Potential of Deficit Irrigation, Irrigation Cutoffs, and Crop Thinning to Maintain Yield and Fruit Quality with Less Water in Northern Highbush Blueberry

Drought and mandatory water restrictions are limiting the availability of irrigation water in many important blueberry growing regions, such as Oregon, Washington, and California. New strategies are needed to maintain yield and fruit quality with less water. To address the issue, three potential options for reducing water use, including deficit irrigation, irrigation cutoffs, and crop thinning, were evaluated for 2 years in a mature planting of northern highbush blueberry (Vaccinium corymbosum L. ‘Elliott’). Treatments consisted of no thinning and 50% crop removal in combination with either full irrigation at 100% of estimated crop evapotranspiration (ETc), deficit irrigation at 50% ETc (applied for the entire growing season), or full irrigation with irrigation cutoff for 4–6 weeks during early (early- to late-green fruit) or late (fruit coloring to harvest) stages of fruit development. Stem water potential was similar with full and deficit irrigation but, regardless of crop thinning, declined by 0.5–0.6 MPa when irrigation was cutoff early and by >2.0 MPa when irrigation was cutoff late. In one or both years, the fruiting season was advanced with either deficit irrigation or late cutoff, whereas cutting off irrigation early delayed the season. Yield was unaffected by deficit irrigation in plants with a full crop load but was reduced by an average of 35% when irrigation was cutoff late each year. Cutting off irrigation early likewise reduced yield, but only in the 2nd year when the plants were not thinned; however, early cutoff also reduced fruit soluble solids and berry weight by 7% to 24% compared with full irrigation. Cutting off irrigation late produced the smallest and firmest fruit with the highest soluble solids and total acidity among the treatments, as well as the slowest rate of fruit loss in cold storage. Deficit irrigation had the least effect on fruit quality and, based on these results, appears to be the most viable option for maintaining yield with less water in northern highbush blueberry. Relative to full irrigation, the practice reduced water use by 2.5 ML·ha−1 per season.

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Effects of Machine-Harvest Interval on Fruit Quality of Fresh Market Northern Highbush Blueberry

Horticulturae ◽

10.3390/horticulturae7080245 ◽

2021 ◽

Vol 7 (8) ◽

pp. 245

Author(s):

Yixin Cai ◽

Fumiomi Takeda ◽

Brian Foote ◽

Lisa Wasko DeVetter

Keyword(s):

Fruit Quality ◽

Titratable Acidity ◽

Vaccinium Corymbosum ◽

Soluble Solids ◽

Highbush Blueberry ◽

Labor Costs ◽

Fresh Market ◽

Harvest Intervals ◽

Northern Highbush Blueberry

Machine harvesting blueberry (Vaccinium sp.) alleviates labor costs and shortages but can reduce fruit quality. Installation of softer catching surfaces inside modified over-the-row harvesters (modified OTR) and adjusting harvest intervals may improve fruit quality and packout. The objective of this study was to determine the effect of harvest interval on fruit quality of fresh market northern highbush blueberry (Vaccinium corymbosum L.) harvested using a modified OTR. ‘Liberty’ blueberry bushes were harvested by hand or using a modified OTR at 3-, 10-, and 14-day intervals in 2019 and at 7-, 11-, and 14-day intervals in 2020. Hand-harvested ‘Liberty’ had greater packout and firmness than machine-harvested fruit. Machine harvesting at the 3-day interval in 2019, and the 14-day interval in 2020 reduced packout from 70–80% to 60% and 54%, respectively. In 2019, machine harvesting at a 3-day interval overall resulted in fruit with greater firmness, higher titratable acidity (TA), and lower total soluble solids (TSS) and SS/TA, compared to other harvest intervals. In 2020, the 7-day machine-harvest interval had a greater TA and lower TSS/TA, compared to the 11- and 14-day intervals. Overall, modified OTR machine-harvest intervals can be extended to 10–11 days for fresh market northern highbush cultivars such as ‘Liberty’ grown in northwest Washington.

