rus
Issue #5/2023
D. V. Bylkov, D. A. Poltoratskiy, V. S. Soldatkin, A. O. Lazareva, A. P. Shkarupo, E. S. Shchepetkin
Comparison of the Influence of Irradiation Devices on Growth and Yield by the Example of Mewa F1 Cucumbers
Comparison of the Influence of Irradiation Devices on Growth and Yield by the Example of Mewa F1 Cucumbers
DOI: 10.22184/1993-7296.FRos.2023.17.5.408.418
The comparative analysis results of the influence of the optic specifications of irradiation devices with different designs on the plant growth and yield (Mewa F1 cucumbers) are given. The design of LED lamps has been optimized, and a lighting engineering model has been prepared to make a laboratory bench for studying the optical radiation effect on the plant growing process in the greenhouse conditions. The experimental prototypes of irradiation devices based on the LEDs have been prepared that ensure the plant performance with a smaller stem growth.
The comparative analysis results of the influence of the optic specifications of irradiation devices with different designs on the plant growth and yield (Mewa F1 cucumbers) are given. The design of LED lamps has been optimized, and a lighting engineering model has been prepared to make a laboratory bench for studying the optical radiation effect on the plant growing process in the greenhouse conditions. The experimental prototypes of irradiation devices based on the LEDs have been prepared that ensure the plant performance with a smaller stem growth.
Теги: greenhouses high-pressure sodium arc lamp (hps) leds mewa f1 cucumbers photosynthesis photosynthetic exposure yield дназ огурец «мева f1» светодиоды теплицы урожайность фотосинтез фотосинтетическая облученность
Comparison of the Influence of Irradiation Devices on Growth and Yield by the Example of Mewa F1 Cucumbers
D. V. Bylkov1, D. A. Poltoratskiy1, V. S. Soldatkin2, A. O. Lazareva2, A. P. Shkarupo2, E. S. Shchepetkin3
Fiztekh-Energo JSC, Tomsk, Russia
Tomsk State University of Control Systems and Radioelectronics, Tomsk, Russia
KDV Yashkinskiye Teplitsy LLC, Polomoshnoye village, Yashkinsky district, Kemerovo region – Kuzbass, Russia
The comparative analysis results of the influence of the optic specifications of irradiation devices with different designs on the plant growth and yield (Mewa F1 cucumbers) are given. The design of LED lamps has been optimized, and a lighting engineering model has been prepared to make a laboratory bench for studying the optical radiation effect on the plant growing process in the greenhouse conditions. The experimental prototypes of irradiation devices based on the LEDs have been prepared that ensure the plant performance with a smaller stem growth.
Keywords: photosynthesis, LEDs, high-pressure sodium arc lamp (HPS), photosynthetic exposure, Mewa F1 cucumbers, greenhouses, yield
Article received: March 19, 2023
Article accepted: July 07, 2023
Introduction
According to the Food Security Doctrine of the Russian Federation [1], the level of vegetable self-sufficiency in the country should be at least 90%. The production of greenhouse cucumbers in the territory of the Russian Federation amounted to 885.7 thousand tons, the self-sufficiency level was 95% [2]. The total area of greenhouses used in winter in the country is 3,298 hectares. To ensure profitability, the yield should be 50 kg per square meter on average with an area of at least five hectares [3]. The energy consumption of one greenhouse hectare consists of the consumption of one megawatt of electric power and two megawatts of thermal energy. The predominant part of electric power is consumed for the supplementary lighting of plants. The energy expenditures account for up to 60% of the cost of greenhouse vegetables [4]. According to GreenTalk.ru, the largest greenhouse facilities in Russia in terms of greenhouse area in hectares in 2020 were Multi-unit Agricultural Enterprise Yuzhny JSC – 144 hectares, Agro-Invest LLC – 105 hectares, Green Line TC LLC – 83 hectares. The greenhouse facilities operated in winter, use the sodium lamps (DNaT, high-pressure sodium arc lamps) or sodium reflector lamps (HPS, high-pressure sodium arc lamps), for example, a Reflax HPS lamp, mainly with the power from 600 watts to 1000 watts. The HPS Reflux 600 W lamp has a luminous power of up to 90,000 lm, a service life of up to 25,000 hours, and is designed to illuminate up to 6.5 m2 of greenhousearea [5].
