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within a given greenhouse facility. Spectral assessments were made six times at the two-tiered and five times each at the one- and three-tiered greenhouses between 4 Apr. and 24 May 2012. Results and discussion Light quantity. Figure 1 shows typical

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The daily light integral (DLI) is a measurement of the total amount of photosynthetically active radiation delivered over a 24-hour period and is an important factor influencing plant growth over weeks and months. Contour maps were developed to demonstrate the mean DLI for each month of the year across the contiguous United States. The maps are based on 30 years of solar radiation data for 216 sites compiled and reported by the National Renewable Energy Lab in radiometric units (watt-hours per m-2·d-1, from 300 to 3,000 nm) that we converted to quantum units (mol·m-2·d-1, 400 to 700 nm). The mean DLI ranges from 5 to 10 mol·m-2·d-1 across the northern U.S. in December to 55 to 60 mol·m-2·d-1 in the southwestern U.S. in May through July. From October through February, the differences in DLI primarily occur between the northern and southern U.S., while from May through August the differences in DLI primarily occur between the eastern and western U.S. The DLI changes rapidly during the months before and after the vernal and autumnal equinoxes, e.g., increasing by more than 60% from February to April in many locations. The contour maps provide a means of estimating the typical DLI received across the U.S. throughout the year.

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Replicated trials were conducted in Summers 1998 and 1999 at two commercial orchards (A and B) to determine the influence of a metalized, high density polyethylene reflective film (SonocoRF) and aminoethoxyvinylglycine (ReTain), on fruit red skin coloration and maturity of `Gala' apples (Malus sylvestris var. domestica). There were four experimental treatments: 1) nontreated control; 2) reflective film (RF); 3) ReTain; and 4) RF + ReTain. RF was applied 4 weeks before anticipated start of harvest by laying a 5-ft-wide (150-cm) strip on each side of the tree row in the row middle. ReTain was applied 4 weeks before harvest at the commercial rate in one orchard and at 60% of the commercial rate in a second test. ReTain delayed fruit maturity. Fruit from RF trees had a significantly greater percent surface red color than fruit from trees not treated with RF. Fruit from RF + ReTain were significantly redder and had higher soluble solids concentration (SSC) than fruit from trees treated with ReTain alone. There were no differences in size, fruit firmness or starch content between fruit from RF and RF + Retain. RF appears to be a method to increase red skin coloration in `Gala' apples treated with ReTain without adversely impacting maturity.

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Replicated trials were conducted during the summers of 1998 and 1999 at commercial orchards in South Carolina to determine the influence of ground application of a metalized, high density polyethylene reflective film on fruit red skin color and maturity of peach (Prunus persica) cultivars that historically have poor red coloration. At each site there were two experimental treatments: 1) control and 2) reflective film (film). Film was applied 2 to 4 weeks before anticipated first harvest date by laying a 150-cm (5-ft) wide strip of plastic on either side of the tree row in the middles. Treatment areas at a given farm ranged from 0.25 to 0.5 ha (0.5 to 1.0 acre) in size and each treatment was replicated four times at each site. At harvest, two 50-fruit samples were picked from each plot per treatment. All fruit were sized and visually sorted for color (1 = 0% to 25%, 2 = 26% to 50%, 3 = 51% to 75%, and 4 = 76% to 100% red surface, respectively). A 10-fruit subsample was selected following color sorting and evaluated for firmness and soluble solids concentration (SSC). All cultivars tested (`CVN1', `Loring', `Bounty', `Summer Gold', `Sunprince', `Cresthaven' and `Encore') experienced significant increases in percent red surface when film was used in 1998 and 1999. This color improvement ranged from 16% to 44% (mean = 28%). On average, fruit from film were 4.2 N (0.9 lb force) softer and had 0.3% higher SSC than control fruit. Growers harvested more fruit earlier and in fewer harvests for film. Fruit size was not affected by film. Reflected solar radiation from film was not different in quality than incident sunlight. Film resulted in an increase in canopy air temperature and a reduction in canopy relative humidity during daylight hours.

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30% to 60% even without hanging baskets ( Critten, 1986 , 1989 , 1993 ). Hanging baskets potentially impact both the light quantity and spectral light quality delivered to the underlying bench crop as leaves differentially absorb, transmit, or

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size and branching. Literature cited Armitage, A.M. 2001 Armitage's manual of annuals, biennials, and half-hardy perennials Timber Press Portland, OR Beckwith, A.G. Zhang, Y. Seeram, N.P. Cameron, A.C. Nair, M.G. 2004 Relationship of light quantity and

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50 estimates observed in Expt. 1 could be due to reduced light quantity and quality when the experiment was conducted (January for Expt. 1 vs. September for Expt. 2). In both experiments, LD 50 estimates were greater than GR 50 estimates, with GR

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measured in the nursery but in other experiments the nets reduced light quantity (37.3 mol·d −1 ) compared with the open treatment (40.1 mol·d −1 ). Fig. 1. Effect of eco-friendly net on daily air temperature and relative humidity during tomato transplant

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received by plants, the daily light integral (DLI) was calculated with the PPF detected at the heights of the plant canopy at certain growing stages ( Table 1 ) to further illustrate the light quantity of different illumination schedules. Fig. 4. The

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production system, fresh-market tomatoes are grown on plastic-mulched raised beds and irrigated and fertilized through drip tape lying under the plastic. Plastic mulches help in suppressing weeds by providing a physical barrier and by altering the light

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