To determine the irrigation requirements, the user capture an
area, farm, field and crop to
reflect the area that he works
in. See figure 2. Provision is
made that back-wards summation from crop irrigation requirement to field, farm and
area irrigation requirement. The
efficiencies of irrigation water
reticulation systems at different
levels are included in this calculation.
Figure 2: Capturing of data to
determine irrigation requirements
The crop for which irrigation
requirement needs to be estimated (see figure 3), is defined
in terms of weather stations
and climate, soil type, irrigation system, planting date, foliage cover, yield, area planted
and irrigation management
strategy. For year-on-year irrigation requirement estimates,
subsets of the weather data,
such as a period that is known
to have had a below average
rainfall, can be selected.
Figure 3: Capturing of crop
data
The results are graphically displayed (see figure 4) as crop
coefficient, evaporation, and
crop evapotranspiration as well
as soil water content over the
growing season.
Figure 4: Graphical display of
outputs