The present-day developments in the field of semiconductor lighting engineering make it possible to develop the irradiation devices for plant growing with higher energy efficiency. It is due to the LEDs that it is possible to design the irradiation devices with high conversion quantum efficiency, more than 2 μmol/ and a service life of about 80,000 hours under normal climatic conditions: ambient temperature (20±10)°C, relative humidity (from 45 to 80)%, atmospheric pressure (from 630 to 800) mm Hg. The operating capabilities of irradiation devices shall have a direct impact on the growth, yield and other consumer qualities of the products, in addition to the consumer qualities. The efficiency and service life of irradiation devices directly affect the production costs. These data show that the research and development of semiconductor irradiation devices for plant growing shall be relevant.
The purpose of this paper is to develop an irradiation device with quantum efficiency and service life exceeding those of HPS.
To achieve this purpose, the following tasks shall be solved:
To conduct an analysis of the up-to-date scientific and technical literature;
To manufacture the experimental prototypes of irradiation devices based on the LEDs;
To conduct a study of experimental prototypes of irradiation devices based on the LEDs in comparison with HPS in terms of yield and changes in the photosynthetic specifications during the period of operation.
Theoretical part
Along with watering and gas composition of the air, light plays a key role in the plant physiology. Photosynthesis is a process when the organic substances are generated from inorganic ones in the plant cells containing chlorophyll, under the influence of irradiation energy in the optical spectrum (350–800) nm. During photosynthesis, the plant absorbs carbon dioxide and water, synthesizes organic substances and releases oxygen as a photosynthesis by-product [6]. Ultraviolet radiation (UV) is of bactericidal nature and is used to disinfect air, surfaces and water [7]. It is well-known that UV radiation of various ranges (UV-A (315–400) nm, UV-B (280–315) nm and UV–C (100–280) nm) has different effects on the plants. The UV radiation range of 210–300 nm corresponds to the common influence of natural sources on the plant growing process. It is UV radiation that induces the biosynthesis of secondary metabolites in the plants, such as flavonoids. Flavonoids enhance the taste and favor, nutritional value and yield of plants [8]. Moreover, infrared radiation also has a natural effect on the plant growth and development. The importance of radiation at the border of red and infrared radiation at the wavelengths of (750–800) nm is especially noted [9]. Exposure of plants to the optical radiation in the blue region of the optical spectrum (430–500) nm strengthens the root system and stem, radiation in the red region of the optical spectrum (620–760) nm stimulates the plant growth, and radiation in the yellow-green region of the optical spectrum (500–620) nm plays a regulatory role in the plant vegetation process, as well as contributes to an increase in the photosynthesis efficiency due to its high penetrating ability, as a result of which the lower layers of the plant head receive optical energy [10–13].
Experimental method
Two types of LED irradiation devices for the plants have been developed (Table 1). A lighting engineering design of a laboratory bench has been developed to study the optical radiation effect on the plant growing process in the under cover conditions. The plant specimen (Mewa F1 cucumber) were provided by KDV Yashkinskiye Teplitsy LLC. The Mewa F1 cucumbers are among the most common cucumber crops grown in the year-round greenhouses. This hybrid was bred in Holland. Its variety is medium-fruited and smooth. Cultivation is recommended for the first and third light zones. The variety belongs to the late types, since the first fruits reach full ripening after 50–55 days. The button shell is shiny and has a dark green color with medium tuberosity and white pubescence, the fruits have cylindrical shape. The Mewa F1 fruit pulp is elastic, crispy, sweet and juicy. The weight of one cucumber is on average 182–209 g, the size reaches an average of 17–20 cm at the beginning of the growing season, 20–24 cm at the end of the growing season. The cucumbers are able to grow up to 40 mm in diameter. The Mewa F1 cucumbers are specified by strong immunity, as they are resistant to the powdery mildew, root and gray rot, as well as fusariosis. They have a high regenerative capacity [14–16].
