Development and Implementation of a New Optimal Supplemental Lighting Control Strategy in Greenhouses

2020 ◽  
Author(s):  
Sahand Mosharafian ◽  
Shirin Afzali ◽  
Javad Mohammadpour Velni ◽  
Marc W. van Iersel
Keyword(s):  
Heuristic Method ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Raspberry Pi ◽  
Photon Flux Density ◽  
Time Step ◽  
Electricity Cost ◽  
Electricity Costs ◽  
Supplemental Lighting ◽  
A Site

Abstract The use of supplemental lighting is an effective way for increasing greenhouse productivity. Recently, using light-emitting diodes (LEDs), capable of precise and quick dimmability, has increased in greenhouses. However, electricity cost of lighting can be significant, and hence, it is necessary to find optimal lighting strategies to minimize supplemental lighting costs. In this paper, we model supplemental lighting in the greenhouse equipped with LEDs as a constrained optimization problem, and we aim at minimizing electricity costs of supplemental lighting. We consider not only plant daily light integral (DLI) need during its photoperiod but also sunlight prediction and variable electricity pricing in our model. We use Markov chain to predict sunlight irradiance throughout the day. By taking sunlight prediction information into account, we avoid supplying more light than plants require. Therefore, our lighting strategy provides sufficient light for plant growth while minimizing electricity costs during the day. We propose an algorithm to find optimal supplemental lighting strategy and evaluate its performance through exhaustive simulation studies using a whole year data and compare it to a heuristic method, which aims to supply a fixed photosynthetic photon flux density (PPFD) to plants at each time-step during the day. We also implement our proposed lighting strategy on Raspberry Pi using Python programming language. Our prediction-based lighting approach shows (on average) about 23% electricity cost reduction compared to a heuristic method throughout the year for a site located at West Virginia.

scholarly journals Comparative Analysis of Horizontal and Vertical Decoupled Aquaponic Systems for Basil Production and Effect of Light Supplementation by LED

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1414
Author(s):  
Víctor M. Fernández-Cabanás ◽  
Luis Pérez-Urrestarazu ◽  
Alexes Juárez ◽  
Nathan T. Kaufman ◽  
Jackson A. Gross
Keyword(s):  
Unit Area ◽  
Growth Parameters ◽  
Parameters Optimization ◽  
Joint Production ◽  
Source Distribution ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Total Production ◽  
Electricity Cost ◽  
Supplemental Lighting

Aquaponic facilities allow the joint production of fish and plants in a reduced space. This hydroponic technique, combined with vertical farming, is not well studied. The main objective of this work was to compare basil production between horizontal and vertical decoupled aquaponic systems and assess the utilization of supplemental lighting in a greenhouse environment. Six independent vertical racks were arranged with hydroponic trays at three heights. Three racks were affixed with LED lighting on the lowest levels and three with supplemental lighting on the intermediate level. Immediately adjacent to the vertical systems, two independent horizontal systems containing three trays were constructed to compare basil production. After 35 days of growth post transplanting, the total production per tray and weight, height, number of leaves, and nodes of 20 selected plants per tray were determined. Records of the intensity of illumination photosynthetic photon flux density (PPFD)) were recorded at dawn (8:00), noon (12:00), and dusk (18:00) at randomly predetermined positions associated with the 20 selected plants per tray. The total basil production in the experiment was 58.79 kg, with an average production per unit area of 2.43 and 0.94 kg m−2 for vertical and horizontal systems, respectively. Productivity per unit area in the vertical systems was 160% greater than in horizontal systems. A significant effect of lighting, the height of the tray, and plant position inside the tray was found on plant growth parameters. Optimization of light source distribution and tray orientation can enhance the productive performance in vertical aquaponic systems. Electricity cost associated with supplemental lighting per kg of production increment was 21.84 and 12.25 $ kg−1 for the bottom and intermediate levels of the vertical system, respectively, the latter being economically the most profitable.

scholarly journals Effect of Supplementary Light Intensity on Quality of Grafted Tomato Seedlings and Expression of Two Photosynthetic Genes and Proteins

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 339 ◽  
Author(s):  
Hao Wei ◽  
Jin Zhao ◽  
Jiangtao Hu ◽  
Byoung Ryong Jeong
Keyword(s):  
Light Intensity ◽  
Dry Weight ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Natural Lighting ◽  
Tomato Seedlings ◽  
Photosynthetic Genes ◽  
Supplemental Lighting