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Individual and Combined Use of Sawdust and Weed Mat Mulch in a New Planting of Northern Highbush Blueberry. III. Yield, Fruit Quality, and Costs

HortScience ◽

10.21273/hortsci15659-20 ◽

2021 ◽

pp. 1-5

Author(s):

Bernadine C. Strik ◽

Amanda J. Davis

Keyword(s):

Fruit Quality ◽

Vaccinium Corymbosum ◽

Soluble Solids ◽

Highbush Blueberry ◽

Growing Seasons ◽

Combined Use ◽

Net Profit ◽

Northern Highbush Blueberry ◽

Effect On Yield ◽

Cost Of Materials

A 4-year trial was established in Oct. 2016 in western Oregon to evaluate the effects of various in-row mulch treatments on yield, fruit quality, and costs of installation and maintenance during establishment of northern highbush blueberry (Vaccinium corymbosum L. ‘Duke’). The treatments included douglas fir [Pseudotsuga menziesii (Mirb.) Franco] sawdust, black weed mat (woven polypropylene groundcover), green weed mat, and sawdust covered with black or green weed mat. Fruit were harvested during 2018–20 (second through fourth growing seasons). Weed mat color had no effect on yield or fruit quality. In 2018, yield was higher with black weed mat over sawdust mulch than with black weed mat alone, whereas mulch had no effects during 2019 and 2020, or on cumulative yield. Percent total soluble solids in the berries was highest with sawdust and weed mat alone compared with weed mat over sawdust mulches, whereas berry weight, diameter, and firmness were unaffected by mulch. Sawdust was the most expensive mulch over the lifespan of the planting because it required replenishment after 2 years. Black weed mat over sawdust resulted in the highest net profit when fruit sales and cost of materials and labor were considered.

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Responses of 'Pink Lady ' apple to deficit irrigation and partial rootzone drying: physiology, growth, yield, and fruit quality

Australian Journal of Agricultural Research ◽

10.1071/ar07033 ◽

2007 ◽

Vol 58 (11) ◽

pp. 1068 ◽

Cited By ~ 31

Author(s):

Mark G. O'Connell ◽

Ian Goodwin

Keyword(s):

Water Potential ◽

Fruit Quality ◽

Vegetative Growth ◽

Deficit Irrigation ◽

Fruit Size ◽

Growth Yield ◽

Stem Water Potential ◽

Crop Evapotranspiration ◽

Stem Water ◽

Partial Rootzone Drying

Partial rootzone drying (PRD) is a new irrigation strategy whereby water is withheld from part of the rootzone while another part is well watered. A successful PRD strategy should reduce tree water use through stomatal control of transpiration and reduce vegetative growth while maintaining fruit size and yield. A field experiment examined crop water relations and production performance of PRD in a commercial apple orchard on loam soil in the Goulburn Valley, Australia. The orchard consisted of high-density (1420 trees/ha) 8-year-old ‘Pink Lady’ apple trees trained as central leader and irrigated by microjets. The effects of PRD on leaf/stem water potential, vegetative growth, yield components and fruit quality were investigated during two seasons (2001–02, Year 1 and 2002–03, Year 2). The 2-year average growing season reference crop evapotranspiration and rainfall was 954 and 168 mm, respectively. Three irrigation treatments were established: (1) deficit irrigation (DI, supplied 50% of water to a fixed side of tree); (2) PRD supplied 50% of water to alternating sides of tree; (3) and conventional irrigation (CI, supplied 100% water to both sides of tree). Irrigation inputs under the CI treatment were 334 and 529 mm for Year 1 and Year 2, respectively. In Year 1, the volume of irrigation applied to CI treatment inputs equated to the replacement of predicted crop evapotranspiration (ETc) based on a mid-season FAO-56 crop coefficient with adjustment for tree size. Vegetative growth, fruit production and water status showed both PRD and DI treatments led to a classical ‘deficit irrigation’ water stress response. Leaf water potential, leaf conductance, fruit size, shoot growth and yield were reduced on PRD and DI trees compared to the fully watered (CI) trees. In Year 2, CI inputs exceeded estimated ETc by 2-fold. Consequently, minimal or no differences between irrigation regimes were measured in stem water potential, vegetative growth, yield components and fruit quality. Fruit disorders (sunburn, russet, misshape, markings, frost damage) were not affected by irrigation regime in either season. We contend that further effort is required to determine under what circumstances or environments there is a PRD response that saves water and maintains yield and quality for apple.