A laboratory bench has been developed to study the optical radiation effect on the plant growing process in the greenhouse conditions that provides normal climatic conditions during the research: ambient temperature 25±3 °C, relative air humidity (45–80) %, atmospheric pressure (630–800) mm Hg. The average irradiance level in all experiments was 101 µmol s/m2, the lamp operation mode: turning on for 12 hours from 8:00 a. m. to 08:00 p. m., turning off for 12 hours from 08:00 p. m. to 08:00 a. m., no natural light, daily watering. During the research process, the temperature and humidity values were monitored daily at the laboratory stand using the TKA-PM device. The number of fruits, fruit dimensions, stem height and leaf size were controlled. The fruit and leaf sizes were measured using a caliper gauge. The emission spectra and photosynthetic irradiance were measured using a UPRtek PG200N spectrometer.
The structure of Diora Unit Agro and Diora Quadro Agro LED irradiation devices is patented (patent No. 209987 U1 dated March 24, 2022 “LED irradiation device for plants”, Phystech-Energy).
The LED irradiation device consists of a square-shaped aluminum LED board with the dimensions 195×195mm, and the board thickness of 3mm. The irradiator does not have a heatsink. The LED board is applied as a heatsink, since it has sufficient area and thickness for efficient heat dissipation. The irradiation device uses two types of LEDs: these are red LEDs with an emission peak of 660 nm and white LEDs with a correlated color temperature of 5000K. A group lens made of polycarbonate is installed on the board to generate the radiation pattern. A frame is attached to the top of the board, on which a bracket with the fasteners and an LED power driver are installed.
The laboratory bench consists of three compartments, where the lamps are placed in pairs: HPS 250 W, Diora Unit Agro and Diora Quadro Agro. The overall dimensions of the compartments (LxWxH) are as follows: 1×0.7×2.6 m. The compartment walls have a white blind surface. Each compartment contains two cucumber seedlings. The power of irradiation devices was adjusted in such a way that the exposure level was on average 100 µmol s/m2.
The lighting engineering program “DiaLux 4.13” was used for a lighting calculation of the required irradiance level. Based on the calculation results, the irradiation devices with photometric parameters given in Table 1 were selected in order to achieve the required exposure level.
The photometric measurements of the selected irradiators were performed and their luminous flux values were obtained, after which the luminous flux values were recalculated from the luminous quantities into the radiation quantities to calculate the PAR flux, as well as the irradiance level values that were recalculated from the illuminance values obtained as a result of lighting calculation in the DiaLux program. The conversion was performed in the Matchad 14 program according to the formula 1:
, (1)
where FФАР is the photosynthetic photon flux, µmol/s;
Eλ is the spectral concentration of the device radiation energy distribution, J/nm;
λ is a wavelength, nm;
h is a Planck’s constant;
c is the speed of light;
NA is Avogadro’s constant.
The quantum efficiency calculation of the irradiation devices in the PAR range was carried out according to the formula 2:
[18], (2)
where ηф is the device efficiency in the PAR region, µmol/J;
FФАР is the photosynthetic photon flux, µmol/s;
P is the power consumed by the device, W.
Table 1 also shows that in comparison to HPS 250 W, the LED lamps consume less electric power: Diora Unit Agro by 69.33%, Diora Quadro Agro by 57.16%.
Discussion of the experimental results
Figures 3–5 show the cucumber specimen on the benches with irradiation devices. Figure 6 demonstrates a photograph of typical cucumbers grown during the research. Table 2 indicates the number of picked cucumber fruits and the height of sample stems. Figures 7–9 show the radiation spectra of the irradiators.
The spectral structure of the irradiation devices differ from each other. The spectral structure of HPS radiation is mostly in the long-wavelength region of the optical range of 570–630 nm. In other words, HPS emits the light quanta in the red region of the visible spectrum. The Diora Unit Agro irradiator has emission peaks in the blue (450 nm) and red (660 nm) regions, while the red region of the spectrum is about 10 times more intense. The Diora Quadro Agro irradiator also has a peak in the red (450 nm) and blue (660 nm) regions with approximately the same proportions, but with the addition of a continuous spectrum in the green region from 480 to 620 nm. Thus, having various spectral specifications of irradiators, it is possible to identify the most efficient spectral structure for photosynthesis.
The spectral specifications of radiation was measured after 200–400 hours in order to track any changes in the spectral structure during the period operation. According to the research results, it was found that most of the fruits (5 pcs.) were obtained when using the Diora Quadro Agro irradiator. Radiation of the Diora Unit Agro and HPS 250W was used to receive an equal number of fruits, namely 4 pcs. in each compartment. It was also found that under the radiation of Diora Quadro Agro, despite the larger yield, the average length of the Mewa F1 cucumber stems turned out to be 93 cm less.
When studying degradation of the photometric specifications of the irradiators, it was found that the spectral structure of all irradiation devices used in the experiment has not changed during 1000 hours.
Conclusion
The analysis of up-to-date scientific and technical literature was performed, the emission spectra of LED irradiation devices were selected and a lighting engineering model was developed to make a laboratory bench for studying the optical radiation effect on the plant growing process in the greenhouse conditions by the example of Mewa F1 cucumbers. The experimental prototypes of irradiators based on the light-emitting diodes have been prepared. The experimental prototypes of LED-based irradiation devices were studied in comparison with HPS to determine the yield and any changes in the photosynthetic specifications during operation. It was found that the emission spectra, mainly in the red region, accelerated the plant growth and performance. The emission spectrum of Diora Quadro Agro provides for the plant performance with less plant stem growth. It has been determined that during the studies, the emission spectra of irradiators and their photosynthetic flux have not changed significantly, and that the further examination of the degradation of irradiators requires a more in-depth study with a longer operating time. The most suitable irradiation devices for growing Mewa F1 cucumbers are Diora Quadro Agro.
AUTHORS
Bylkov Denis Vasilievich, lighting engineer at Phystech-Energo JSC. Developed a lighting engineering project of a laboratory bench to study the optical radiation effect on the plant growing process, developed the draft design documentation for Diora Unit Agro and Diora Quadro Agro LED irradiators.
Poltoratskiy Dmitriy Alekseevich, chief technical officer of Phystech-Energo JSC. Developed the draft design documentation for Diora Unit Agro and Diora Quadro Agro LED irradiators, arranged research into the effect of optical parameters of irradiators on the plant growth and performance.
Soldatkin Vasiliy Sergeevich, Ph.D. in technical sciences, associate professor of the Department of Radioelectronic Technologies and Environmental Monitoring, Tomsk State University of Control Systems and Radioelectronics. Prepared a laboratory bench for studying the optical radiation effect on the plant growing process, provided the research conditions to study the effect of optical parameters of irradiation devices on the plant growth and performance.
Lazareva Alena Olegovna, Engineer of the Department of Radioelectronic Technologies and Environmental Monitoring, Tomsk State University of Control Systems and Radioelectronics. Conducted research on the effect of optical radiation on the plant growing process.
Shkarupo Anastasiia Petrovna, senior lecturer, Department of Radioelectronic Technologies and Environmental Monitoring, Tomsk State University of Control Systems and Radioelectronics. Conducted research on the effect of optical radiation on the plant growing process.
Schepetkin Egor Sergeevich, chief power engineer of KDV Yashkinskiye Teplitsy LLC, selected a variety of cucumber and provided process support during the experiment in terms of developing the care and solution preparation methods for plant watering.
D. V. Bylkov1, D. A. Poltoratskiy1, V. S. Soldatkin2, A. O. Lazareva2, A. P. Shkarupo2, E. S. Shchepetkin3
Fiztekh-Energo JSC, Tomsk, Russia
Tomsk State University of Control Systems and Radioelectronics, Tomsk, Russia
KDV Yashkinskiye Teplitsy LLC, Polomoshnoye village, Yashkinsky district, Kemerovo region – Kuzbass, Russia
The comparative analysis results of the influence of the optic specifications of irradiation devices with different designs on the plant growth and yield (Mewa F1 cucumbers) are given. The design of LED lamps has been optimized, and a lighting engineering model has been prepared to make a laboratory bench for studying the optical radiation effect on the plant growing process in the greenhouse conditions. The experimental prototypes of irradiation devices based on the LEDs have been prepared that ensure the plant performance with a smaller stem growth.