Lower quality and longer production periods of grafted seedlings, especially grafted plug seedlings of fruit vegetables, may result from insufficient amounts of light, particularly in rainy seasons and winter. Supplemental artificial lighting may be a feasible solution to such problems. This study was conducted to evaluate light intensity’s influence on the quality of grafted tomato seedlings, ‘Super Sunload’ and ‘Super Dotaerang’ were grafted onto the ‘B-Blocking’ rootstock. To improve their quality, grafted seedlings were moved to a glasshouse and grown for 10 days. The glasshouse had a combination of natural lighting from the sun and supplemental lighting from LEDs (W1R2B2) for 16 h/day. Light intensity of natural lighting was 490 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) and that of supplemental lighting was 50, 100, or 150 μmol·m−2·s−1 PPFD. The culture environment had 30/25 °C day/night temperatures, 70% ± 5% relative humidity (RH), and a natural photoperiod of 14 h as well. Compared with quality of seedlings in supplemental lighting of 50 μmol·m−2·s−1 PPFD, that of seedlings in supplement lighting of 100 or 150 μmol·m−2·s−1 PPFD improved significantly. With increasing light intensity, diameter, fresh weight, and dry weight, which were used to measure shoot growth, greatly improved. Leaf area, leaf thickness, and root biomass were also greater. However, for quality of seedlings, no significant differences were discovered between supplement lighting of 100 μmol·m−2·s−1 PPFD and supplement lighting of 150 μmol·m−2·s−1 PPFD. Expressions of PsaA and PsbA (two photosynthetic genes) as well as the corresponding proteins increased significantly in supplement lightning of 100 and 150 μmol·m−2·s−1 PPFD, especially in 100 μmol·m−2·s−1 PPFD. Overall, considering quality and expressions of two photosynthetic genes and proteins, supplemental light of 100 μmol·m−2·s−1 PPFD (W1R2B1) would be the best choice to cultivate grafted tomato seedlings.

scholarly journals Development and Implementation of an IoT-Enabled Optimal and Predictive Lighting Control Strategy in Greenhouses

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2652
Author(s):  
Shirin Afzali ◽  
Sahand Mosharafian ◽  
Marc W. van Iersel ◽  
Javad Mohammadpour Velni
Keyword(s):  
Heuristic Method ◽  
Experimental Studies ◽  
Growth Parameter ◽  
Environmental Parameters ◽  
Cost Effective ◽  
Time Step ◽  
Lighting Control ◽  
Electricity Cost ◽  
Supplemental Lighting ◽  
The Cost

Global population growth has increased food production challenges and pushed agricultural systems to deploy the Internet of Things (IoT) instead of using conventional approaches. Controlling the environmental parameters, including light, in greenhouses increases the crop yield; nonetheless, the electricity cost of supplemental lighting can be high, and hence, the importance of applying cost-effective lighting methods arises. In this research paper, a new optimal supplemental lighting approach was developed and implemented in a research greenhouse by adopting IoT technology. The proposed approach minimizes electricity cost by leveraging a Markov-based sunlight prediction, plant light needs, and a variable electricity price profile. Two experimental studies were conducted inside a greenhouse with “Green Towers” lettuce (Lactuca sativa) during winter and spring in Athens, GA, USA. The experimental results showed that compared to a heuristic method that provides light to reach a predetermined threshold at each time step, our strategy reduced the cost by 4.16% and 33.85% during the winter and spring study, respectively. A paired t-test was performed on the growth parameter measurements; it was determined that the two methods did not have different results in terms of growth. In conclusion, the proposed lighting approach reduced electricity cost while maintaining crop growth.

scholarly journals Effect of Pre-Harvest Supplemental UV-A/Blue and Red/Blue LED Lighting on Lettuce Growth and Nutritional Quality

Horticulturae ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 80
Author(s):  
Triston Hooks ◽  
Joseph Masabni ◽  
Ling Sun ◽  
Genhua Niu
Keyword(s):  
Blue Light ◽  
Nutritional Quality ◽  
Uv Light ◽  
Ultra Violet ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Daily Light Integral ◽  
Lettuce Growth ◽  
Supplemental Lighting

Blue light and ultra-violet (UV) light have been shown to influence plant growth, morphology, and quality. In this study, we investigated the effects of pre-harvest supplemental lighting using UV-A and blue (UV-A/Blue) light and red and blue (RB) light on growth and nutritional quality of lettuce grown hydroponically in two greenhouse experiments. The RB spectrum was applied pre-harvest for two days or nights, while the UV-A/Blue spectrum was applied pre-harvest for two or four days or nights. All pre-harvest supplemental lighting treatments had a same duration of 12 h with a photon flux density (PFD) of 171 μmol m−2 s−1. Results of both experiments showed that pre-harvest supplemental lighting using UV A/Blue or RB light can increase the growth and nutritional quality of lettuce grown hydroponically. The enhancement of lettuce growth and nutritional quality by the pre-harvest supplemental lighting was more effective under low daily light integral (DLI) compared to a high DLI and tended to be more effective when applied during the night, regardless of spectrum.

scholarly journals LED Illumination Spectrum Manipulation for Increasing the Yield of Sweet Basil (Ocimum basilicum L.)

