Parametric Design and Genetic Algorithm Optimization of a Natural Light Stereoscopic Cultivation Frame

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

What considerations were made for user-friendliness in terms of assembly, disassembly, and maintenance of the cultivation frame? What performance metrics were used to evaluate the success of the design in terms of plant growth, yield, and overall efficiency? What were the key parameters and constraints incorporated into the genetic algorithm

Section1 , motivation is very week

How was the performance of the genetic algorithm assessed, and were there any noteworthy findings? If yes describe in section 2.6

The author needs to mention the architectural or engineering considerations that were taken into account to achieve stereoscopic effects in the cultivation frame

The author needs to explain in what ways the cultivation frame leverages natural light, and were there any mathematical models or algorithms used to optimize light exposure for plant growth.

is there trade-offs between achieving stereoscopy and other functional aspects of the frame? If yes , how were these trade-offs managed?

Comments on the Quality of English Language

Ok 

Author Response

Response to the Reviewers

Re: “Parametric Design and Genetic Algorithm Optimization of a Natural Light Stereoscopic Cultivation Frame”

We gratefully appreciate the editors and reviewers for their time spent making positive and constructive comments. In response to the concerns raised, we have revised the manuscript accordingly. Below we address each comment in turn. Reviewers’ comments are in bold, our responses are immediately below.

*************************

Reviewer: 1
Comments and Suggestions for Authors

*************************

1. What considerations were made for user-friendliness in terms of assembly, disassembly, and maintenance of the cultivation frame? What performance metrics were used to evaluate the success of the design in terms of plant growth, yield, and overall efficiency? What were the key parameters and constraints incorporated into the genetic algorithm.

R1: The design of the NLSCF mainly considers the user-friendliness of the maintenance process. The structural parameters of the NLSCF were designed for ease of manual operation, and thus reduce labor intensity and increase productivity. Other considerations for daily planting operations include the use of Slides at the ends of the cultivation troughs for easy handling, and U-shaped structural cultivation troughs for easy cleaning of the interior. User-friendliness during assembly and disassembly was not considered in this study because these processes are generally performed by professionals in a single pass, and the benefits of improving the user-friendliness of assembly and disassembly are relatively small.

The corresponding revisions can be found in lines 131-137: “As Figure 2, the CTU in this study is composed of a planting board, a planting cup, slides, and a U-shaped cultivation trough. Slides are installed at both ends of the cultivation trough, facilitating the handling of the cultivation plates. The U-shaped cultivation troughs are used for easy interior cleaning. The width of the CTU is 350 mm, the spacing of cultivation holes is 175 mm, and the height is 70 mm. Each cultivation board is capable of planting 6 lettuces. To facilitate manual operation, the structural parameters of the designed NLSCF need to meet the following conditions.”

We followed the Lei and colleague’s experiences in terms of plant yield and overall performance metrics, which is now introduced in Line 265 of the manuscript: “In accordance to Lei et al.[38] experiences in lettuce yield and quality, the indicators of design effectiveness include plant height (length from the base of the stem to the tallest part of the plant) and plant width (the widest part of the canopy) obtained by measuring live samples from the field, as well as the fresh weight of single plants (with roots removed) determined by taking samples in freshness and measuring in laboratory. ”

We thank the two reviewers for pointing out the missing information on the genetic algorithm. We have added those key parameters and constraints in lines 232-238: “The constraint variables of the genetic algorithm are cultivation trough unit spacing d and layer height H (see Table 1). The range of d is constrained to be 0-700 mm, and the range of H is constrained to be 300-700 mm. The key parameters incorporated into the genetic algorithm were Elitism, Mutation Probability, Mutation Rate, Mutation Rate, Crossover Rate, Population Size, Max Generations Record interval and Save interval. The values of each operational parameter were set as shown in Table 2.”

2. Section1, motivation is very week

R2: To enhance the research motivation, we have thoroughly revised the introduction section, with a focus on a more explicitly stated research gap, strengthening the transition to parametric design, clarifying research contributions and future applications, and better language and cohesion. Please see the revised introduction.

3. How was the performance of the genetic algorithm assessed, and were there any noteworthy findings? If yes describe in section 2.6

R3: We evaluated the performance of the genetic algorithm based on its ability to find high-quality solutions, convergence speed, and practical trade-offs to obtain the optimal structural configurations. The processes of genetic algorithm performance evaluation are elaborated in the revised Section 2.6:

“2.6 Genetic Algorithm

To homogenize and maximize the light conditions in the lower layer, this study optimally calculated the solar radiation in the lower layer of the cultivation frame for two objectives, inner and outer CTU, using a genetic algorithm that is commonly used for multi-objective optimization problems. The instrument used in this study, Octopus, is a multi-objective optimization plug-in in Grasshopper. Octopus exhibits a fast solution speed, ease of operation for multi-objective optimization problems, and integrates Pareto optimality principles with genetic algorithms. It features a visually intuitive 3D interface for observing and selecting optimal solutions, providing insights into the convergence of the genetic algorithm [37]. Based on the solution set obtained from the Pareto-front distribution graph, we employed an iterative approach to optimize the results by adjusting the number of iterations until convergence and extracting the corresponding optimal solutions. Subsequently, we filtered out the optimized parameters and values that met the specified requirements.

As Octopus operators are designed to minimize objectives, we converted the desired maximization problem into a minimization problem through mathematical transformations. The optimization parameters in this study are the spacing of CTU (d) and layer height (H). The optimization objective aims to maximize the light intensity for both inner and outer cultivation trough units in the lower layer, with a preference for solutions minimizing the difference between inner and outer light intensities. The optimization parameters were connected to the G-end, and the calculated solar radiation values of the optimization objectives were connected to the O-end (see Figure 7). "

4. The author needs to mention the architectural or engineering considerations that were taken into account to achieve stereoscopic effects in the cultivation frame

R4: To achieve stereoscopic effects, the design of the cultivation frame considered three architectural and engineering factors: installation site, pipeline installation, and operational space. We have supplemented relevant information in lines 275-283: “Figure 8. Cultivation experiment. (a) Planting effect of NLSCF. (b) Lettuce fresh weight measurement. The total length of the cultivation frame was 20 m. The spacing between the middle CTU was 350 mm, the height of all layers was 685 mm, and the height of the lower layer from the ground was 400 mm. The ground of the greenhouse installation site was hardened and leveled to ensure the stability of the cultivation frame installation and the stability of drainage from cultivation troughs. Pipeline installation was arranged at both ends of the cultivation frame and buried underground to prevent the pipes from interfering with the movement of cultivation boards. The operational aisle width was set to 500 mm to ensure sufficient operational space while minimizing the use of aisle space resources.”

5. The author needs to explain in what ways the cultivation frame leverages natural light, and were there any mathematical models or algorithms used to optimize light exposure for plant growth.

R5: We used multiple ways of utilizing natural light. Specifically, when the sun trajectory is perpendicular to the cultivation frame's direction, the shaded areas of its lower layer would move accordingly as the sun moves. This enables all areas of the lower layer to receive certain amounts of sunlight within the day. Besides, we have ensured that the accumulated light exposure for the lower layer meets the growth requirements of the crops, using a set of methods or algorithms to simulate, calculate, and optimize the structure of the cultivation frame. This, in turn, achieves the rational application of the sunlight in the NLSCF. We added the explanation to the manuscript in lines 319-324:" Further analysis revealed the critical importance of the relationship between the direction of the sun's trajectory and the direction of the cultivation frame. When the sun's trajectory was perpendicular to the frame direction, the shading areas of the upper layers on the lower layer will move with the sun's trajectory, resulting in periodic exposure to sunlight for various areas of the lower layer, partially shaded areas were formed in the east-west direction (as depicted in Figure 10 for the north-south direction)."

We explained the use of algorithms and models to optimize light exposure for plant growth, including regression models (see Section 3.2.1 for details), and the multi-objective genetic algorithm to optimize of the uniformity of light exposure in the lower layer (see Section 2.6 for details).

6. is there trade-offs between achieving stereoscopy and other functional aspects of the frame? If yes, how were these trade-offs managed?