Keywords: photosynthesis, LEDs, high-pressure sodium arc lamp (HPS), photosynthetic exposure, Mewa F1 cucumbers, greenhouses, yield
Article received: March 19, 2023
Article accepted: July 07, 2023
Introduction
According to the Food Security Doctrine of the Russian Federation [1], the level of vegetable self-sufficiency in the country should be at least 90%. The production of greenhouse cucumbers in the territory of the Russian Federation amounted to 885.7 thousand tons, the self-sufficiency level was 95% [2]. The total area of greenhouses used in winter in the country is 3,298 hectares. To ensure profitability, the yield should be 50 kg per square meter on average with an area of at least five hectares [3]. The energy consumption of one greenhouse hectare consists of the consumption of one megawatt of electric power and two megawatts of thermal energy. The predominant part of electric power is consumed for the supplementary lighting of plants. The energy expenditures account for up to 60% of the cost of greenhouse vegetables [4]. According to GreenTalk.ru, the largest greenhouse facilities in Russia in terms of greenhouse area in hectares in 2020 were Multi-unit Agricultural Enterprise Yuzhny JSC – 144 hectares, Agro-Invest LLC – 105 hectares, Green Line TC LLC – 83 hectares. The greenhouse facilities operated in winter, use the sodium lamps (DNaT, high-pressure sodium arc lamps) or sodium reflector lamps (HPS, high-pressure sodium arc lamps), for example, a Reflax HPS lamp, mainly with the power from 600 watts to 1000 watts. The HPS Reflux 600 W lamp has a luminous power of up to 90,000 lm, a service life of up to 25,000 hours, and is designed to illuminate up to 6.5 m2 of greenhousearea [5].
The present-day developments in the field of semiconductor lighting engineering make it possible to develop the irradiation devices for plant growing with higher energy efficiency. It is due to the LEDs that it is possible to design the irradiation devices with high conversion quantum efficiency, more than 2 μmol/ and a service life of about 80,000 hours under normal climatic conditions: ambient temperature (20±10)°C, relative humidity (from 45 to 80)%, atmospheric pressure (from 630 to 800) mm Hg. The operating capabilities of irradiation devices shall have a direct impact on the growth, yield and other consumer qualities of the products, in addition to the consumer qualities. The efficiency and service life of irradiation devices directly affect the production costs. These data show that the research and development of semiconductor irradiation devices for plant growing shall be relevant.
The purpose of this paper is to develop an irradiation device with quantum efficiency and service life exceeding those of HPS.
To achieve this purpose, the following tasks shall be solved:
To conduct an analysis of the up-to-date scientific and technical literature;
To manufacture the experimental prototypes of irradiation devices based on the LEDs;
To conduct a study of experimental prototypes of irradiation devices based on the LEDs in comparison with HPS in terms of yield and changes in the photosynthetic specifications during the period of operation.
Theoretical part
Along with watering and gas composition of the air, light plays a key role in the plant physiology. Photosynthesis is a process when the organic substances are generated from inorganic ones in the plant cells containing chlorophyll, under the influence of irradiation energy in the optical spectrum (350–800) nm. During photosynthesis, the plant absorbs carbon dioxide and water, synthesizes organic substances and releases oxygen as a photosynthesis by-product [6]. Ultraviolet radiation (UV) is of bactericidal nature and is used to disinfect air, surfaces and water [7]. It is well-known that UV radiation of various ranges (UV-A (315–400) nm, UV-B (280–315) nm and UV–C (100–280) nm) has different effects on the plants. The UV radiation range of 210–300 nm corresponds to the common influence of natural sources on the plant growing process. It is UV radiation that induces the biosynthesis of secondary metabolites in the plants, such as flavonoids. Flavonoids enhance the taste and favor, nutritional value and yield of plants [8]. Moreover, infrared radiation also has a natural effect on the plant growth and development. The importance of radiation at the border of red and infrared radiation at the wavelengths of (750–800) nm is especially noted [9]. Exposure of plants to the optical radiation in the blue region of the optical spectrum (430–500) nm strengthens the root system and stem, radiation in the red region of the optical spectrum (620–760) nm stimulates the plant growth, and radiation in the yellow-green region of the optical spectrum (500–620) nm plays a regulatory role in the plant vegetation process, as well as contributes to an increase in the photosynthesis efficiency due to its high penetrating ability, as a result of which the lower layers of the plant head receive optical energy [10–13].
