GAEZ - Global Agro-Ecological Zones
 


Agricultural Suitability and Potential Yields

For the assessment of rain-fed land productivity a water-balance model is used to determine the beginning and duration of the period when sufficient water is available to sustain crop growth. Soil moisture conditions together with other climate characteristics (radiation and temperature) are used in a robust crop growth model to calculate potential biomass production and yield. For the assessment of irrigated land productivity each crop growth cycle length is matched with the period with temperatures conducive for crop growth. The calculated potential agro-climatic yields are subsequently combined with a number of reduction factors directly or indirectly related to climate (e.g., pest and diseases), and with soil and terrain conditions. [...]

Agro–climatic yields

Agro–climatic yields

The constraint-free crop yields calculated in the AEZ biomass model reflect yield potentials with regard to temperature, radiation and moisture regimes prevailing in the respective grid-cells. The model requires the following crop characteristics: Length of growth cycle (days from emergence to full maturity); length of yield formation period; maximum rate of photosynthesis at prevailing temperatures, leaf area index at maximum growth rate; harvest index; crop adaptability group; sensitivity of crop growth cycle length to heat provision; development stage specific crop water requirements, and coefficients of crop yield response to water stress. Agro-climatically attainable yields were calculated at crop/LUT level for three input levels (high, intermediate and low) and three water supply system types (rain-fed, rain-fed with water conservation, and irrigation.

Climate yield constraints

Climate yield constraints

Apart from providing estimates of agro-climatically attainable crop yields the model provides information on the climate-related constraints affecting crop yields. These constraints include temperature constraints, moisture constraints, and yield constraints due to pests, diseases and workability. Crop water deficits (rain-fed conditions) or crop irrigation water requirements (irrigated conditions) are provided as model output.

Crop calendars

Crop calendars

The results of the biomass and yield calculation depend on timing of the crop growth cycle (crop calendar). For each grid-cell the starting and ending dates of each crop/LUT growth cycle are determined optimally to obtain best possible crop yields, separately for rain-fed and irrigated conditions. This procedure also guarantees adaptation in simulations with year-by-year historical weather conditions and allows major crop calendar shifts and adaptations under climate distortions applied in accordance with various climate change scenarios.

Agro-ecological suitability and productivity

Agro-ecological suitability and productivity

Adequate agricultural exploitation of the climatic potentials and maintenance of land productivity largely depend on soil fertility and the management of soils on an ecologically sustained basis. Soil fertility is concerned with the ability of the soil to retain and supply nutrients and water in order to enable crops to maximally utilize the climatic resources of a given location. The fertility of a soil is determined by both its physical and chemical properties. An understanding of these factors and insight in their interrelations is essential for the effective utilization of climate, terrain and crop resources for optimum use and production. From the basic soil requirements of crops, a number of soil characteristics have been established related to crop yield. For most crops and cultivars, optimal, sub-optimal, marginal and unsuitable levels of these soil characteristics are known and have been quantified. Beyond critical ranges, crops cannot be expected to yield satisfactorily unless special precautionary management measures are taken. Soil suitability classifications are based on knowledge of crop requirements, of prevailing soil conditions, and of applied soil management. In other words, soil suitability procedures quantify to what extent soil conditions match crop requirements under defined input and management circumstances. The agro-ecological suitability and productivity are presented for four input levels (high, intermediate, low and mixed), five water supply system types (rain-fed, rain-fed with water conservation, gravity irrigation, sprinkler irrigation and drip irrigation), at crop level (49 crops) for baseline climate (1961-1990) and future climate conditions. In addition comprehensive crop summary tables by administrative units are available for viewing and download.

Crop Suitability Index (mixed input level) Rain-Fed Wheat, Baseline period: 1961-1990

Crop Suitability Index (mixed input level) Rain-Fed Wheat, © Fao

Photogallery

Rice terraces. Indonesia. ©FAO/Roberto Faidutti / FAO
Dominant land cover pattern. GAEZ. ©FAO/IIASA
Input supply to vulnerable populations under the ISFP. Kenya. ©FAO/Sarah Elliott / FAO
Thermal zones. GAEZ. ©FAO/IIASA
Close up of apples, limes, oranges and tomatoes on sale at a local market in Nepal. ©FAO/Giampiero Diana / FAO
Aggregate crop yield in 2000. GAEZ. ©FAO/IIASA
Harvesting rice in east Java. Indonesia. H. Null / FAO
Dominant land cover pattern. GAEZ. ©FAO/IIASA
Flood recession rice fields. Cambodia. ©FAO/ Giuseppe Bizzarri/ FAO
Access Data Portal

Get Connected!
Twitter    RSS
Share me: