Growth of Tomatoes Under Hybrid Led and HPS Lighting

Abstract

The use of LEDs can be promising for greenhouse horticulture, but before it can be put into practice on a large scale more knowledge must be acquired on effects of LED lighting on crops. Furthermore, the growers will have to learn to grow their crops under LEDs and the efficiency of LEDs must increase even more. In order to gain more insight into the influence of LEDs on crop growth and production, an experiment was performed in the Wageningen UR greenhouses with a small Santa type tomato ( Differences in production were small, although the production under all LEDs was lower. There were only small differences in fruit quality. The amount of energy required per kilogram tomato was highest in the LED treatment and hybrid with top LED lighting. This was primarily due to the fact that a higher air temperature was necessary and these LEDs were cooled and the cost of cooling added to the use of energy. The consequences and future perspectives of the different types of supplementary lighting for crop growth and production as well as for crop management practices will be discussed. INTRODUCTIONThe use of LED assimilation lighting can become an important player in greenhouse horticulture if energy efficient LEDs can increase production in the winter. However, before LEDs can be broadly applied in horticulture, more knowledge is necessary on the effects of LEDs on crops, how to manage crops growing under LEDs and how efficient they really are, not only in terms of light output, but also in relation to crop production. While the energy efficiency of LEDs is the result of technical improvement, knowledge on the effects of various lighting systems with LEDs on greenhouse crops and crop management as well as the efficiency of LED lighting per unit production must result from experimental research. To date, in experiments with LED lighting systems in greenhouses problems with crop growth and physiology have been encountered and are thought to be due to insufficient tuning of crop cultivation to assimilation lighting with LEDs (Nederhoff et al., 2010). These problems seem to focus on plant temperature, plant load and the influence of LED lighting on plant morphology

Significant reduction in energy for plant-growth lighting in space using targeted LED lighting and spectral manipulation

“…More recently, Gomez et al (2013) showed that intracanopy LED lighting during highwire greenhouse tomato cultivation enabled the consumption of 4.3 times less energy for supplemental lighting than with overhead HPS lamps. In recent years, LED plant research has indeed become more active in the horticulture greenhouse industry because of potential energy savings, as indicated by the study of Dueck et al (2012) on hybrid supplemental lighting utilizing overhead HPS lamps and "interlighting" with LEDs.…”

Sustainable crop production in greenhouses based on understanding crop physiology

“…Several authors concluded that positioning the lamps in between the canopy can improve production compared to lamps above the canopy, due to the better light absorption and better vertical light distribution (e.g. Hovi-Pekkanen and Tahvonen, 2008), although in some experiments no substantial yield improvement was found by interlighting compared to lamps above the canopy (Trouwborst et al, 2010;Dueck et al, 2012). More attempts at optimization of interlighting are needed to fully exploit its potential benefits.…”

“…For instance the optimum temperature for photosynthesis varies with growth temperature (acclimation), CO2 concentration and light intensity (Qian et al, 2012;Yamori et al, 2014). The optimal set-point for air temperature is different whether LEDs or high pressure sodium lamps are used as supplementary light in a greenhouse (Dueck et al, 2012). Furthermore, short and long term responses can be very different due to acclimation and feed-back mechanisms.…”

Effect of source-sink manipulation on yield and related yield components in cassava, Manihot esculenta Crantz

“…Cultivars may also vary in strength as the source of the property leaf photosynthesis, leaf area and plant architecture may be different. Dueck et al (2010) observed that under the influence of additional lighting management of commercial crops that are small in comparison with the cherry tomato cultivars with large-sized fruits. A large bottom size, as well as efficient transport of photo-assimilates from the leaves and stems to develop the sink are required in the manufacture of high yield and high harvest index of the entire plant.…”