Land Evaluation for Extensive Grazing
The main goal of these guidelines is to provide a methodology for implementing in agricultural systems based on extensive grazing the key principles of the Framework for Land Evaluation (FLE): (1) matching the requirements of the land use against the qualities of the land, (2) comparing alternative sustainable uses, and (3) multidisciplinary approach. Similar guidelines have been prepared by FAO for rainfed agriculture, irrigated agriculture, and forestry.
Extensive grazing is the predominant form of land use on at least a quarter of the world’s land surface, in which livestock are raised on food that comes mainly from rangelands. Evaluation for extensive grazing is in a special category because, unlike that for cropping or forestry, it must take into account the production of both grazing forage, termed primary production, and the livestock that feed on this forage, termed secondary production. Extensive grazing also differs from intensive grazing, in which the animal feed comes mainly from artificial, seeded pastures and not from unimproved rangeland.
Chapter 1 introduces the types of livelihood systems that depend on extensive grazing, and the objectives and scales of land evaluation for extensive grazing.
Chapter 2 explains the basic principles and concepts used in land evaluation: land use (major land uses, land utilization types), land (land qualities and characteristics), land suitability and suitability classification (structure, subdivisions, types of classification).
Chapter 3 gives an overview of themain steps involved in a land evaluation exercise for extensive grazing: (1) planning the evaluation, (2) studies of the relevant land utilization types, (3) determination of the land use requirements, (4) studies of the land units, (5) collection of economic and social data, (6) matching land use requirements with land qualities or characteristics, (7) social and economic analysis, and environmental impact assessment, (8) land suitability classification, (9) presentation of results, (10) converting recommended land uses into a land use plan. Each step is explained in more detail in the following chapters 4-11 and 13.
Chapter 12 describes an approach for modeling livestock productivity and population supporting capacity. The livestock productivity model consists of five steps: (1) estimation of primary productivity; (2) characterization of livestock systems; (3) determination of herd performance; (4) estimation of feed requirements; (5) quantification of secondary productivity.
The model for assessing the population supporting capacity serves to determine how many people can subsist on land used for extensive grazing and is based on the output of a land evaluation study, in physical, financial and economic terms, using the results from the livestock productivity model.
Annexes to this publication contain useful information on conversion of different types of nutrients and amounts of animal feed into use of energy and conversion of animal species weights into livestock units.