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New Foliar-applied Biofilm Had No Impact on Splitting or Fruit Quality in ‘Elliott’ and ‘Legacy’ Blueberry in Oregon

HortTechnology ◽

10.21273/horttech04196-18 ◽

2018 ◽

Vol 28 (6) ◽

pp. 836-842

Author(s):

Amanda J. Vance ◽

Bernadine C. Strik

Keyword(s):

Fruit Quality ◽

Color Change ◽

Vaccinium Corymbosum ◽

Sprinkler System ◽

Soluble Solids ◽

Highbush Blueberry ◽

Fresh Market ◽

Visual Rating ◽

Berry Size ◽

Current Product

Fresh market blueberry (Vaccinium sp.) sales require high-quality, firm fruit with no significant defects. A new phospholipid biofilm product was developed to reduce splitting and increase firmness when applied directly to blueberry fruit. Two trials were undertaken to test the effects of the biofilm using various application timings and methods. In highbush blueberry cultivar Elliott (Vaccinium corymbosum), four treatments included: 1) rate and timing on the current product label (5- to 10-mm berry size, 10% to 20% color change, and between the first and second harvests), 2) addition of a preharvest timing (5- to 10-mm berry size, 10% to 20% color change, and 7 to 10 days preharvest); 3) starting applications later (10% to 20% color change, 7 to 10 days preharvest, and between the first and second harvests), and 4) a water-sprayed control. Biofilm was applied at a rate of 2 qt/acre for all applications. In highbush blueberry cultivar Legacy (Vaccinium corymbosum × Vaccinium sp.), the same volume of biofilm was applied via an airblast sprayer or through an overhead sprinkler system typically used for chemigation and compared with a water-sprayed control. Data collected included yield (in ‘Elliott’), berry weight, firmness, skin toughness, total soluble solids (TSS), weight loss during storage, percent splitting (in ‘Legacy’), and a visual rating, evaluated on the day of harvest and about 14 and 28 days postharvest. There were no visual defects caused by application of biofilm. Compared with the controls in either study, biofilm had no consistent impact on fruit quality, firmness, shelf life, yield in ‘Elliott’, or splitting in ‘Legacy’.

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Thermal Cooling with Sprinklers or Microsprinklers Reduces Heat Damage and Improves Fruit Quality in Northern Highbush Blueberry

HortScience ◽

10.21273/hortsci15119-20 ◽

2020 ◽

Vol 55 (8) ◽

pp. 1365-1371

Author(s):

Fan-Hsuan Yang ◽

David R. Bryla ◽

Scott T. Orr ◽

Bernadine C. Strik ◽

Yanyun Zhao

Keyword(s):

