scholarly journals High Tunnel Apricot Production in Frost-prone Northern New Mexico

2019 ◽  
Vol 29 (4) ◽  
pp. 457-460
Author(s):  
Shengrui Yao ◽  
Steve Guldan ◽  
Robert Heyduck
Keyword(s):  
New Mexico ◽  
Open Field ◽  
Block Design ◽  
Fruit Production ◽  
Prunus Armeniaca ◽  
Market Prices ◽  
Spindle System ◽  
High Tunnel ◽  
High Tunnels ◽  
High Yields

Late frost is the number one issue challenging fruit production in northern New Mexico. We had apricot (Prunus armeniaca) trees in an open field planting at Alcalde, NM, and not a single fruit was harvested from 2001 through 2014. Apricot trees in surrounding communities produce sporadic crops. In 2012, we planted apricots in two 16 × 40-ft high tunnels (9.5-ft high point). Trees were trained to a spindle system in one high tunnel and an upright fruiting offshoot (UFO) system in the other, and there were identical plantings in the open field for each high tunnel. Supplemental heating was provided starting at blooming time. There were five cultivars planted in each high tunnel at 4 × 8-ft spacing in a randomized complete block design with two replications (rows) and two trees per cultivar in each plot. In 2015, relatively high yields were obtained from all cultivars. The average yields for the spindle system were (lb/tree): ‘Puget Gold’ (29.0), ‘Harcot’ (24.1), ‘Golden Amber’ (19.6), ‘Chinese Apricot’ (18.6), and ‘Katy’ (16.7). Yields for the UFO system were (lb/tree): ‘Golden Amber’ (18.6), ‘Katy’ (14.9), ‘Puget Gold’ (11.3), ‘Chinese Apricot’ (10.2), and ‘Harcot’ (8.6). On average across all cultivars, the UFO system produced 60% of the yield of the spindle system in 2015. A heating device is necessary for high tunnel apricot fruit production in northern New Mexico because trees normally bloom in early to late March, depending on the year, while frosts can continue until mid-May. In years like 2017 and 2018 with temperatures below 10 °F in late February/early March, some of the expanded flower buds were killed before bloom. On those cold nights, one 100-lb tank of propane may or may not be enough for 1 night’s frost protection. Economically, it would not be feasible in those years. Only in years with a cool spring, late-blooming trees, and mild temperatures in April and May can high tunnel apricot production generate positive revenue with high, direct-market prices. High tunnel apricot production with heating devices is still risky and cannot guarantee a reliable crop in northern New Mexico or similar areas.

scholarly journals Effect of Harvest Schedule on Organic Kale Grown during the Winter in High Tunnels

2020 ◽  
Vol 30 (5) ◽  
pp. 570-575
Author(s):  
Robert F. Heyduck ◽  
Dawn VanLeeuwen ◽  
Steven J. Guldan
Keyword(s):  
New Mexico ◽  
Brassica Napus ◽  
Growth Stage ◽  
Total Yield ◽  
Market Demand ◽  
High Tunnel ◽  
Mature Leaves ◽  
Growing Seasons ◽  
High Tunnels ◽  
Delayed Growth

We examined the effect of harvest schedule on the yield of ‘Red Russian’ kale (Brassica napus ssp. napus var. pabularia) grown during the winter in 16 × 32-ft high tunnels in northern New Mexico. We conducted the study for two growing seasons: 2013–14 and 2014–15. All plots were sown on 16 Oct. and harvested four times according to four harvest schedules: A) 8, 16, 20, and 24 weeks after sowing; B) 10, 17, 21, and 25 weeks after sowing; C) 12, 18, 22, and 26 weeks after sowing; and D) 14, 19, 23, and 27 weeks after sowing. The first harvest of each treatment was the greatest, averaging 216 g/ft2, compared with 88, 109, and 104 g/ft2 for harvests 2, 3, and 4, respectively. Season total yield of treatments B, C, and D (harvests beginning at 10, 12, and 14 weeks after sowing) yielded significantly more than treatment A, but only in year 2, when delayed growth resulted in very low yields for treatment A at harvest 1. Considering the entire 240-ft2 cropped area of the high tunnel, staggered harvests of 60 ft2 at a time can yield 2.6 to 17.5 kg per harvest or up to 124 kg over an entire season. Although we examined the yield of mature leaves, harvests could possibly begin earlier than in this study for “baby” kale or salad mixes, and the area harvested could be tailored to plant growth stage and market demand.

scholarly journals Growing Organic Heirloom Tomatoes in the Field and High Tunnels in North Carolina: Comparative Economic Analysis

2013 ◽  
Vol 23 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Olha Sydorovych ◽  
Cary L. Rivard ◽  
Suzanne O’Connell ◽  
Chris D. Harlow ◽  
Mary M. Peet ◽  
...  
Keyword(s):  
North Carolina ◽  
Economic Analysis ◽  
Open Field ◽  
Production Systems ◽  
Farming Systems ◽  
Quality Parameters ◽  
Climatic Conditions ◽  
Production Costs ◽  
High Tunnel ◽  
High Tunnels

In this study, we conducted an economic analysis of high tunnel and open-field production systems of heirloom tomato (Solanum lycopersicum) based on a two-year study at the Center for Environmental Farming Systems (CEFS) located in Goldsboro, eastern North Carolina. The research site was transitional organic using organically certified inputs and practices on land not yet certified. Production costs and returns were documented in each system and provide a useful decision tool for growers. Climatic conditions varied dramatically in 2007 compared with 2008 and differentially affected total and marketable yields in each system. Profits were higher in the open-field system and the high tunnels in 2007 and 2008, respectively. Sensitivity analysis was conducted using a range of market prices from $1.60/lb to $3.60/lb and a range of fruit marketability levels from 35% to 80%. Both systems were profitable except at the lowest price point and the lowest percent marketability level in high tunnel in 2007. At $2.60/lb, seasonal average sale price reported by growers for this region, and depending on percent marketability levels, the payback period for high tunnels ranged from two to five years. Presented sensitivity tables will enable decision makers to knowledgably estimate economic potential of open-field and high tunnel systems based on expected local prices and fruit quality parameters.

scholarly journals Summer Production of Lettuce, and Microclimate in High Tunnel and Open Field Plots in Kansas

2009 ◽  
Vol 19 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Xin Zhao ◽  
Edward E. Carey
Keyword(s):  
Open Field ◽  
Air Temperature ◽  
Meteorological Data ◽  
Marked Change ◽  
Daily Basis ◽  
Daily Maximum ◽  
High Tunnel ◽  
Horticultural Crops ◽  
High Tunnels ◽  
Open Fields

High tunnels have been shown to be a profitable season-extending production tool for many horticultural crops. Production of cool-season vegetables during the hot summer months represents a challenge to market growers in the midwestern United States. Two experiments were conducted to investigate the microclimate and production of eight leaf lettuce (Lactuca sativa) cultivars in high tunnels and open fields, using unshaded and shaded (39% white shadecloth) tunnels in Summer 2002 and 2003, respectively. Wind speed was consistently lower in high tunnels with the sidewalls and endwalls open. An unshaded high tunnel resulted in an increase of daily maximum and minimum air temperatures by ≈0.2 and 0.3 °C, respectively, in comparison with the open field. In contrast, daily maximum air temperature in a shaded high tunnel decreased by 0.4 °C, while the daily minimum air temperature was higher than that in the open field by 0.5 °C. Using high tunnels did not cause a marked change in relative humidity compared with the open field. When using shadecloth, the daily maximum soil temperature was lowered by ≈3.4 °C and the leaf surface temperature was reduced by 1.5 to 2.5 °C. The performance of lettuce during summer trials varied significantly among cultivars. Unshaded high tunnels generally led to more rapid bolting and increased bitterness of lettuce compared with the open field. Lettuce grown in high tunnels covered by shadecloth had a lower bolting rate, but decreased yield relative to the open field. Based on our results, summer lettuce production would not be recommended in high tunnels or open fields in northeastern Kansas, although the potential of shaded high tunnels deserves further studies. Reference crop evapotranspiration (ET0) was estimated from meteorological data on a daily basis using the FAO-56 method. The ET0 was lowest in the shaded high tunnel and was the highest in the open field. Relatively lower ET0 in high tunnels indicated a likely lower water requirement and therefore improved water use efficiency compared with the open field.

scholarly journals Lettuce Yield and Quality When Grown in High Tunnel and Open-Field Production Systems Under Three Diverse Climates

2012 ◽  
Vol 22 (5) ◽  
pp. 659-668 ◽  
Author(s):  
Russell W. Wallace ◽  
Annette L. Wszelaki ◽  
Carol A. Miles ◽  
Jeremy S. Cowan ◽  
Jeffrey Martin ◽  
...  
Keyword(s):  
Open Field ◽  
Production Systems ◽  
Organic Production ◽  
High Tunnel ◽  
Mount Vernon ◽  
Yield And Quality ◽  
High Tunnels ◽  
Lettuce Yield ◽  
Field Plots ◽  
Field Production

Field studies were conducted during 2010 and 2011 in Knoxville, TN; Lubbock, TX; and Mount Vernon, WA; to compare high tunnel and open-field organic production systems for season extension and adverse climate protection on lettuce (Lactuca sativa) yield and quality. The climates of these locations are diverse and can be typified as hot and humid (Knoxville), hot and dry (Lubbock), and cool and humid (Mount Vernon). In both years, 6-week-old lettuce seedlings of ‘New Red Fire’ and ‘Green Star’ (leafy type), ‘Adriana’ and ‘Ermosa’ (butterhead type), and ‘Coastal Star’ and ‘Jericho’ (romaine type) were transplanted in the late winter or early spring into subplots covered with black plastic and grown to maturity (43 to 65 days). Lettuce harvest in Knoxville occurred at 50 to 62 days after transplanting (DAT), with open-field lettuce harvested an average of 9 days earlier compared with high tunnel plots both years (P > 0.0001). The earlier than anticipated harvests in the open-field in Knoxville in 2010 were due to lettuce bolting. In Lubbock, high tunnel lettuce was harvested an average 16 days earlier in 2010 compared with open-field lettuce (P > 0.0001), while in 2011, high temperatures and bolting required that open-field lettuce be harvested 4 days earlier than lettuce grown in high tunnels. On average, lettuce cultivars at Mount Vernon matured and were harvested 56 to 61 DAT in 2010 and 54 to 64 DAT in 2011 with no significant differences between high tunnel and open-field production systems. Total and marketable yields at Mount Vernon and Lubbock averaged across cultivars were comparable in both high tunnel and open-field plots. At Knoxville, although total yields were significantly higher (P > 0.0062) in high tunnels than open-field plots, incidence of insect, disease, and physiological damage in high tunnel plots reduced lettuce quality and marketable yield (P > 0.0002). Lettuce head length:diameter ratio (LDR) averaged across cultivars was equal between high tunnel and the open field at all three locations. High tunnel production systems offer greater control of environments suitable for lettuce production, especially in climates like Knoxville and Lubbock where later-planted open-field systems may be more susceptible to temperature swings that may affect lettuce quality. These results suggest that although high tunnel culture alone may influence lettuce yield and quality, regional climates likely play a critical role in determining the impact of these two production systems on marketable lettuce yields.

scholarly journals Fertilizer Source and High Tunnel Production Environment Affect Antioxidant Levels of Pac Choi

