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Chapter 5: Examples

5.1 General
5.2 Land uses and land qualities in Brazil
5.3 Smallholders, oil palm cultivation in Surinam
5.4 Land utilization types in Kenya
5.5 Location as a land quality

5.1 General

This chapter is intended to illustrate some of the concepts and procedures discussed in the earlier chapters.

Few completed land suitability evaluation have so far followed the full range of recommendations set out in the draft edition (FAO, 1973) of this Framework, but in several countries new procedures have been adopted and incorporated. Some results from Brazil, Surinam and Kenya are given below to illustrate important aspects of the Framework. The examples given include:

- descriptions of land utilization types to different levels of detail;

- descriptions of the structure and composition of land qualities;

- rating tables to determine land suitability for a given use from specified levels of land qualities or of their main component properties that can be measured or estimated; and

- a description of a land mapping unit with suitability ratings for different uses.

Although the form of these examples may be applied in other areas and circumstances, it should be noted that the actual data and ratings cannot be transferred to other environments or other land utilization types. They should be worked out specifically for a given climatic zone, social and economic context and land use.

In Brazil, an attempt was made to cover the main kinds of annual and perennial crop production by the summary description of six land utilization types. The main land qualities (termed agricultural soil conditions in the original report) are described and rated in terms of degrees of limitation, more or less independently of the uses. Suitability is then rated on the basis of the degrees of limitation of the land qualities for each land utilization type separately.

The example of this procedure, below, is summarized and adapted from Beek, Bennema and Camargo (1964). Later work in several other countries follows a similar procedure, rating land qualities without immediate reference to a specific use. In Sudan, for example, many land qualities are rated in detail. These are subsequently used in suitability classifications for a wide range of summarily described land utilization types (Van der Kevie, ed., 1976).

In Surinam, land utilization types are described in somewhat greater detail than in the previous examples, and the social and economic context is described in addition to technical specifications. The land utilization types are designed to explore a small number of promising alternatives in a given area of interest for development, rather than to give an overall estimate of land suitability for all possible main uses over large regions.

On the basis of the limited agronomic, social and economic data available, the land qualities required for a given use are listed, and the composition of these qualities is analysed. The land qualities are then rated to determine the suitability for the given use in terms of properties that can be measured or estimated.

The example of this procedure reproduced below is translated and adapted from Working Group on Land Evaluation, 1975. The section on social and economic context was based upon a manuscript by M. van Romondt and J.H. Kolader.

In Kenya, the characterization of the land utilization types was the subject of a special study. Several important land utilization types was the subject of a special study. Several important land utilization types were described in rather more detail than has been usual up to the present. One example of a description is given below, adapted from Luning, 1973. Quantifiable factors from the descriptions of all land utilization types are set out in Table 10 at the end of this chapter.

5.2 Land uses and land qualities in Brazil

The land suitability classifications from which the following examples are adapted were designed to provide an overall view of the suitability for some of the most important and widespread uses over very large areas in Brazil. Descriptions of land utilization types are broad, to encompass their variability over large distances.

5.2.1 Description of the Land Utilization Types

In Brazil, as in many tropical and sub-tropical countries, there is such a great variety in social, economic and technical conditions that almost every combination of management practices is represented. It has to be recognized that various levels of technological development will exist side by side for a long time. The existing Brazilian agricultural practices have been grouped into six land utilization types on the basis of their specific relationship with the land qualities. These six uses are basically different in their dependence on the land qualities. Each has different requirements from these qualities, and can therefore be limited in a different way by them, falling short of an optimal production. Each also has different possibilities to improve the land qualities to meet the requirements.

