Effect of Light Characteristics on the Sensory Properties of Red Lettuce (Lactuca sativa)

Leafy green production in high tunnels (HTs) results in increased yields, improved visual quality, and extended production with polyethylene (poly) film and/or shade cloth coverings. However, altering visible and ultra-violet light with HT coverings may reduce phytochemicals, thus influencing plant pigmentation and taste. The objective of this study was to examine various HT coverings on the sensory perceptions, soil temperature, color, and anthocyanin accumulation of red leaf lettuce. The coverings included standard poly, standard poly with removal two weeks prior to harvest (movable), diffuse poly, clear poly, UV-A/B blocking poly (block), standard poly with 55% shade cloth, and the open field. A highly trained descriptive panel evaluated the samples using a scale from 0 (none) to 15 (extremely high) and determined a list of 20 sensory attributes. The color intensity attribute had the most differentiation between coverings, and the open field was higher (i.e., darker) than the others at 7.5 (p < 0.0001), followed by clear and movable coverings at 6.8, and the shade covering scored a 2. Strong relationships existed between both colorimetric (hue°) and anthocyanin analysis to panelist-based scores (R2 = 0.847 and 0.640, respectively). The initial crispness was similar for movable, standard, diffuse, and block coverings at 5.3 on average, which was higher than the open field at 4 (p < 0.01). The open field lettuce grew under cooler soil temperatures, which may have slowed down maturation and resulted in softer tissue. Based on this study, HT growers can implement specific coverings to cater to markets that value visual quality.

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Impact of Shade and Fogging on High Tunnel Production and Mineral Content of Organically Grown Lettuce, Basil, and Arugula in Georgia

Agriculture ◽

10.3390/agriculture11070625 ◽

2021 ◽

Vol 11 (7) ◽

pp. 625

Author(s):

Savanah Laur ◽

Andre Luiz Biscaia Ribeiro da Silva ◽

Juan Carlos Díaz-Pérez ◽

Timothy Coolong

Keyword(s):

Mineral Content ◽

Planting Date ◽

High Tunnel ◽

Lactuca Sativa L ◽

Air Temperatures ◽

Shade Cloth ◽

High Tunnels ◽

Soil Temperatures ◽

Organically Grown ◽

The Impact

This study evaluated the impact of shade cloth and fogging systems on the microclimate at the plant canopy level and yield of basil (Oscimum basilicum L.), arugula (Eruca vesicaria subsp. Sativa L.), and lettuce (Lactuca sativa L.) planted in mid-September and early October in high tunnels. Fogging systems were installed at canopy level in plots within shaded (30%) and non-shaded high tunnels. Average air temperatures in the shaded high tunnels were 0.9 °C lower than non-shaded high tunnels during the day. Shade cloth significantly reduced soil temperatures during the day and night periods by 1.5 °C and 1.3 °C, respectively, compared to non-shaded treatments. Fogging systems did not have an impact on air temperature, soil temperature, or relative humidity, but did increase canopy leaf wetness. Shade and fogging did not impact the yield of any of the crops grown. Yield was impacted by planting date, with earlier planting result in higher yields of lettuce and basil. Yields for arugula were greater during the second planting date than the first. Planting date and shade cloth interacted to affect the concentrations of macronutrients.

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Spectral Blocking of Solar Radiation in High Tunnels by Poly Covers: Its Impact on Nutritional Quality Regarding Essential Nutrients and Health-Promoting Phytochemicals in Lettuce and Tomato

Horticulturae ◽

10.3390/horticulturae7120524 ◽

2021 ◽

Vol 7 (12) ◽

pp. 524

Author(s):

Myungjin Lee ◽

Cary Rivard ◽

Weiqun Wang ◽

Eleni Pliakoni ◽

Kelly Gude ◽

...