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1000D-1001 ◽  
Author(s):  
Xin Zhao ◽  
Edward E. Carey ◽  
Takeo Iwamoto
Keyword(s):  
Open Field ◽  
Production Environment ◽  
Organic Fertilization ◽  
Fertilizer Rate ◽  
High Tunnel ◽  
Phytochemical Content ◽  
Application Rates ◽  
High Tunnels ◽  
Pac Choi ◽  
Field Plots

An experiment was conducted at Olathe, Kan., in Spring 2004 to investigate the influence of organic and conventional fertilizer sources and application rates on antioxidant levels of pac choi (Brassica rapa L. cv. Mei Qing) in open fields and poly-covered high-tunnel plots. Organic plots received pre-plant application of composted cattle manure and alfalfa (Hu-More 1–1–1) at 0 kg/ha N, 156 kg/ha N, or 314 kg/ha N, and conventional plots received preplant application of 13N–13P–13K at 0 kg/ha N, 78 kg/ha N, or 156 kg/ha N. Antioxidant levels were measured using the oxygen radical absorbance capacity (ORAC) assay. There were significant effects of fertilizer source and high-tunnel environment on the antioxidant capacity of pac choi. Organic fertilization significantly increased hydrophilic ORAC of pac choi in open field plots, but not in high tunnels. Regardless of the fertilizer source, pac choi grown in the open field had significantly higher hydrophilic ORAC than that grown in tunnels. Lipophilic ORAC was significantly increased by organic fertilization but was not affected by high-tunnel production. Total ORAC (hydrophilic + lipophilic) was significantly higher in pac choi from organic or open-field plots, compared to conventional and high-tunnel plots, respectively. Although fertilizer rate did not show significant impact on antioxidant level of pac choi, hydrophilic and total ORAC seemed to decrease as the fertilizer rate increased, especially under conventional fertilization, while lipophilic ORAC reached the highest level at the medium fertilizer rate. Differences in antioxidant levels were likely associated with the enhanced phytochemical content of pac choi from organically fertilized and open-field plots.

scholarly journals Primocane-fruiting Raspberry Production in High Tunnels in a Cold Region of the Upper Midwestern United States

2011 ◽  
Vol 21 (4) ◽  
pp. 429-434 ◽  
Author(s):  
Shengrui Yao ◽  
Carl J. Rosen
Keyword(s):  
Block Design ◽  
Climatic Conditions ◽  
Rubus Idaeus ◽  
Department Of Agriculture ◽  
High Tunnel ◽  
Grand Rapids ◽  
High Tunnels ◽  
Randomized Complete Block Design ◽  
Bare Root ◽  
Plant Hardiness

Five primocane raspberry (Rubus idaeus) cultivars were evaluated in a high tunnel and in the field at Grand Rapids, MN, which is located in U.S. Department of Agriculture (USDA) plant hardiness zone 3b. Bare root plants of five cultivars (Autumn Bliss, Autumn Britten, Caroline, Joan J, and Polana) were planted in the high tunnel and in the field, each with a randomized complete block design at 2 × 5.2-ft spacing on 8 May and 14 May 2008, respectively. A propane heater was used periodically for frost protection in the high tunnel. All five cultivars overwintered well and primocanes emerged with minor or no winter damage in the high tunnel in 2009. The high tunnel extended the growing season for ≈4 weeks in both years. Raspberry plants in the high tunnel produced higher yield than those in the field, total 154 lb (6655 lb/acre) from the high tunnel vs. 0.5 lb (43 lb/acre) from the field in 2008 and 379 lb (16,378 lb/acre) vs. 80 lb (3457 lb/acre) in 2009. ‘Caroline’ and ‘Polana’ had higher yields than ‘Autumn Bliss’; ‘Joan J’ and ‘Autumn Britten’ yields were intermediate and not different from ‘Caroline’, ‘Polana’, or ‘Autumn Bliss’ yields. In terms of harvest date, ‘Polana’ was the earliest among the five cultivars tested, followed by ‘Autumn Britten’, ‘Autumn Bliss’, and ‘Joan J’. ‘Caroline’ was the latest. Essential nutrients in leaves for all cultivars both in the field and in the high tunnel were within sufficient ranges. Spider mites (Tetranychidae) and raspberry sawflies (Monophanoides geniculatus) were the major insect problems. In conclusion, primocane-fruiting raspberries can be successfully grown in high tunnels and produce substantially higher yields than in field plantations in northern Minnesota or areas with similar climatic conditions.

scholarly journals Visual Assessments of Biodegradable Mulch Deterioration Are Not Indicative of Changes in Mechanical Properties

HortScience ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 245-254 ◽  
Author(s):  
Jeremy S. Cowan ◽  
Arnold M. Saxton ◽  
Hang Liu ◽  
Karen K. Leonas ◽  
Debra Inglis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Open Field ◽  
Production Systems ◽  
Agricultural Field ◽  
Plastic Mulch ◽  
High Tunnel ◽  
High Tunnels ◽  
Biodegradable Mulch ◽  
Visual Assessments

The functionality of biodegradable mulch can be evaluated in agricultural field settings by visually assessing mulch intactness over time (a measure of deterioration), but it is unclear if mulch deterioration is indicative of mulch degradation as measured by mechanical properties (like breaking force and elongation). This 3-year study (2010–12) examined mulch percent visual deterioration (PVD) during the summer growing season in open-field and high tunnel production systems, and compared these to mulch mechanical properties at mulch installation (12–30 May), midseason (22 July–9 Aug.), and season end (6–25 Oct.), to determine if the field-based measures reliably predict degradation as revealed by changes in mulch mechanical properties. Four different types of biodegradable mulches [two plastic film mulches marketed as biodegradable (BioAgri and BioTelo); one fully biodegradable paper mulch (WeedGuardPlus); and, one experimental spunbonded plastic mulch designed to biodegrade (SBPLA)] were evaluated against a standard nonbiodegradable polyethylene (PE) mulch where tomato (Solanum lycopersicum L. cv. Celebrity) was planted as the model crop. Each year for the 3 years, PVD increased earlier for WeedGuardPlus than the other mulches in both the high tunnel and open field, and WeedGuardPlus had the greatest PVD in both high tunnels and the open field (6% and 48%, respectively). Mechanical strength of WeedGuardPlus also declined by the end of the season both in the high tunnel (up to 46% reduction) and in the open field (up to 81% reduction). PVD of BioAgri and BioTelo reached a maximum of 3% in the high tunnel and 28% in the open field by the end of the season. Mechanical strength of BioAgri and BioTelo did not change over the course of the season in either the open field or high tunnel, even though the ability of these mulches to elongate or stretch declined 89% in the open field and 82% in the high tunnel. SBPLA and PE mulches did not show a change in PVD or mechanical properties in either the high tunnel or the open field. Overall, PVD was three to six times greater by midseason in the open field than in the high tunnels. Although there were significant relationships between visual assessments and various mechanical properties for each mulch except SBPLA, the relationships differed for each mulch when evaluated separately and had coefficients of determination (R2) below 30%. Furthermore, PVD overestimated mechanical deterioration of BioAgri and BioTelo. Results of this study indicate that mulch visual assessments may reflect general trends in changes in certain mechanical properties of the mulch; however, visual assessment and mechanical properties provide different information on deterioration. Each should be used as needed, but not as a substitute for each other.

scholarly journals The Effect of Open-Ended High Tunnels in Western Washington on Late Blight and Physiological Leaf Roll Among Five Tomato Cultivars

Plant Disease ◽  
2014 ◽  
Vol 98 (12) ◽  
pp. 1639-1647 ◽  
Author(s):  
M. Powell ◽  
B. Gundersen ◽  
J. Cowan ◽  
C. A. Miles ◽  
D. A. Inglis
Keyword(s):  
Late Blight ◽  
Open Field ◽  
Leaf Roll ◽  
Leaf Wetness ◽  
High Tunnel ◽  
Tomato Yield ◽  
High Tunnels ◽  
Western Washington ◽  
Tomato Cultivars ◽  
Field Plots

