Agriculture Reference
In-Depth Information
Best-practice salinity management under irrigation involves
• Keepingthe
LR
aslowaspossible(≤0.1)byusinglow-
EC
water wherever
available.hismayrequireblendinggood-qualitywaterwithhigh-
EC
water.
• Usingsalt-tolerantrootstockswhenappropriate(see“Rootstocks,”
chapter5)
• Matchingtheapplicationofwatertothevines'demandasassessed
visually, from
ET
data, or by monitoring soil water status
• Monitoringdrainagesothat
LF
is as close as possible to
LR
(see
“MonitoringDeepDrainage”inthischapter)
Irrigation Methods
Irrigation methods for vineyards fall into two broad categories:
1. Microirrigation using drippers, microjets, or minisprinklers
2. Macroirrigation using overhead sprinklers, flood, or furrow systems
Topography and soil type influence the choice of system, as well as the availabil-
ity and price of water, the capital costs of installation, and the skill of vineyard staff.
Microirrigation systems are all under-canopy methods of applying water.
They offer the best means of accurately applying predetermined amounts at
known rates, targeted to specific areas with minimum losses. Hence, the effi-
ciencyofwaterusefrompumptotargetareacanbeashighas80to90%for
well-managed systems. Although easily automated and controllable by wireless
signals, these systems are the most capital-intensive.
Macroirrigationsystemsaretheleasteicient,rangingfromabout60%for
ixedoverheadsprinklerstolessthan50%forfurrowandloodsystems.helat-
ter tend to be found in older, established vineyards because of their low installa-
tion cost. However, they have become less viable with the increasing cost of water
(resultingfromscarcity)andbecausetheyaretime-consumingtooperate(and
hencehavehighlaborcosts).
Microirrigation Systems
DripSystems
Dripsystemsconsistofemitters(drippers)spacedatregularintervalsalonglex-
ible PVC pipes, usually suspended 0.3 to 0.5 m above the soil under the vines.
However, in an effort to save water, subsurface drippers are also being installed
