FloraPulse Crop Compatibility
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Olive

Validated

Compared against the pressure chamber over multiple seasons and sites. Solid enough to drive commercial irrigation decisions.

Performance

Recommended for experimental and commercial use. Favorable comparison with the pressure chamber.

Installation Tips

Known Issues

Research Library

The FloraPulse olive advisory engine draws on 50 sources — 34 peer-reviewed papers plus university extension, industry and vendor guidance. All 50 citations are verified — against the Crossref or DataCite registry, the live document, or by hand against the publisher's record — and marked ✓. Each entry notes the specific finding it contributes. See these sources in the research library, which spans every crop.

Questions this research answers

Peer-reviewed research (34)
  1. Ahumada-Orellana, L.E., Ortega-Farías, S., Searles, P.S. & Retamales, J.B. (2017). Yield and water productivity responses to irrigation cut-off strategies after fruit set using stem water potential thresholds in a super-high density olive orchard. Frontiers in Plant Science, 8, 1280. ✓
    Four seasons in a super-high-density Arbequina orchard in Chile. Cutting irrigation after fruit set until midday stem water potential reached -3.5 MPa, then rewatering through harvest, matched the fully irrigated control on yield, oil yield and fruit size while applying about 20% less water.
  2. Aybar, V.E., De Melo-Abreu, J.P., Searles, P.S., Matias, A.C., Del Río, C., Caballero, J.M. & Rousseaux, M.C. (2015). Evaluation of olive flowering at low latitude sites in Argentina using a chilling requirement model. Spanish Journal of Agricultural Research, 13(1), e0901. ✓
    Validated a chill-then-heat flowering model at eight low-latitude Argentine sites. Cultivar chilling requirements differ sharply - 'Arbequina' 339 chill units, 'Leccino' 612, 'Frantoio' 671 - and the model called normal-versus-failed bloom correctly in 92%, 83% and 61% of cases respectively.
  3. Berenguer, M.J. et al. (2006). Tree irrigation levels for optimum chemical and sensory properties of olive oil. HortScience, 41(2), 427-432. ✓
    Seven irrigation levels on super-high-density Arbequina I-18 in California's Sacramento Valley: more water lowered oil polyphenols, oxidative stability, fruitiness, bitterness and pungency, while the driest treatments gave harshly bitter oils; intermediate rates near 33-40 percent of ETc produced the most balanced oil.
  4. Calderón, R., Lucena, C., Trapero-Casas, J.L., Zarco-Tejada, P.J. & Navas-Cortés, J.A. (2014). Soil temperature determines the reaction of olive cultivars to Verticillium dahliae pathotypes. PLOS ONE, 9(10), e110664. ✓
    Controlled soil-temperature work: defoliating-pathotype infection was promoted at 16-24 C (61-75 F) in Picual and 20-24 C in Arbequina, and at 32 C (90 F) incidence, severity and vascular colonization all dropped sharply - explaining the spring/fall risk windows and summer remission.
  5. Caruso, G. et al. (2014). Effect of different irrigation volumes during fruit development on quality of virgin olive oil. Agricultural Water Management, 134, 94-103. ✓
    Over three years in a Frantoio orchard, irrigation volume barely moved free acidity, peroxide value or fatty acid profile, but strongly changed phenolics: fully irrigated trees gave oil with lower total phenols and secoiridoids than deficit- or complementary-irrigated trees. Deficit irrigation was the best yield-quality compromise.
  6. Casanova, L., Corell, M., Suárez, M.P., Rallo, P., Martín-Palomo, M.J. & Morales-Sillero, A. (2019). Bruising response in 'Manzanilla de Sevilla' olives to RDI strategies based on water potential. Agricultural Water Management, 222, 265-273. ✓
    In Manzanilla de Sevilla table olives, the RDI treatment with the highest stress integral (-3.5 MPa at pit hardening, normal late recovery) lowered pulp-to-pit ratio but left fruit weight and oil content unchanged, kept over 90 percent of fruit in commercial size grades, and bruised less than early rehydration.
  7. Daane, K.M. & Johnson, M.W. (2010). Olive fruit fly: managing an ancient pest in modern times. Annual Review of Entomology, 55, 151-169. ✓
