Method for the cultivation of potato minitubers in a multi-layer substrate using lateral light

Abstract

The application discloses a kind of indoor potato microtuber lateral light induction multi-layer substrate cultivation methods. Potato tissue culture seedling is planted in sterile coconut shell substrate of each layer of multi-layer cultivation frame, and vertical LED light bar extending along the height direction of plant growth is arranged in the side of each layer of cultivation frame, the vertical LED light bar is irradiated to plant from side, and the stem of plant is guided to grow laterally;The cultivation period is divided into growth stage and tuber formation stage, and different light periods and different formula nutrient solution are set for the two stages respectively, and the nutrient solution is supplied by drip irrigation system with decreasing frequency;Each layer is equipped with ventilation device and is operated in linkage with illumination period. The application makes the stem of plant grow horizontally by lateral light induction, inhibits apical dominance, promotes lateral branch occurrence and underground creeping stem horizontal directional elongation, so as to increase tuber formation site and improve the proportion of medium and large size tubers, and the plant type is compact, suitable for multi-layer intensive cultivation.

Description

Technical Field

[0001] This invention relates to the field of indoor substrate cultivation technology for potato microtubers, specifically to a method for indoor side-light induced multi-layer substrate cultivation of potato microtubers. Background Technology

[0002] Potato mini-tubers are an important intermediate propagation material for producing virus-free seed potatoes, and their quality and yield directly affect the efficiency of the seed potato breeding system. With the development of plant factory technology, the production of potato mini-tubers using substrate cultivation in a controlled indoor environment has a certain research and application foundation.

[0003] Existing indoor potato substrate cultivation methods typically place the light source above the cultivation rack, guiding the plants to grow vertically upwards with elongated stems under top lighting. In this growth pattern, apical dominance is strong, the downward transport of auxin along the stem is unimpeded, and the development of lateral branches is somewhat inhibited, resulting in a limited number of lateral branches per plant. Since tubers mainly form at the stem nodes and the base of lateral branches, the insufficient number of lateral branches directly restricts the number of tuber formation sites per plant.

[0004] More importantly, in indoor micro-tuber production, simply increasing the number of tubers often fails to simultaneously improve yield. There is competition between the number of sink organs (tubers) and their individual size. When the number of tuber-forming sites on a single plant increases, competition for the limited assimilated products from the source organs intensifies, easily leading to a higher number of tubers but smaller individual tubers, resulting in a higher proportion of small tubers while the proportion of medium-to-large tubers with higher commercial value remains difficult to increase. Therefore, the key to improving the efficiency of micro-tuber production lies in how to effectively fill the newly added tuber-forming sites with medium-to-large tubers, rather than simply increasing the number of small tubers.

[0005] Furthermore, in multi-layer vertical cultivation rack structures, when top lighting is used, the vertical growth of plants leads to the stems occupying a large longitudinal space. Larger gaps need to be reserved between each layer to accommodate the height of the plants, which limits the number of cultivation layers per unit space. The space utilization rate of indoor plant factories needs to be improved.

[0006] Therefore, how to increase the proportion of medium and large-sized tubers while increasing the number of tuber-forming sites by adjusting the cultivation environment and management, and how to obtain a compact plant type suitable for multi-layer dense cultivation that can reduce the spacing between layers, are the technical problems that need to be solved in the current indoor potato micro-tuber production. Summary of the Invention

[0007] This invention addresses the problems existing in existing indoor potato microtuber substrate cultivation, such as the limited number of lateral branches and tuber-forming parts per plant, the difficulty in increasing the proportion of medium and large-sized tubers when increasing the number of tubers, and the low space utilization rate of multi-layer cultivation. It provides a method for indoor potato microtuber side-light induced multi-layer substrate cultivation.

[0008] This invention is implemented through the following technical solutions:

[0009] This invention discloses a method for indoor potato microtuber side-light induced multi-layer substrate cultivation, comprising the following steps:

[0010] (1) Transplant potato tissue culture seedlings into the substrate of each layer of the multi-layer cultivation rack;

[0011] (2) Vertical LED light strips extending along the plant growth height direction are set on the side of each layer of the multi-layer cultivation rack. The vertical LED light strips serve as the only photosynthetic light source for the cultivation layer. No top light source is set above each cultivation layer. The vertical LED light strips illuminate the plant horizontally from the side, guiding the plant stem to grow laterally and forming a dwarf, multi-branched plant type.

[0012] (3) Divide the cultivation cycle into a growth stage and a tuber formation stage, and set different photoperiods for the growth stage and the tuber formation stage respectively;

[0013] (4) Nutrient solutions with different formulations are supplied to the substrate during the growth stage and the tuber formation stage, respectively;

[0014] (5) Ventilation devices are installed in each cultivation layer, and the ventilation devices are operated at different intermittent periods during the LED light source’s on and off periods.

[0015] Furthermore, the LED light source includes white LEDs and red LEDs, with a light intensity ratio of (8~12):1 for white light and a photosynthetically active radiation (PPFD) of 500~700 μmol·s⁻¹. -1 ·m -2 .

[0016] Furthermore, the substrate is sterilized coconut coir with a thickness of 4-7 cm.

[0017] Furthermore, during the growth stage, the light cycle of the LED light source is set to 14-18 hours of light and 6-10 hours of darkness; during the tuber formation stage, the light cycle of the LED light source is set to 8-12 hours of light and 12-16 hours of darkness.

[0018] Furthermore, during the growth stage, the concentrations of each element in the nutrient solution are as follows: nitrogen 180–200 ppm, phosphorus 40–50 ppm, potassium 200–220 ppm, calcium 150–180 ppm, magnesium 40–50 ppm, EC value 1.8–2.2 mS / cm, and pH 5.6–5.8.

[0019] Furthermore, during the tuber formation stage, the concentrations of each element in the nutrient solution are as follows: nitrogen 80–140 ppm, phosphorus 50–90 ppm, potassium 220–300 ppm, calcium 80–140 ppm, magnesium 25–50 ppm, EC value 1.8–2.7 mS / cm, and pH 5.5–6.0.

[0020] Furthermore, the nutrient solution also contains the following trace elements: iron 1.5–4 ppm, boron 0.2–0.7 ppm, manganese 0.3–1.5 ppm, zinc 0.03–0.15 ppm, copper 0.01–0.08 ppm, and molybdenum 0.008–0.03 ppm.

[0021] Furthermore, the nutrient solution is supplied through a drip irrigation system, with each supply lasting 0.5 to 2 minutes. The number of daily supplies decreases as follows: 6 to 10 times per day in the early stage of planting, 4 to 6 times per day in the early stage of growth, 2 to 4 times per day in the later stage of growth, 1 to 3 times per day during the tuber formation period, and the supply is stopped 5 to 10 days before harvest.

[0022] Furthermore, the ventilation device operates for 45-75 minutes and stops for 15-45 minutes when the LED light source is on; and operates for 5-20 minutes and stops for 40-60 minutes when the LED light source is off.

[0023] Furthermore, the cultivation container has a depth of 4–7 cm, and the planting density in each cultivation container is 30–50 plants per square meter.

[0024] The beneficial effects of this invention are:

[0025] This invention uses vertical LED light strips positioned on the sides of the cultivation rack, extending along the plant's growth height, as the sole photosynthetic light source for each cultivation layer. No top light source is provided above each layer. This allows the plants to grow laterally under the guidance of horizontal lateral illumination, forming a dwarfed, multi-branched plant shape. This changes the traditional upright, elongated growth pattern under top-light conditions. The horizontal growth of the stem helps suppress apical dominance and slows down the downward polar transport of auxin, thereby promoting the occurrence and development of lateral branches, increasing the number of lateral branches, and expanding the tuber formation site. Furthermore, this invention divides the cultivation cycle into a growth stage and a tuber formation stage. During the tuber formation stage, the nitrogen concentration in the nutrient solution is reduced, while the phosphorus and potassium concentrations are increased to inhibit excessive stem and leaf growth and promote the directional accumulation and enrichment of photosynthetic products in the tubers. The synergistic effect of these two factors allows the present invention to increase the number of tubers per plant while enriching the newly added tuber-forming parts into medium and large-sized tubers, rather than simply increasing the number of small tubers. Specifically, while increasing the number of tubers per plant, the proportion of small tubers (≤9g) decreases instead of increasing, while the number and proportion of medium and large-sized tubers (≥20g) with higher commercial value are both increased, the average weight of a single tuber increases, and the overall weight distribution of tubers shifts towards medium and large sizes.