R6: We considered the trade-offs between the cultivation density and light intensity requirements while designing the cultivation frame, aiming to maximize the number of CTUs while ensuring adequate and balanced solar radiation for each layer. Additionally, we considered the trade-offs between personnel operation and the structure optimization of the cultivation frame. For example, the design specifications include a maximum height of 2m, a width of 1.4m, a spacing of 500 mm between cultivation frames, and the inclusion of slides at both ends of the cultivation trough, all intended to meet the light requirements of the crop in the cultivation frame while facilitating user operation.

We thank both reviewers for their insightful comments, which have greatly improved the quality of this manuscript.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Parametric Design and Genetic Algorithm Optimization of a Natural Light Stereoscopic Cultivation Frame

by

D. Jia, W. Zheng, X. Wei, W. Guo, Q. Zhao, and G. Gao

Agriculture-2759612

1.      Line 97; change ‘Besides, we combined’ to ‘We combined’.

2.      Line 118; change ‘Besides, Grasshopper also’ to ‘Grasshopper also’.

3.      Figure 4; the figure is complex and the author(s) need to define/describe what each unit in the layers is and its function. The reviewer sees the figure basically conveying that each layer has many components. Does this figure relate to Figure 1?

4.      Figure 5; this figure has some detail, but could use more. If the figure is intended to be general the author(s) should just use basic blocks with an overarching title and leave out all the detail.

5.      Equation 1; the reviewer believes that the equation should be, RAD = 5(DLI)/36 which yields kW/m² not W/m².

6.      Line 136; more of a comment follows. Photosynthesis is a photon driven process not an energy driven process, would it be better to talk in terms of μmol_photons/m²-d? It is realized that the author(s) are using solar radiation, but the procedure may get used by people using artificial light and a mole of red photons has a different energy content than a mole of blue photons.

7.      Line 193; it is stated that general light transmittance of greenhouse glass is 60-90%. Do the author(s) intend to say that 60-90% of the PAR solar radiation is transmitted? The glass may transmit more or less long and short wave solar radiation which is not in the PAR spectrum.

8.      Figure 7; the figure has a lot of detail that does not appear to be needed (only ‘Octopus’ is noted). The author(s) should at least show where end ‘O’ and end ‘G’ are.

9.      Table 2; explain what the optimization parameters are and how they indicate that you have obtained the best solution.

10. Line 225; please provide a short explanation as to why the north side was chosen for sampling.

11. Figures 10 and 11; it would be helpful if the colors were explained. It is assumed means shaded, red is not shaded, and yellow is some shading. Also, the reviewer anticipated that the red area of the bottom layer of the right side of Figure 10 would have black on most of the surface. How is the bottom layer getting lit?

12. Figure 12; it is interesting that lines for N=1 and N=2 and basically parallel as well as lines for N=3 and N=4. However, the slope for N=3 and 4 is steeper. Does this suggest that at some height the N=3 and N=4 lines would be greater than the N=1 and 2 lines? Would this encourage work with taller systems? The reviewer sees the height limit being due to physical limits of equipment which can change.

13. Equation 2; please provide units. Also, did you check to see if NH had any impact on RAD?

14. Lines 323-341; is there an upper limit to light intensity on the upper layers? Do you need to ensure photo saturation and photo inhibition light intensities are not reached? Could systems be devised to maintain all layers within a light intensity range?

15. Line 364; in Figure 15, the reviewer sees little difference between 1a and 2a even though the author(s) say there is. Please expand on this.

16. Table 4 and figure 14; The middle layer of 1a and 2a appear to both be orangish (numerical value of 1.8 to 2.1). Table 4 indicates numerical averages of 1.69 (yellow) and 1.46 9edge of yellow and green). If the reviewer sees this correctly, the information inconsistent. Please provide more explanation.

17. Figure 16; the figure requires an explanation about what the dots and lines mean.

18. Lines 382-402; it would be helpful to readers if the author(s) used the same units for comparison. Fan used ICL units and Chen used percentage of light relative to top layer. Put these values into a table and add the author(s) results in the same units.