    A review of olive fruit fly, the world's major pest of commercial olives. It covers the fly's biology, ecology and management, notes that organophosphate resistance in frequently treated populations has pushed growers toward other control options, and argues that several braconid parasitoids from its native range deserve study.
  8. Dag, A., Bustan, A., Avni, A., Tzipori, I., Lavee, S. & Riov, J. (2010). Timing of fruit removal affects concurrent vegetative growth and subsequent return bloom and yield in olive (Olea europaea L.). Scientia Horticulturae, 123(4), 469-472. ✓
    Stripping the crop off 'Coratina' olives by about 120 days after full bloom restarted shoot growth at once - new shoots grew twice as long as on later-stripped trees - and gave a full return bloom and high next-year yield, while late-stripped and control trees barely bloomed. Too few flowering sites is the primary driver of alternate bearing.
  9. De Melo-Abreu, J.P. et al. (2004). Modelling olive flowering date using chilling for dormancy release and thermal time. Agricultural and Forest Meteorology, 125, 117-127. ✓
    Compared three models for predicting olive bloom date across Spanish and Portuguese sites. A chill-then-heat model fit best (modelling efficiency 0.92, RMSE 2.2 days) and is preferred because it is physiologically meaningful. Under warming scenarios flowering advanced about 10 days, and in some varieties and years no normal flowering occurred.
  10. Denney, J.O., McEachern, G.R. & Griffiths, J.F. (1985). Modeling the thermal adaptability of the olive in Texas. Agricultural and Forest Meteorology, 35, 309-327. ✓
    Built a two-index climate model for olive, plotting the temperatures that induce flowering and fruiting against the temperatures that damage the tree. Applied to Oct-May daily max/min records from established olive regions and 15 Texas sites, it mapped a Texas olive thermal adaptability zone below about 350 m elevation.
  11. Erel, R., Yermiyahu, U., Yasuor, H., Ben-Gal, A., Zipori, I. & Dag, A. (2023). Elevated fruit nitrogen impairs oil biosynthesis in olive. Frontiers in Plant Science, 14. ✓
    Across a three-year container trial and a six-year commercial field trial, higher nitrogen fertilization raised fruit nitrogen and suppressed oil accumulation in the fruit, and the penalty was strongest on heavily cropping trees. Over-fertilizing an oil orchard with N costs oil content, not just fertilizer dollars.
  12. Fernandes-Silva, A.A. et al. (2018). Deficit Irrigation in Mediterranean Fruit Trees and Grapevines: Water Stress Indicators and Crop Responses. In Irrigation in Agroecosystems, InTech. ✓
    A review of deficit irrigation in Mediterranean orchards and vineyards, olive among them: it argues that deliberately holding trees at mild water deficit saves water with minimal yield penalty, and that doing this safely requires both a quantified crop water requirement and validated water-stress indicators with defined thresholds.
  13. Fernández, J.E. (2014). Understanding olive adaptation to abiotic stresses as a tool to increase crop performance. Environmental and Experimental Botany, 103, 158-179. ✓
    A review of the morphological and physiological traits behind olive's high tolerance of abiotic stress, and of its biennial vegetative and reproductive cycle; it shows how that understanding is being used to design more sustainable and efficient crop management practices.
  14. Girón, I.F., Corell, M., Martín-Palomo, M.J., Galindo, A., Torrecillas, A., Moreno, F. & Moriana, A. (2015). Feasibility of trunk diameter fluctuations in the scheduling of regulated deficit irrigation for table olive trees without reference trees. Agricultural Water Management, 161, 114-126. ✓
    A three-season follow-up in the same Manzanillo table olive orchard, holding deficit irrigation through pit hardening and rehydrating before harvest. Yield, fruit size and pulp:stone ratio were all maintained, and midday stem water potential tracked fruit drop and fruit size; the paper proposes about -2.2 MPa as a working threshold.
