A leafy vegetable laser precision light supplementing cultivation method, device and application

Abstract

The application discloses a kind of facilities leafy vegetable laser precision light supplementing cultivation method, device and application.The method is planted in greenhouse, plant factory, light-shield shed or weak light period and other facilities cultivation environment, and the conductivity of nutrient solution and planting density are suitable;The laser light supplementing light source formed by red light laser and blue light laser is configured above leafy vegetable canopy, and the power ratio is 1:1, wherein the red light wavelength is 640-680 nm, the blue light wavelength is 440-480 nm, and both are linearly polarized light;The laser light supplementing light source is installed at a position 70-120 cm away from the canopy, so that the laser light supplementing PPFD at the canopy is 1-3 μmol·m ‑2 ·s ‑1 , and the daily cumulative light supplement is 6-12 hours during the whole growth period and / or weak light period.The application improves the light energy utilization efficiency under low energy consumption conditions, avoids light inhibition, promotes leafy vegetable yield and improves quality indicators.

Description

Technical Field

[0001] This invention relates to the field of facility agriculture cultivation technology, and in particular to a method, device and application of laser precision supplemental lighting for facility leafy vegetable cultivation. Background Technology

[0002] Protected cultivation is an important production method for achieving a stable year-round supply of leafy vegetables, and it is widely used in greenhouses, multi-span sheds, plastic greenhouses, plant factories, and other enclosed cultivation spaces. However, during winter and spring, prolonged cloudy days, smoggy days, and under shading or enclosed cultivation conditions, there are often problems such as insufficient natural light intensity, short light duration, and poor light quality in protected cultivation facilities. These issues can easily lead to reduced photosynthetic efficiency in leafy vegetables, manifesting as small leaf area, fewer leaves, and slow growth, ultimately resulting in decreased yield and quality.

[0003] To address the issue of low light in greenhouse cultivation, existing technologies typically employ LED light sources for artificial lighting. However, this approach has the following significant drawbacks: (1) Poor spectral characteristics: Although LED supplementary lighting can provide a certain proportion of red light, blue light or composite light, its LED spectrum half-width is usually 20-30 nm, with poor monochromaticity and a lot of stray light, resulting in a low matching degree between its spectrum and chlorophyll absorption peak, and the light energy utilization rate is only 15%-20%.

[0004] (2) Energy consumption and heat effect issues: LED supplementary lighting equipment has high energy consumption, large heat generation and low light efficiency.

[0005] (3) Lack of systematic solutions: Existing laser supplementary lighting technology in leafy vegetable cultivation is mostly researched for single parameters, single crops, and single scenarios, lacking systematic solutions that include parameter range, category generalization, and broad scenario coverage.

[0006] (4) Unstable effect: Existing technologies have problems such as light suppression, insufficient supplementary light, high energy consumption and unstable effect.

[0007] Laser light sources possess advantages such as high monochromaticity, strong directionality, and narrow spectral half-wavelength, theoretically allowing for precise matching of the red light absorption peak of chlorophyll and increasing light energy utilization to over 30%. While existing technologies include the use of red and blue lasers for plant lighting and light source structure design, most studies remain focused on the light source itself, power adjustment, or general plant supplemental lighting. They lack a systematic design for the synergistic relationships between low-intensity laser supplemental lighting windows, red-blue light ratios, canopy installation distance, supplemental lighting periods, nutrient solution conductivity, planting density, and other cultivation conditions for leafy vegetables in low-light environments. Especially in leafy vegetable production, where it's crucial to promote fresh and dry weight accumulation while avoiding photoinhibition and improving quality indicators such as antioxidant activity, proanthocyanidins, ascorbic acid, soluble sugars, and nitrites, current supplemental lighting methods struggle to simultaneously achieve low energy consumption, stable yield increases, and quality optimization. Summary of the Invention