19. Table 5; is the data presented statistically different from each other? Is that what the ‘a’ and ‘b’ indicate? If it is ,please state so and tell why upper and middle layer are different than lower layer inner and outer sides for weight and height. All layers are the same in width.

20. Line 427; does ‘substance accumulation’ equate to ‘biomass production’?

21. Line 445; change to ‘The novel optimization methods for the structure design of VF cultivation frames were explored.’

22. Line 473; should ‘Patents’ be removed if there are none?

Comments on the Quality of English Language

English is good. A bit more mechanical than the reviewer prefers though.

Author Response

Response to the Reviewers

Re: “Parametric Design and Genetic Algorithm Optimization of a Natural Light Stereoscopic Cultivation Frame”

We gratefully appreciate the editors and reviewers for their time spent making positive and constructive comments. In response to the concerns raised, we have revised the manuscript accordingly. Below we address each comment in turn. Reviewers’ comments are in bold, our responses are immediately below.

*************************

Reviewer: 2
Comments and Suggestions for Authors

*************************

Q1. Line 97; change ‘Besides, we combined’ to ‘We combined’.

R1: We thank the reviewer for the advice, and we have changed the corresponding description on line 102: "We combined cultivation verification experiments as to ensure the completeness of this research path. " 

Q2.  Line 118; change ‘Grasshopper also’ to ‘Grasshopper also’.

R2: We have changed the corresponding description.

Q3. Figure 4; the figure is complex and the author(s) need to define/describe what each unit in the layers is and its function. The reviewer sees the figure basically conveying that each layer has many components. Does this figure relate to Figure 1?

R3: Figure 4 shows the parametric modeling process of the cultivation frame, which is one of the research processes in Figure 1. We have revised the original Figure 4 by supplementing the functional description of every unit type in the layers, to illustrate the battery connection diagram of the three cultivation layers in the parametric modeling. The revisions of Figure 4 is as follows:

“Figure 4. The battery connection diagram of the model in Grasshopper.”

Q4. Figure 5; this figure has some detail, but could use more. If the figure is intended to be general the author(s) should just use basic blocks with an overarching title and leave out all the detail.

R4: We appreciate your suggestions. We have removed redundant details and enhanced the clarity among the basic blocks (i.e., the import of EPW meteorological data, the simulation of sunshine duration and solar radiation, and the result output) in the revised Figure 5 as follows:

“Figure 5. The description of solar radiation analysis and sunshine duration analysis in Ladybug.”

Q5. Equation 1; the reviewer believes that the equation should be, RAD = 5(DLI)/36 which yields kW/m2 not W/m2.

R5: We agree to revise the equation 1 in lines 201-202 as : “RAD＝5（DLI）/36，DLI is the daily light integral (mol·m^-2·day^-1); RAD is the simulated value of solar radiation (kWh·m^-2). ”

Q6. Line 136; more of a comment follows. Photosynthesis is a photon driven process not an energy driven process, would it be better to talk in terms of μmolphotons/m²-d? It is realized that the author(s) are using solar radiation, but the procedure may get used by people using artificial light and a mole of red photons has a different energy content than a mole of blue photons.

R6: Your suggestions have a good rationale. To clarify the understanding and use of our results for readers who, for example, use artificial light, we have added the equivalent converted DLI values in lines 454-458: “The spacing between CTUs is 348 mm, the layer height is 685 mm, the maximum average solar radiation on the outer side of the lower layer is 1.26 kWh·m-2 (i.e., DLI ≈ 9.07 mol·m^-2·day^-1), on the inner side is 1.13 kWh·m-2 (i.e.,DLI≈8.14 mol·m^-2·day^-1), and in the middle layer is 1.66 kWh·m-2 (i.e.,DLI≈11.95 mol·m^-2·day^-1).”

Yet, we hope that you could agree with us to keep the RAD for the following reasons. On one hand, this study's central concern is whether crop yields can be ensured in cultivated frames under purely solar light, and RAD is closer to the usage context of natural daylight studies. The principle of photon drive or the effect of different artificial lights are slightly beyond our research scope. On the other hand, RAD is the direct output of the simulation and the direct input variable for subsequent design, so retaining RAD helps in research design and computational optimization.

