from which data can easily be imported into ALES; conversely, results from ALES can easily be exported to programs that perform further computations such as land valuation.
The ALES project was the outgrowth of the interests of Professor Armand Van Wambeke of the International Soils Group at Cornell, to make soil survey and other natural resource inventory information more useful to those responsible for land use decisions. This followed several years of work in the International Soils Group on the adequacy of soil resource inventories. The project was initiated in summer 1987 with the hiring of David Rossiter to design and implement an automated land evaluation software.
The FAO land evaluation methodology seemed to provide a useful starting point, being based on many years of expert consultation. However, methods based on the FAO methodology are involve many repetitive calculations or table lookups, and so are tedious if many alternatives are to be compared. Manual procedures, both for construction of matching tables or similar methods, and for calculation of suitability, are time-consuming and error prone. Hence an automated procedure seemed like a natural development, and indeed there had been a few previous efforts in this direction, most notably the LECS system in Indonesia (Wood & Dent 1983, Purnell 1987). However, this successful system was developed for a specific area of the world and for a specific set of land uses, and requires a specific set of data. ALES, by contrast, is applicable to any area and any set of land uses; of course the evaluator must build a model and database for each situation.
We have attempted make the FAO methodology more widely applicable by making it available as a microcomputer program to individual development projects. We have also incorporated a definite method of economic land evaluation. Consistent with the 'small is beautiful' philosophy of the project, we hoped to allow evaluators to use locally-available knowledge and data in a flexible model framework. Finally, we wanted a fun, easy-to-use computer program, which would make the task of developing, refining, and testing land evaluation models as enjoyable as possible.
ALES has gone through several major revisions since 1987, with improvements in the areas of:
Page author: D. G. Rossiter
Last modified: Mon Mar 23 09:51:35 EDT 2020