Crop cultivation potential describes the agronomically possible upper limit to produce individual crops under given agro-climatic, soil and terrain conditions and applying specific management assumptions and agronomic input levels. Soil moisture conditions together with other climate characteristics (radiation and temperature) during different crop development stages are used in an eco-physiological crop growth model to calculate potential biomass production and yield. The constraint-free crop yields calculated in the AEZ biomass model reflect yield potentials with regard to temperature and radiation regimes prevailing in each grid-cell. Maximum biomass and yields depend on the timing of the crop growth cycle (crop calendar) and are separately calculated for irrigated and rain-fed conditions.

Crop specific requirements are matched with temperature regimes prevailing in individual grid-cells. Matching is tested for the full range of possible starting dates. For rain-fed conditions the crop calendar resulting in the highest expected (water-limited) yield is selected to represent maximum biomass and agro-climatic potential yield of the respective crop in a particular grid-cell. The estimation of yield losses due to water stress is based on crop-specific water balances. Yield estimation for irrigation conditions assumes that irrigation is scheduled such that no yield-reducing crop water deficits occur during the crop growth cycle.

Differences in crop types and production systems are empirically characterized by the concept of Land Utilization Types (LUTs). A LUT comprises technical specifications for crop production within a given socioeconomic setting. Specific LUT attributes include agronomic information, type of the main produce, water supply type, information on typical cultivation practices, and utilization of main produce. GAEZ v4 distinguishes more than 300 crops/LUTs per level of inputs/management, which are separately assessed for rain-fed and irrigated conditions. These LUTs are grouped into 67 crop sub-types and 53 different food, feed, fiber, and bio-energy crops.

Theme 3 provides crop-wise information about: (1) Agro-Climatic Yield, (2) Constraint Factors, (3) Growth Cycle Attributes, and (4) Land Utilization Types (LUT) Selection.

GAEZ methodology development, data base compilation, production of results and establishing the Data Portal were accomplished in close technical collaboration and with inputs of the International Institute for Applied Systems Analysis (IIASA).

For further details, please refer to the GAEZ v4 Model Documentation.