Method for laser regulation of growth of field crops and application in rice

Abstract

The application discloses a method for laser regulation and control of growth of field crops and application in rice, and belongs to the technical field of planting. Red light and blue light laser light sources are used to adjust light quality ratio, light intensity output, time control and irradiation direction, to realize a complementary irradiation mode when natural light is insufficient or light distribution of a canopy is uneven, and to improve photosynthetic efficiency. Light energy supply matched with growth demand of each key growth period is obtained, and group light interception and light energy utilization efficiency are improved as a whole. Through reasonable configuration of total irradiation amount, irradiation time period and irradiation space distribution, the application promotes rice green recovery and effective tiller formation after transplanting, maintains higher photosynthetic capacity of functional leaves, improves the grain filling process, and thus improves yield formation capacity under the premise of controlling power consumption. The system adopts low-power semiconductor lasers to realize transformation of laser from a laboratory photobiology research tool to a production light environment regulation and control element, and has remarkable novelty and application value.

Description

A method for laser-controlled field crop growth and its application in rice. Technical Field

[0001] This invention relates to the field of rice cultivation technology, specifically a method for laser-controlled field crop growth and its application in rice. Background Technology

[0002] Throughout the entire rice growth period from transplanting to maturity (including stages such as greening, tillering, jointing, heading, and grain filling), the light environment has long relied primarily on natural sunlight. However, the natural light environment in the field exhibits significant temporal and spatial heterogeneity, making it difficult to meet the differentiated light requirements of rice at each key growth stage. Specifically:

[0003] The inherent limitations of natural light environments: During the critical period of greening and tillering 20-30 days after transplanting, prolonged cloudy and low-light weather can severely inhibit seedling greening and the formation of effective tillers due to persistently low photosynthetically active radiation (PAR). Furthermore, in high-density cultivation, the upper leaves of the canopy are prone to photoinhibition due to excessive light intensity, while the middle and lower functional leaves are subjected to prolonged low light conditions due to shading from the upper canopy, resulting in low photosynthetic efficiency, increased ineffective tillers, insufficient panicle differentiation, and inadequate grain filling, ultimately affecting yield.

[0004] Limitations of existing light source technologies: To compensate for insufficient natural light, existing technologies employ artificial light sources such as fluorescent lamps, high-pressure sodium lamps, and LEDs. However, these technologies are primarily used in greenhouses, plant factories, and other facility environments, and are difficult to apply directly to open field conditions. Their limitations are mainly reflected in the following aspects: First, these light sources have a wide spectrum and limited precision in light quality control, making it difficult to accurately match the specific red / blue light ratio requirements of crops at different growth stages; second, their deployment methods are limited, and their energy consumption is high, making them unsuitable for application in field production.

[0005] There is a gap in the application of laser technology in field production: Laser sources have advantages such as strong directionality, good monochromaticity, and concentrated energy. Existing research mainly focuses on using lasers for short-term indoor treatment of seeds or seedlings, but lacks a laser growth regulation method suitable for complex open-air environments, especially for rice from transplanting to maturity. How to transform lasers from laboratory tools into a key element of light environment regulation in field production, achieving coordinated and precise control of light quality, light intensity, illumination time, and spatial distribution, to actively compensate for the limitations of natural light in time and space, and effectively improve the illumination conditions in the lower and middle layers of the canopy, is a pressing technical challenge that needs to be solved. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, the present invention aims to provide a method for laser-controlled crop growth in open field environments, particularly for laser irradiation control of rice from transplanting to maturity. This method makes parameters such as light quality, light intensity, and illumination time visible and controllable, and matches them with the light energy requirements of rice at each key growth stage, thereby actively compensating for the deficiencies of natural light in terms of temporal and spatial distribution.

[0007] By optimizing the light distribution within the canopy through directional and zoned irradiation, an east-west laser irradiation path is formed that complements the north-south projection direction of natural light. Combined with the control of beam divergence angle and incident angle, the laser beam can enter the interior of the canopy along the gaps between the upper leaves, focusing on improving the long-term lack of light for the functional leaves in the middle and lower parts of the canopy, and improving the rationality and utilization efficiency of light energy distribution in the canopy.

[0008] To construct a laser irradiation control technology system suitable for field application, utilizing the directionality and coherence of laser beams to penetrate narrow gaps between leaves and irradiate the middle and lower leaves, continuously enhancing the photosynthetic potential and dry matter accumulation capacity of the population, thereby promoting grain filling and nutrient accumulation, increasing rice yield and its stability, and filling the technological gap in the field of refined active control of light environment for paddy rice.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows:

[0010] A method for laser-controlled growth regulation of field crops includes the following steps:

[0011] Deployment steps: Around the perimeter of the large field plot, deploy multiple semiconductor laser lights in an east-west direction. Each semiconductor laser light can emit both red and blue laser light simultaneously.

[0012] Regulation steps: Adjust the supplemental lighting period, the light quality ratio of each semiconductor laser lamp, the photosynthetic photon flux density, and the elevation angle of the laser beam according to the growth stage of the crop to provide directional illumination to the crop canopy.

[0013] Furthermore, the adjustment of supplemental lighting time in the control steps specifically includes: turning on laser irradiation 2-3 hours before sunrise; turning off laser irradiation when the natural light intensity reaches or approaches the crop light saturation point; turning on laser irradiation again when the measured light intensity in the field is lower than the crop light saturation point in the afternoon, and continuing to extend the irradiation for 2-3 hours after sunset, so that the effective light duration of crops per day is ≥12 hours.

[0014] Furthermore, in the control steps, adjusting the light quality ratio of each semiconductor laser lamp includes: during the greening period to the early tillering stage, the light quality ratio of red light to blue light is preferably set to R:B = 1:1; during the mid-tillering stage to the grain-filling and maturation stage, the light quality ratio of red light to blue light is preferably set to R:B = 9:6.

[0015] Furthermore, in the regulation steps, adjusting the photosynthetic photon flux density specifically includes: during the greening stage to the early tillering stage, the photosynthetic photon flux density is 0.05-0.2 μmol·m⁻¹. -2 ·s -1 During the mid-tillering to grain-filling maturity stage, the photosynthetic photon flux density is 0.5-1.5 μmol·m⁻¹. -2 ·s -1 .

[0016] Furthermore, in the control steps, adjusting the elevation angle of the laser beam specifically includes: adjusting the elevation angle of the laser beam to 5° to 15° during the greening stage to the early tillering stage; adjusting the elevation angle of the laser beam to 15° to 45° during the mid-tillering stage to the early heading stage; and adjusting the elevation angle of the laser beam to 45° to 60° during the early heading stage to the grain-filling and ripening stage; wherein, the elevation angle is the angle between the laser beam and the vertical direction.

[0017] Furthermore, in the deployment step, semiconductor laser lights are deployed at 4-meter intervals along the perimeter of the field, and the long axis of the laser spot is parallel to the direction of the crop planting row.

[0018] A laser-controlled field crop growth system for implementing the above methods includes: multiple semiconductor laser lamps deployed around the field to emit red and blue laser light; an angle adjustment mechanism connected to the semiconductor laser lamps to adjust the pitch angle of the laser beam; and a controller connected to the semiconductor laser lamps to control the light quality ratio, output photosynthetic photon flux density, and on / off time of each semiconductor laser lamp.

[0019] Furthermore, the red light wavelength of semiconductor laser lamps is 650-670nm, and the blue light wavelength is 440-460nm.

[0020] A field operation method for improving rice yield based on laser modulation includes the following steps:

[0021] S1. In the paddy field, a semiconductor laser lamp is set up every 4 meters along the perimeter of the field in an east-west direction. The red light wavelength of the semiconductor laser lamp is 650-670 nm and the blue light wavelength is 440-460 nm.

[0022] S2. During the rice's greening stage to the early tillering stage, the light quality ratio of the semiconductor laser lamp is R:B=1:1, the beam pitch angle is adjusted to 5°-15°, and the lamp is turned on 2-3 hours before sunrise each day. When the natural light intensity reaches the rice's light saturation point, the lamp is turned off. In the afternoon, when the natural light intensity drops below the rice's light saturation point, the lamp is turned on again, and the illumination is extended for 2-3 hours after sunset.

[0023] S3. During the mid-tillering stage to the grain-filling and ripening stage of rice, the preferred light quality ratio of the semiconductor laser lamp is set to R:B=9:6, and the beam pitch angle is gradually adjusted from 15° to 60° as the rice grows. The illumination period is the same as in step S2.

[0024] In particular, through steps S2 and S3, the effective daily sunshine duration for rice is ≥12 hours.

[0025] The beneficial effects of this invention are:

[0026] Compared with the unirradiated group, the laser irradiation group using the method of this invention showed a 10%-17.5% reduction in the time from greening to tillering, a 12%-17% increase in the number of effective tillers, a 15%-30% increase in the net photosynthetic rate of the canopy, and a 5%-30% increase in final yield. By adjusting the light distribution and staged angle adjustments, the photosynthesis of the lower and middle leaves of the canopy was effectively improved, verifying the beneficial effects of this invention. Attached Figure Description

[0027] Figure 1 is a schematic diagram of the semiconductor laser lamp of the present invention being deployed in Daegu;

[0028] Figure 2 is a schematic diagram of the semiconductor laser lamp pitch adjustment mechanism of the present invention;

[0029] Figure 3 shows the effect of laser irradiation on the greening state in Embodiment 1 of the present invention;

[0030] Figure 4 shows the effect of laser irradiation on heading time in Example 1 of the present invention.

[0031] Figure 5 shows the effect of laser irradiation on the number of tillers in Embodiment 1 of the present invention;

[0032] Figure 6 shows the results of plant height changes during the tillering stage in each experimental component in Example 1 of the present invention;

[0033] Figure 7 shows the results of plant height changes during the heading stage in each experimental group in Example 1 of the present invention.

[0034] Figure 8 shows the results of plant height changes at maturity in each experimental group in Example 1 of the present invention.

[0035] In the picture:

[0036] 1. Die-cast aluminum heat dissipation body, 2. U-shaped metal bracket, 3. Angle scale locking assembly. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] This invention is particularly applicable to rice.

[0039] Field semiconductor laser light installation and lighting structure:

[0040] The field semiconductor laser light (model CXL1-X0220-0601) is provided by Zhejiang Changxin Optoelectronic Technology Co., Ltd. It can emit red and blue light simultaneously. The laser is emitted by a semiconductor laser. The wavelength of the red light is (660±10)nm and the wavelength of the blue light is (450±10)nm.

[0041] The light quality ratio of this system adopts a preset program control strategy based on the growth period, rather than relying on expensive and unstable real-time spectral feedback.

[0042] Phase 1: From the greening stage to the early tillering stage (critical period of vegetative growth)

[0043] Mixing ratio: R:B = 1:1.

[0044] The focus at this stage is on promoting strong seedlings and root development. Blue light sources are used to induce stomatal opening, promoting root development, while cryptochromes inhibit excessive stem elongation, ensuring short and sturdy seedlings and laying the foundation for lodging resistance.

[0045] Stage Two: Mid-tillering to Early Heading

[0046] Formula: R:B = 9:6 (Red light dominant)

[0047] At this stage, the canopy has closed, and the primary goal shifts to maximizing photosynthetic efficiency and dry matter accumulation. Red light's quantum energy efficiently drives photosynthesis; blue light can concentrate more energy on carbohydrate synthesis and grain filling, thereby significantly increasing yield.

[0048] Stage 3: From the initial heading stage to the grain-filling and ripening stage

[0049] Formula: R:B = 9:6 (Red light dominant)

[0050] At this stage, although the canopy has closed, it faces the risk of senescence. The primary goal shifts to maximizing the photosynthetic characteristics of functional leaves and the directional accumulation of dry matter into the grains. By concentrating more photosynthetic potential on grain filling and ripening, the thousand-grain weight and final yield can be significantly increased while extending the photosynthetic functional period.

[0051] The semiconductor laser lights should be installed approximately 2.5 meters above the top of the rice seedlings. One semiconductor laser light should be placed every 4 meters along the perimeter of the field or along the field ridges. These laser lights are connected in series. The laser beam emitted by each laser light is expanded by its built-in microlens array to form a rectangular light spot. The long axis of this rectangular light spot is parallel to the direction of the rice planting rows. By adjusting the divergence angle of the rectangular light spot, it can precisely cover one or more rows of rice canopies, preventing light scattering into ineffective areas.

[0052] Considering the characteristics of rice canopy densities gradually increasing from bottom to top during the greening and early tillering stages, and the tendency of upper leaves to shade lower and middle functional leaves, the lighting structure of semiconductor laser lamps was optimized. A lighting method was adopted where the long axis of the rectangular light spot emitted by the semiconductor laser lamp was parallel to the direction of the rice planting rows, preferably using an east-west orientation, so that the laser irradiation direction intersects with the main projection direction of natural sunlight (usually north-south). By adjusting the installation orientation, tilt angle, and beam divergence angle of the semiconductor laser lamps, the laser beam can penetrate through the narrow gaps between the upper leaves to the lower and middle functional leaves, effectively improving the problem of insufficient light penetration within the canopy.

[0053] Upper leaves: the part above 2 / 3 of the average plant height. This is the area that receives the most sunlight.

[0054] Middle leaves: between 1 / 3 and 2 / 3 of the average plant height. This is the part where light begins to decrease, but it is still the core area for photosynthesis.

[0055] Lower leaves: The part below 1 / 3 of the average plant height. Usually refers to the base, where humidity is high and light is weak, and it is also the site where tillering occurs.

[0056] Laser irradiation parameters and irradiation time settings:

[0057] After the semiconductor laser lamp is installed, the controller is used to set the laser output power, light quality ratio, and working period. The illumination angle and coverage area of ​​the semiconductor laser lamp are then adjusted in the evening or under low light conditions to ensure the beam covers all areas and complements the natural light areas. During adjustment, a spectrometer is used to measure the light intensity at different locations. Measurements are taken at the nearest (approximately 1m), midpoint (approximately 10m), and farthest (approximately 20m) points from the semiconductor laser lamp. Based on the effective radiation requirements of rice during its field growth, the following supplementary lighting parameters are determined:

[0058] From the greening stage to the early tillering stage: supplemental lighting was used to maintain the photosynthetic photon flux density at 0.05-0.2 μmol·m⁻¹. -2 ·s -1 Within the range, it is used to provide basic supplemental lighting to the middle and lower leaves when the canopy has not yet fully closed;

[0059] From mid-tillering to early heading stage: As canopy closure increases, the photosynthetic photon flux density of supplemental lighting increases to 0.5-1.5 μmol·m⁻¹. -2 ·s -1 Within a certain range, to meet the photosynthetic needs of leaves in different regions.

[0060] From the early heading stage to the grain-filling and ripening stage: supplemental lighting was used to maintain the photosynthetic photon flux density at 0.5-1.5 μmol·m⁻¹. -2 ·s -1 The intensity range is as follows. During this stage, the canopy closure reaches its peak, and the natural light transmittance is at its lowest. Maintaining this photosynthetic photon flux density aims to enhance penetration, delay the aging of the middle and lower functional leaves, prolong the duration of photosynthesis, thereby promoting the efficient accumulation of photosynthetic products in the ear and improving the seed setting rate and thousand-grain weight.

[0061] Laser irradiation schedule: Morning pre-activation: Taking advantage of the early sunrise in summer, the laser is turned on around 3:00 AM, 2-3 hours before sunrise, during the low temperature and high humidity photosynthetic window, to induce stomatal opening in advance; Midday high temperature avoidance: Between 11:30 AM and 2:00 PM, when the field temperature is ≥32℃ or the natural light intensity reaches the crop light saturation point, the light source is turned off to prevent high temperature and light inhibition; Finally, evening extended supplemental lighting: From 2:00 PM to 4:00 PM, the laser is turned on again as the natural light decays, extending the off-time to 8:00 PM to 9:00 PM. Through the above timing control, the effective daily light duration for rice is maintained at no less than 12 hours.

[0062] Adjustable illumination angle structure: The laser beam forms an angle with the vertical direction, and the illumination angle is adjustable using a pitch adjustment mechanism. In this embodiment, the pitch adjustment mechanism uses a damping hinge and a locking screw for manual adjustment.

[0063] Brief description of the adjustment mechanism: It consists of three parts: a die-cast aluminum heat sink body 1, a U-shaped metal bracket 2, and an angle scale locking assembly 3, as shown in Figure 2. The die-cast aluminum heat sink body 1 is rotatably connected to the U-shaped metal bracket 2 via the angle scale locking assembly 3. The angle scale locking assembly 3 consists of bolts and nuts.

[0064] Pitch adjustment: Manual adjustment. The structure consists of a "U-shaped metal bracket 2 and angle scale locking assembly 3", and is not motor-driven. The design is intended to adapt to the high humidity and muddy environment of paddy fields, as the manual mechanical structure is more durable and less expensive than a precision motor.

[0065] Horizontal adjustment: Available. The lamp base is fixed to the die-cast aluminum heat sink 1 by bolts, allowing the laser lamp to rotate 360° on the die-cast aluminum heat sink 1 for alignment or fine-tuning of the azimuth angle.

[0066] Laser beam angle adjustment control logic: The angle adjustment is not linked to the clock mechanism, but executes a semi-active control logic based on the reproductive period model.

[0067] Basis: Based on changes in rice canopy structure (plant height, canopy closure), rather than a single time period.

[0068] Execution: Differentiated settings will be implemented in three phases.

[0069] 5-15° from the greening stage to the early tillering stage: suitable for the stage when the canopy is relatively sparse during the greening stage, so that the light beam can penetrate the canopy with a longer path, the supplementary light energy is distributed to a deeper layer, and the horizontal light penetrates and covers a deeper layer;

[0070] Mid-tillering to early heading stage 15-45°: Applicable to the early tillering stage when the number of leaves increases and the canopy gradually densifies, making it easier for the beam to cut into the gaps between the leaves and enter the interior of the canopy, with oblique beam cutting in and avoiding interference from the leaves;

[0071] From the early heading stage to the grain-filling and maturity stage, 45-60°: This is suitable for the stage when the canopy height increases and the upper leaves provide stronger shading during the grain-filling and maturity stage. It allows the supplemental light to be more concentrated on the functional leaves in the middle and lower parts of the canopy, improving their long-term weak light conditions. The steep angle direct sunlight helps to target the functional leaves in the middle and lower parts of the canopy.

[0072] Example 1

[0073] The rice seeds were provided by the Gongzhuling Rice Research Institute, and the variety is Akita Komachi.

[0074] Nonlinear gradient design for laser irradiation treatment groups (S1LD-S7LD):

[0075] This embodiment establishes six laser irradiation treatment groups, numbered S1LD to S7LD. Regarding the timing of light quality control, each treatment group maintains a uniform R:B ratio of 1:1 from the greening stage to the early tillering stage. From the mid-tillering stage to the grain-filling maturity stage, the red light ratio is kept constant, while a gradient increasing strategy for the blue light ratio is implemented. The specific parameters are set as follows: S1LD (9R:1B), S2LD (9R:2B), S3LD (9R:3B), S5LD (9R:5B), S6LD (9R:6B), and S7LD (9R:7B). The linear node with low response discrimination, R:B=9:4 (S4), is skipped.

[0076] Control groups (S group and CK group)

[0077] First level: Paired controls within the same area (S1-S7). For each laser-treated group (LD), a corresponding natural light control group is set up in its adjacent location, such as S1 corresponding to S1LD. Both are located in the same area, and apart from differences in light environment, their soil fertility and water and fertilizer management are completely consistent, eliminating the interference of local spatial heterogeneity on the results of a single treatment and ensuring the accuracy of inter-group comparisons.

[0078] Second level: Global control (CK1, CK2). Two independent blank control groups, CK1 and CK2, were set up diagonally in fields far from the laser irradiation area.

[0079] CK1: Used to monitor basic growth indicators in fields under natural conditions.

[0080] CK2: Used for cross-sectional comparison with CK1 and other groups. If there is no significant difference between CK1 and CK2 data, and they match the baseline values ​​of groups S1-S7, then the reliability and representativeness of the data are proven.

[0081] After soaking and germination, the seeds were cultivated in greenhouses for approximately 25 days before being transplanted to the field. The experimental field was divided into two areas: a field laser irradiation group (S1LD-S7LD) and a field non-irradiation group (S1-S7), totaling 14 groups. Seedlings were transplanted manually, with four points on a 9cm × 6cm rectangle as the transplanting area, using a single-plant transplanting method. The experimental area contained approximately 2000 seedlings.

[0082] The field laser irradiation groups, namely S1LD-S7LD groups, were subjected to the following operations:

[0083] Operating hours: Correspond to the season.

[0084] Early morning: Turn on the semiconductor laser lights 2-3 hours before sunrise, specifically between 2:00 and 4:00.

[0085] Mid-term: Turn off the semiconductor laser lamps at noon (when light saturation / temperature is high), specifically between 11:00 and 14:00, when the field temperature is ≥32℃.

[0086] Evening: Extend the operating time of the semiconductor laser lights by 2-3 hours after sunset, specifically from 14:00 to 16:00.

[0087] Target duration: Ensure effective laser illumination duration of ≥12 hours per day.

[0088] Light quality ratio standard:

[0089] From the greening stage to the early tillering stage (0-20 days after transplanting): Tilting angle 5-15°, light quality ratio R:B = 1:1, photosynthetic photon flux density 0.05-0.2 μmol·m⁻¹ -2 ·s-1 ,

[0090] Mid-tillering to early heading stage (20-50 days after transplanting): Tilting angle 15-45°, light quality ratio S1LD to S7LD as described above, photosynthetic photon flux density 0.5-1.5 μmol·m⁻¹ -2 ·s -1 ,

[0091] From the early heading stage to the grain-filling and ripening stage (50-100 days after transplanting): the elevation angle is 45-60°, the light quality ratio S1LD to S7LD is as described above, and the photosynthetic photon flux density is 0.5-1.5 μmol·m. -2 ·s -1 .

[0092] Seedling greening: During the greening period, the seedlings were observed at fixed times every day to record the process of leaf color changing from yellow to green, the uprightness of the plants, the emergence of new leaves, and other greening status. At the same time, the number of days from transplanting to the start of tillering, the time of the first tillering, and the tillering ratio were continuously recorded to analyze the impact of different laser irradiation schemes on the seedling greening process and the speed at which the seedlings enter the tillering stage.

[0093] Tillering Data Collection: Multiple dynamic monitoring sessions were conducted manually in the early stages of rice tillering, with four observation points set up at 10-day intervals to comprehensively reflect the tillering progress and growth differences under different treatments. During each survey, a five-point sampling method was used within each group, specifically one observation point at each of the four corners and the center of each experimental field, with each observation point at least two rows from the field edge to eliminate edge effects. Quadrat Quantitative Standard: Ten consecutive healthy rice plants were selected from each observation point as a standard quadrat. All plants within the quadrat were tagged, and the number of tillers, plant height, and leaf age were recorded and statistically analyzed. The average value was taken as the observation result for that time point.

[0094] Rice seedling heading status:

[0095] Records were taken when 20% of the seedlings in each experimental group reached the heading stage, and then again when 80% of the seedlings in each experimental group reached the heading stage. Representative plants were selected, and the length of the main panicle was measured from the neck node to the tip of the panicle, focusing solely on the main panicle. On the same plant, the length (from ligule to leaf tip) and width (at the maximum width of the leaf) of the flag leaf, second-to-last leaf, and third-to-last leaf were measured, and the morphological characteristics of the functional leaves were recorded to evaluate the effects of different treatments on panicle development and leaf growth. Simultaneously, a field survey of lodging was conducted. Lodging areas were classified and the degree of lodging was quantified based on plant tilt angle and lodging area to analyze the impact of each experimental group on the lodging resistance of rice.

[0096] Seedling grain filling and setting: The time when each group entered the waxy ripening stage, yellow ripening stage and full ripening stage was continuously observed and recorded. The ripening time of the first panicle and the ripening time of 50% of the panicles in the group were specially marked. By comparing with the control group, the number of days that rice entered the ripening stage earlier and the changes in the ripening period under different light conditions such as laser irradiation were statistically analyzed to comprehensively evaluate the regulatory effect of field irradiation on the grain filling and ripening process.

[0097] Production forecast vs. actual production measurement:

[0098] At maturity, the ear weight, seed setting rate, thousand-grain weight, and dry weight of each plant were recorded, along with the number of effective tillers, to prepare for subsequent yield assessment. Yield prediction was performed for each experimental area, using a 1m² plot. 2 The total number of plants is approximately 20. Count the number of effective ears on each plant, repeat 3 times, and calculate the average value.

[0099] The actual yield was measured by weight after manual harvesting. The predicted yield data was compared with the actual yield data, and the differences between the prediction and the actual yield were analyzed. The results were then compared with the control group to select the better and worse experimental groups. The data with the largest differences were analyzed to make a reasonable judgment on the actual situation.

[0100] As shown in Figure 3, the time from the greening stage to the early tillering stage of seedlings in each experimental group was generally between 8 and 10 days, while the control groups CK1 and CK2 were approximately 10 days. In the unirradiated field groups: S1, S2, S5, and S6 were mostly between 8.9 and 9.3 days, only slightly earlier than the control group; S3 was the shortest (approximately 8.55 days), while S7 was close to or slightly slower than the control group. The field laser irradiated groups further shortened the time from the greening stage to the early tillering stage. S1LD and S5LD were approximately 8.8-9.0 days, about 1 day earlier than the control group; S2LD and S7LD were similar to some unirradiated field groups, with only moderate effects; S3LD and S6LD were approximately 8.25 days and 8.85 days respectively, significantly better than the control group and the unirradiated field groups. Specific laser ratios can significantly accelerate the transition of seedlings from the slow greening stage to the tillering stage.

[0101] Four data collections were conducted from the early to mid-tillering stages. As shown in Tables 1 and 2, the number of tillers in each experimental group initially increased and then slightly decreased from the early to late tillering stages. At the initial survey on June 18th, the number of tillers in each experimental group was approximately 8–10 stems, with no significant difference between irradiated and unirradiated groups. By June 28th, the number of tillers had increased significantly, with the control group having approximately 20 stems and most field laser-irradiated groups reaching over 23 stems. S3LD had the highest number, while S1LD and S2LD were also significantly higher than the control. Tillering peaked on July 8th, with the overall number of tillers in the field laser-irradiated groups being even higher. S1LD and S3LD had the highest numbers among all field laser-irradiated groups. On July 18th, the number of tillers decreased slightly, but S1LD, S3LD, S5LD, and S6LD still maintained 28–31 stems, higher than the control group and most unirradiated field groups. This indicates that although field laser irradiation does not change the tillering dynamics, it can significantly increase the peak tillering and prolong the duration of higher tillering levels, with S3LD, S1LD, and S6LD showing the best promoting effects.

[0102] Table 1. Dynamic changes in the number of Ck1 tillers in the field laser irradiation group.

[0103] Date Ck1 (Number of Tillers) S1LD (Number of Tillers) S2LD (Number of Tillers) S3LD (Number of Tillers) S5LD (Number of Tillers) S6LD (Number of Tillers) S7LD (Number of Tillers) 6.18 7.8±2.1 8.8±2.6 9.7±2.3 10.4±3.2 8.6±2.7 9.6±1.9 8.6±2.1 6.28 19.7±5.2 25.7±5.3 26.1±5.5 28.9±6.7 24±4.3 25.2±4.4 24.2±5.2 7.8 29.5±5.4 33.0±4.7 31.7±4.9 34.5±7.3 31.8±5.7 30.8±6.3 31.3±5.4 7.18 26.5±4.6 28.9±4.5 28.1±4.6 30.6±5.8 29.3±6.1 28.6±5.8 29±5.1 surface

[0104] Table 2. Dynamic changes in tiller number between the unirradiated group and Ck2 in the field.

[0105] Date Ck2 (Number of Tillers) S1 (Number of Tillers) S2 (Number of Tillers) S3 (Number of Tillers) S5 (Number of Tillers) S6 (Number of Tillers) S7 (Number of Tillers) 6.18 8.9±2.08±1.9 9.2±2.2 9.5±2.3 8.1±2.0 9.5±2.5 8.1±1.8 6.28 20.3±4.7 22.9±5.0 24.6±5.3 25.7±5.7 23.8±4.0 24.9±5.3 21.7±5.8 7.8 29.4±4.9 30.8±4.6 31.1±5.4 32±6.0 30.7±5.5 31.3±5.6 29.6±5.4 7.18 27.4±4.6 27.7±4.5 28.7±4.3 29.8±5.0 28±4.2 28.7±5.1 27.6±4.9 surface

[0106] After the rice in each experimental group entered the heading stage, continuous field observations were conducted on the heading dynamics. The earliest heading was observed in the S6LD group. Analysis was performed on the heading stages of 20% and 80% of the seedlings in each experimental group. As shown in Figure 4, the overall time from the beginning of heading to the heading stages of 20% and 80% of the seedlings in each experimental group was relatively stable: the heading time of 20% was mainly concentrated in 3.0–3.8 days, and the heading time of 80% was mostly in 5.5–6.5 days. Compared with CK1 and CK2, the heading times of 20% and 80% of the seedlings in the field laser irradiation groups (S2, S3, S1LD, S2LD, S3LD) were slightly earlier, with relatively small variations. This indicates that laser irradiation can moderately promote earlier heading and improve heading synchronization without disrupting the growth process. Only S7 and S7LD showed a slight delay, with little overall difference.

[0107] When 80% of the seedlings in each experimental group entered the heading stage, the number of effective panicles was analyzed. As shown in Figure 5, the peak tillering number in each group before heading was approximately 27–34 plants / hill, and the effective tillering number was 21–28 plants / hill. Compared with CK1, CK2, and the unirradiated field group, the field laser irradiated group showed an overall increase in the peak tillering number and the number of effective tillers. In particular, the effective tillering number accounted for a higher proportion of the peak value in S3LD and S6LD, indicating that laser irradiation is beneficial to increasing the number of effective panicles, providing a good foundation for uniform heading and increased yield in the later stages.

[0108] Figure 6-8 shows the height changes of different experimental groups during the early tillering, mid-tillering, early heading, and grain-filling stages. From the perspective of the growth cycle, plant height gradually increased with the progression of the growth period. Regarding inter-group differences, the height of the control group and the unirradiated field group remained at similar levels, with small differences within and between groups. However, the height of the laser-irradiated field group was significantly higher than that of the control group and the unirradiated field group at each growth stage, and the height fluctuation within this group was smaller, demonstrating the stability of the laser irradiation effect. Overall, laser irradiation has a continuous and significant promoting effect on plant height at different growth stages, while the height increase of the control group and the unirradiated field group was relatively gradual and showed no significant difference.

[0109] The bidirectional regulatory effect of laser irradiation on lodging resistance in rice: Based on the data analysis in Table 3, the effect of laser irradiation on stem strength exhibits a significant spectrally specific bidirectional effect. Negative effects dominated by red light: Under low blue light ratios, lodging conditions deteriorated sharply to level 3 (severe lodging), more than 50% worse than the control group in the same area. This indicates that the red light-induced longitudinal elongation effect of stems, in the absence of sufficient blue light antagonism, leads to a significant decrease in basal mechanical strength, unable to support the panicle load brought about by increased yield in the field. Corrective effect of high blue light: In contrast, the S6LD and S7LD programs successfully controlled the lodging level to the same level as in the field by increasing the proportion of blue light (40%-44%). Overall evaluation: Although the S6 natural light control group showed a level 0 (no lodging) characteristic, the S6LD group, under the premise of bearing a significantly increased yield load, did not experience the devastating lodging as the S1LD group. This confirms that the R:B=9:6 ratio effectively balances the contradiction between photosynthetic growth promotion and stem reinforcement, and avoids the risk of severe lodging through the blue light induction effect, which is the key threshold for achieving stable yield and increased efficiency.

[0110] Table 3 Effects of different treatments on lodging resistance of rice

[0111] Experimental group CK1CK2S1S2S3S5S6S7S1LDS2LDS3LDS5LDS6LDS7LD Lodging level 2 Level 2 Level 2 Level 2 Level 1 Level 0 Level 1 Level 3 Level 3 Level 3 Level 2 Level 2 surface

[0112] Note: Level 0 (no lodging) <15°; Level 1 (slight lodging) 15°-30°; Level 2 (moderate lodging) 30°-60°; Level 3 (severe lodging) >60°

[0113] As shown in Table 4 after rice maturity, compared with the control group, both the unirradiated and laser-irradiated groups in the field generally increased the number of tillers per plant, the total number of grains per panicle, and the dry matter accumulation. Specifically, the number of tillers in S3, S5, S6, S3LD, S5LD, S6LD, and S7LD were all above 24-26. The laser-irradiated groups in the field showed better performance in terms of grain number per panicle and dry weight, especially the S6LD treatment, which had the highest total number of grains per panicle and the highest number of filled grains, with a significantly higher dry weight than the control. This indicates that laser irradiation in the field is beneficial for increasing grain number per panicle and biomass, although the seed setting rate of some treatments was slightly lower than that of the control. Overall, laser irradiation in the field significantly promoted rice yield formation by increasing tillering and grain number per panicle without significantly reducing the thousand-grain weight.

[0114] Table 4. Components of Rice Yield and Dry Matter Accumulation

[0115] Treatment | Number of tillers per plant | Ear length (cm) | Total number of grains per ear | Number of filled grains per ear | Grain filling rate (%) | 1000-grain weight (g) | Dry weight (g) | CK1 | 22.3 | 18.1 | 1687 | 1640 | 97.24% | 24.65 | 42.08 | CK2 | 22.9 | 18.0 | 1746 | 1691 | 96.86% | 24.5 | 144.73 | S1 | 23.2 | 18.6 | 1871 | 1805 | 96.45 %25.5848.21S223.117.51612157197.48%24.6653.65S324.617.41821176797. 02%25.5846.97S524.917.81989194097.55%25.1149.19S623.417.5195018819 6.47%25.5946.93S723.217.91850173993.99%25.1948.87S1LD23.717.617531 66795.07%25.4942.06S2LD23.418.51979185693.79%24.7048.02S3LD26.218. 32019192395.24%24.2048.67S5LD25.418.22123198693.53%24.5448.88S6LD2 5.017.82214212596.00%24.9958.51S7LD25.018.61842173694.27%24.4751.33 surface

[0116] After the production forecast and actual production weighing were completed, the forecast results were analyzed. Under non-irradiation conditions, the production in groups S2-S6 was consistent with the forecast, with an increase of 3% to 15%. However, in groups S1 and S7, both the forecast and actual production decreased, by about 10%.

[0117] In the field laser irradiation group, S1LD, S3LD and S6LD all showed significant yield increases, with S6LD showing the best results, with an increase of 5% to 30%. However, S2LD, S5LD and S7LD all showed slight yield decreases, ranging from 1% to 5%.

[0118] This invention proposes a field laser lighting structure that can be dynamically adjusted according to the needs of different growth stages of rice, constructs a middle and lower layer directional irradiation system based on the structural characteristics of rice canopy, and proposes a field-based synergistic light environment regulation method for laser light quality, light intensity and photoperiod, so as to realize the directional regulation of rice nutrient accumulation and growth traits under real field production conditions.

[0119] This invention addresses the practical problems of low light utilization efficiency, lack of effective lighting technology, and the fact that in rice seedlings during the greening-up stage to the early tillering stage, natural light is affected by the rapid closure of the canopy, resulting in the lower and middle functional leaves being in a weak light environment for a long time. The invention constructs a field lighting technology system based on the three elements of "laser lighting structure + directional irradiation strategy + plant light environment regulation".

[0120] During the canopy formation process after the greening period, natural light is mainly intercepted by the upper leaves, resulting in a significant decrease in light energy utilization efficiency in the middle and lower layers of the canopy. Utilizing the strong directionality and good coherence of laser light sources, supplemental lighting can penetrate deep into the canopy, improving the vertical uniformity of illumination. This invention, through an adjustable semiconductor laser lamp structure and illumination angle setting, allows the laser beam to cut into the canopy interior along the narrow gaps between leaves, precisely supplementing the light deficiency of the middle and lower functional leaves, activating their photosynthetic potential, and fundamentally promoting the effective accumulation of photosynthetic products and nutrients in the plant.

[0121] This invention employs an east-west oriented light distribution, complementing the main north-south projection direction of natural light. It incorporates a multi-degree-of-freedom adjustment mechanism to dynamically optimize the light vector based on variations in plant height and canopy closure at different growth stages of rice. During the seedling stage, a large downward angle of coverage is used, gradually raising the light source and leveling the angle of incidence as plant height increases, ensuring the laser beam always penetrates the upper leaves and precisely targets the photosynthetic leaves in the lower and middle parts of the canopy. In terms of light quality control, based on the spectral response characteristics of rice photosynthesis, red and blue laser light are precisely configured to maximize photosynthetic efficiency. Simultaneously, the light intensity is dynamically adjusted inversely to the natural light intensity—weaker laser light for stronger natural light, and stronger laser light for weaker natural light—achieving low-energy operation while ensuring the crop's physiological needs are met.

Claims

1. A method for laser-controlled growth of field crops, characterized in that, The steps include: Deployment steps: Deploy multiple semiconductor laser lights along the east-west direction of the field. Each semiconductor laser light can emit both red and blue laser light simultaneously. Control steps: Based on the crop's growth stage, adjust the supplemental lighting time, the light quality ratio of each semiconductor laser lamp, the photosynthetic photon flux density, and the elevation angle of the laser beam to provide directional illumination to the crop canopy. Specifically, adjusting the supplemental lighting time includes: turning on laser illumination 2-3 hours before sunrise; turning off laser illumination when the natural light intensity reaches the crop's light saturation point; and turning laser illumination back on when the measured field light intensity is lower than the crop's light saturation point in the afternoon, extending illumination for another 2-3 hours after sunset to ensure a daily effective light duration of ≥12 hours for the crop. Adjusting the light quality ratio of each semiconductor laser lamp includes: setting the red light to blue light ratio to R:B = 1:1 from the greening stage to the early tillering stage; and setting the red light to blue light ratio to R:B = 1:1 from the mid-tillering stage to the grain-filling and ripening stage. 9:6, In the regulation steps, adjusting the photosynthetic photon flux density specifically includes: during the greening stage to the early tillering stage, the photosynthetic photon flux density is 0.05-0.2 μmol·m⁻¹. -2 ·s -1 During the mid-tillering to grain-filling maturity stage, the photosynthetic photon flux density is 0.5-1.5 μmol·m⁻¹. -2 ·s -1 In the control steps, adjusting the elevation angle of the laser beam specifically includes: adjusting the elevation angle of the laser beam to 5° to 15° during the greening stage to the early tillering stage; adjusting the elevation angle of the laser beam to 15° to 45° during the mid-tillering stage to the early heading stage; and adjusting the elevation angle of the laser beam to 45° to 60° during the early heading stage to the grain-filling and ripening stage; wherein, the elevation angle is the angle between the laser beam and the vertical direction.

2. The method according to claim 1, characterized in that, In the deployment process, semiconductor laser lights are deployed every 4 meters along the east-west direction of the field, and the long axis of the laser spot is parallel to the direction of the crop planting row.

3. A laser-controlled field crop growth system for implementing the above methods, characterized in that, include: Multiple semiconductor laser lights are deployed in the east-west direction of the field to emit red and blue laser light; an angle adjustment mechanism is connected to the semiconductor laser lights to adjust the pitch angle of the laser beam; a controller is connected to the semiconductor laser lights to control the light quality ratio, output light intensity and on / off time of each semiconductor laser light.

4. The system according to claim 3, characterized in that, The red light wavelength of a semiconductor laser lamp is 650-670nm, and the blue light wavelength is 440-460nm.

5. A field operation method for improving rice yield based on laser modulation, characterized in that, Includes the following steps: S1. In the paddy field, a semiconductor laser lamp is deployed every 4 meters along the east-west direction. The red light wavelength of the semiconductor laser lamp is 650-670 nm, and the blue light wavelength is 440-460 nm. S2. During the rice's greening stage to the early tillering stage, the light quality ratio of the semiconductor laser lamp is R:B = 1:1, and the photosynthetic photon flux density is 0.05-0.2 μmol·m⁻¹. -2 ·s -1 The beam elevation angle is adjusted to 5°-15°, and illumination is turned on 2-3 hours before sunrise each day. It is turned off when the natural light intensity reaches the rice's light saturation point, and turned back on in the afternoon when the natural light intensity drops below the rice's light saturation point. Irradiation is extended for 2-3 hours after sunset. S3. During the mid-tillering to grain-filling maturity stage of rice, the semiconductor laser lamp quality ratio is R:B=9:6, and the photosynthetic photon flux density is 0.5-1.5 μmol·m⁻¹. -2 ·s -1 The beam pitch angle is gradually adjusted from 15° to 60° as the rice grows, and the illumination period is the same as in step S2; wherein, through steps S2 and S3, the effective daily illumination duration of the rice is ≥12 hours.

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