The ability of land to produce is limited and the limits to production are set by climate, soil and landform conditions, and the use and management applied to the land. Accordingly, knowledge on land resource endowment and its potential is an essential prerequisite to planning of optimum land use and subsequent sound ‘long-term’ agricultural and economic development.
In particular, for planning optimum land use, answers are needed to the following questions:
- is there sufficient land to meet future food and agricultural needs?
- where are the potentially utilizable areas and what are their extents?
- for which land uses are they suitable and what is the range of their potential?
- which level of technology is required under these various circumstances?
- what is the risk of degradation and what measures are required to minimize the risk?
- where can maximum returns from increased inputs be obtained and on what land uses?
- what levels of investment are needed to obtain these returns?
- what are the limitations to production increases?
- where should research, extension and education efforts be concentrated?
Aware of these facts FAO began in 1976 the Agro-ecological Zones Project (AEZ, FAO 1978–81) to assess production potential of land resources in the developing world, and to provide the physical data base necessary for planning future agricultural development. Climate, soil and landform data were combined into a 1: 5 million scale land resources data base of about 91 000 unique agro-ecological cells. For each of these, crop requirements and crop growth models were applied to estimate rainfed yields and output at a range of levels of agricultural inputs.
This subsequently made it possible for FAO to undertake, with support from UNFPA, and in collaboration with II AS A, assessments of the potential population supporting capacities of 117 developing nations, grouped into five regions - Africa, South-west Asia, South-east Asia, Central and South America (FAO 1980, 1982). The methodology and the findings were discussed at the 1983 FAO Conference which, recognizing the importance of such work for development, recommended that future activities be concentrated at the national level (FAO 1984a).
The regional assessments, in effect, ascertained country situations within a regional context; the national assessments of land productivity and population supporting capacity are intended to quantify sub-national situations within national contexts.
The programme of work covered under the title: ‘Agro-ecological Land Resources Assessment for Agricultural Development Planning, a Case Study of Kenya’ is concerned with the development and implementation of a national level methodology for the determination of land use potentials of land resources in each of the 41 districts in Kenya, as a tool in policy formulation and development planning. This case study has been carried out by FAO and IIASA in collaboration with the Government of Kenya (FAO 1984b), and is part of the follow-up programme thrust to implement the 1983 FAO Conference recommendations.
The national methodology developed for Kenya is based on the principles fundamental to any sound evaluation of land. These principles are described in ‘A Framework for Land Evaluation’ (FAO 1976). The set of methods used in the compilation of the national land inventory as well as the land use productivity models, have followed the philosophy and concepts developed in the FAO-AEZ regional assessments of land and population potentials of land resources of individual nations (FAO 1978–81, 1982).
The main objective of the Kenya national assessment is to apply the methodology to quantify:
how much land of different quality is contained by each district in Kenya;
what alternative kinds of land uses can be considered on land of different qualities in different districts, and what are their productivity potentials at different levels of production inputs;
how many people can be supported at those different levels of production inputs, and at what costs; and
what are the policy implications of these land and population potentials for food and economic self-sufficiency, when examined against the background of present and future populations, food and agricultural demands, and socio-economic needs, opportunities and constraints.
All four above mentioned objectives are addressed through methods and techniques that can operate within Kenya for future use (and refinements) by national planners and experts.
This Main Report presents: (a) the 1:1 million scale computerized land resources data base of Kenya, and (b) the crop, livestock and fuelwood productivity models developed for the estimation of potential productivity of land resources. An overview of the methodology is presented in Chapter 2. The land resources data base is presented in Chapter 3, which is followed in Chapter 4 by the model to assess soil erosion hazard and its impact on productivity. Chapter 5 presents the crop productivity model, which is followed in Chapter 6 by the livestock productivity model. The report ends with the fuelwood productivity model which is presented in Chapter 7. The main report is supported by technical annexes which deal with details.
The technical annexes are:
