note that, in favourable open field conditions, Kc values in
many cereals are generally between 0.3 and 1.2, however, they are
strong influenced by age and the growth stage of the plant. In our
research, it was not possible to compare Kc values with those
provided by the FAO, as these latter were obtained in extremely
different growth conditions, and also considering the fact that we
used an inert substrate, we used wastewater as a nutrient and we
calculated ETc using a continuous flow of subsurface water.
However, despite the different environmental conditions during
the test and the use of 5-year plants, Kc trends for both species
were found to be similar to those found in traditional, open field
crops during the various growth stages. Furthermore, there was a
certain increase during the initial growth stages, peaking during
the mid-season stage. These values then fell during senescence,
with minimum values recorded during plant harvesting. This
pattern was identical for both years and can be explained if we
consider the harvesting period, which was always in November.
This allowed the plants to recover vegetative activity immediately,
in both years, at the beginning of spring and allowed for maximum
growth during the summer month