A 3-year study in western Washington from 2010 to 2012 evaluated five tomato cultivars for tomato disease development and yield in open-ended high-tunnel versus open-field settings. Findings in 2010 revealed that severity of late blight, caused by Phytophthora infestans (US-11), was significantly (P = 0.002) lower in high-tunnel compared with open-field experimental plots based on area under disease progress curve (AUDPC) values of 0.02 versus 321, respectively. In spite of rescue foliar fungicide applications to open-field plots in 2011 and 2012, the mean number of late blight infections across cultivars was 1.8 to 30.8 compared with only 0 to 6.5 in high tunnels for these years. Furthermore, accumulated hours of leaf wetness were fewer in high tunnels than the open field each year (857 versus 1,060 in 2010, 598 versus 998 in 2011, and 885 versus 923 in 2012). Cultivar susceptibility to late blight could not be differentiated in high tunnels due to low disease pressure. However, all five cultivars proved susceptible in the open field, with ‘Oregon Spring’ consistently having the most lesions. In contrast, high-tunnel production contributed to an increased severity of physiological leaf roll compared with open-field production each year, and these values differed significantly (P = 0.0335 and 0.0252) in 2011 and 2012, respectively. AUDPC values for physiological leaf roll showed that Oregon Spring was significantly (P = <0.0001) less susceptible than other cultivars each year. Physiological leaf roll correlated positively (r values of 0.758 to 0. 960) and significantly (P < 0.05) with leaf wetness and air temperature in all years in both high-tunnel and open-field settings but the same was not true for relative humidity. Even with severe physiological leaf roll, high-tunnel production in 2010 resulted in significantly (P < 0.0001) greater total tomato yield than open-field production (35.0 versus 10.6 t ha−1). Although a significant interaction between production system and cultivar occurred in 2011 and 2012, tomato yield always was greater in high-tunnel than open-field plots. Open-ended high tunnels offer tomato growers a potential tool for managing late blight in western Washington while also increasing yield, and could be especially useful in organic production.

scholarly journals Strawberry yields with high-tunnel and open-field cultivations and the relationship with vegetative and reproductive plant characteristics

2015 ◽  
Vol 33 (2) ◽  
pp. 147-154 ◽  
Author(s):  
Carlos Mario Grijalba ◽  
María Mercedes Pérez-Trujillo ◽  
Diana Ruiz ◽  
Ana María Ferrucho
Keyword(s):  
Open Field ◽  
Block Design ◽  
Fruit Size ◽  
Growth Conditions ◽  
Calcium Deficiency ◽  
High Tunnel ◽  
High Precipitation ◽  
Positive Correlations ◽  
Tunnel System ◽  
The Relationship

In Colombia, high-tunnel systems may be a viable alternative for increasing the yields of strawberry crops due to their ability to prevent fruit losses and plant damage caused during periods of high precipitation. This study aimed to compare the yield and its relationship with vegetative and reproductive components of Albion and Monterey strawberry cultivars, established in open-field and high-tunnel systems in Cajica (Colombia), at 2,562 m a.s.l. and 4°56'N, 74°00'W. A combined analysis of the environments was carried out. A random complete block design was used in each environment with six replications for each cultivar. This study evaluated the relationship between the leaf area, the number of crowns, the number of leaflets, the number of flowers, the number of inflorescences, the number of flowers per inflorescence, the number of fruits, the incidence of foliar damage, the yield per plant and the fruit size. There were positive correlations between the vegetative variables and the reproductive variables, which explained why 'Monterey', a cultivar with more vigor, presented a higher yield that 'Albion'. The growth conditions in the high-tunnel system promoted rapid vegetative growth in the 'Monterey' plants, with an increase in yield and a decrease in losses. The 'Albion' cultivar plants in the high-tunnel system presented a decrease in fruit losses; however, these plants did not present differences in the yield, as compared to the plants established in the open-filed system. Despite the benefits of a decrease in fruit losses due to rot seen in the high-tunnel system, this system had an increase in powdery mildew and calcium deficiency.