Keyword(s):

Phenolic Compounds ◽

Solar Radiation ◽

Nutritional Quality ◽

Spectral Characteristics ◽

Green Leaf ◽

Essential Nutrients ◽

Shade Cloth ◽

High Tunnels ◽

Health Promoting ◽

Leaf Lettuce

Spectral characteristics of solar radiation have a major role in plant growth and development and the overall metabolism, including secondary metabolism, which is important for the accumulation of health-promoting phytochemicals in plants. The primary focus of this study was to determine the effect of spectral characteristics of solar radiation on the nutritional quality of lettuce (Lactuca sativa L., cv. red leaf ‘New Red Fire’ and green leaf ‘Two Star’ and tomato (Solanum lycopersicum L., cv. BHN-589) grown in high tunnels in relation to the accumulation of essential nutrients and phytochemicals. Solar spectrum received by crops was modified using photo-selective poly covers. Treatments included commonly used standard poly, luminescence poly (diffuse poly), clear poly, UV blocking poly, exposure of crops grown under the standard poly to full sun 2 weeks prior to harvest (akin to movable tunnel), and 55% shade cloth on the standard poly. All the poly covers and shade cloth reduced the PAR levels in the high tunnels, and the largest reduction was by the shade cloth, which reduced the solar PAR by approximately 48%. Clear poly allowed the maximum UV-A and UV-B radiation, while standard poly allowed only a small fraction of the solar UV-A and UV-B (between 15.8% and 16.2%). Clear poly, which allowed a higher percentage of solar UV-A (60.5%) and UV-B (65%) than other poly covers, increased the total phenolic concentration and the antioxidant capacity in red leaf lettuce. It also increased the accumulation of flavonoids, including quercetin-3-glucoside, luteolin-7-glucoside, and apigenin-3-glucoside in red leaf lettuce, compared to the standard poly. Brief exposure of crops grown in high tunnels to full sun prior to harvest produced the largest increase in the accumulation of quercetin-3-glucoside, and it also resulted in an increase in luteolin-7-glucoside and apigenin-3-glucoside in red leaf lettuce. Thus, clear poly and brief exposure of red leaf lettuce to the full sun, which can increase UV exposure to the plants, produced a positive impact on its nutritional quality. In contrast, shade cloth which allowed the lowest levels of solar PAR, UV-A and UV-B relative to the other poly covers had a negative impact on the accumulation of the phenolic compounds in red leaf lettuce. However, in green leaf lettuce, luminesce poly, clear poly, UV-block poly, and shade treatments increased the accumulation of many essential nutrients, including protein, magnesium, and sulfur in green leaf lettuce compared to the standard poly. Poly cover treatments including shade treatment did not affect the accumulation of either carotenoids (lutein, β-carotene, and lycopene) or essential nutrients in mature tomato fruits. The results show that clear poly cover can enhance the accumulation of many phenolic compounds in red leaf lettuce, as does the brief exposure of the crop to the full sun prior to harvest. Thus, UV radiation plays an important role in the accumulation of phenolic compounds in red leaf lettuce while the overall spectral quality of solar radiation has a significant influence on the accumulation of essential nutrients in green leaf lettuce.

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(202) Microclimate and Reference Crop Evapotranspiration in High Tunnels and Open Field during Summer Lettuce Production

HortScience ◽

10.21273/hortsci.40.4.1054d ◽

2005 ◽

Vol 40 (4) ◽

pp. 1054D-1055

Author(s):

Xin Zhao ◽

Edward E. Carey

Keyword(s):