  15. Goldhamer, D.A. (1999). Regulated deficit irrigation for California canning olives. Acta Horticulturae, 474, 369-372. ✓
    In a four-year San Joaquin Valley trial on mature Manzanillo canning olives, mid-season (June-July) deficit irrigation that cut applied water about 25 percent below full ETc maintained fruit load, fruit size and fruit value; the most severe cut (about 44 percent) lowered gross revenue in a heavy on year.
  16. Grattan, S.R. et al. (2006). Olive oil production as influenced by different quantities of applied water. Agricultural Water Management, 85(1-2), 133-140. ✓
    In a super-high-density Arbequina orchard irrigated at seven levels, fruit yield rose with applied water but the share of oil extracted from the fruit fell linearly, so oil yield per area peaked over a broad range of applied water (about 40-89 percent of ETc in 2002) rather than at one precise level.
  17. Gucci, R. & Caruso, G. (2011). Environmental stresses and sustainable olive growing. Acta Horticulturae, 924, 19-30. ✓
    Reviews how olive copes with its main environmental stresses. The tree is resistant to soil water deficit, high irradiance, high temperature and high vapour pressure deficit, and more salt-tolerant than most perennial crops, but it is sensitive to low soil oxygen and to low temperature.
  18. Hartmann, H.T. (1953). Effect of winter chilling on fruitfulness and vegetative growth in the olive. Proceedings of the American Society for Horticultural Science, 62, 184-190. ✓
    Showed that olive needs winter chilling to bloom, not merely to grow. Potted trees held in a warm greenhouse through winter grew vegetatively but produced no flowers, while sister trees left outdoors bloomed normally, and flower and fruit numbers rose with the amount of chilling received.
  19. Iniesta, F., Testi, L., Orgaz, F. & Villalobos, F.J. (2009). The effects of regulated and sustained deficit irrigation on the water use, growth and yield of olive trees. European Journal of Agronomy, 30(4), 258-265. ✓
    Over three seasons on mature Arbequina in Cordoba, Spain, deficit treatments received only about 25 percent of the control's irrigation (65-70 percent of full ET) and sharply cut vegetative growth, yet oil yield fell only about 15 percent because deficit fruit had a higher oil concentration; regulated and continuous deficit performed the same.
  20. Johnson, M.W. et al. (2011). High temperature affects olive fruit fly populations in California. California Agriculture, 65(1), 29-33. ✓
    In California's Central Valley, olive fruit fly trap counts fall through mid and late summer and rebound from September to November, partly because of heat stress in mid-July and August. Adults die within days if they cannot reach enough water and carbohydrate, and may use black scale honeydew to survive hot spells.
  21. Koubouris, G.C., Metzidakis, I.T. & Vasilakakis, M.D. (2009). Impact of temperature on olive pollen performance in relation to relative humidity and genotype. Environmental and Experimental Botany, 67(1), 209-214. ✓
    Held olive pollen from four Greek cultivars for 24 h at 10-40 C with matching low humidity, then germinated it. The 40 C treatment prevented germination in 'Koroneiki' and 'Mastoidis' and left the other two at only 2-7.6%; 30 C already cut germination sharply (-65% in 'Koroneiki'). Heat tolerance at bloom is strongly cultivar-dependent.
  22. Lavee, S. (2015). Alternate bearing in olive initiated by abiotic induction leading to biotic responses. Advances in Horticultural Science, 29(4), 213-219. ✓
    Review of olive on/off physiology: developing fruit antagonizes shoot growth, so an ON year leaves fewer buds and fewer potential flower sites for the next; harvesting late sharply lowers return bloom; and controlled irrigation and nutrition reduce, but never eliminate, biennial bearing.
  23. Lodolini, E.M., Polverigiani, S., Ali, S., Mutawea, M., Qutub, M., Pierini, F. & Neri, D. (2016). Effect of complementary irrigation on yield components and alternate bearing of a traditional olive orchard in semi-arid conditions. Spanish Journal of Agricultural Research, 14(2), e1203. ✓