Q7. Line 193; it is stated that general light transmittance of greenhouse glass is 60-90%. Do the author(s) intend to say that 60-90% of the PAR solar radiation is transmitted? The glass may transmit more or less long and short wave solar radiation which is not in the PAR spectrum.

R7: The "general transmittance of greenhouse glass" refers to the transmittance of direct solar radiation, i.e. the RAD transmittance, not the PAR solar radiation transmittance.

Q8. Figure 7; the figure has a lot of detail that does not appear to be needed (only ‘Octopus’ is noted). The author(s) should at least show where end ‘O’ and end ‘G’ are.

R8: We removed the redundant details and clearly labeled the objects connected to the O end and end G end. The revised figure 7 is as follows:

Figure 7. Multi-objective optimization components connection diagram in Grasshopper.

Q9. Table 2; explain what the optimization parameters are and how they indicate that you have obtained the best solution.

R9: We sincerely apologize for the misrepresentation in the headers of Table 2. Table 2 actually represents the operational setting parameters of the Octopus, not the optimization parameters. These parameter settings have default values in the system and do not require modification unless there are specific requirements.

We have revised the Table 2 to reflect operational setting parameters and their meanings. The quality of these parameter settings is assessed based on the convergence of the results (in lines 242-251):

“Table 2. The operational parameter settings of the Octopus.

Note: Elitism refers to the percentage of new solutions selected from the elite solutions of the previous generation. Mutation Probability represents the probability of mutation for each gene, affecting the convergence speed. Mutation Rate indicates the degree of gene mutation, where a higher value corresponds to more drastic mutations. Crossover Rate represents the probability of exchanging parameters between two generations. Population Size indicates the size of the population, influencing the computation time. Max Generation specifies the termination generation of genetic operation; 0 indicates an infinite process until convergence. Record Interval and Save Interval denote the production interval for storing historical records and the time interval for saving file data, respectively."

Q10. Line 225; please provide a short explanation as to why the north side was chosen for sampling.

R10: At this study site (Beijing), shading problem is a bit worse on the north side than on the south side, so the north side generally requires more artificial supplemental light. We intentionally sampled the north side, as which gives a better understanding of the extent to which the design of this cultivation stand addresses the research concerns.

Q11. Figures 10 and 11; it would be helpful if the colors were explained. It is assumed means shaded, red is not shaded, and yellow is some shading. Also, the reviewer anticipated that the red area of the bottom layer of the right side of Figure 10 would have black on most of the surface. How is the bottom layer getting lit?

R11: Thank you for your insightful suggestion. Initially, we only used yellow to represent unshaded areas in Figure 10, and used black to indicate fully shaded areas in Figure 11 (i.e., continuous lack of sunlight throughout the day). However, we did not depict the degree of shading in other areas, meaning the original orange-red did not signify the degree of shading.

After careful consideration, we agree that the color of the cultivation troughs should systematically reflect the degree of shading. Therefore, we have modified and clarified the colors of each cultivation trough in Figures 10 and 11 to align with reader expectations: “

Figure 10. The north-south directions of the cultivation frame sunshine schematic diagram. Note: The yellow blocks represent unshaded areas of the cultivation troughs during the day, the orange-red blocks represent periodic shading areas, and the gray blocks represent fully shaded areas.

Figure 11. The east-west directions of the cultivation frame sunshine schematic diagram. Note: The yellow blocks represent unshaded areas of the cultivation troughs during the day, the orange-red blocks represent periodic shading areas, and the gray blocks represent fully shaded areas.

When the arrangement direction of the cultivation troughs is perpendicular to the sun's trajectory, the shading areas of the upper layers on the lower layer will move with the sun's trajectory, resulting in periodic exposure to sunlight for various areas of the lower layer. Therefore, the red area on the lower layer's right side in Figure 10 would be represented as orange-red.

Q12. Figure 12; it is interesting that lines for N=1 and N=2 and basically parallel as well as lines for N=3 and N=4. However, the slope for N=3 and 4 is steeper. Does this suggest that at some height the N=3 and N=4 lines would be greater than the N=1 and 2 lines? Would this encourage work with taller systems? The reviewer sees the height limit being due to physical limits of equipment which can change.