[0008] This invention provides a method, device, and application for precise laser-based supplemental lighting cultivation of leafy vegetables in greenhouses. The core of this invention addresses the problems of insufficient photosynthetically active light and low energy utilization and energy waste associated with conventional LED supplemental lighting under low-light conditions. Instead of simply increasing the intensity of supplemental lighting, it utilizes the narrow-band, linearly polarized, and highly directional optical characteristics of red and blue lasers. The wavelength, power ratio, and half-width of the red and blue lasers are matched with the low-PPFD supplemental lighting window at the leafy vegetable canopy. Furthermore, it incorporates basic cultivation conditions such as canopy installation distance, daily supplemental lighting duration, low-light supplemental lighting stages, nutrient solution conductivity, and planting density to form a low-intensity precise supplemental lighting system suitable for greenhouse leafy vegetables. Through this synergistic design, red and blue lasers can effectively act on the photosynthetic regulation and quality metabolism processes of leafy vegetables at a lower photon flux. This avoids photoinhibition caused by excessive supplemental lighting while improving biomass accumulation and functional quality improvement per unit of energy consumption, thereby achieving stable, high-yield, and high-quality cultivation of greenhouse leafy vegetables in low-light environments.

[0009] According to a first aspect of the present invention, a method for precise laser-assisted cultivation of leafy vegetables in greenhouses is provided, comprising the following steps: Select a leafy vegetable cultivation area within a protected cultivation environment and plant leafy vegetable crops; The basic cultivation conditions for the leafy vegetable crop are controlled, wherein the conductivity of the nutrient solution is 1.5–2.5 mS·cm. -1 The planting density is 25-50 plants / m². 2 ; A laser supplementary light source formed by combining red and blue lasers is arranged above the leafy vegetable crop. The wavelength of the red laser is 640-680 nm, the wavelength of the blue laser is 440-480 nm, the power ratio of the red laser to the blue laser is 1:1, and both the red laser and the blue laser are linearly polarized light. The laser supplementary lighting source is installed at a distance of 70–120 cm from the canopy of the leafy vegetable crop, so that the laser supplementary lighting PPFD at the canopy of the leafy vegetable crop is 1–3 μmol·m⁻¹. -2 ·s -1 ; Supplemental lighting should be provided throughout the entire growth period and / or during periods of low light intensity for the leafy vegetable crop, with a cumulative supplemental lighting of 6 to 12 hours per day.

[0010] In some technical solutions, the facility cultivation environment includes one or more of the following: greenhouse, multi-span shed, plastic greenhouse, plant factory, shading shed, and enclosed cultivation space; and / or, The low-light period includes one or more of the following: winter and spring low-light periods, consecutive cloudy days, and smoggy days; and / or, The leafy vegetables include one or more of the following: bok choy, Chinese cabbage, romaine lettuce, lettuce, and spinach.

[0011] In some technical solutions, the wavelength of the red laser is 650–670 nm, preferably with a center wavelength of 660 nm; and / or, The wavelength of the blue laser is 445–455 nm, preferably with a center wavelength of 450 nm; and / or, The half-width of both the red laser and the blue laser is ≤5 nm, preferably ≤2 nm.

[0012] In some technical solutions, the laser supplementary light source is a red-blue composite laser lamp, and the total rated power of a single red-blue composite laser lamp is 5-15 W, preferably 8 W; and / or, One to three red-blue composite laser lamps are provided per square meter of cultivation unit, preferably one lamp; and / or... The red-blue composite laser lights are evenly suspended in a manner where the light tubes are parallel to the long side, parallel to the short side, perpendicular to the long side, or perpendicular to the short side of the seedbed, with the preferred arrangement being that the light tubes are perpendicular to the short side of the seedbed.

[0013] In some technical solutions, the laser supplementary lighting source is installed at a distance of 60-90 cm from the canopy of the leafy vegetable crop, preferably at a distance of 75 cm from the canopy; and / or, The laser supplemental lighting PPFD at the canopy of the leafy vegetable crop was 2.0–3.0 μmol·m⁻¹. -2 ·s -1 Preferably 2.5 μmol·m -2 ·s -1 .

[0014] In some technical solutions, the cumulative daily supplemental lighting is 8-10 hours, preferably 9 hours; and / or, The supplementary lighting periods include a morning supplementary lighting period and an afternoon supplementary lighting period, wherein the morning supplementary lighting period is from 5:30 to 11:30 and the afternoon supplementary lighting period is from 13:30 to 18:30; preferably, the morning supplementary lighting period is from 6:00 to 11:00 and the afternoon supplementary lighting period is from 14:00 to 18:00.