Air Temperature ◽

Fruit Quality ◽

Ambient Air ◽

Soluble Solids ◽

Highbush Blueberry ◽

Fruit Firmness ◽

Experimental Site ◽

Heat Damage ◽

Berry Weight ◽

Northern Highbush Blueberry

Hot and sunny weather can cause a considerable amount of fruit damage in northern highbush blueberry (Vaccinium corymbosum L.) and result in millions of dollars of crop loss each year. To combat this issue, many growers use over-canopy sprinkler or microsprinkler systems to cool the fruit, but questions remain on the amount of time and frequency these systems should be run and whether they have any effect on fruit quality. Two series of studies were conducted to evaluate the efficacy of using sprinklers or microsprinklers for reducing blueberry fruit temperature and improving fruit quality in western Oregon. With sprinklers, treatments were applied in 2014 and 2015 to ‘Elliott’ blueberry and included irrigation (night) and cooling (day) with sprinklers, sprinkler irrigation (at night only) with no cooling, and drip irrigation with no cooling. The sprinklers were run for cooling for 15 minutes every hour whenever air temperature was ≥32 or 35 °C. Berry temperature declined rapidly within the first 15 minutes of cooling and never exceeded ambient air temperature during the cooling cycles. While the percentage of fruit with heat damage was low even without cooling (<2%), cooling reduced damage to nearly 0% in 1 of 2 years and increased berry weight relative to no cooling in both years when it was run at ≥32 °C. Cooling also reduced the concentration of soluble solids (sugars) in the berries in 2014 but had no effect on yield, fruit firmness, titratable acidity, harvest date, or the total content of phenolics or anthocyanins in the berries in either year. With microsprinklers, cooling was tested at a commercial farm and at an experimental site. At the farm, 1.3-ha blocks of ‘Aurora’ blueberry were irrigated by drip and either had no cooling or were cooled using microsprinklers run continuously or pulsed in 1-hour or 20-minute cycles during three extreme heat events (≥35 °C) in 2015. Continuous cooling was the most effective treatment for reducing berry temperature, but it resulted in wetter conditions, which might impede fruit harvest afterward and increase the presence of slugs, insect pests, and fungal diseases. Pulsed cooling, especially with short cycles, effectively maintained fruit temperatures near that of ambient air and reduced water use by 50%. At the experimental site, cooling with microsprinklers, which in this case were pulsed in 20-min cycles when air temperature was ≥ 32 °C, reduced heat damage in ‘Aurora’ and ‘Elliott’ in 2016. Cooling at this site also increased berry weight by an average of 10% in both cultivars and increased fruit firmness by 32% during the first of three harvests in ‘Aurora’; however, it reduced the concentration of soluble solids in the berries in both cultivars. In general, cooling with microsprinklers used considerably less water than cooling with sprinklers, but it appeared to be equally effective at reducing berry temperature.

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Vegetative and Reproductive Traits of Two Southern Highbush Blueberry Cultivars Grafted onto Vaccinium arboreum Rootstocks

HortScience ◽

10.21273/hortsci.51.7.880 ◽

2016 ◽

Vol 51 (7) ◽

pp. 880-886 ◽

Cited By ~ 3

Author(s):

Bruno Casamali ◽

Rebecca L. Darnell ◽

Alisson P. Kovaleski ◽

James W. Olmstead ◽

Jeffrey G. Williamson

Keyword(s):

Fruit Quality ◽

Reproductive Traits ◽

Vaccinium Corymbosum ◽

Soluble Solids ◽

Soil Conditions ◽

Highbush Blueberry ◽

Canopy Volume ◽

Southern Highbush ◽

Vaccinium Arboreum ◽

Amended Soil

Vaccinium arboreum Marsh is a wild species adapted to high pH (above 6.0) and low organic matter soils (below 2.0%). The use of V. arboreum rootstocks may be a viable option to increase soil adaptation of southern highbush blueberry (SHB) (Vaccinium corymbosum interspecific hybrid) under marginal soil conditions. The objective of this research was to evaluate the vegetative and reproductive traits of ‘Farthing’ and ‘Meadowlark’ SHB own-rooted or grafted onto V. arboreum and grown in pine bark–amended or nonamended soil. The study was conducted from 2012 through 2014 at a research center in Citra, FL, and a grower’s farm in Archer, FL. Vaccinium arboreum rootstock generally induced the same effects in both cultivars. Grafted plants in both soil treatments had reduced canopy growth in the first year after field planting compared with own-rooted plants in amended soil. However, canopy volume of grafted plants was greater than own-rooted plants in nonamended soil and similar to own-rooted plants in amended soil 2 years after field planting for ‘Meadowlark’ and 3 years after planting for ‘Farthing’. Fruit yield was lower in grafted plants compared with own-rooted plants in the first fruiting year (2 years after field planting). By the second fruiting year, yields of grafted plants were similar to or greater than yields of own-rooted plants when grown in nonamended soil, whereas in amended soil, yields of grafted plants were similar to yields of own-rooted plants. Grafted plants had greater mean berry weight, but lower berry firmness; however, the firmness values were still considered acceptable (greater than 160 g⋅mm−1). Internal fruit quality [total soluble solids (TSS) and total titratable acidity (TTA)] was not consistently affected by the rootstock or soil treatments. These results suggest that grafting SHB onto V. arboreum does not increase yield in the establishment years compared with own-rooted SHB when grown in amended soils, but may have the ability to increase yield with no negative effects on fruit quality when grown in nonamended soils.

