| Summary: | Rit LbhÍ nr. 61 Final report of the research project „Áhrif LED lýsingar á vöxt, uppskeru og gæði gróðurhúsasalats að vetri“ In Iceland, winter production of greenhouse crops is totally dependent on supplementary lighting and has the potential to extend seasonal limits and replace imports during the winter months. However, in autumn and winter is it difficult to get the red colour in red salad. Therefore, adequate guidelines for winterproduction of salad are not yet in place and need to be developed. The objective of this study was to test the development, growth and yield of red salad under HPS lights compared to LED lights. The time that is necessary under LED’s, when in the growth period the red colour can be encouraged by LED’s and which lighting treatment is economically viable was investigated. An experiment with red salad (cv. Carmoli) was conducted in winter 2014, from the end of November to December, in the research greenhouse of the Agricultural University of Iceland at Reykir. Plants were grown in NFT channels in four repetitions under toplighting with high-pressure vapour sodium lamps (HPS) and / or under LED lights for 18 hours. Day temperature was 19 °C and night temperature 15 °C. Salad received standard nutrition through drip irrigation. The plant density was 68, 40, 28 and 22 plants per squaremeter after one, two, three and four weeks after planting. The lighting treatment that resulted in a satisfactory red colour in salad and in good yield was always under HPS lights and the last week under LEDs. A redder colour was reached with LED lights at the end of the growth period, while is was not paying off to use this lighting source in the first part of the growth period, because whose effect was gone after the use of HPS lights and the red colour was even less compared to plants that got only HPS lights. Two times more kWh were used by only HPS lights compared to the only use of LED lights. In contrast, the yield with the only use of LED lights was around ¼ less. More yield was going ahead with a ...
|
|---|