Open Field ◽

Meteorological Data ◽

Daily Basis ◽

Crop Evapotranspiration ◽

Reference Crop Evapotranspiration ◽

Horticultural Crops ◽

High Tunnels ◽

Use Efficiency ◽

Leaf Lettuce ◽

Reference Crop

High tunnels, unheated greenhouses, have been shown to be a profitable season-extending production tool for many horticultural crops. Production of cool-season vegetables during hot summer months can be achieved using shaded high tunnels. Microclimate in high tunnels and open field was monitored during summer trials of leaf lettuce, in which unshaded tunnels and shaded tunnels (39% PAK white shadecloth) were used, respectively, in 2002 and 2003. Wind speed was consistently lower in high tunnels. Compared to open field, daily air temperature was about 0.7 °C higher in unshaded high tunnels, and 0.5 °C lower in shaded high tunnels. Relative humidity was slightly lower in unshaded tunnels, but tended to increase in shaded tunnels, in comparison to the open field. When using shadecloth, soil temperature was lowered by 1∼3 °C and the leaf surface temperature was significantly reduced by 1.5∼2.5 °C. In shaded high tunnels, PAR light dropped by at least 50% relative to the outside, where the maximum PAR light intensity reached 1800 μmol·m-2·s-1. Overall, shaded high tunnels resulted in higher quality lettuce, with less bolting and bitterness. Reference crop evapotranspiration (ET0) was estimated from meteorological data on a daily basis using the FAO-56 method. ET0 was lowest in shaded high tunnels, and 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.

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High Tunnel Coverings Alter Crop Productivity and Microclimate of Tomato and Lettuce

HortScience ◽

10.21273/hortsci16208-21 ◽

2022 ◽

Vol 57 (2) ◽

pp. 265-272

Author(s):

Kelly M. Gude ◽

Eleni D. Pliakoni ◽

Brianna Cunningham ◽

Kanwal Ayub ◽

Qing Kang ◽

...

Keyword(s):

Net Photosynthetic Rate ◽

Photosynthetic Rate ◽

Crop Productivity ◽

Full Spectrum ◽

High Tunnel ◽

High Tunnels ◽

Soil Temperatures ◽

Subsequent Crop ◽

Leaf Lettuce ◽

The Impact

The implementation of high tunnels has shown to increase marketability and/or yield of tomato (Solanum lycopersicum) and lettuce (Lactuca sativa) crops compared with open-field systems. These structures provide the opportunity to alter light intensity and spectral quality by using specific polyethylene (poly) films and/or shadecloth, which may affect microclimate and subsequent crop productivity. However, little is known about how specific high tunnel coverings affect these parameters. The overall goal of this study was to evaluate the impact of various high tunnel coverings on the microclimate and crop productivity of tomato and lettuce. The coverings included standard, ultraviolet (UV)-stabilized poly film (standard); diffuse poly (diffuse); full-spectrum clear poly (clear); UV-A/B blocking poly (block); standard + 55% shadecloth (shade); and removal of standard poly 2 weeks before initial harvest to simulate a movable tunnel (movable). Microclimate parameters that were observed included canopy and soil temperatures, canopy growing degree-days (GDD), and photosynthetic active radiation (PAR), and crop productivity included yield and net photosynthetic rate. Hybrid red ‘BHN 589’ tomatoes were grown during the summer, and red ‘New Red Fire’ and green ‘Two Star’ leaf lettuce were grown in both spring and fall in 2017 and 2018. Increased temperature, GDD, and PAR were observed during the spring and summer compared with the fall. The soil temperatures during the summer increased more under the clear covering compared with the others. For tomato, the shade produced lower total fruit yield and net photosynthetic rate (Pn) compared with the other treatments, which were similar (P < 0.001 and <0.001, respectively). The greatest yield was 7.39 kg/plant, which was produced under the clear covering. For red leaf lettuce grown in the spring, the plants under the clear, standard, and diffuse coverings had significantly greater yield than the movable and shade coverings (P < 0.001). The coverings had less effect on the yield during the fall lettuce trials, which may have been attributed to the decrease in PAR and environmental temperatures. The findings of this study suggest that high tunnel coverings affect both microclimate and yield of lettuce and tomato.