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Sensitivity of Northern Highbush Blueberry Cultivars to Soil Water Deficits during Various Stages of Fruit Development

HortScience ◽

10.21273/hortsci15493-20 ◽

2020 ◽

pp. 1-9

Author(s):

Khalid F. Almutairi ◽

David R. Bryla ◽

Bernadine C. Strik

Keyword(s):

Soil Water ◽

Fruit Development ◽

Vaccinium Corymbosum ◽

Soluble Solids ◽

Highbush Blueberry ◽

Critical Periods ◽

Volumetric Soil Water Content ◽

Water Deficits ◽

Late Season ◽

Northern Highbush Blueberry

In many regions, water limitations are increasing because of frequent and persistent droughts and competition for water resources. As a result, growers in these regions, including those producing blueberries, must limit irrigation during drier years. To identify the most critical periods for irrigation, we evaluated the effects of soil water deficits during various stages of fruit development on different cultivars of northern highbush blueberry (Vaccinium corymbosum L.). The study was conducted for 2 years in western Oregon and included two early season cultivars, ‘Earliblue’ and ‘Duke’, a midseason cultivar, ‘Bluecrop’, and two late-season cultivars, ‘Elliott’ and ‘Aurora’. Volumetric soil water content and stem water potentials declined within 1 to 2 weeks with no rain or irrigation in each cultivar and were lowest during the later stages of fruit development. Water deficits reduced berry weight by 10% to 15% in ‘Earliblue’ and ‘Elliott’ when irrigation was withheld in the second year during early or late stages of fruit development and by 6% to 9% in ‘Aurora’ when irrigation was withheld in either year during the final stages of fruit development. However, water deficits only reduced yield significantly in ‘Aurora’, which produced 0.8 to 0.9 kg/plant fewer fruit per year when irrigation was withheld during fruit coloring. In many cases, water deficits also reduced fruit firmness and increased the concentration of soluble solids in the berries, but they had inconsistent effects on titratable acidity and sugar-to-acid ratios. As a rule, water deficits were most detrimental during later stages of fruit development, particularly in midseason and late-season cultivars, which ripened in July and August during the warmest and driest months of the year.

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Physiological Responses of Apple Trees to Different Irrigation Practices

HortScience ◽

10.21273/hortsci.40.4.1095a ◽

2005 ◽

Vol 40 (4) ◽

pp. 1095A-1095

Author(s):

Luis R. Valenzuela ◽

Denise Neilsen ◽

Gerry Neilsen ◽

David Eissenstat

Keyword(s):

Soil Water ◽

Fruit Quality ◽

Deficit Irrigation ◽

Irrigation Treatment ◽

Fruit Yield ◽

Soluble Solids ◽

Root Production ◽

Stem Water Potential ◽

Apple Trees ◽

Irrigation Practices

New irrigation practices using controlled soil water deficits offer the opportunity of reducing tree vegetative growth and enhancing fruit quality without decreasing fruit size or yield. We tested partial root zone drying (PRD) and deficit irrigation in `Golden Delicious' trees on M9 rootstock, at Summerland, B.C., Canada. There were four treatments: full irrigation (100% daily ET replacement), both sides irrigation (50%daily ET replacement), deficit irrigation (1 side, 50% daily ET replacement) and PRD (alternating sides, 50% daily ET replacement). The purpose of this study was to determine how deficit irrigation and PRD affect above- and below-ground physiology of apple trees where the amount of irrigation was the same. Soil water content, stem water potential, stomatal conductance and transpiration were significantly higher for deficit irrigation than PRD irrigation (P < 0.05) for both years (2003 and 2004). Root dynamics varied among years. For both years, root production was higher in trees under PRD than in trees under deficit irrigation. Root survivorship was significantly higher for trees exposed to PRD treatment than those exposed to deficit irrigation treatment in 2003 (P < 0.0003), but not in 2004 (P > 0.662). Stem growth, fruit yield, and fruit quality were generally not affected by treatments in 2003. In 2004, however, fruit yield was 37% higher in deficit irrigation than in PRD (P < 0.05). Soluble solids and sugar: acid ratio did not differ between these two treatments. For conditions where the amount of irrigation applied was the same, our results suggest that PRD may be less effective than deficit irrigation.