[0015] In some technical solutions, the conductivity of the nutrient solution is 1.8–2.2 mS·cm. -1 Preferably 2.0 mS·cm -1 ; and / or, The planting density is 30-40 plants / m². 2 The preferred density is 36 plants / m². 2 ; and / or, The ambient temperature of the facility cultivation environment is 12-25℃, and the relative humidity is 40%-85%.

[0016] According to a second aspect of the present invention, a cultivation device for implementing the above-described method of laser-based precision supplemental lighting for leafy vegetables is provided, comprising a laser light source module, a hanging bracket, a control module, and a power supply module; The laser source module includes multiple sets of red-blue composite laser lamps. The red-blue composite laser lamps are formed by combining red laser and blue laser at a power ratio of 1:1. The wavelength of the red laser is 640-680 nm and the wavelength of the blue laser is 440-480 nm. Both the red laser and the blue laser are linearly polarized light, and the total rated power of a single lamp is 5-15 W. The suspension bracket is used to install the red-blue composite laser light above the canopy of the leafy vegetable crop, and can adjust the distance between the red-blue composite laser light and the canopy of the leafy vegetable crop. The control module is connected to the laser source module and is used to control the supplementary lighting period and / or supplementary lighting intensity of the red-blue composite laser lamp; The power supply module is connected to the laser source module and the control module, and is used to supply power to the laser source module and the control module.

[0017] In some technical solutions, the height adjustment range of the suspension bracket is 50–120 cm, preferably 60–90 cm; and / or, The suspension bracket supports the installation of the red-blue composite laser lights in a direction parallel or perpendicular to the seedbed, and supports horizontal spacing adjustment of multiple red-blue composite laser lights; and / or, The control module includes one or more of the following: a timer switch, a branch dimmer, an overcurrent protection circuit, and a heat dissipation component; and / or, The power supply module is compatible with 110 V and / or 220 V AC power and supports independent group control of the red and blue composite laser lights.

[0018] The cultivation device of the present invention can realize height adjustment, direction arrangement, timed supplemental lighting, branch lighting, overcurrent protection, heat dissipation and group control of red and blue composite laser lamps. It can be flexibly configured according to different facility environments, seedbed layouts and leafy vegetable growth stages. It has the advantages of simple structure, convenient installation, low energy consumption, wide applicability and strong large-scale promotion.

[0019] According to a third aspect of the present invention, the application of the above-mentioned method for precise laser-assisted supplemental lighting cultivation of leafy vegetables in greenhouses, or the above-mentioned supplemental lighting device, is further provided in the low-light cultivation of leafy vegetables in greenhouses. The application is used to increase the yield and / or improve the quality of leafy vegetables; the improvement of leafy vegetable quality includes one or more of the following: increasing chlorophyll content, increasing antioxidant enzyme activity, increasing proanthocyanidin content, increasing ascorbic acid content, increasing soluble sugar content, and reducing nitrite content.

[0020] The present invention, by employing the above technical solution, has at least the following beneficial effects: 1. This invention employs a 1:1 power ratio combination of red and blue laser light to form a supplementary lighting source, and defines the wavelength range, linear polarization characteristics, and narrow half-width of the red and blue lasers. This allows the supplementary lighting spectrum to more effectively match the red and blue light utilization needs of leafy vegetables. Compared to conventional supplementary lighting sources with broad spectrum or large half-width, this invention reduces the dispersion of ineffective spectral energy, improves the effective response of the leafy vegetable canopy to supplementary lighting energy, and thus promotes leafy vegetable growth under lower supplementary lighting intensity. This invention can improve light energy utilization by 25%–40% compared to LED supplementary lighting, and reduce energy consumption by 5–10 times, thereby achieving high light efficiency and low energy consumption in greenhouse leafy vegetable supplementary lighting cultivation.

[0021] 2. This invention controls the laser-assisted PPFD at the canopy layer of leafy vegetables to 1–3 μmol·m⁻¹. -2 ·s -1 This method, combined with a canopy installation distance of 70–120 cm, a single lamp power of 5–15 W, and a daily supplemental lighting duration of 6–12 hours, creates precise supplemental lighting conditions characterized by low intensity, low energy consumption, and uniformity. This approach does not simply increase light exposure; rather, it avoids excessive light stress caused by high supplemental light intensity through a low-PPFD laser window, while simultaneously compensating for insufficient effective light under low-light conditions, allowing leafy vegetables to maintain a relatively stable photosynthetic physiological state throughout their entire growth period or during periods of low light. Under the supplemental lighting conditions of this invention, the plant's chlorophyll fluorescence parameter Fv / Fm remains stable at 0.80–0.88, demonstrating strong adaptability to low light.

[0022] 3. This invention combines laser supplemental lighting parameters with the basic cultivation conditions for greenhouse leafy vegetables, controlling the conductivity of the nutrient solution to be 1.5–2.5 mS·cm. -1 Planting density is 25-50 plants / m² 2 Furthermore, by coordinating suitable temperature and humidity conditions, the light supply, nutrient supply, and plant density can be matched. Therefore, this invention not only promotes individual plant growth but also meets the needs of large-scale, high-density cultivation of leafy vegetables in greenhouses, reducing yield instability caused by uneven supplemental lighting and mismatched nutrient supply.

[0023] 4. This invention preferably applies supplemental lighting during low-light periods such as morning and afternoon, which helps prolong the effective photosynthetic time of leafy vegetables and avoids photoinhibition caused by superimposed strong supplemental lighting at noon when natural light is strong or the temperature is high. By matching the timing of supplemental lighting with the low-light environment, this invention can improve the actual utilization efficiency of supplemental lighting energy and alleviate the energy waste and physiological stress problems caused by fixed supplemental lighting throughout the day or high-intensity continuous supplemental lighting in traditional methods.

[0024] 5. This invention can improve yield indicators such as fresh weight and dry weight of leafy vegetables while simultaneously improving quality indicators such as chlorophyll content, antioxidant enzyme activity, proanthocyanidin content, ascorbic acid content, soluble sugar content, and nitrite content, achieving a synergistic effect of increased yield and improved quality. Verification has shown that this invention can increase the fresh weight of leafy vegetables by 10%–35%, the dry weight by 10%–15%, and the yield by 12%–20%; simultaneously, it can increase chlorophyll content by 5%–10%, decrease nitrate content by 3%–7%, and increase proanthocyanidin content by 10%–38%. These results indicate that the laser supplemental lighting of this invention, through low-intensity narrow-band red and blue laser lighting, has a comprehensive regulatory effect on the photosynthetic metabolism and quality metabolism of leafy vegetables, making it particularly suitable for facility-based leafy vegetable production scenarios such as greenhouses, plant factories, shade houses, enclosed cultivation spaces, and the low-light period in winter and spring. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the laser precision supplemental lighting device for leafy vegetables in embodiment 1 of the present invention; Figure 2 This is a real-world image of the laser-guided precision supplemental lighting device for leafy vegetables involved in Embodiment 1 of the present invention; Figure 3 This is a comparison diagram of the growth phenotypes of Chinese cabbage under different supplemental lighting treatments involved in Embodiment 1 of the present invention.

[0026] The meanings of the symbols in the diagram are as follows: 1—Laser lamp tube; 2—Laser lamp connection cable; 3—Hanging bracket; 4—Ground; 5—Seedling bed; 6—Control module. Detailed Implementation

[0027] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to those skilled in the art. Furthermore, any method similar to or equivalent to the described content can be applied to the methods of the present invention.

[0028] Example 1: Laser Precision Lighting Experiment for Greenhouse Cultivation of Chinese Vegetables This embodiment illustrates the application effect of the laser precision supplemental lighting method for leafy vegetables of the present invention in greenhouse cultivation of leafy greens. For example... Figure 1-2 As shown, the precision laser-based supplemental lighting device for leafy vegetables used in this embodiment includes a laser light source module, a hanging bracket 3, a control module 6, and a power supply module. The laser light source module includes a red-blue composite laser lamp, forming a laser tube 1, which is connected to the control module 6 and the power supply module via a laser lamp connecting cable 2. The hanging bracket 3 is positioned above the seedbed 5 to suspend the laser tube 1 above the canopy of the leafy vegetable crop, and can adjust the distance between the laser tube 1 and the canopy according to the height of the leafy vegetable canopy. The control module 6 includes a timer switch, a dimmer switch, an overcurrent protection circuit, and a heat dissipation component, used to control the supplemental lighting period, intensity, and operational safety of the red-blue composite laser lamp. The power supply module supplies power to the laser light source module and the control module 6. In specific installation, the seedbed 5 is positioned above the ground 4, and the laser tube 1 is arranged above the seedbed 5 via the hanging bracket 3, ensuring that the laser supplemental lighting covers the canopy area of ​​the leafy vegetables in the seedbed.

[0029] Specifically, the red-blue composite laser lamp is formed by combining red and blue lasers at a 1:1 power ratio. The center wavelength of the red light is 660 nm, and the center wavelength of the blue light is 450 nm. The half-width of both the red and blue lasers is <2 nm, and both are linearly polarized light. The total rated power of a single lamp is 8 W. The red-blue composite laser lamp is installed above the canopy of the cabbage, at a height of 75–90 cm from the canopy. The lamp tubes are arranged perpendicular to the short side of the seedbed to ensure that the supplemental light beam can evenly cover the canopy area of ​​the seedbed. The daily supplemental lighting periods are set from 6:00 to 11:00 AM and from 2:00 to 6:00 PM, for a total of 9 hours of supplemental lighting. The supplemental lighting cycle is from the time the cabbage is transplanted until harvest.

[0030] This experiment was conducted in a glass greenhouse during the winter and spring low-light season. The cultivated crop was bok choy, specifically the variety 'Yanqing'. The bok choy was transplanted and managed using conventional greenhouse cultivation methods, with the nutrient solution conductivity controlled at 2.0 mS·cm. -1 The planting density is 36 plants / m². 2 The greenhouse temperature was controlled between 12 and 25°C, and the relative humidity between 45% and 85% RH. These cultivation conditions ensured that the leafy vegetables were under suitable water, fertilizer, and group growth conditions, thus facilitating the evaluation of the effects of laser supplemental lighting parameters on the growth and quality of the vegetables.

[0031] To screen for suitable low-intensity laser illumination windows for leafy greens, this embodiment sets up multiple laser illumination treatment groups and a control group (CK) without illumination. By adjusting the number, placement, or irradiation conditions of the laser lamps, the PPFD of the laser illumination at the leafy green canopy was adjusted to 3.5 μmol·m⁻¹. -2 ·s-1 2.5 μmol·m -2 ·s -1 1.5 μmol·m -2 ·s -1 1.0 μmol·m -2 ·s -1 and 0.5 μmol·m -2 ·s -1 These are designated as T1, T4, T3, T2, and T5, respectively. Except for the difference in laser-assisted PPFD, the crop variety, cultivation substrate or method, nutrient solution conductivity, planting density, ambient temperature and humidity, supplemental lighting time, and supplemental lighting cycle remained consistent across all treatment groups.

[0032] During the experiment, the fresh weight, dry weight, plant height, and plant width of Chinese cabbage under different treatments were measured on days 14, 21, 28, and 35 after transplanting. Physiological quality indicators such as chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, nitrite content, ascorbic acid content, soluble sugar content, SOD activity, and proanthocyanidin content were measured at harvest. Data records are shown in Tables 1-6; comparisons of growth phenotypes of Chinese cabbage under different laser lighting treatments are also included. Figure 3 .

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] Experimental results: (1) Growth and yield indicators: The fresh weight of each supplemental lighting treatment was higher than that of the control group (CK), with the overall trend being T4 > T3 > T2 > T1 > T5 > CK. This indicates that red-blue combined laser supplemental lighting can improve the problem of limited growth of Chinese cabbage under low light conditions in winter and spring. Specifically, the fresh weight of the T4 treatment reached 101.64 ± 12.83 g on day 35, an increase of 15.19% compared to CK; the dry weight reached 7.18 ± 0.65 g, an increase of 20.49% compared to CK. Although the T1 treatment was higher than CK, it showed a slight light stress effect. Plant height and plant width also showed a significant increasing trend with T4, indicating that laser supplemental lighting at this intensity can promote the aboveground morphology and dry matter accumulation of Chinese cabbage. The results show that in the example, T4 (PPFD: 2.5 μmol m -2s -1 ( ) is the optimal intensity for regulating yield and phenotypic growth.

[0040] (2) Physiological indicators: The responses of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids to supplemental light intensity differed from the above indicators, with the overall order being T5 > T2 > T3 > T4 > CK > T1. Treatment T5 showed the highest values ​​for all indicators, with chlorophyll a, b, total chlorophyll, and carotenoids increasing by 8.33%, 8.22%, 8.30%, and 8.08% respectively compared to CK. Treatments T2, T3, and T4 all showed higher values ​​for all indicators than CK, with the increase decreasing sequentially. Treatment T1 (high intensity) showed significantly lower values ​​for all indicators than CK, with a decrease of 4.68%–4.82%, reflecting the inhibitory effect of excessively high laser intensity.

[0041] (3) Quality Indicators: Antioxidant capacity: The SOD activity of T4 treatment increased by 123.26% compared with CK, and the content of proanthocyanidins (OPC) increased significantly by 38.96%.

[0042] Safety: T4 and T3 treatments can reduce nitrite (NO2) levels. - NO2 accumulation, T3 processes NO2 - The content was 7.14% lower than that of the control (CK).

[0043] Nutritional quality: The T4 treatment had the highest ascorbic acid (AsA) content, which was 2.08% higher than the CK treatment; low-intensity supplemental lighting (T5) was most conducive to the accumulation of soluble sugars.

[0044] This embodiment demonstrates that by matching red-blue narrowband linearly polarized laser light with the low PPFD supplemental lighting window of the canopy, installation height, supplemental lighting period, nutrient solution conductivity, and planting density, the present invention can significantly promote the growth and improve the quality of Chinese cabbage under low-light greenhouse conditions in winter and spring. In particular, the PPFD is 2.5 μmol·m⁻¹. -2 ·s -1 The treatment showed superior performance in terms of yield, dry matter accumulation, and overall quality, while higher PPFD treatments may exhibit a tendency towards light stress, indicating that the 1–3 μmol·m⁻¹ treatment specified in this invention is appropriate. -2 ·s -1 The low-intensity laser supplementation range is both reasonable and technically effective.

[0045] Example 2: Verification Experiment of Laser Supplemental Lighting for Lettuce Greenhouse Cultivation This embodiment illustrates the applicability of the laser-based precision supplemental lighting method for greenhouse leafy vegetables of the present invention to different leafy vegetable varieties. This embodiment uses lettuce, specifically the variety 'Elegance', as the cultivation object, and conducts a verification experiment in a greenhouse cultivation environment. The lettuce is cultivated and managed using conventional greenhouse leafy vegetable cultivation methods, maintaining suitable nutrient solution supply, temperature and humidity conditions, and water management during the cultivation period. A control group (CK) without supplemental lighting is used, and a laser-supplemented lighting group is also included.

[0046] In specific implementation, the laser supplementary lighting group adopts the same or similar red-blue composite laser configuration as in Example 1. The red-blue composite laser lamp is formed by combining red and blue lasers at a power ratio of 1:1, wherein the center wavelength of the red light is 660 nm, the center wavelength of the blue light is 450 nm, the half-width of both the red and blue lasers is less than 2 nm, and both are linearly polarized light; the total rated power of a single lamp is 8 W. The laser lamp is installed above the lettuce canopy, so that the laser supplementary lighting PPFD at the lettuce canopy is 2.5 μmol·m⁻¹. -2 ·s -1 The daily supplemental lighting periods were 6:00-11:00 AM and 2:00-6:00 PM, totaling 9 hours of supplemental lighting. The supplemental lighting period was from the time the lettuce was transplanted until harvest. Except for whether laser supplemental lighting was used, the variety, cultivation method, nutrient solution management, temperature and humidity management, and other cultivation conditions of the laser-supplied lighting group were the same as those of the control group.

[0047] During the harvest period, the fresh weight and dry weight of the above-ground parts of lettuce, as well as quality indicators such as nitrite, soluble sugar, and proanthocyanidins, were measured. Data recording is shown in Tables 7 and 8.

[0048]

[0049]

[0050] Experimental results: Yield indicators: The fresh weight of the aboveground parts of the laser-treated group (74.24±1.70 g) was significantly increased by 26.47% compared with the control group (58.70±3.75 g); the dry weight of the aboveground parts was increased by 33.33%.

[0051] Quality indicators: The nitrite content in the laser-treated group was 4.92% lower than that in the control group; the proanthocyanidin (OPC) content was 47.56% higher than that in the control group.

[0052] The above results demonstrate that, in lettuce cultivation, the low-intensity red-blue composite laser supplemental lighting scheme of the present invention can significantly promote the accumulation of aboveground biomass.

[0053] This embodiment demonstrates that the present invention also exhibits significant yield-increasing and quality-improving effects in lettuce cultivation, in addition to leafy greens. This indicates that the red-blue narrowband linearly polarized laser, with a red-blue power ratio of 1:1 and a canopy PPFD of approximately 2.5 μmol·m⁻², established in this invention... -2 ·s -1 The proposed 9-hour-per-day supplemental lighting solution is not only applicable to a single leafy vegetable variety, but also has good versatility for greenhouse leafy vegetables. As shown in Example 1, this invention can promote growth and improve quality under low-intensity supplemental lighting in different greenhouse leafy vegetables, and is suitable for low-light cultivation scenarios such as greenhouses, plant factories, shade houses, enclosed cultivation spaces, and the low-light period in winter and spring.

[0054] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for precise laser-assisted supplemental lighting cultivation of leafy vegetables in greenhouses, characterized in that, Includes the following steps: Select a leafy vegetable cultivation area within a protected cultivation environment and plant leafy vegetable crops; The basic cultivation conditions for the leafy vegetable crop are controlled, wherein the conductivity of the nutrient solution is 1.5–2.5 mS·cm. -1 The planting density is 25-50 plants / m². 2 ; A laser supplementary light source formed by combining red and blue lasers is arranged above the leafy vegetable crop. The wavelength of the red laser is 640-680 nm, the wavelength of the blue laser is 440-480 nm, the power ratio of the red laser to the blue laser is 1:1, and both the red laser and the blue laser are linearly polarized light. The laser supplementary lighting source is installed at a distance of 70–120 cm from the canopy of the leafy vegetable crop, so that the PPFD of the laser supplementary lighting at the canopy of the leafy vegetable crop is 1–3 μmol·m⁻¹. -2 ·s -1 ; Supplemental lighting should be provided throughout the entire growth period and / or during periods of low light intensity for the leafy vegetable crop, with a cumulative supplemental lighting of 6 to 12 hours per day.

2. The method for precise laser-assisted cultivation of leafy vegetables in greenhouses according to claim 1, characterized in that, The facility cultivation environment includes one or more of the following: greenhouse, multi-span shed, plastic greenhouse, plant factory, shade shed, and enclosed cultivation space; and / or, The low-light period includes one or more of the following: winter and spring low-light periods, consecutive cloudy days, and smoggy days; and / or, The leafy vegetables include one or more of the following: bok choy, Chinese cabbage, romaine lettuce, lettuce, and spinach.

3. The method for precise laser-assisted supplemental lighting cultivation of leafy vegetables in greenhouses according to claim 1, characterized in that, The wavelength of the red laser is 650–670 nm, preferably with a center wavelength of 660 nm; and / or, The wavelength of the blue laser is 445–455 nm, preferably with a center wavelength of 450 nm; and / or, The half-width of both the red laser and the blue laser is ≤5 nm, preferably ≤2 nm.

