WHY IS IRRIGATION IMPORTANT?• Avocadosarenativetothehumidsub-tropicalandtropicalregions

ofcentralandnorthernSouthAmericawhererainfallisabundant• InCaliforniaavocadosaregrowninanaridMediterraneanclimate

withalowrainfall• Forbestgrowthandyieldsavocadotreesneedaminimumamount

ofwatereachyear,approximately40-50inchesofrain• Alackofwatercanreduceyields• Irrigationcanbethegreatestcostofproductionsoneedstobe

usedasefficientlyaspossible• Theexactamountofwaterdiffersforeachgroveduetodifferences

insoiltype,micro-climatetreesizeandhealth,andtheaspectofthegrove

• Theavocadotreedoesnotsearchforwaterthereforewaterneedstobeprovidedtothetreesattherighttimes

• Moistsoilsareneededtosupportthelargenumbersofrootsneededforhealthytrees

• Mostoftheavocadorootsareinonlythetopsixinchesofsoilandareunderthecanopyouttothedripline

• Thesoilwheretherootsareispronetodryingout

Disclaimer: All care has been used in compiling this fact sheet. The California Avocado Commission accepts no liability for commercial or personal loss when using the provided information.

WHEN TO IRRIGATE:• Beforethetreesbecomewaterstressed• Atkeyphenologicaltimeslikefloweringandfruitsetfollowedbytherapidfruitgrowthphase• Decidingwhentoirrigatecanbedoneusingweather-basedmethods,soil-basedschedulesorafixedfre-

quencyeverysomanydays• Oftenthedepthofirrigationmatchesthelocationoftheavocadoroots• Tocalculatetheamountofwaterandthebestirrigationscheduleforyourgrove,theCIMISsystemcanbe

usedtocalculatethedailywateruse• AccessCIMISthroughthewebsite:wwwcimis.water.ca.gov/cimis/welcome.jsp• Tofurtherrefinetheamountofirrigationwaterneededforyourgrovemeasurethesoilmoisturedirectly

thenmakeadjustmentstotheCIMIScalculations

Irrigating AvocadosAvoFacts 5

1

• Properlymaintained12”and24”tensiometerscanbeausedfordirectsoilmeasurementtorefinewhentostartirrigatingandtoseeifyouareoverirrigating

• Dependingonthesoiltypeirrigationcangenerallystartwhen12”tensiometersread25-30centibars,earlierifthesoilisverysandyandlaterifthesoilhashighclaycontent

AvoFacts 5

2

FURTHER READING:Avocado Growers Handbook, Frank D. Koch,1983.Irrigation and Mineral Nutrition, E. Lahav and A.W. Whiley, TheAvocado:Botany,ProductionandUses,2002,CABInternationalPublisher

Irrigating Avocados

HOW TO APPLY THE WATER:• Theefficiencyoftheirrigationsystemisimportant,aimforabout80%efficiencywithahighdistribu-

tionuniformity• MostCaliforniagrowersuseundertreeindividuallow-volume

sprinklersforhighdistributionuniformityandtominimizeover-wettingthesoilpotentiallyspreadingrootrot

• Manygrowersirrigatein24hourincrements• Thedesignofanirrigationsystemisajobforaprofessional,

seekadvicewhendecidingwhatirrigationsystemtoinstall

SAVING WATER:• Capoffsprinklerstodiseasedanddamagedtrees• Stumpcanopiedtrees• Thincrowdedgrovesbeforetheycanopyover• Top-workoverfromanundesirabletoadesirablevariety• Applymulchandremoveweeds• Keepskirtslowonthetrees• Checkandrecheckyourirrigationsystemforleaksandmeasure

thesprinkleroutputasmeetingdesignspecifications

HOW MUCH WATER TO USE:• OverirrigationoftenoccursinCaliforniaavocadoorchardswhichwastesgrowersmoneyandcanbe

harmfultotreehealth• Avocadorootsaresensitivetowaterloggingwheretheycandrown• Differentsoilsneeddifferentamountsofwaterassandysoilsholdlesswaterandhavelesslateralmove-

mentofwaterthanclaybasedsoils

• Uselesswateronsickordefoliatedtreesastheyhavesmallerrootsystemsthanhealthytrees• Takecarenottoirrigatefortoolongonslopesorthereisariskofwashingsoilaway• Largeandsmalltreesrequiredifferentamountsofwater,enoughwaterforalargetreewithagoodlayer

ofmulchcanbelessthanforasmalltree