    Three seasons of complementary irrigation on a rainfed 'Nabali Baladi' orchard across a full on/off cycle: fruit and oil yield per tree beat rainfed only once irrigation passed 15 m3/tree (about 36% of seasonal ET), with the largest gain in the ON year; nothing carried over into the year after irrigation stopped.
  24. Maas, E.V. & Hoffman, G.J. (1977). Crop salt tolerance — current assessment. Journal of the Irrigation and Drainage Division, ASCE, 103(2), 115-134. ✓
    The original Maas and Hoffman salt-tolerance table gives olive (Olea europaea) a qualitative rating of moderately tolerant only - both the threshold salinity and the percent yield loss per unit of salinity above it are left as dashes, because the available data were not enough for a quantitative evaluation.
  25. Moral, J. et al. (2017). Identification of fungal species associated with branch dieback of olive and resistance of table cultivars to Neofusicoccum mediterraneum and Botryosphaeria dothidea. Plant Disease, 101(2), 306-316. ✓
    In surveys of olive branch dieback in southern Spain, Neofusicoccum mediterraneum was the most virulent fungus recovered and one of only two that reproduced the typical dieback and cankers; table cultivars differed in susceptibility. Cankered branches tolerate water stress poorly and conduct water and nutrients badly.
  26. Morales-Sillero, A. et al. (2021). Calcium applications throughout fruit development enhance olive quality, oil yield, and antioxidant compounds’ content. Journal of the Science of Food and Agriculture, 101(5), 1944-1952. ✓
    Foliar calcium chloride at 0.5 or 1.0 percent, applied at the end of fruit set, the end of pit hardening and before harvest, raised fruit calcium, improved the fruit's mechanical properties and increased pulp oil content and phenols such as hydroxytyrosol and oleuropein, with no phytotoxicity and no change in fruit shape or cuticle thickness.
  27. Moriana, A. et al. (2012). Midday stem water potential as a useful tool for estimating irrigation requirements in olive trees. Agricultural Water Management, 112, 43-54. ✓
    Irrigating on midday stem water potential alone (-1.2 MPa before massive pit hardening, -1.4 MPa after) matched water-balance scheduling on growth and on fruit and oil yield, with similar water applied, over three seasons at two Spanish sites; a -2.0 MPa deficit cut yield only in the young low-canopy orchard.
  28. Moriana, A., Corell, M., Girón, I.F., Conejero, W., Morales, D., Torrecillas, A. & Moreno, F. (2013). Regulated deficit irrigation based on threshold values of trunk diameter fluctuation indicators in table olive trees. Scientia Horticulturae, 164, 102-111. ✓
    Three seasons of regulated deficit irrigation in a mature Manzanillo table olive orchard near Seville, scheduled by trunk-diameter thresholds derived for a minimum stem water potential near -2.5 MPa, with rehydration before harvest. Yield matched the fully irrigated control, but fruit volume ran 14-20% smaller in the heavy-crop years.
  29. Moriana, A., Orgaz, F., Pastor, M. & Fereres, E. (2003). Yield responses of a mature olive orchard to water deficits. Journal of the American Society for Horticultural Science, 128(3), 425-431. ✓
    Four seasons on mature Picual olives in Cordoba, Spain: fruit and oil yield followed a curved response to seasonal crop ET, and sustained versus regulated deficit gave similar losses for the same ET deficit; concentrating the whole deficit in summer drove stem water potential to -7 MPa, with quick recovery in fall.
  30. Orgaz, F., Testi, L., Villalobos, F.J. & Fereres, E. (2006). Water requirements of olive orchards — II. Determination of crop coefficients for irrigation scheduling. Irrigation Science, 24, 77-84. ✓
    Gives a practical way to schedule olive irrigation: a monthly crop coefficient built by adding four parts - tree transpiration, evaporation of rain intercepted by the canopy, bare soil evaporation, and evaporation from the emitter-wetted area - so an orchard's water requirement follows from its tree density, canopy volume and reference ET.
  31. Santos-Rufo, A. & Rodríguez-Jurado, D. (2021). Unravelling the relationships among Verticillium wilt, irrigation, and susceptible and tolerant olive cultivars. Plant Pathology, 70. ✓
