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Agro-ecological cell (AEC). An area or point with a unique combination of land, soil, and climatic characteristics. The AEC is the basic processing unit for physical analysis in an AEZ study.

Agro-ecological zone. A land resource mapping unit, defined in terms of climate, landform and soils, and/or land cover, and having a specific range of potentials and constraints for land use.

Agro-ecological zoning (AEZ). The division of an area of land into smaller units, which have similar characteristics related to land suitability, potential production and environmental impact.

Agronomically attainable yield. The maximum yield that can be achieved by a given crop cultivar in a given area, taking account of climatic, soil and other physical or biological constraints.

Cropping pattern. The yearly sequence and spatial arrangement of crops or of crops and fallow on a given area.

Cropping system. A system, comprising soil, crop, weeds, pathogen and insect subsystems, that transforms solar energy, water, nutrients, labour and other inputs into food, feed, fuel or fibre. The cropping system is a subsystem of a farm system.

Database. An organized, integrated collection of data stored so as to be capable of use by relevant applications with data being accessed by different, logical paths. In theory the data are application independent.

Ecological-economic zoning. A kind of zoning which integrates physical land resources elements with socio-economic factors and a wider range of land uses in zone definitions.

Ecotype. A crop cultivar adapted to a particular range of climatic or soil conditions.

Edaphic requirement. A requirement of the crop for a particular condition or range of conditions in the soil environment.

Evapotranspiration. The combined loss of water from a given area over a specified period of time by evaporation from the soil surface and by transpira- tion by plants.

Farming System. A decision making unit, comprising a farm household, cropping and livestock systems, that produces crop and animal products for consumption and sale.

Geographical Information System (GIS). A system for capturing, storing, checking, integrating, manipulating, analyzing and displaying data which is spatially referenced to the earth.

Growing Period. The period of the year when both moisture and temperature conditions are suitable for crop production (see Text Box 2, p.8 for definition of types of growing period and growing period components).

Land equivalent Ratio (LER). The ratio of the area needed under sole cropping to one of intercropping at the same management level to give an equal amount of yield. LER is the sum of the fractions of the yields of the intercrops relative to their sole crop yields.

Land Utilization Type (LUT). A use of land defined in terms of a product, or products, the inputs and operations required to produce these products, and the socio-economic setting in which production is carried out.

Land evaluation. The assessment of land performance when used for a specified purpose.

Land Quality. A complex attribute of land which acts in a distinct way in its influence on the suitability of land for a specified use.

Land Characteristic. A property of the land that can be measured or estimated.

Land. An area of the Earth's surface. In the context of land evaluation, land includes all properties of the surface, soil and climate, together with any resident plant and animal communities.

Length of growing period (LGP). The continuous period of the year when precipitation exceeds half of Penman evapotranspiration plus a period required to evapotranspire an assumed soil moisture reserve and when mean daily temperature exceeds 6.5 �C.

Model. A simplified representation of a limited part of reality with related elements .

Multi-criteria decision analysis (MCDA). A set of techniques used to solve problems which involve several objectives being considered simultaneously. In the context of integrated land use planning and management, MCDA techniques are applied to analyse various land use scenarios considering simultaneously several objectives such as maximizing revenues from crop and livestock production, minimizing costs of production and environmental damage from erosion.

Phenological requirement. A crop requirement for certain environmental conditions to occur at times which are related to the crop growth cycle.

Population supporting capacity. Assessment of the number of people a given area can support, based on the nutritional output of the crop and livestock production systems.

Potential yield. The maximum yield that can be achieved by a given crop cultivar in a given area, based on radiation and temperature.

Production system. A particular series of activities (the management system) carried out to produce a defined set of commodities or benefits (produces).

Resource management domains. Regions designated for identical treatments, i.e. land development plans, nature conservation programmes, and classified on the basis of ecological-economic zoning.

Soil type. A specific unit of soil with definable ranges of characteristics. May correspond to the lowest hierarchical unit of a soil classification system, including specification of phase.

Soil mapping unit. An area of land delineated on a map. A soil mapping unit may consist either of a single soil type, or of multiple soil types occurring as a complex or association.

Stakeholder. An individual, community, government or NGO which has a traditional, current or future right to take decisions on land.

Sustainable land use. Use of the land that does not progressively degrade its productive capacity for a defined purpose.

Thermal regime. The amount of heat available during the growing period. Thermal regime can be defined either in terms of temperature or degree days.

References and further reading

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