Crop yield response to water - Cra

FIGURE 8 A soil profile with more than one soil horizon and 12 soil compartments. The total number ofcompartnents remains always 12, regardless of the number of horizon (varying from 1 to 5).Soilhorizon 1Soilhorizon n123456789101112Soil compartmentscompartments are divided into a number of cells where salts can be figuratively stored. A cellis a representation of a bundle of pores with a specific diameter. The driving force for thehorizontal diffusion is the salt concentration gradient that exists between the water solutionin the cells at a particular soil depth. To avoid the building up of high salt concentrations ata particular depth, vertical salt diffusion is also taken into account. The driving force for thisvertical redistribution process is the salt concentration gradient that builds up at various soildepths in the soil matrix.The managementAquaCrop encompasses two categories of management practices: the irrigation management,which is quite complete in its various features, and the field management, which is limited toselected aspects and is relatively simple in approaches.Irrigation managementHere options are provided to assess and analyse crop production and water managementand use, under either rainfed or irrigated conditions. Management options includethe selection of water application methods (sprinkler, surface, or drip either surface orunderground), defining the schedule by specifying the time, depth and quality of theirrigation water of each application, or let the model automatically generate the schedulebased on fixed time interval, fixed depth per application, or fixed percentage of allowablewater depletion. An additional feature is the estimation of full water requirement of acrop in a given climate.AquACrop: ConCepts, rAtionAle And operAtion 29