As the year 2050 approaches, the world population will reach 9 billion - so does the challenge
of doubling crop yields. To meet this crop yields demand, the associated dramatic improving
of water productivity (WP) must necessarily be accompanied by maximization of water use
efficiency (WUE) (Ragab 2011, UNEP 2014). In this work, a recently developed software
(IrriLab, https://www.facebook.com/irrilab) moving in this direction is presented. IrriLab is a
very simple toll allows to design microirrigation unit optimizing WUE, pressure energy and
irrigation unit costs.
Irrigation software available in commerce provide microirrigation system designs, by
mainly looking at the maximum flow rate uniformity criteria. Thus, each emitter installed
along the laterals operates with an operating pressure head occurring in between an
established range of pressure head variability (Dh < Dhadm). However, the latter condition
does not always corresponds to the cheapest and to the maximizing WUE solution; in fact, it
is not assured if the entire range of the admitted pressure head is profited and used by the
emitters. IrriLab allows this occurrence because, for the entire Irrigation Unit Area, IUA,
each design solution assures that at least two emitters rigorously operates, one with the
minimum admitted pressure head, and the other one with the maximum admitted (Dh =
Dhadm), (Baiamonte et al., 2015; Baiamonte, 2016). The same extreme values of
pressure head are those that in the common design criteria delimit the range of
pressure head, but without assuring their achievement. Compared to the common
design criteria, this condition i) for fixed laterals’ length and inside diameter, allows
reducing the inlet required pressure head whereas, ii) for fixed pressure head at the
inlet, provides an increasing in laterals and manifold lengths and in the associated
IUA.
Based on analytical solutions, IrriLab follows a very simple rectangular sketch, any way
oriented in the space, and defined by two slope values, one for the laterals and one for the
manifold. By considering the possible combinations of i) horizontal, downward or upward
sloped laterals and manifold, ii) the manifold position in respect to the laterals
and iii) the inlet position in respect to the manifold, which can be equal to 0%,
24% or 50%, in respect to their lengths (Baiamonte, 2016), IrriLab accounts for
25 optimal irrigation unit layouts, for each of them providing maximum WUE. |