[0026] Because this invention uses side vertical light strips as the only light source and eliminates the top light source above each cultivation layer, it saves the space between layers required for top lighting fixtures, heat dissipation, and operation. On the other hand, side light induction makes the plant shape dwarf and compact, effectively controlling the plant height. The two work together to significantly reduce the spacing between adjacent cultivation layers of the multi-layer cultivation rack, so that more cultivation layers can be arranged in the same indoor vertical space, improving the output efficiency per unit volume (per unit area) of the indoor plant factory.

[0027] Furthermore, this invention matches the nutrient solution formula and the frequency of nutrient solution supply with the cultivation stage, and links the operation cycle of the ventilation device with the light period, thereby achieving coordinated and precise management of cultivation elements such as water, air, and light, which helps to create a suitable growth environment for the formation and enlargement of potato micro-tuber. Attached Figure Description

[0028] The accompanying drawings are provided to further explain the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0029] Figure 1 This is a photograph of the actual side-light-induced cultivation device of the present invention.

[0030] Figure 2 This is a close-up frontal view of a single LED light strip and the growth status of the plants on both sides in this invention.

[0031] Figure 3The photograph shown is of a conventional top-light cultivation device for Comparative Example 1, showing LED tubes installed above each cultivation layer. Detailed Implementation

[0032] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0033] Example 1: A method for indoor potato micro-tuber side-light induced multi-layer substrate cultivation, comprising the following steps:

[0034] (1) Construction of cultivation equipment:

[0035] like Figure 1 , Figure 2 As shown, vertical LED light strips extending along the plant's growth height are installed on the sides of each layer of the cultivation rack. These vertical LED light strips serve as the sole photosynthetic light source for that cultivation layer, and no top light source is installed above each cultivation layer. The vertical LED light strips illuminate the plants horizontally from the sides, guiding the stems to grow laterally. The LED light source consists of a combination of white and red LEDs, with a white to red light intensity ratio of 10:1, and a photosynthetically active radiation (PPFD) of 600 μmol·s⁻¹. -1 ·m -2 .

[0036] A ventilation system consisting of PVC pipes and DC fans is arranged longitudinally along each cultivation layer, with air outlets evenly distributed to ensure that airflow evenly covers each cultivation container; drip irrigation pipes are laid along the top of each cultivation container, and each plant is equipped with an independent dripper. Nutrient solution is supplied through the drip irrigation system and then naturally discharged from the bottom of the container, without being recycled.

[0037] (2) Planting:

[0038] Potato tissue culture seedlings with uniform stem thickness, intact leaves, and no diseases were selected and transplanted into sterilized coconut coir substrate at a rate of 6 seedlings per pot, evenly distributed between the seedlings. The planting depth should be such that the base of the stem is just submerged in the substrate surface. In this example, a total of 5 cultivation pots (Pot 1 to Pot 5) were set up, with 6 seedlings per pot (Plant 1 to Plant 6), for a total of 30 seedlings.

[0039] (3) Management during the growth stage (days 1-50 after transplanting):

[0040] Light management:

[0041] like Figure 1 , Figure 2 As shown, horizontal side illumination from the LED light source guides the plant stem to extend laterally, inhibiting vertical stem elongation, keeping the plant height low, and promoting the abundant development of lateral branches. The photoperiod during the growth stage was set to 16 hours of light and 8 hours of darkness.

[0042] Ventilation management:

[0043] During the daytime (when the LED light source is on), the ventilation system runs for 1 hour and stops for 30 minutes, alternating to ensure CO2 supply and regulate temperature and humidity during photosynthesis. During the nighttime (when the LED light source is off), the ventilation system runs for 10 minutes and stops for 50 minutes to maintain minimum air circulation and prevent humidity buildup.

