The Project Manager requires a clear understanding on
who is responsible for what.
The following highlights some of the key aspects of a
greenhouse irrigation design to be dealt with early in
the project.
Water Supply
A system must be designed to take water from the
water source to head control / irrigation pump room,
where there is a bulk storage tank. A flooded suction is
essential in a greenhouse irrigation system. This supply
to the bulk tank is not necessarily carried out by the
irrigation designer.
This water supply includes:
Irrigation water - involving the agronomist
Service water
- involving the grower
Cooling water
- involving the greenhouse designer
Once the total flow rate is from these three is decided,
it cannot feasibly be changed later.
Water from the head control to the greenhouses
Having received the relevant information from the
grower and the greenhouse designer for the service
water and cooling water respectively, the systems to
take this water from the head control to the greenhouses are normally designed by the irrigation
designer.
The norms for the irrigation water supply are usually
based around a flow rate of 1,2 ℓ/m²/h (mm/h) comprising:
Crop water requirement
= 0,8 ℓ/m²/h
Leaching
= 0,4 ℓ/m²/h (33%)
Irrigation flow rate
= 1,2 ℓ/m²/h
The irrigation flow is the probably largest single contributing factor to the size and cost of the irrigation
design. It must be decided with reasonable accuracy as
it cannot feasibly be increased later.
Agronomy – Nutrition – Dosing unit
A common pitfall is getting the right fertiliser mixture
into F