As a matter of fact, between these land utilization types there are important economic and social differences as well; however, in this study only the technical aspects have been considered. The six land utilization types, described below, deal only with crop production and not with forestry or animal husbandry.

i. A modern land utilization type, producing mainly annual crops. Intensive use is made of capital and there is a high level of technical knowledge. Management practices are carried out with the help of power-operated machinery. These practices include intensive drainage works, elaborate anti-erosion measures and intensive fertilizing when necessary. Also the other practices are based on power-operated machinery either self-driven or drawn by tractors (ploughing, sowing, planting, weeding, harvesting, transport, threshing, part of processing, etc.).

ii. A land utilization type with intermediate technology (in comparison to primitive agriculture), producing mainly annual crops. A restricted use is made of capital and the level of technical knowledge is reasonable. Draught power is provided by animals; the accompanying set of implements is lightweight and rather simple, but includes recently designed, efficient implements which are factory made. This set may include: cultivators, steel ploughs, harrows, fertilizer spreaders, sowing and planting machines intercultivating machines and threshers. Besides the yearly practices with the help of the above-mentioned implements, management practices include simple drainage works and application of fertilizer, although to a lesser extent than is possible in type i. The vegetation is generally cleared by burning, after which the roots are not removed.

iii. A primitive land utilization type, producing mainly annual crops with draught power provided by animals. No capital is used for soil management or improvement, the level of technical knowledge is low. The set of agricultural implements includes only the most simple, animal drawn implements a wooden plough with iron courter, seldom steel or iron implements. The farming practices depend on traditional knowledge. Only the Most simple drainage measures are taken, if necessary, and no use is made of fertilizers. The vegetation is cleared by burning, roots are not removed. Land use is rarely permanent as the land is abandoned for recuperation when yields decline markedly.

iv. A very primitive land utilization type, producing mainly annual crops, based upon hand labour only. No capital is used for farm or soil man agreement. The level of technical knowledge is low, management practices depend on traditional knowledge. The set of agricultural implements only comprises a few hand tools: spade, digging hoe, machete, knife, sometimes the sickle.
Due to the restricted power (only hand labour), the area which one far mer can cultivate is very small. Occasionally some primitive drainage works are executed.
The natural vegetation is cleared by burning, often only partially, bigger trees and stumps not being removed. Land use is seldom permanent
(shifting cultivation).

v. A technologically advanced land utilization type, producing tree crops. Intensive use is made of capital and there is a high level of technical knowledge. Machinery is very limited, since only clearing, spraying of insecticides, transport and perhaps processing need power-operated equipment, which still can be lightweight. In comparison to the cultivation of annual crops, erosion can be controlled more easily. On the other hand, protection against overflow is essential. Fertilizer use is common.
Sometimes part of the original vegetation is kept for protection of soil and crops, or trees or soil cover plants are planted for this purpose together with the tree crops. This practice may be part of this land utilization type, provided that the rest of the practices fit the description.

vi. A primitive land utilization type, producing tree crops. No capital is invested in soil management or improvement. The level of technical knowledge is low. Management practices depend on traditional knowledge. The set of agricultural implements is very restricted: spade, digging hoe, machete and knife. Clearing is not always done, usually only partly. Planting of tree crops in between the forest vegetation is a common practice. Farming depends on the natural fertility, the land is abandoned when production stops or when the yields become too low.

3.2.2 Example of a Land Quality: Limitations to Mechanization

Limitations to mechanization (use of agricultural implements) in Brazil depend on slope; absence or presence of stones or rocks; absence or presence of extreme shallowness of the soil, at least if underlain by consolidated material or by material unfavourable to being ploughed up; poor drainage conditions; and extreme constitution of the soil material, such as clayey texture with the presence of 2:1 layer silicate clays (often together with poor drainage conditions), or organic or loose sandy material. Microrelief may sometimes add an extra impediment such as frequent ant hills, termite mounds, or many gullies due to erosion. An area which has no impediments to mechanization should be larger than the defined minimum size to be considered. Small areas which have no impediments for mechanization, but are scattered among other areas which do not allow it can be neglected.