R12: This is an inspiring suggestion! Without considering the physical limitations of layer height, we extended the simulation to model the effects of the CTU numbers and a wider range of layer heights (H from 300 to 7500 mm) on the maximum average solar radiation. As review Figure 1 shows, with unlimited increase in layer height, all the four CTU numbers (N=1 to 4) tend to have smaller slopes and tend to maximize (approximate no shading) at H=3300, 5500, 6500, and 7500 mm, respectively. However, the lines for N=3 and 4 fail to exceed those for N=1 and 2 at the same layer height, probably because the former always has larger shading layer areas than the latter. Even if the physical limitation of layer height is broken, the layer height of N=4 (H about 1400) is still nearly twice as high as that of the NLSCF (N=2, H=685) in order to fulfill the solar radiation requirements for lettuce. However, its production costs, such as construction and labor costs will probably increase greatly. So, the results of this study fail to encourage taller systems, but rather support more studies of the A-shape cultivation frame.

review Figure 1. Simulation of the Influence of the Number of CTU and the Layer Height on the solar radiation.

Q13. Equation 2; please provide units. Also, did you check to see if NH had any impact on RAD?

R13: We added the unit information for Equation 2 in line 366-371: “RAD= 1.547-0.326·N+0.001·H, RAD is the maximum average solar radiation (kWh·m^-2, H is layer height (mm), and N is the number of CTU. The results indicate a negative impact of the CTU numbers and a positive impact of the layer height. Specifically, when the independent variables are limited to practical ranges, for each additional CTU, RAD decreases by 0.326 kWh·m^-2. Simultaneously, with every 100 mm increase in layer height, RAD increases by 0.1 kWh·m^-2.”

Besides, we have re-analyzed the linear regression of solar radiation, using data from the new review Table 1. If the physical limitations of layer height is not taken into account, the regression formula could be represented as: RAD= 1.447-0.170·N+0.0004·H, Adjusted R²=0.873. This shows a consistent but decreasing impact of N and H on the solar radiation.

Q14. Lines 323-341; is there an upper limit to light intensity on the upper layers? Do you need to ensure photo saturation and photo inhibition light intensities are not reached? Could systems be devised to maintain all layers within a light intensity range?

R14: Yes, the upper limit to light intensity on the upper layers is the light intensity of direct sunlight. Photo saturation and photo inhibition are not considered in this study, as they are observed seldomly in crops cultivated under natural light in the greenhouse. This is because various shading techniques, including shading nets or curtains, can be used in the greenhouse to provide shade, even during the bright summer months.

We agree that it is essential to monitor and control light intensity range to avoid both photo-saturation and photo-inhibition in the context of plant cultivation or greenhouse management. So, we have added this work to the future implication section in lines 565-567: “The NLSCF system may also benefit from better light intensity range management, including avoiding photo-saturation and photo-inhibition and optimizing light distribution among layers.”

Q15. Line 364; in Figure 15, the reviewer sees little difference between 1a and 2a even though the author(s) say there is. Please expand on this.

R15: We are sorry for our ambiguous figure and expression, which have caused your misunderstanding. We have corrected the error in Figure 15 (please see the revision process in R16) and made the color scale on the right side of Figure 15 more refined and intuitive.

new Figure 15. Solar radiation simulation results of Mode 1 and Mode 2.

Our intention was not to compare the differences between 1a and 2a, but to compare the relatively best design among the five Modes. We have revised the manuscript to clarify the mode comparisons in lines 422-431: “Figure 15 illustrates that with the solar radiation in the lower layer of the cultivation frame is set the same, Mode 1b outperforms the rest structures in uniformity of solar radiation distribution. Regard to the solar radiation in the middle layer, Modes 1(1a, 1b) show higher solar radiation than that of Modes 2(2a, 2b, 2c). The uniformity difference in the middle layer between Mode 1a and Mode 1b is not significant, while in Mode 2, the Mode 2a is significantly better than that of the Modes 2b and 2c. According to Table 4, Mode 1b also shows the lowest minimum layer height (670 mm) and the lowest total height (1950 mm), showing the best convenience and efficiency for manual operation. Based on the above analysis, we followed the design of the Mode 1b by setting 1 group of CTU in the center position of the upper layer.”