Experimental method
Two types of LED irradiation devices for the plants have been developed (Table 1). A lighting engineering design of a laboratory bench has been developed to study the optical radiation effect on the plant growing process in the under cover conditions. The plant specimen (Mewa F1 cucumber) were provided by KDV Yashkinskiye Teplitsy LLC. The Mewa F1 cucumbers are among the most common cucumber crops grown in the year-round greenhouses. This hybrid was bred in Holland. Its variety is medium-fruited and smooth. Cultivation is recommended for the first and third light zones. The variety belongs to the late types, since the first fruits reach full ripening after 50–55 days. The button shell is shiny and has a dark green color with medium tuberosity and white pubescence, the fruits have cylindrical shape. The Mewa F1 fruit pulp is elastic, crispy, sweet and juicy. The weight of one cucumber is on average 182–209 g, the size reaches an average of 17–20 cm at the beginning of the growing season, 20–24 cm at the end of the growing season. The cucumbers are able to grow up to 40 mm in diameter. The Mewa F1 cucumbers are specified by strong immunity, as they are resistant to the powdery mildew, root and gray rot, as well as fusariosis. They have a high regenerative capacity [14–16].
A laboratory bench has been developed to study the optical radiation effect on the plant growing process in the greenhouse conditions that provides normal climatic conditions during the research: ambient temperature 25±3 °C, relative air humidity (45–80) %, atmospheric pressure (630–800) mm Hg. The average irradiance level in all experiments was 101 µmol s/m2, the lamp operation mode: turning on for 12 hours from 8:00 a. m. to 08:00 p. m., turning off for 12 hours from 08:00 p. m. to 08:00 a. m., no natural light, daily watering. During the research process, the temperature and humidity values were monitored daily at the laboratory stand using the TKA-PM device. The number of fruits, fruit dimensions, stem height and leaf size were controlled. The fruit and leaf sizes were measured using a caliper gauge. The emission spectra and photosynthetic irradiance were measured using a UPRtek PG200N spectrometer.
The structure of Diora Unit Agro and Diora Quadro Agro LED irradiation devices is patented (patent No. 209987 U1 dated March 24, 2022 “LED irradiation device for plants”, Phystech-Energy).
The LED irradiation device consists of a square-shaped aluminum LED board with the dimensions 195×195mm, and the board thickness of 3mm. The irradiator does not have a heatsink. The LED board is applied as a heatsink, since it has sufficient area and thickness for efficient heat dissipation. The irradiation device uses two types of LEDs: these are red LEDs with an emission peak of 660 nm and white LEDs with a correlated color temperature of 5000K. A group lens made of polycarbonate is installed on the board to generate the radiation pattern. A frame is attached to the top of the board, on which a bracket with the fasteners and an LED power driver are installed.
The laboratory bench consists of three compartments, where the lamps are placed in pairs: HPS 250 W, Diora Unit Agro and Diora Quadro Agro. The overall dimensions of the compartments (LxWxH) are as follows: 1×0.7×2.6 m. The compartment walls have a white blind surface. Each compartment contains two cucumber seedlings. The power of irradiation devices was adjusted in such a way that the exposure level was on average 100 µmol s/m2.
The lighting engineering program “DiaLux 4.13” was used for a lighting calculation of the required irradiance level. Based on the calculation results, the irradiation devices with photometric parameters given in Table 1 were selected in order to achieve the required exposure level.
The photometric measurements of the selected irradiators were performed and their luminous flux values were obtained, after which the luminous flux values were recalculated from the luminous quantities into the radiation quantities to calculate the PAR flux, as well as the irradiance level values that were recalculated from the illuminance values obtained as a result of lighting calculation in the DiaLux program. The conversion was performed in the Matchad 14 program according to the formula 1:
, (1)
where FФАР is the photosynthetic photon flux, µmol/s;
Eλ is the spectral concentration of the device radiation energy distribution, J/nm;
λ is a wavelength, nm;
h is a Planck’s constant;
c is the speed of light;
NA is Avogadro’s constant.
The quantum efficiency calculation of the irradiation devices in the PAR range was carried out according to the formula 2:
[18], (2)
where ηф is the device efficiency in the PAR region, µmol/J;
FФАР is the photosynthetic photon flux, µmol/s;
P is the power consumed by the device, W.
Table 1 also shows that in comparison to HPS 250 W, the LED lamps consume less electric power: Diora Unit Agro by 69.33%, Diora Quadro Agro by 57.16%.
