scholarly journals Foliar Applications of Calcium and Boron Do Not Increase Fruit Set or Yield in Northern Highbush Blueberry (Vaccinium corymbosum)

HortScience ◽  
2017 ◽  
Vol 52 (9) ◽  
pp. 1259-1264 ◽  
Author(s):  
Matthew Arrington ◽  
Lisa Wasko DeVetter

Fruit set in northern highbush blueberry (Vaccinium corymbosum L.) can be low under certain climatic conditions, contributing to reduced yields in northwestern Washington. The mechanisms influencing fruit set are complex, but reduced fruit set may be associated with inadequate nutrient availability during critical stages of flowering, ovule fertilization, and initial fruit development. Calcium (Ca) and boron (B) are of particular interest for reproductive developmental processes and are frequently applied annually by growers in the Pacific Northwest region because of the perception that these nutrients enhance fruit set and corresponding yields. Evaluation of commonly applied products containing these nutrients and their effects on fruit set and yield are of specific importance to justify the application of these nutrients. To address this, commercially available fertilizers containing Ca and B were applied to ‘Draper’ and ‘Bluecrop’ blueberry as foliar sprays, either alone or in combination, during the 2015 and 2016 growing seasons in northwestern Washington. Treatments included calcium chloride (750 and 1500 ppm Ca), calcium sulfate (150 ppm Ca), and tetra borate (125 and 250 ppm B) foliar sprays, repeated six times per season every 7–10 days from early pink bud through petal fall. No significant increases were observed for fruit set, estimated yield, and fruit quality (firmness and berry weight) across the treatments. Increased concentrations of B were observed in leaf tissues in 2015 and 2016, and to a lesser extent fruit tissues. Calcium remained unchanged regardless of treatment and tissue type. Under the conditions of this study, foliar applications of Ca and B did not lead to increased fruit set or yield. This research suggests that other approaches should be explored to increase fruit set and corresponding yields of highbush blueberry grown in northwest Washington.

HortScience ◽  
2021 ◽  
pp. 1-5
Author(s):  
Bernadine C. Strik ◽  
Amanda J. Davis

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.


HortScience ◽  
2017 ◽  
Vol 52 (6) ◽  
pp. 844-851 ◽  
Author(s):  
Bernadine C. Strik ◽  
Amanda J. Vance ◽  
Chad E. Finn

Northern highbush blueberry (Vaccinium corymbosum L.) cultivars were evaluated from planting (Oct. 2006) through 2014 in a certified organic research site in Aurora, OR. The treatments included cultivar (Duke, Bluecrop, Reka, Bluejay, Bluegold, Draper, Legacy, Liberty, Ozarkblue, and Aurora), amendment-mulch [“compost + sawdust” (included preplant amendment and a surface mulch of either an agricultural on-farm crop waste compost or yard-debris compost and sawdust), and “weed mat” (no preplant amendments but with a sawdust mulch topped with weed mat)]. Adding on-farm compost as a preplant amendment and as part of the mulching program increased soil pH from 4.9 to 6.9, organic matter content (OM), and calcium (Ca), magnesium (Mg), and potassium (K) levels compared with the weed mat treatment. The reduced plant growth and yield in some cultivars grown in the compost + sawdust treatment was likely due to the higher soil pH. ‘Bluegold’ and ‘Draper’ were among the cultivars with consistently high flower bud set (40% to 57%), whereas others had consistently low values (e.g., 22% to 45% in ‘Bluecrop’). The number of flowers per bud was affected only by cultivar. There was no effect of year or amendment-mulch treatment on percent fruit set which averaged 93% during the study; however, ‘Ozarkblue’ had a significantly lower fruit set (88%) than only ‘Aurora’ (96%). Berry weight was affected by year (plant age), cultivar, and amendment-mulch treatment. ‘Ozarkblue’ produced the largest berries. Type of amendment-mulch had little effect on berry weight, except in ‘Ozarkblue’, ‘Aurora’, and ‘Reka’ where plants grown with weed mat produced larger fruit than those grown with compost + sawdust. On average, ‘Bluejay’, ‘Draper’, and ‘Liberty’ fruit had the highest percent soluble solids (TSS) and ‘Ozarkblue’ the lowest. Fruit harvested from plants grown with weed mat were firmer than when compost + sawdust was used. ‘Draper’ fruit were much firmer than those of the other cultivars in all years of the study. The number of flower buds per plant multiplied by the number of flowers/bud and berry weight (cultivar specific) and average fruit set was a good predictor of yield in young plants. Yield per plant increased from the second through seventh growing seasons as plants matured in all cultivars except for ‘Duke’ which had the greatest yield in 2014. Cumulative yield was highest in ‘Legacy’ and lowest in ‘Bluejay’ and in ‘Draper’, which had relatively low yield when plants were young. Most cultivars had greater yield when grown with weed mat, whereas ‘Bluegold’ and ‘Liberty’ were unaffected by amendment-mulch treatment. Because weeds were managed in all plots, the cultivar response to amendment-mulch was likely a reflection of sensitivity to preplant amendment with on-farm compost and the resulting higher soil pH. It is possible that the cultivars differed in their adaptability to the various fertility regimes caused by the amendment-mulch treatments and fertilizers used in our study.