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Improving Almond Productivity under Deficit Irrigation in Semiarid Zones

The Open Agriculture Journal ◽

10.2174/1874331501105010056 ◽

2011 ◽

Vol 5 (1) ◽

pp. 56-62 ◽

Cited By ~ 4

Author(s):

I.F. García-Tejero ◽

V.H. Durán-Zuazo ◽

L.M. Vélez ◽

A. Hernández ◽

A. Salguero ◽

...

Keyword(s):

Water Potential ◽

Water Use ◽

Deficit Irrigation ◽

Water Status ◽

Low Frequency ◽

Canopy Temperature ◽

Prunus Dulcis ◽

Stem Water Potential ◽

Irrigation Period ◽

Stem Water

Sustainable water use is one of the greatest challenges of irrigated agricultural systems. This study presents the results related to the agronomic and physiological response to the deficit irrigation of almond trees (Prunus dulcis DA Webb Mill cv. Guara) under semiarid Mediterranean conditions in the Guadalquivir river basin (SW Spain). Two deficitirrigation strategies were tested: i) regulated deficit irrigation (RDI), which was irrigated at 100% of crop evapotranspiration (ETC) throughout the irrigation period, except during the kernel-filling stage, when these trees where irrigated at 30% ETC, and ii) low-frequency deficit irrigation (LFDI), in which trees were subjected to different irrigationrestriction periods, defined in terms of stem water potential at midday (ΨStem). As control, a fully irrigated treatment (C-100) was used, which received irrigation covering the 100% of ETC. The stem water potential (ΨStem), the stomatal conductance (gS), the photosynthesis rate (Pn) and canopy temperature (TC) were monitored, revealing significant differences mainly in LFDI in comparison with C-100. Also, highly significant relationships were found among plant physiological parameters, showing that the water status is strongly related to the crop water availability. On other hand, in terms of nut yield, there was a notable improvement under LFDI compared with RDI, with increases of 16% in relation to C-100, and with water savings of close to 170 mm. Thus, these findings demonstrate that the LFDI is a sustainable strategy to improve almond productivity as well as water-use efficiency under limited water resources.

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Effects of regulated deficit irrigation on physiology, yield and fruit quality in apricot trees under Mediterranean conditions

Spanish Journal of Agricultural Research ◽

10.5424/sjar/2016144-9943 ◽

2016 ◽

Vol 14 (4) ◽

pp. e1205 ◽

Cited By ~ 3

Author(s):

Francisco Pérez-Sarmiento ◽

José M. Mirás-Avalos ◽

Rosalía Alcobendas ◽

Juan J. Alarcón ◽

Oussama Mounzer ◽

...

Keyword(s):

Fruit Quality ◽

Deficit Irrigation ◽

Irrigation Management ◽

Fruit Growth ◽

Soluble Solids ◽

Arid Environments ◽

Stem Water Potential ◽

Cross Sectional ◽

Regulated Deficit Irrigation ◽

Semi Arid

Scarce water resources mainly in arid and semi-arid areas have caused an increasing interest for applying irrigation protocols aiming to reduce water spends. The effects of regulated deficit irrigation (RDI) on the performance of apricot trees (Prunus armeniaca L. cv. “Búlida”) were assessed in Murcia (SE Spain), during three consecutive growing seasons (2008-2010). The hypothesis was that RDI would not restrict yield but increase fruit quality while saving water. Two irrigation treatments were established: i) control, irrigated to fully satisfy crop water requirements (100% ETc) and ii) RDI, that reduced the amount of applied water to: a) 40% of ETc at flowering and stage I of fruit growth; b) 60% of ETc during the stage II of fruit growth and c) 50% and 25% of ETc during the late postharvest period (from 60 days after harvest). Stem water potential, gas exchanges, trunk cross-sectional area (TCSA), fruit diameter, yield and fruit quality traits were determined. Vegetative growth was decreased by the use of RDI (12% less TCSA on average for the three years), whereas yield was unaffected. In addition, some qualitative characteristics of the fruits, such as the level of soluble solids, sweetness/acidity relation and fruit colour, were improved by the use of RDI. These results and average water savings of approximately 30%, lead us to conclude that RDI strategies are a possible solution for irrigation management in areas with water shortages, such as arid and semi-arid environments.

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