Discussion of the experimental results
Figures 3–5 show the cucumber specimen on the benches with irradiation devices. Figure 6 demonstrates a photograph of typical cucumbers grown during the research. Table 2 indicates the number of picked cucumber fruits and the height of sample stems. Figures 7–9 show the radiation spectra of the irradiators.
The spectral structure of the irradiation devices differ from each other. The spectral structure of HPS radiation is mostly in the long-wavelength region of the optical range of 570–630 nm. In other words, HPS emits the light quanta in the red region of the visible spectrum. The Diora Unit Agro irradiator has emission peaks in the blue (450 nm) and red (660 nm) regions, while the red region of the spectrum is about 10 times more intense. The Diora Quadro Agro irradiator also has a peak in the red (450 nm) and blue (660 nm) regions with approximately the same proportions, but with the addition of a continuous spectrum in the green region from 480 to 620 nm. Thus, having various spectral specifications of irradiators, it is possible to identify the most efficient spectral structure for photosynthesis.
The spectral specifications of radiation was measured after 200–400 hours in order to track any changes in the spectral structure during the period operation. According to the research results, it was found that most of the fruits (5 pcs.) were obtained when using the Diora Quadro Agro irradiator. Radiation of the Diora Unit Agro and HPS 250W was used to receive an equal number of fruits, namely 4 pcs. in each compartment. It was also found that under the radiation of Diora Quadro Agro, despite the larger yield, the average length of the Mewa F1 cucumber stems turned out to be 93 cm less.
When studying degradation of the photometric specifications of the irradiators, it was found that the spectral structure of all irradiation devices used in the experiment has not changed during 1000 hours.
Conclusion
The analysis of up-to-date scientific and technical literature was performed, the emission spectra of LED irradiation devices were selected and a lighting engineering model was developed to make a laboratory bench for studying the optical radiation effect on the plant growing process in the greenhouse conditions by the example of Mewa F1 cucumbers. The experimental prototypes of irradiators based on the light-emitting diodes have been prepared. The experimental prototypes of LED-based irradiation devices were studied in comparison with HPS to determine the yield and any changes in the photosynthetic specifications during operation. It was found that the emission spectra, mainly in the red region, accelerated the plant growth and performance. The emission spectrum of Diora Quadro Agro provides for the plant performance with less plant stem growth. It has been determined that during the studies, the emission spectra of irradiators and their photosynthetic flux have not changed significantly, and that the further examination of the degradation of irradiators requires a more in-depth study with a longer operating time. The most suitable irradiation devices for growing Mewa F1 cucumbers are Diora Quadro Agro.
AUTHORS
Bylkov Denis Vasilievich, lighting engineer at Phystech-Energo JSC. Developed a lighting engineering project of a laboratory bench to study the optical radiation effect on the plant growing process, developed the draft design documentation for Diora Unit Agro and Diora Quadro Agro LED irradiators.
Poltoratskiy Dmitriy Alekseevich, chief technical officer of Phystech-Energo JSC. Developed the draft design documentation for Diora Unit Agro and Diora Quadro Agro LED irradiators, arranged research into the effect of optical parameters of irradiators on the plant growth and performance.
Soldatkin Vasiliy Sergeevich, Ph.D. in technical sciences, associate professor of the Department of Radioelectronic Technologies and Environmental Monitoring, Tomsk State University of Control Systems and Radioelectronics. Prepared a laboratory bench for studying the optical radiation effect on the plant growing process, provided the research conditions to study the effect of optical parameters of irradiation devices on the plant growth and performance.
Lazareva Alena Olegovna, Engineer of the Department of Radioelectronic Technologies and Environmental Monitoring, Tomsk State University of Control Systems and Radioelectronics. Conducted research on the effect of optical radiation on the plant growing process.
Shkarupo Anastasiia Petrovna, senior lecturer, Department of Radioelectronic Technologies and Environmental Monitoring, Tomsk State University of Control Systems and Radioelectronics. Conducted research on the effect of optical radiation on the plant growing process.
Schepetkin Egor Sergeevich, chief power engineer of KDV Yashkinskiye Teplitsy LLC, selected a variety of cucumber and provided process support during the experiment in terms of developing the care and solution preparation methods for plant watering.
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