    Drip-irrigated 'Picual' and 'Frantoio' under daily, twice-weekly and mixed schedules: daily irrigation strongly accelerated Verticillium wilt onset and severity in susceptible Picual, tying disease pressure to irrigation frequency rather than to any saturation-hours threshold.
  32. Servili, M. et al. (2007). Irrigation effects on quality, phenolic composition, and selected volatiles of virgin olive oils. J. Agricultural and Food Chemistry, 55(16), 6609-6618. ✓
    On Leccino olives held to predawn leaf water potential targets, moderate deficit trees produced over 90 percent of the fully irrigated fruit and oil yield while severe deficit dropped to 61-76 percent; oil phenol content rose as predawn leaf water potential fell, and volatile composition shifted with tree water status.
  33. Vossen, P.M. (2007). Olive oil: history, production, and characteristics of the world's classic oils. HortScience, 42(5), 1093-1100. ✓
    A survey of world olive oil history, production, varieties and processing. On the horticulture it notes that the olive requires some chilling, tolerates hot dry conditions, dislikes moisture during bloom, and actually produces better with some stress - which is why it was traditionally planted on land where little else would survive.
  34. Wilcox, W.F. & Mircetich, S.M. (1985). Effects of flooding duration on the development of Phytophthora root and crown rots of cherry. Phytopathology, 75, 1451-1455. ✓
    Controlled flooding of cherry rootstocks in infested soil: biweekly floods of 8, 12, 24 and 48 hours took Mahaleb root rot from 6% (unflooded) to 15, 18, 65 and 99 percent respectively, with crown rot and seedling death only at 48 hours - the duration-response curve behind the 24-hour saturation rule of thumb.
University & extension guidance (16)
  1. Allen, R.G., Pereira, L.S., Raes, D. & Smith, M. (1998). Crop evapotranspiration — Guidelines for computing crop water requirements. FAO Irrigation and Drainage Paper 56. ✓
    FAO-56 Table 12 lists olive orchards at 40-60 percent canopy ground cover with Kc ini 0.65, Kc mid 0.70 and Kc end 0.70 and a mean maximum height of 3-5 m. A footnote offers Spanish monthly coefficients (0.45-0.65) for 60 percent ground cover as an alternative to the four-stage curve.
  2. CDFA FREP. California Fertilization Guidelines — Olives. ✓
    California guidance treats olive as a light nitrogen feeder: a crop removes roughly 4-8 lb N per ton of harvested fruit, and mature oil orchards are fertilized at about 40-100 lb N/acre/year, with rates adjusted so annual shoot growth stays between 8 and 20 inches and July leaf N between 1.5 and 2.0 percent.
  3. FAO. Annex 1: Crop Salt Tolerance Data. ✓
    FAO's crop salt-tolerance annex rates olive only qualitatively, as moderately tolerant: its woody-crop table gives no ECe threshold and no yield-decline slope for olive because the experimental data were judged inadequate. Most other fruit and nut crops in the same table are rated salt sensitive.
  4. Sibbett, G.S. & Ferguson, L. (eds.) (2005). Olive Production Manual (2nd ed.). UC ANR Publication 3353. ✓
    UC ANR's 180-page California olive production manual and the standard grower reference for the crop. It covers orchard planning and maintenance, pollination, pruning, deficit irrigation, mechanical harvest, postharvest handling and olive oil production, plus newer pests including the olive fruit fly.
  5. Snyder, R.L. & de Melo-Abreu, J.P. (2005). Frost Protection: Fundamentals, Practice and Economics, Volume 1 — Chapter 4, Frost Damage: Physiology and Critical Temperatures. FAO. ✓
    The FAO frost manual's fruit and vegetable table puts the highest freezing temperature of fresh olive fruit at -1.4 C. The chapter's crop-specific critical-damage tables cover almond varieties and field crops, not olive, so this fruit freezing point is the only olive-specific temperature the page supplies.
  6. Snyder, R.L. & de Melo-Abreu, J.P. (2005). Frost Protection: Fundamentals, Practice, and Economics. FAO Environment and Natural Resources Series No. 10. ✓
    FAO's practical frost-protection guide, written for growers rather than scientists. It covers the physics and biology of frost, the plant physiology of freeze damage and critical damage temperatures for a wide range of crops, passive and active protection methods, minimum-temperature forecasting, and whether active protection pays for itself.
  7. UC ANR. Pre-bloom Foliar Boron Application in Olive. ✓
    A foliar boron spray about three weeks before bloom can raise the share of perfect flowers, fruit set and yield in olive, with the benefit concentrated in OFF years and present even where leaf boron is not deficient. A California Manzanillo trial at 1-2 lb/acre Solubor improved yield by roughly 30 percent.
  8. UC Davis Olive Center. Olive production resources and variety information. ✓
    A university-based center for olives and olive oil that runs research, education and outreach aimed at quality, profitability and sustainability for California olive growers and processors, and points growers to the UC ANR Olive Production Manual for Oil.
  9. UC IPM. Black Scale — Olive Pest Management Guidelines. ✓
    Black scale builds up in dense, unpruned canopies, and its honeydew turns leaves black with sooty mold, cutting tree vigor and the following year's bloom. UC IPM leans on biological control plus pruning for open, airy trees, and rates infestation by counting adult scales on branch terminals in May.
  10. UC IPM. Olive Fruit Fly — Olive Pest Management Guidelines. ✓
    Olive fruit fly larvae feed only in olive fruit, and the rot that follows their tunneling is what ruins oil flavor. UC IPM advises hanging McPhail or sticky traps by March 1, then starting spinosad bait sprays when catches rise in early summer or at pit hardening when fruit reach about 10 mm.
  11. UC IPM. Olive Knot — Olive Pest Management Guidelines. ✓
    Olive knot incidence tracks rainfall, and the bacteria need a wound to get in - leaf scars, pruning cuts, or freeze-cracked bark. UC IPM treats it as a preventive problem: a minimum of two bactericide applications a year where incidence is high, plus dry-season pruning in July to August to cut out galls.
  12. UC IPM. Olive Psyllid — Olive Pest Management Guidelines. ✓
    Olive psyllid feeds on buds, flowers and small fruit, and heavy infestations can cost 30 to 60% of yield. UC IPM advises monitoring March through May and treating before the nymphs form the waxy coating that shields them from pesticides; loss can start above 6 to 8 psyllids per flower cluster in low-set years.
  13. UC IPM. Peacock Spot — Olive Pest Management Guidelines. ✓
    Peacock spot infects olive leaves in cool, wet fall and winter weather, and the resulting defoliation weakens the next bloom and cuts the crop; the fungus is inactive through California's hot dry summers. UC IPM advises a preventive treatment in late October before the rains, repeated in spring if wet weather persists.
  14. UC IPM. Phytophthora Root and Crown Rot — Olive Pest Management Guidelines. UC ANR Publication 3452. ✓
    UC IPM's olive guideline: Phytophthora needs free soil moisture to make and spread the swimming zoospores that infect roots and crowns, so frequent, prolonged saturation drives the disease; the species attacking olive differ in aggressiveness and moisture/temperature response. Management is cultural - drainage, berms, emitters away from the trunk.
  15. UC IPM. Verticillium Wilt — Olive Pest Management Guidelines. ✓
    There is no reliable control for Verticillium wilt once olives are planted, so UC IPM puts the decision before planting: avoid ground cropped to cotton, cucurbits, eggplant, pepper, potato, or tomato, and avoid soil holding more than one microsclerotium per gram. Microsclerotia survive at least 30 years.
  16. Vossen, P.M. Fertilizing Olive Trees. UC ANR. ✓
    Nitrogen is the only nutrient deficiency that is common in California olives, and over-fertilizing backfires by driving vigorous unfruitful shoots and lowering oil quality. Diagnose from July leaf samples: N is adequate at 1.5-2.0 percent and deficient below 1.4 percent; boron is adequate at 19-150 ppm.

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