4. The method for precise laser-assisted cultivation of leafy vegetables in greenhouses according to claim 1, characterized in that, The laser supplementary light source is a red-blue composite laser lamp, and the total rated power of a single red-blue composite laser lamp is 5-15 W, preferably 8 W; and / or, One to three red-blue composite laser lamps are provided per square meter of cultivation unit, preferably one lamp; and / or... The red-blue composite laser lights are evenly suspended in a manner where the light tubes are parallel to the long side, parallel to the short side, perpendicular to the long side, or perpendicular to the short side of the seedbed, with the preferred arrangement being that the light tubes are perpendicular to the short side of the seedbed.

5. The method for precise laser-assisted supplemental lighting cultivation of leafy vegetables in greenhouses according to claim 1, characterized in that, The laser supplementary lighting source is installed at a distance of 60-90 cm from the canopy of the leafy vegetable crop, preferably at a distance of 75 cm from the canopy of the leafy vegetable crop; and / or, The laser supplemental lighting PPFD at the canopy of the leafy vegetable crop was 2.0–3.0 μmol·m⁻¹. -2 ·s -1 Preferably 2.5 μmol·m -2 ·s -1 .

6. The method for precise laser-assisted supplemental lighting cultivation of leafy vegetables in greenhouses according to claim 1, characterized in that, Daily supplemental lighting should be accumulated for 8–10 hours, preferably 9 hours; and / or, The supplementary lighting periods include a morning supplementary lighting period and an afternoon supplementary lighting period, wherein the morning supplementary lighting period is from 5:30 to 11:30 and the afternoon supplementary lighting period is from 13:30 to 18:30; preferably, the morning supplementary lighting period is from 6:00 to 11:00 and the afternoon supplementary lighting period is from 14:00 to 18:

00.

7. The method for precise laser-assisted cultivation of leafy vegetables in greenhouses according to claim 1, characterized in that, The conductivity of the nutrient solution is 1.8–2.2 mS·cm. -1 Preferably 2.0 mS·cm -1 ; and / or, The planting density is 30–40 plants / m², preferably 36 plants / m²; and / or, The ambient temperature of the facility cultivation environment is 12-25℃, and the relative humidity is 40%-85%.

8. A cultivation apparatus for implementing the facility-grown leafy vegetable laser precision supplemental lighting cultivation method according to any one of claims 1-7, characterized in that, Includes a laser source module, a suspension bracket, a control module, and a power supply module; The laser source module includes multiple sets of red-blue composite laser lamps. The red-blue composite laser lamps are formed by combining red laser and blue laser at a power ratio of 1:

1. The wavelength of the red laser is 640-680 nm and the wavelength of the blue laser is 440-480 nm. Both the red laser and the blue laser are linearly polarized light, and the total rated power of a single lamp is 5-15 W. The suspension bracket is used to install the red-blue composite laser light above the canopy of the leafy vegetable crop, and can adjust the distance between the red-blue composite laser light and the canopy of the leafy vegetable crop. The control module is connected to the laser source module and is used to control the supplementary lighting period and / or supplementary lighting intensity of the red-blue composite laser lamp; The power supply module is connected to the laser source module and the control module, and is used to supply power to the laser source module and the control module.

9. The cultivation device according to claim 8, characterized in that, The height adjustment range of the suspension bracket is 50–120 cm, preferably 60–90 cm; and / or, The suspension bracket supports the installation of the red-blue composite laser lights in a direction parallel or perpendicular to the seedbed, and supports horizontal spacing adjustment of multiple red-blue composite laser lights; and / or, The control module includes one or more of the following: a timer switch, a branch dimmer, an overcurrent protection circuit, and a heat dissipation component; and / or, The power supply module is compatible with 110 V and / or 220 V AC power and supports independent group control of the red and blue composite laser lights.

10. The application of the method for precise laser-assisted cultivation of leafy vegetables in greenhouses according to any one of claims 1-7 or the cultivation device according to any one of claims 8-9 in low-light cultivation of leafy vegetables in greenhouses, characterized in that, The application is used to increase the yield and / or improve the quality of leafy vegetables; the improvement of leafy vegetable quality includes one or more of the following: increasing chlorophyll content, increasing antioxidant enzyme activity, increasing proanthocyanidin content, increasing ascorbic acid content, increasing soluble sugar content, and reducing nitrite content.

Images