Agriculture Reference
In-Depth Information
Table 4.7
Advantages and Disadvantages of Drip Irrigation
Advantages
Disadvantages
Waterappliedtoindividualvinescanbeclosely
controlled; particularly suited to regulated
deicitirrigationandpartialroot-zone
drying.Withfrequentapplication,soil
watercontent(andsuction)ismaintainedin
a narrow range.
Suspendedsediment,chemicalprecipitates,
or microbial growths may cause blockage
ofemitters,ascanrootinvasionforSSDI;
frequentlushinghelpstopreventthis.
Vacuum relief valves should be installed at
the head of the system and at high points
along the laterals.
Littlelossbysoilevaporationandrunof
(especiallyforSSDI),becauseareaofwet
soil is small and rates of application are low;
no foliar salt damage as is possible with
overhead sprinklers.
Saltaccumulatesattheedgeofthewetted
zone,especiallyifthereisinsuicient
winterraintoleachsalts(moreserious
withwater>0.8dS/m).
Lowdrainagelosses(hencelowlossof
nutrientsandpotentialcontaminants),
especially if drainage is monitored.
Rodents, other mammals, and birds seeking
water can damage the soft, flexible pipes
(notaproblemforSSDI).
Targetedfertilizerapplicationbyfertigation
(see“NitrogenCycling,”chapter3).
Lessefectivecontrolofvinemicroclimate
than with overhead sprinklers, which can
be used to avoid frost damage to vines at
critical times.
Allows use of water of greater salinity than with
overhead sprinklers or flood/furrow systems
(whereirrigationislessfrequentandthesoil
driesbetweenapplications).
More expensive to install and maintain than
gravity-flow flood and furrow systems.
Wastewatercanbeusedbecausechanceof
pathogens contaminating foliage or fruit is
minimal(noneforSSDI).
Wastewatermayneedtobetreatedtoahigh
standard to prevent excessive bacterial
growth and blockages.
Lowoperatingpressures(100-200kPa)mean
low pumping costs; restricted weed growth,
especiallywithSSDI,andnoconstraintson
access because of wet soil.
Effective on marginal soils and in difficult
topography(stonysoils,steepslopes)
Note.
SSDI=subsurfacedripirrigation.
In frost-prone areas, overhead sprinklers can be used to raise humidity in the
vineyard and provide a water film on leaf surfaces when a frost is likely. The high
heatcapacityofwaterandthelatentheatreleasedasitfreezeshelptopreventleaf
temperaturesfallingbelow0ºC.Figure4.29showsanexampleofoverheadsprin-
klers in operation in a vineyard in the high-altitude Rueda district of Castilla y
Leónregion,Spain.