[0044] Nutrient solution management:

[0045] The nutrient solution during the growth stage aims to promote stem and leaf growth. The concentrations of each element and recommended fertilizer dosages (per ton of water) are as follows: Nitrogen 190 ppm (800 g calcium nitrate, 150 g ammonium nitrate), Phosphorus 45 ppm (200 g potassium dihydrogen phosphate), Potassium 210 ppm (300 g potassium nitrate, 100 g potassium sulfate), Calcium 165 ppm (800 g calcium nitrate), Magnesium 45 ppm (400 g magnesium sulfate), Sulfur 55 ppm (from magnesium sulfate and potassium sulfate); Micronutrients: Iron 2–3 ppm (30–50 g Fe-EDTA), Boron 0.3–0.5 ppm (2–3 g boric acid), Manganese 0.5–1 ppm (2–4 g manganese sulfate), Zinc 0.05–0.1 ppm (0.2–0.4 g zinc sulfate), Copper 0.02–0.05 ppm (0.1–0.2 g copper sulfate), Molybdenum 0.01–0.02 ppm (sodium molybdate 0.02–0.04 g); EC value adjusted to 1.8–2.2 mS / cm, pH adjusted to 5.6–5.8.

[0046] The frequency of nutrient solution supply should be based on the number of days after transplanting as follows: 8 times a day for 1 minute each time from day 1 to 3 after transplanting (seedling establishment period); 5 times a day for 1 minute each time from day 4 to 20 (early growth period); and 3 times a day for 1 minute each time from day 21 to 50 (late growth period).

[0047] (4) Management during the tuber formation stage (51 days after transplanting to 7 days before harvest):

[0048] Light management:

[0049] Starting from day 51, the photoperiod was adjusted to 10 hours of light and 14 hours of darkness to promote the initiation and expansion of tubers under short-day conditions.

[0050] Ventilation management:

[0051] The ventilation system operates in accordance with the growth stage, running for 1 hour and stopping for 30 minutes when the LED light source is on, and running for 10 minutes and stopping for 50 minutes when it is off.

[0052] Nutrient solution management:

[0053] The nutrient solution formula for the tuber formation stage is adjusted as follows: The concentrations of each element and recommended fertilizer dosages (per ton of water) are: Nitrogen 110 ppm (calcium nitrate 400 g, ammonium nitrate 50 g), Phosphorus 70 ppm (potassium dihydrogen phosphate 300 g), Potassium 265 ppm (potassium nitrate 400 g, potassium sulfate 150 g), Calcium 110 ppm (calcium nitrate 400 g), Magnesium 35 ppm (magnesium sulfate 300 g), Sulfur 45 ppm (from magnesium sulfate and potassium sulfate); the micronutrient composition is the same as in the growth stage; the EC value is adjusted to 2.0–2.5 mS / cm, and the pH is adjusted to 5.6–5.8. Compared to the growth stage, the nitrogen concentration is reduced by approximately 42%, the phosphorus concentration is increased by approximately 56%, and the potassium concentration is increased by approximately 26% in this stage to inhibit excessive vegetative growth and promote the accumulation of photosynthetic products in the tubers.

[0054] The frequency of nutrient solution supply is further reduced: twice a day for 1 minute each time from day 51 to 60 (early stage of tuber formation); once a day for 1 minute each time after day 60 (late stage of tuber formation); stop supplying nutrient solution 7 days before harvest to allow the substrate to dry moderately and facilitate the separation of tubers from the substrate.

[0055] (5) Harvest:

[0056] Harvest 70 days after planting. Remove the substrate, collect all the micro-tubers, remove any remaining coconut coir from the surface, and grade and count them by weight.

[0057] Comparative Example 1: Traditional vertical growth scheme with overhead light source.

[0058] Comparative Example 1, except for the different light source installation location, maintained all other cultivation conditions strictly the same as Example 1, using a single-variable approach for comparison and verification. Figure 3 As shown in the comparative example, LED light sources of the same specifications were installed above each cultivation layer to illuminate the plants vertically downwards. The light intensity (PPFD 600 μmol·s⁻¹) was [not specified]. -1 ·m -2 The ratio of white light to red light (10:1), photoperiod, nutrient solution formula and frequency of supply, ventilation management plan, and cultivation cycle were all exactly the same as in Example 1. The comparative plant stems grew vertically upwards under top lighting guidance, with slender, upright stems, strong apical dominance, and suppressed lateral branching; the plants were taller, requiring a larger interlayer spacing for multi-layer cultivation.

[0059] Comparative Example 2:

[0060] The light source arrangement is exactly the same as in Example 1 (the side vertical LED light strip is the only light source, and there is no top light source), but only a single constant formula nutrient solution is supplied throughout the entire cultivation cycle (the formula of the growth stage in Example 1 is used and remains unchanged throughout the entire process, and the nitrogen, phosphorus and potassium ratio is not adjusted during the tuber formation stage), and the other conditions are the same as in Example 1.

[0061] Experimental example:

[0062] (1) Comparison of the number of lateral branches:

[0063] At the end of the growth stage (50 days after transplanting), the number of lateral branches in each pot of Example 1 and Comparative Example 1 was counted plant by plant, and the original data are shown in Table 1.

[0064] Table 1. Raw data on the number of lateral branches per individual (unit: number)

[0065]

[0066] As shown in Table 1, the average number of lateral branches per plant in Example 1 was 5.2, an increase of approximately 36.8% compared to 3.8 in Comparative Example 1. The data from all five cultivation pots showed a consistent pattern, indicating that lateral light induction has a stable and repeatable effect on promoting lateral branch development. The significant increase in the number of lateral branches directly expanded the number of tuber formation sites, laying a morphological foundation for subsequent improvements in tuber quantity and quality.

[0067] (2) Comprehensive comparison of the number of micro-tuber formations, weight distribution, and average weight:

[0068] The tubers were harvested 70 days after transplanting. The number, proportion, and average weight of tubers formed in each weight class of the two groups were comprehensively statistically analyzed. The complete results are shown in Table 2.

[0069] Table 2. Statistics on the average weight increment of Example 1 and the comparative example.

[0070]

[0071] As can be seen from Table 2:

[0072] Example 1 had a total of 30 tubers per pot and an average of 5 tubers per plant, which was significantly higher than the 24 tubers per pot and 4 tubers per plant in Comparative Example 1. Combined with the data in item (1) showing an increase of about 36.8% in the number of lateral branches, the changes in the two sets of data were highly consistent, indicating that the technical path of lateral light induction, which promotes the occurrence of lateral branches, increases the tuber formation sites, and ultimately increases the total number of tubers, has been effectively verified. Comparative Example 2 had a total of 32 tubers per pot and an average of about 5.3 tubers per plant, which was similar to or even slightly higher than that of Example 1. Both Example 1 and Comparative Example 2 were irradiated laterally and horizontally, and the nutrient solution formulas during the growth stages were the same. The plant type and the number of lateral branches were similar in both, and the total number of tubers was similar. Comparative Example 2 had a slightly higher total number of tubers because it maintained a higher nitrogen concentration throughout the cultivation period and the stolons continued to set tubers.

[0073] In Example 1, tubers weighing less than 5g accounted for 24%, tubers weighing 5-9g accounted for 22%, and small tubers accounted for 46% in total; in Comparative Example 1, tubers weighing less than 5g accounted for 24.2%, tubers weighing 5-9g accounted for 25.8%, and small tubers accounted for 50% in total. While Example 1 showed a higher tuber quantity, the proportion of small tubers was actually lower than in Comparative Example 1, indicating that the present invention not only increased the number of tubers but also shifted the overall tuber weight distribution towards medium and large tubers, rather than simply increasing the number of small tubers.

[0074] In Example 1, there were a total of 81 tubers of various weight grades above 10g (10-19g, 20-29g, 30-49g, ≥50g), accounting for 54% of the total; in Comparative Example 1, there were a total of 60 tubers, accounting for 50% of the total. The absolute number of high-marketability tubers above 10g in Example 1 was higher than that in Comparative Example 1, and the proportion was also improved, indicating a significant improvement in marketability.

[0075] In Example 1, there were 51 medium-to-large tubers weighing over 20g, accounting for 34% of the total; in Comparative Example 1, there were 37 tubers, accounting for 30.8% of the total. The absolute number of large tubers in Example 1 was higher than that in Comparative Example 1, and the number and proportion of medium-to-large tubers with higher commercial value were significantly better than those in Comparative Example 1, which has a direct significance for improving production efficiency.

[0076] The average tuber weight in Example 1 was 18.18 g, while that in Comparative Example 1 was 17.33 g. The weight of tubers in Example 1 was higher than that in Comparative Example 1, which is consistent with the analysis conclusion that the weight distribution shifted towards medium and large sizes in the above-mentioned items, further confirming the positive impact of the present invention on tuber quality.

[0077] Under the premise of similar total number of tubers (even slightly more in Comparative Example 2), the number of medium and large tubers (≥20g) in Example 1 (51 tubers) was about 59% more than that in Comparative Example 2 (32 tubers), and the average weight of a single tuber (18.18g) was about 41% higher than that in Comparative Example 2 (12.91g), while the number of small tubers (69 tubers) was significantly less than that in Comparative Example 2 (94 tubers). Further looking at the changes in the number of tubers at each weight level, compared with Example 1, Comparative Example 2 had 2 fewer medium and large tubers (20~29g, 30~49g, ≥50g), 8 fewer tubers (≥50g), and 9 fewer tubers (≥5g). Tubers that should have expanded to medium and large sizes remained at a smaller size due to a lack of directional filling. At the same time, under high nitrogen conditions, an additional batch of small tubers was produced, resulting in an increase of 12, 13, and 4 tubers in the ≤5g, 5~9g, and 10~19g sizes, respectively. This indicates that, given the same number of tuber-forming parts, whether the nitrogen concentration is reduced and the phosphorus and potassium concentrations are increased during the tuber formation stage directly determines whether these tuber-forming parts eventually develop into medium-to-large marketable tubers or remain or even proliferate into small tubers. The result of Comparative Example 2, "more tubers but smaller individual tubers," corresponds to the problem in the background technology that simply increasing the number of tubers easily leads to an increase in the proportion of small tubers.

[0078] (3) Comparison of plant growth morphology and space utilization:

[0079] like Figure 1 , Figure 2 As shown, in Example 1, the vertical elongation of the stem was inhibited under side light induction, while horizontal growth became dominant. The plant height remained low, and the overall plant shape was compact. The spacing between each layer of the multi-layer cultivation rack could be reduced accordingly, which is beneficial for increasing the number of cultivation layers that can be arranged in the same indoor vertical space, and significantly improving the output efficiency per unit area of ​​the indoor plant factory. Figure 3 As shown, the plants in Comparative Example 1 have strong upward growth and slender, upright stems. When cultivating in multiple layers, a large gap needs to be reserved between layers to accommodate the upright, elongated stems. The number of cultivation layers that can be arranged is relatively limited, and the space utilization rate is low.

[0080] (4) Comprehensive analysis:

[0081] Based on the results of the three experiments above, Example 1 and the comparative example, under strict single-variable control conditions, were repeatedly verified in 5 cultivation pots and 30 plants, and the data from each pot showed a consistent pattern. This invention forms a complete technical effect chain through horizontal side lighting, specifically manifested as follows: horizontal side lighting induces lateral stem growth, weakens apical dominance, and increases the number of lateral branches per plant by approximately 36.8%; the increased number of lateral branches expands the tuber formation site, resulting in an increase in the total number of tubers by approximately 25%; in terms of weight distribution, the total proportion of small tubers (≤9g) decreased from 50% to 46%, the number of commercial tubers over 10g increased from 60 to 81, an increase of approximately 35.0%, the number of medium and large tubers over 20g increased from 37 to 51, an increase of approximately 37.8%, and the proportion increased from 30.8% to 34%, with the average tuber weight increasing from 17.33 g to 18.18 g; simultaneously, the plant type is compact, the spacing between multi-layer cultivation layers can be effectively reduced, and the output efficiency per unit area of ​​the indoor plant factory is further improved.

[0082] Finally, it should be noted that the above embodiments are merely illustrative of several implementations of the present invention and are not intended to limit the scope of the invention. For those skilled in the art, any modifications, equivalent substitutions, or improvements made without departing from the concept of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for indoor side-light induced multi-layer substrate cultivation of potato micro-tubers, characterized in that, Includes the following steps: (1) Transplant potato tissue culture seedlings into the substrate of each layer of the multi-layer cultivation rack; (2) Vertical LED light strips extending along the plant growth height direction are set on the side of each layer of the multi-layer cultivation rack. The vertical LED light strips serve as the only photosynthetic light source for the cultivation layer. No top light source is set above each cultivation layer. The vertical LED light strips illuminate the plant horizontally from the side, guiding the plant stem to grow laterally and forming a dwarf, multi-branched plant type. (3) Divide the cultivation cycle into a growth stage and a tuber formation stage, and set different photoperiods for the growth stage and the tuber formation stage respectively; (4) Nutrient solutions with different formulations are supplied to the substrate during the growth stage and the tuber formation stage, respectively; (5) Ventilation devices are installed in each cultivation layer, and the ventilation devices are operated at different intermittent periods during the LED light source’s on and off periods.

2. The method according to claim 1, characterized in that, The LED light source includes white LEDs and red LEDs, with a light intensity ratio of (8~12):1 for white light and red light, and a photosynthetically active radiation (PPFD) of 500~700 μmol·s⁻¹. -1 ·m -2 .

3. The method according to claim 1, characterized in that, The substrate is sterilized coconut coir with a thickness of 4-7 cm.

4. The method according to claim 1, characterized in that, During the growth stage, the light cycle of the LED light source is set to 14-18 hours of light and 6-10 hours of darkness; during the tuber formation stage, the light cycle of the LED light source is set to 8-12 hours of light and 12-16 hours of darkness.

5. The method according to claim 1, characterized in that, During the growth stage, the concentrations of each element in the nutrient solution are as follows: nitrogen 180–200 ppm, phosphorus 40–50 ppm, potassium 200–220 ppm, calcium 150–180 ppm, magnesium 40–50 ppm, EC value 1.8–2.2 mS / cm, and pH 5.6–5.

8.

6. The method according to claim 1, characterized in that, During the tuber formation stage, the concentrations of each element in the nutrient solution are as follows: nitrogen 80–140 ppm, phosphorus 50–90 ppm, potassium 220–300 ppm, calcium 80–140 ppm, magnesium 25–50 ppm, EC value 1.8–2.7 mS / cm, and pH 5.5–6.

0.

7. The method according to claim 5 or 6, characterized in that, The nutrient solution also contains the following trace elements: iron 1.5–4 ppm, boron 0.2–0.7 ppm, manganese 0.3–1.5 ppm, zinc 0.03–0.15 ppm, copper 0.01–0.08 ppm, and molybdenum 0.008–0.03 ppm.

8. The method according to claim 1, characterized in that, The nutrient solution is supplied through a drip irrigation system, with each supply lasting 0.5 to 2 minutes. The number of daily supplies decreases as follows: 6 to 10 times per day in the early stage of planting, 4 to 6 times per day in the early stage of growth, 2 to 4 times per day in the later stage of growth, 1 to 3 times per day during the tuber formation period, and the supply is stopped 5 to 10 days before harvest.

9. The method according to claim 1, characterized in that, The ventilation device operates for 45-75 minutes and stops for 15-45 minutes when the LED light source is on; and operates for 5-20 minutes and stops for 40-60 minutes when the LED light source is off.

10. The method according to claim 1, characterized in that, The substrate is contained in cultivation containers, the depth of which is 4 to 7 cm, and the planting density in each cultivation container is 30 to 50 plants per square meter.

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