Degrees of limitation for mechanization are defined as follows:

i. None

Land on which in the greater part of the area all types of agricultural machinery can be used without difficulty during the whole year. Tractor efficiency (percent of tractor hours effectively used) is more than 90%.
This land has a level topography, with slopes less than 8% and has no other impediments to mechanization.

ii. Slight
Land on which in the greater part of the area tee majority of agricultural machinery can be used without, or with slight difficulty. Tractor efficiency 60-90%. This comprises land with:

- slopes of 8-20% with a topography which is gently undulating or sometimes hilly when no other impediments of a more serious nature are present. In this class, the use of power-operated equipment (tractors) is still possible. Contour cultivation will be necessary;

- level topography with slight impediments due to stoniness (0.05-1%), rockiness (2-1 010) or shallowness;

- level topography with slight impediments due to sandy texture, or clayey texture with the presence of montmorillonitic or illitic clays; heavy textured soils may also present a slight impediment due to lack of drainage or irregular drainage (compact soils with low permeability which can be very hard during the dry season).

iii. Moderate
Land on which in the greater part of the area only the lighter types of agricultural equipment can be used, sometimes only part of the year; draught power provided by animals. If tractors are used, their efficiency is less than 60%. This comprises land with:

- slopes of 20-40% with a topography which is usually hilly and without other impediments to mechanization of a more serious nature. Where ratings are for arable use, there may be frequent and deep erosion rills;

- slope less than 20% but with moderate impediments due to stoniness (1-15%), rockiness (10-25%) or shallowness;

- level topography with moderate impediments due to sandy texture? or clayey texture, with the presence of montmorillonitic or illitic clays; heavy textured soils may also present a moderate impediment due to lack of drainage or very irregular drainage (compact soils with low permeability, which are very hard during the dry season).

iv. Strong
Land which in most of the area can only be cultivated with the use of hand tools. This comprises land with:

- slopes of 40-70% in a mountainous topography, or a topography which may be partly hilly. Where ratings are for arable use, a pattern of frequent, shallow or deep erosion gullies may be present, being a strong impediment to the use of agricultural machinery;

- slopes of less than 40% with strong impediments due to stoniness (15-40%) rockiness (25-70%) or shallowness.

v. Very strong

Land which cannot, or can only with great difficulty be used for agriculture; no possibility for drawn implements or even hand implements. This comprises land with:

- slopes of more than 70% in mountainous topography and escarpments;

- slopes of less than 70% but with very strong impediments due to stoniness (more than 40%), rockiness (more than 70%) or shallowness or, where ratings are for arable use, a pattern of frequent shallow or deep gullies.

Table 4 DEGREES OF LIMITATION FOR MECHANIZATION (USE OF AGRICULTURAL IMPLEMENTS) IN BRAZIL

1/ In the case of impediments due to rockiness and stoniness.

5.2.3 Suitability Description of a Land Mapping Unit

Rhodic Ferralsols, cerrado (savanna) phase
Furnas area, Minas Gerais State

Degrees of limitations: fertility strong; water deficiency slight; excess of water - none; erosion slight; impediments to mechanization - none.

Suitability for land utilization types 1, 2 end 5: S2; for 3, 4 and 6: N. Suitable for extensive grazing.

The main limitation is the low fertility, which may be corrected in uses 1, 2 and 5. This correction implies much knowledge if it is to be total, but it is easily feasible if the correction is partial. With development in research and extension services, this land may in the future be classified as S1 for uses 1, 2 and 5.

The limitation of fertility is strong, which implies that crop production without the use of fertilizers (uses 3, 4 and 6) is, in general, practically impossible. The natural vegetation may be used for extensive grazing, however, while the formation of artificial pastures is also possible.

This example is representative of many Ferralsols with cerrado (savanna) vegetation in Brazil. Sometimes the deficiency of water is moderate instead of slight, or the limitation of fertility very strong. This difference in water deficiency does not affect the classification at this moment. If, however, with the development of research and extension, the improvement of fertility becomes easy, the soils with a moderate limitation for water deficiency will generally remain in class S2, and not change to S1, as in the case of the example.

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