scholarly journals High Tunnel versus Open Field: Management of Primocane-fruiting Blackberry Using Pruning and Tipping to Increase Yield and Extend the Fruiting Season

HortScience ◽  
2009 ◽  
Vol 44 (6) ◽  
pp. 1581-1587 ◽  
Author(s):  
Ellen Thompson ◽  
Bernadine C. Strik ◽  
Chad E. Finn ◽  
Yanyun Zhao ◽  
John R. Clark
Keyword(s):  
Open Field ◽  
Fruit Production ◽  
State University ◽  
Cumulative Yield ◽  
High Tunnel ◽  
Cultural Systems ◽  
Season Extension ◽  
Lateral Branches ◽  
Extension Center ◽  
Fruit Harvest

Primocane-fruiting blackberries (Rubus subgenus Rubus Watson) may offer opportunities for season extension and off-season fruit production, particularly in mild climates with protected culture. In May 2005, plants of ‘Prime-Jan’® were established at the Oregon State University–North Willamette Research and Extension Center, Aurora, OR. Half of the planting was established under a high tunnel and the remainder planted in an adjacent open field. In 2006 to 2007, primocanes were subjected to four treatments to promote branching and/or delay harvest: 1) all primocanes within the plot were cut to the ground when averaging 0.25 m tall, then later emerging canes soft-tipped when reaching 0.5 m tall (C0.25m/T0.5m); 2) all primocanes within the plot were cut to the ground when averaging 0.5 m tall, then later emerging canes soft-tipped when reaching 0.5 m (C0.5m/T0.5m); 3) primocanes double-tipped: all primocanes within the plot were soft-tipped when averaging 0.5 m tall with subsequent lateral branches then soft-tipped when reaching 0.5 m long (T0.5m/Tb0.5m); and 4) primocanes were soft-tipped when averaging 0.5 m tall (T0.5m; control). The tunnel was covered with plastic from 5 Sept. 2006 and 31 Aug. 2007, ≈1 to 2 weeks before harvest until the end of harvest to protect fruit from inclement weather. On average, fruit harvest began on 12 Sept. in the open field and tunnel, but lasted ≈3 weeks longer in the tunnel, ending on 16 Nov., on average. Primocanes that were double-tipped had nearly twice the flowers and fruit than canes that were soft-tipped only once (T0.5m; control). In the tunnel, cumulative yield of double-tipped primocanes averaged 10.7 t·ha−1 in 2006 and 19.3 t·ha−1 in 2007, a 267% and 159% increase compared with the control, respectively. On average, cumulative yield for all treatments was less in the open field than in the tunnel, although cultural systems could not be compared statistically. Harvest was not delayed in the C0.25m/T0.5m treatment in 2006 compared with the control and the double-tipped treatments; however, in 2007, harvest was delayed by 2 weeks in C0.25m/T0.5m. In contrast, harvest was delayed by ≈4 weeks when primocanes were cut to the ground at 0.5 m (C0.5m/T0.5m). Primocanes that were double-tipped produced heavier fruit than other treatments (33% heavier than the control, on average). Double-tipped primocanes did not have more ovules per flower, but had significantly more drupelets set compared with the control. In addition, plants growing under the tunnel tended to produce heavier fruit (32%, on average) than those grown in the open field. Harvest date affected fruit pH in 2006, but not in 2007. In 2006, fruit pH was highest in the early season. All other differences in fruit chemistry were not significant. The pruning and tipping systems used here increased yield and offered options for season extension.

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