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(23) High Tunnels for High Latitude Snap Bean Production

HortScience ◽

10.21273/hortsci.41.4.1074c ◽

2006 ◽

Vol 41 (4) ◽

pp. 1074C-1074

Author(s):

Heidi Rader ◽

Meriam Karlsson

Keyword(s):

Open Field ◽

Soluble Solids ◽

Production Environment ◽

Fresh Market ◽

High Quality ◽

Snap Bean ◽

High Tunnel ◽

Significant Difference ◽

High Tunnels ◽

Soil Temperatures

Two snap bean (Phaseolus vulgaris L.) cultivars, `Provider' and `Concesa', were planted successionally in a high tunnel in Fairbanks, Alaska (64°49'N and 147°52'W), from late May to late July. For the entire growing season, air/soil temperatures averaged 1.7 °C/1.1 °C higher in the tunnel than the field. The temperature differential was, however, largely dependent on amount of high tunnel ventilation. With tunnel ends not yet erected in May, the air temperature difference averaged 0.5 °C while in September the difference was 2.5 °C in the enclosed tunnel. On average, both cultivars flowered 4 days earlier in the tunnel compared to the contiguous open field. `Provider' had high overall yields with no significant difference between the tunnel and the field, although the tunnel did offer protection from an early frost. `Provider' produced an average of 3454 g·m-2 in the tunnel and 2860 g·m-2 in the field. Average yields of `Concesa' inside the tunnel were significantly greater (P < 0.01), with 1719 g·m-2 compared to 756 g·m-2 in the open field. `Provider' pods were larger in diameter and more fibrous than `Concesa' pods, which we concluded were of improved quality with higher soluble solids content (°Brix refractometer readings). High tunnels could be an important way to provide an advantageous production environment for high quality cultivars without sacrificing the reliability of cold-tolerant cultivars. To consistently produce high quality snap beans to meet local Alaska fresh market demands, cultivars suited for high tunnel production need to be identified.

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

HortTechnology ◽

10.21273/horttech.23.2.227 ◽

2013 ◽

Vol 23 (2) ◽

pp. 227-236 ◽

Cited By ~ 3

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.

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High Tunnel Apricot Production in Frost-prone Northern New Mexico

HortTechnology ◽

10.21273/horttech04315-19 ◽

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.

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

HortTechnology ◽

10.21273/hortsci.19.1.113 ◽

2009 ◽

Vol 19 (1) ◽

pp. 113-119 ◽

Cited By ~ 12

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.

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176 Effect of Plastic Rowcover on Watermelon Crop

HortScience ◽

10.21273/hortsci.34.3.472d ◽

1999 ◽

Vol 34 (3) ◽

pp. 472D-472

Author(s):

Elattir Hassan ◽

Youness Chabi

Keyword(s):

Open Field ◽

Sandy Soil ◽

Block Design ◽

Experiment Design ◽

Citrullus Vulgaris ◽

Experiment Station ◽

Randomized Block Design ◽

Soil Temperatures

Citrullus vulgaris cv Rocio hybrid F1 was seeded 18 Jan. 1994 and transplanted 1 month later in loam-sandy soil at the experiment station of the Complexe Horticole, 16 km south of Agadir. Watermelon plants grown under perforated plastic rowcover with 800 holes per square meter were compared to the open-field plants. The experiment design used was a randomized block design with two treatments (rowcover and open field) and four repetitions. Rowcover was put at planting and removed 90 days later. Under the rowcover the minimal and maximal temperatures were higher than the ones of the open field by 0.9 to 2.4 and 3 to 6.8 °C, respectively. Soil temperatures at 10-cm depth measured at 7:00 am and 4:00 pm were higher under cover by 1.2 and 2.7 °C, respectively. Early yield of watermelon obtained under perforated plastic rowcover and in open field were 6.55 kg/plant (78.6 t/ha) and 2.45 kg/plant (29.4 t/ha), respectively.

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

HortTechnology ◽

10.21273/horttech.22.5.659 ◽

2012 ◽

Vol 22 (5) ◽

pp. 659-668 ◽

Cited By ~ 12

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.

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