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Software for Irrigation Water

MABIA-REGION integrates various complex model components for the purposes of water balance modeling throughout crop development cycle.
These components are modules for calculating the daily soil water budget, potential and actual evapotranspiration, and yield loss based on the dual crop coefficient (Kc = Ke + Kcb) method of the FAO Irrigation and Drainage Paper No.
56 (FAO-56) which is intended to improve daily simulation of crop ET by considering separately the contribution of evaporation from soil..
Many extensions are added to the original FAO procedures and therefore integrated in the model. Two extensions to the evaporation calculation procedure are intended to improve the accuracy of the estimated soil evaporation component. The first extension uses parallel water balances representing the portion of the soil surface wetted by irrigation and precipitation together and the portion wetted by precipitation alone. The second one integrates the extraction of the transpiration component from the soil surface layer.

The water balance used in MABIA

Different options to estimate ETc

Besides, the natural resources conservation services curve number (NRCS-CN) method is added for quick and accurate estimation of surface runoff.

Different options for calculating Run-Off

Furthermore, to express the combined effect on yield of water deficiency at time steps smaller than growth stages (e.g. daily steps) the multiplicative approach (Jensen, 1968) which is based on the use of the Ky coefficient, is added.
This model was built to be as much flexible as possible, regarding the Climate, Soil, Crop and Irrigation inputs which could be hard to define by farmers. Therefore, two databases with a list of crops and soils that include all the required parameters are added. Furthermore, to minimize the impact of the lack of agro-climatic data at field scale, the tool include in addition options for choosing (i) different methods to estimate reference evapotranspiration (ETo) depending on climatic data availability and (ii) different hydraulic pedotransfer functions to estimate soil water characteristics depending on the availability of data about physical soil components.

Option to choose the readily available climate data to estimate ETo

Also, the software offers a choice of one or more irrigation scheduling criteria (fixed depth, fixed interval, variable depth and variable interval) according to water availability at field level.

Different irrigation scheduling criteria

The MABIA-REGION performs the soil water balance simulation using a daily time step, and can be applied either at a field level or at a regional level allowing the assessment of regional water irrigation requirements, through the integration of a GIS module (GISmod). GISmod facilitates GIS-based simulation projects by using polygons that are automatically derived or that could be derived from MapWindow® or Arc/Info® GIS. Each polygon represents a field block fragment. MABIA-GIS generates a new polygon attribute table of MABIA-REGION output variables, which is used to produce maps of the different outputs.

Real Shapefile for an irrigation district imported into MABIA-Region