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Agricultural planning, at the national level, is the most important application of the AEZ methodology. All developing countries have to develop policies that seek to provide sufficient food for their populations. Any shortfalls that occur have to be made up through food imports. Imports have to be paid for through the export of other commodities, such as non-food cash crops.
Many policies of this kind are based on an analysis of past performance, coupled to future production targets that planners believe can be met through appropriate development. The weakness of this approach is two-fold: first, the limits to production (what is and what is not possible) are usually unknown; and, second, scant account is taken of the concept of sustainable production.
Unless targets for agricultural production fall within the limits set by the soil and the climate, the result will be to 'mine' the country's agricultural resources- soil erosion and degradation being the inevitable result of over-ambitious policies. Decreasing productivity, malnutrition, hunger and human suffering soon follow. Countries should adopt a balance sheet approach to match present and future demands with resource potentials, identify required inputs and resolve competition between crops, livestock and forest.
The need for national AEZ studies
National AEZ studies can lead directly to improved land-use planning, and hence better sustainable crop production and quality, improved conservation, higher agricultural incomes and more efficient use of agricultural inputs. Inputs can be concentrated on areas of high potential and marginal land taken out of production and conserved.
AEZ country studies can provide the information needed to assess the limits of sustainable production. They can also be used to identify those areas in which development efforts will pay the highest dividends - in terms of food production, employment prospects and income generation.
The key questions that AEZ country studies can answer include:
• where are the potential food-deficit areas that cannot attain self-sufficiency?
• which areas, with high production potentials, could provide food for, or support people moving from, food-deficit areas?
• in which areas are population-planning programmes most urgently needed?
• which crops are best suited to the soil and growing conditions that exist in different parts of the country?
• what agricultural policies would make best use of a country's land resources?
• where are the best prospects for expanding production including cash crops?
• how, and how fast, should rainfed and irrigated land resources be developed in specific areas?
• what levels of farming inputs and soil conservation need to be developed to meet specific targets for sustainable self-sufficiency and crop exports?
• what are the future requirements for seed, fertilizer, pesticide and agricultural power to meet future population demands?
• how much production and land will be lost if adequate soil conservation programmes are not implemented?
• where do the research priorities lie and to which areas can current research findings be safely applied?
Some refinements are to be made to the AEZ methodology in order to undertake country studies. The land inventory needs to be more detailed, for example a 1:1 million scale soil map may need to be used in place of the 1:5 million map used in the original AEZ study. New 'rules' need to be formulated for the additional detail in the land inventory. The land inventory is also developed by administrative unit, i.e. by state, district or province. Nonagricultural land use can be accurately specified (the original study made a simple 0.05 ha/person deduction for :non-agricultural use), and requirements for fuelwood and timber taken into account. The crop list can be greatly expanded, to include additional food crops as well as non-food crops such as coffee, tea, sesame, tobacco and fuelwood.
Ten steps to national land-use planning
While these are modifications or expansions of steps already incorporated in the study of potential population-supporting capacities, country studies must also include a number of new steps: the likely level of inputs such as fertilizer and labour can be quantified, and the outputs from fisheries and from livestock production from crop residues can be included.
Country studies can be run with a range of different objectives. For example, a decision may be made to set specific targets for self-sufficiency and for the export of both food and non-food crops. This can be done on the basis of the crop potentials of different parts of the country.
Once these targets have been set, the model can be asked to select those crop mixes and input levels which will meet both targets. To do this, of course, requires additional inputs: assumptions about the future of overseas markets, and agricultural non-agricultural demand have to be made and fed into the program.
The flow chart on pages 26-27 outlines the basic elements of an AEZ country study. Because every country has different problems, each study will require different modifications to the original AEZ methodology. Fortunately, the latter is easily adapted to take account of changing requirements. At the beginning of 1990, country studies were in progress or had been completed in Bangladesh, China, Ethiopia, Malaysia, Kenya, Mozambique, the Philippines and Thailand.
Typical cost of a national AEZ study
The costs of a country study are considerably lower than many planners expect. The figures on the right are for a typical study and indicate the estimated expenses involved. Actual costs inevitably vary; depending mainly on the size of country and the amount and detail of information on soil, climate, irrigation, fisheries, forestry, labour, transport and other variables that is already available. These costs include the production of a number of specific outputs:
• an overall report;
• determination of potential production of food and cash crops;
• identification of degradation hazards and conservation requirements;
• determination of current rates of soil and productivity losses;
• computation of potential population-supporting capacities of administrative areas;
• identification of self-sufficient and deficit areas under differing input assumptions; and
• identification of the major constraints to food self-sufficiency and the alternative strategies needed to overcome them.
|
man-months |
computer and mapping costs (US$) | |
|
1. Identification of crops, inputs and other assumptions required in the assessment |
1 |
- |
|
2. Preparation of climatic inventory from long-term climatic records including variability |
5 |
15000 |
|
3. Computation of agroclimatic potential crop yields |
4 |
- |
|
4. Preparation of soil inventory from available national surveys |
6 |
15000 |
|
5. Soil ratings for specific crops |
2 |
- |
|
6. Overlaying climatic and soil inventories Compiling land resource data base Determining land potential for crop production |
3 |
50000 |
|
7. Including data from administrative areas on: population, fuel, irrigation, labour, fish, transport, cash crop requirements, etc. |
8 |
10000 |
|
8. Soil erosion and conservation inputs |
3 |
- |
|
9. Computation of potential population-supporting capacities |
3 |
15000 |
|
Quantification of degree of self-sufficiency by area | ||
|
10. Mapping of 9 Identification of constraints to self-sufficiency and strategies to overcome them Preparation of report |
6 |
15000 |
|
41 |
120000 |
|
41 man-months at $10000 |
410000 |
|
computer and mapping costs |
120000 |
|
TOTAL ESTIMATED COST PER COUNTRY |
$530000 |
Generalized agroclimatic suitability for rainfed groundnuts (high inputs)
Mozambique gets ahead
Mozambique was the first country to carry out a national AEZ study, under a UNDP-FAO project which began in June 1981. The assessment of the country's land resources suitable for rainfed crop production was published in 1982, and its policy implications are currently being analysed. These are likely to be especially valuable to Mozambique, where land and population resources are very unevenly distributed and where there is intense interest in agrarian reform.
The study was conducted on the province level, at a scale of 1:2 million, and dealt with eight crops at two input levels. The crops considered were cassava, cotton, groundnuts, maize, millet, sorghum, soybean and wheat. The methodology and software developed are suitable for detailed follow-up studies covering more crops at district and project levels.
The methodology closely follows the original AR study. Some notable departures include a more detailed assessment of suitability classifications in five classes: very suitable, suitable, moderately suitable, marginally suitable and unsuitable. This refinement was applied to the agroclimatic classifications, the soil assessment (which enabled soil constraints on crop production to be quantified more exactly; only three soil ratings were used in the original study) and to the land suitability classifications.
The principal findings of the study are summarized below, at the country level:
Percentage of land suitable* for production of crops
*includes all suitability classes except unsuitable.
|
Crop |
Low inputs |
High inputs |
|
maize |
28 |
34 |
|
sorghum |
31 |
37 |
|
millet |
32 |
40 |
|
wheat |
0.5 |
0.5 |
|
soybean |
25 |
31 |
|
groundnut |
32 |
40 |
|
cassava |
6 |
12 |
|
cotton |
7 |
23 |
Source: FAO,
Assessment of land resources for rainfed crop production in Mozambique. Rome, FAO, 1982.
Agroclimatic suitability map for groundouts in Mozambique. Five suitability classes were used in the Mozambique study compared to four in the original AEZ project