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 344
Author(s):  
Md Momtazur Rahman ◽  
Mikhail Vasiliev ◽  
Kamal Alameh
Keyword(s):  
Growth Rate ◽  
Fold Increase ◽  
Photosynthetic Photon Flux Density ◽  
Ocimum Basilicum ◽  
Photon Flux ◽  
Photon Flux Density ◽  
White Led ◽  
Experimental Conditions ◽  
Sweet Basil ◽  
Optimal Illumination

Manipulation of the LED illumination spectrum can enhance plant growth rate and development in grow tents. We report on the identification of the illumination spectrum required to significantly enhance the growth rate of sweet basil (Ocimum basilicum L.) plants in grow tent environments by controlling the LED wavebands illuminating the plants. Since the optimal illumination spectrum depends on the plant type, this work focuses on identifying the illumination spectrum that achieves significant basil biomass improvement compared to improvements reported in prior studies. To be able to optimize the illumination spectrum, several steps must be achieved, namely, understanding plant biology, conducting several trial-and-error experiments, iteratively refining experimental conditions, and undertaking accurate statistical analyses. In this study, basil plants are grown in three grow tents with three LED illumination treatments, namely, only white LED illumination (denoted W*), the combination of red (R) and blue (B) LED illumination (denoted BR*) (relative red (R) and blue (B) intensities are 84% and 16%, respectively) and a combination of red (R), blue (B) and far-red (F) LED illumination (denoted BRF*) (relative red (R), blue (B) and far-red (F) intensities are 79%, 11%, and 10%, respectively). The photosynthetic photon flux density (PPFD) was set at 155 µmol m−2 s−1 for all illumination treatments, and the photoperiod was 20 h per day. Experimental results show that a combination of blue (B), red (R), and far-red (F) LED illumination leads to a one-fold increase in the yield of a sweet basil plant in comparison with only white LED illumination (W*). On the other hand, the use of blue (B) and red (R) LED illumination results in a half-fold increase in plant yield. Understanding the effects of LED illumination spectrum on the growth of plant sweet basil plants through basic horticulture research enables farmers to significantly improve their production yield, thus food security and profitability.

scholarly journals Plant buffering against the high-light stress-induced accumulation of CsGA2ox8 transcripts via alternative splicing to finely tune gibberellin levels and maintain hypocotyl elongation

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Bin Liu ◽  
Shuo Zhao ◽  
Pengli Li ◽  
Yilu Yin ◽  
Qingliang Niu ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Light Intensity ◽  
Intron Retention ◽  
Light Stress ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Rna Seq ◽  
Multiple Transcripts ◽  
Novel Transcript

AbstractIn plants, alternative splicing (AS) is markedly induced in response to environmental stresses, but it is unclear why plants generate multiple transcripts under stress conditions. In this study, RNA-seq was performed to identify AS events in cucumber seedlings grown under different light intensities. We identified a novel transcript of the gibberellin (GA)-deactivating enzyme Gibberellin 2-beta-dioxygenase 8 (CsGA2ox8). Compared with canonical CsGA2ox8.1, the CsGA2ox8.2 isoform presented intron retention between the second and third exons. Functional analysis proved that the transcript of CsGA2ox8.1 but not CsGA2ox8.2 played a role in the deactivation of bioactive GAs. Moreover, expression analysis demonstrated that both transcripts were upregulated by increased light intensity, but the expression level of CsGA2ox8.1 increased slowly when the light intensity was >400 µmol·m−2·s−1 PPFD (photosynthetic photon flux density), while the CsGA2ox8.2 transcript levels increased rapidly when the light intensity was >200 µmol·m−2·s−1 PPFD. Our findings provide evidence that plants might finely tune their GA levels by buffering against the normal transcripts of CsGA2ox8 through AS.

scholarly journals Effects of Light Quality on the Chlorophyll Degradation Pathway in Rice Seedling Leaves

2016 ◽  
Vol 44 (2) ◽  
pp. 393-398
Author(s):  
Chang-Chang CHEN ◽  
Kuan-Hung LIN ◽  
Meng-Yuan HUANG ◽  
Wen-Dar HUANG ◽  
Chi-Ming YANG
Keyword(s):  
Light Quality ◽  
Protoporphyrin Ix ◽  
Degradation Pathway ◽  
Photosynthetic Photon Flux Density ◽  
Rice Seedling ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Rice Seedlings ◽  
Rice Varieties ◽  
Enriched Environments

The objective of this study was to investigate the dynamics of chlorophyll (Chl), biosynthetic intermediates (protoporphyrin IX, magnesium protoporphyrin IX, and protochlorophyllide), degradation intermediates [chlorophyllide (Chlide), pheophytin (Phe), and pheophorbide (Pho)], and carotenoids (Car) in leaves of rice seedlings. Two rice varieties, 'Taichung Shen 10' ('TCS10') and 'IR1552', were grown under different light quality conditions controlled by light emitting diodes (LED). Lighting treatments for rice seedlings were included by red (R), blue (B), green (G), and red + blue (RB), with fluorescent lighting (FL) as the control and photosynthetic photon flux density being set at 105 µmol m-2 s-1. The results show that lower levels of Chl and Car in leaves were detected under G lighting, and light quality did not mediate porphyrins in biosynthetic pathways. Rice seedling leaves took Chl→Phe→Pho and Chl→Chlide→Pho as the major and minor degradation routes, respectively. Furthermore, higher Phe/Chlide ratios were observed under G and FL lighting conditions, indicating that green-enriched environments can up-regulate the minor degradation route in leaves.

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