2019 ◽  
Vol 13 (4) ◽  
pp. 2521-2528
Author(s):  
Rafał Nadulski ◽  
Andrzej Masłowski ◽  
Artur Mazurek ◽  
Paweł Sobczak ◽  
Marek Szmigielski ◽  
...  

1992 ◽  
Vol 37 (1) ◽  
pp. 42-59 ◽  
Author(s):  
James C. Chatters ◽  
Karin A. Hoover

AbstractAn understanding of the response of a fluvial system to past climatic changes is useful for predicting its response to future shifts in temperature and precipitation. To determine the response of the Columbia River system to previous climatic conditions and transitions, a well-dated sequence of floodplain development in the Wells Reservoir region was compared with the paleoenvironmental history of the Columbia River Basin. Results of this comparison indicate that aggradation episodes, occurring approximately 9000-8000, 7000-6500, 4400-3900, and 2400-1800 yr B.P., coincided with climatic transitions that share certain characteristics. The inferred climates associated with aggradation had at least moderate rates of precipitation that occurred mainly in winter coupled with moderate winter temperatures. Such conditions would have resulted in the buildup of snowpacks and a high frequency of rain-on-snow events. The warming and precipitation increases predicted for the Pacific Northwest under most CO2-doubling scenarios are likely to repeat these conditions, which could increase the frequency of severe, sediment-laden floods in the Columbia River Basin.


1997 ◽  
Vol 66 (2) ◽  
pp. 267-272 ◽  
Author(s):  
Akira Suzuki ◽  
Toru Kikuchi ◽  
Koji Aoba

Horticulturae ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 245
Author(s):  
Yixin Cai ◽  
Fumiomi Takeda ◽  
Brian Foote ◽  
Lisa Wasko DeVetter

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.


HortScience ◽  
2019 ◽  
Vol 54 (6) ◽  
pp. 1067-1076 ◽  
Author(s):  
Ryan C. Costello ◽  
Dan M. Sullivan ◽  
David R. Bryla ◽  
Bernadine C. Strik ◽  
James S. Owen

New markets for organic northern highbush blueberry (Vaccinium corymbosum L.) have stimulated interest in using composts specifically tailored to the plant’s edaphic requirements. Because composts are typically neutral to alkaline in pH (pH 7 to 8), and blueberry requires acidic soil (pH 4.2 to 5.5), we investigated elemental sulfur (S0) addition as a methodology for reducing compost pH. The objectives were to 1) characterize initial compost chemistry, including the pH buffering capacity of compost (acidity required to reduce pH to 5.0), 2) measure changes in compost chemistry accompanying acidification, and 3) evaluate plant growth and mineral nutrition of blueberry in soil amended with an untreated or acidified compost. Ten composts prepared from diverse feedstocks were obtained from municipalities and farms. Addition of finely ground S0 reduced compost pH from 7.2 to 5.3, on average, after 70 d at 22 °C, and increased the solubility of nutrients, including K (from 22 to 36 mmol(+)/L), Ca (from 5 to 19 mmol(+)/L), Mg (from 5 to 20 mmol(+)/L), and Na (from 6 to 9 mmol(+)/L). Sulfate-S, a product of S0 oxidation, also increased from 5 to 45 mmol(−)/L. The composts were incorporated into soil at a high rate (30% v/v) in a greenhouse trial to evaluate their suitability for use in blueberry production. Shoot and root growth were strongly affected by compost chemical characteristics, including pH and electrical conductivity (EC). Potassium in compost was highly variable (2–32 g·kg−1). Concentration of K in the leaves increased positively in response to compost K, whereas shoot dry weight and root growth declined. Leaf Mg also declined in response to compost K, suggesting that elevated K concentrations in compost may cause Mg deficiency. Composts with the highest K were also high in total N, pH, and EC. Compost acidification to pH ≤ 6 improved growth and increased leaf Mg concentration. On the basis of these results, composts derived from animal manures or young plant tissues (e.g., green leaves) appear to be unsuitable for high-rate applications to blueberry because they usually require high amounts of S0 for acidification and are often high in EC and K, whereas those derived from woody materials, such as local yard debris, appear promising based on their C:N ratio, compost acidification requirement, and EC.


Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 768-768 ◽  
Author(s):  
A. M. C. Schilder ◽  
T. D. Miles

Leaf rust symptoms have been noticed sporadically on northern highbush blueberry plants (Vaccinium corymbosum L.) in Michigan for the past 8 years. In 2009, leaf rust was seen in several cultivated blueberry fields and on greenhouse-grown blueberry plants in southwest Michigan. In 2010, leaf rust was widespread throughout western Michigan and particularly evident in the fall, sometimes resulting in premature defoliation. Cultivars Rubel, Jersey, Elliott, Liberty, and Brigitta were most commonly affected. Both the 2009 and 2010 growing seasons were characterized by above-average precipitation in early to mid-summer. Early symptoms on the adaxial leaf surface consisted of roughly circular yellow spots that later developed brown, necrotic centers. Older lesions were more angular and sometimes surrounded by a purplish border. In the fall, a “green island” effect was sometimes apparent around the lesions. On the abaxial side, numerous yellow-to-orange rust pustules (uredinia) were visible. Uredinia were dome shaped, erumpent, 100 to 400 μm in diameter, clustered, and sometimes coalescing. Urediniospores were broadly obovate with dark yellowish content and measured 19 to 25 × 16 to 20 μm (average 22 × 18 μm, n = 30). Spore walls were hyaline, echinulate, and 1.0 to 1.5 μm thick with obscure germ pores. Uredinia were examined with light and scanning electron microscopy for the presence of conspicuous ostiolar cells characteristic of Naohidemyces vaccinii (Wint.) Sato, Katsuya et Y. Hiratsuka, but none were observed. No telia or teliospores were observed. On the basis of morphology, the pathogen was identified as Thekopsora minima P. Syd. & Syd. (3,4) and a sample was deposited in the U.S. National Fungus Collection (BPI 881107). Genomic DNA was extracted from urediniospores of rust isolates from six different locations, and a 267-bp fragment of the ITS2 region was amplified and sequenced using the primers ITS3 and ITS4 (GenBank Accession No. HQ661383). All sequences were identical to each other and shared 99% identity (232 of 234 bp) with a T. minima isolate from South Africa (GenBank Accession No. GU355675). The alternate host, hemlock (mostly Tsuga canadensis L.) is a common and valuable conifer in the Michigan landscape. Hemlock trees were not examined for the presence of aecia but are assumed to play a role in the epidemiology of the disease in Michigan because leaf rust tends to be more severe near hemlock trees. Pucciniastrum vaccinii (G. Wint.) Jorst. was considered the causal agent of blueberry leaf rust until Sato et al. (1,4) identified three unique species. While T. minima has been reported on black huckleberry (Gaylussacia baccata [Wangenh.] K. Koch) in Michigan (4), to our knowledge, this is the first report of T. minima on highbush blueberry in the state. T. minima has been reported on highbush blueberry in Delaware and New York (4), Japan (2), and South Africa (3). The severity of the outbreak in 2010 warrants further research into economic losses, epidemiology, and management of the disease. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Botany and Mycology Laboratory, ARS, UDSA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , 2010. (2) T. Kobayashi. Page 1227 in: Index of Fungi Inhabiting Woody Plants in Japan. Host, Distribution and Literature. Zenkoku-Noson-Kyoiku Kyokai Publishing Co., Tokyo, 2007. (3) L. Mostert et al. Plant Dis. 94:478, 2010. (4) S. Sato et al. Trans. Mycol. Soc. Jpn. 34:47, 1993.


HortScience ◽  
2021 ◽  
pp. 1-7
Author(s):  
Fan-Hsuan Yang ◽  
David R. Bryla ◽  
R. Troy Peters

Heat-related fruit damage is a prevalent issue in northern highbush blueberry (Vaccinium corymbosum L.) in various growing regions, including the northwestern United States. To help address the issue, we developed a simple climatological model to predict blueberry fruit temperatures based on local weather data and to simulate the effects of using over-canopy sprinklers for cooling the fruit. Predictions of fruit temperature on sunny days correlated strongly with the actual values (R2 = 0.91) and had a root mean-square error of ≈2 °C. Among the parameters tested, ambient air temperature and light intensity had the greatest impact on fruit temperature, whereas wind speed and fruit size had less impact, and relative humidity had no impact. Cooling efficiency was estimated successfully under different sprinkler cooling intervals by incorporating a water application factor that was calculated based on the amount of water applied and the time required for water to evaporate from the fruit surface between the intervals. The results indicate that water temperature and nozzle flow rate affected the extent to which cooling with sprinklers reduced fruit temperature. However, prolonging the runtime of the sprinklers did not guarantee lower temperatures during cooling, because cooling efficiency declined as the temperature of the fruit approached the temperature of the irrigation water. Users could incorporate the model into weather forecast programs to predict the incidence of heat damage and could use it to make cooling decisions in commercial blueberry fields.


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