Q16. Table 4 and figure 15; The middle layer of 1a and 2a appear to both be orangish (numerical value of 1.8 to 2.1). Table 4 indicates numerical averages of 1.69 (yellow) and 1.46 9edge of yellow and green). If the reviewer sees this correctly, the information inconsistent. Please provide more explanation.

R16: We sincerely apologize for the error during the generation of Figure 15, where the model mistakenly included the background color of the cultivation trough, resulting in all images turning orange. We have rectified this mistake, and the current scale values and colors in Figure 15 are now consistent with Table 4.

Q17. Figure 16; the figure requires an explanation about what the dots and lines mean.

R17: We have added explanatory notes below Figure 16(in lines 440-447):

“Notes: The left image represents a spatial schematic of the optimal solution set obtained through the optimization processes, where the deep red cubes represent the Pareto frontier solution set. The right image illustrates the parameter distance diagram from the optimization processes, with each line representing an optimized solution. The intersection of the line with the axis indicates the value of that parameter. The smaller and more concentrated slopes of the line indicate a higher degree of optimization. Densely populated areas of lines represent the region of the optimal solution set, while dispersed areas signify eliminated solutions during the iteration processes.”

We added explanations of the results in lines 449-451:“After 11 iterations, the Octopus achieved convergence in optimizing the average solar radiation of the CTUs on the inner and outer sides of the lower layer. Combining the optimization parameter values and optimization target values corresponding to each solution on the Pareto frontier in Figure 16, we selected the conditions that meet the design requirements of the cultivation frame. The optimal simulation results are as follows.

Q18.  Lines 382-402; it would be helpful to readers if the author(s) used the same units for comparison. Fan used ICL units and Chen used percentage of light relative to top layer. Put these values into a table and add the author(s) results in the same units.

R18: We thank the reviewer for the kind advice. We agree that the same units could be beneficial for comparison, so we use multiple units that are consistent with the results of Fang et al. and Chen et al., to represent the results of this study. The revised manuscript in lines 453-458 is as follows: “The spacing between CTUs is 348 mm, the layer height is 685 mm, the maximum average solar radiation on the outer side of the lower layer is 1.26 kWh·m^-2 (i.e., DLI ≈ 9.07 mol·m^-2·day^-1), on the inner side is 1.13 kWh·m^-2 (i.e., DLI ≈ 8.14 mol·m^-2·day^-1), and in the middle layer is 1.66 kWh·m^-2(i.e., DLI ≈ 11.95 mol·m^-2·day^-1). The solar radiation on the inner and outer sides of the lower layer and the middle layer are 60.6%, 54.3%, and 79.8% of those on the upper layer, respectively. For convenience in subsequent design, d is set to 350 mm, and L is set to 685 mm. Therefore, the optimized design of the NLSCF is shown in Figure 17.”

and in lines 464-472: “For example, Fang et al. [42] found that the DLIs of the middle and lower layers in a stereoscopic cultivation frame were only 1.30 and 1.26 mol·m-2·day-1, far lower than the result of this study, 11.95 and 8.61 mol·m^-2·day^-1. Chen et al.[24] studied the light-temperature effect of A-shape cultivation frames for strawberries, measuring that the photosynthetically active radiation in the middle and lower layers was only from56.9%, and from 39.3% of those in the upper layer on average, 22.9% and 18.2% lower than the present study. The NLSCF significantly increased the solar radiation of the lower and middle layers, making it possible to investigate the effects of natural lighting on lettuce yield and quality.”

Q19. Table 5; is the data presented statistically different from each other? Is that what the ‘a’ and ‘b’ indicate? If it is, please state so and tell why upper and middle layer are different than lower layer inner and outer sides for weight and height. All layers are the same in width.

R19: Yes, different letter superscripts after the standard error indicate significant differences between treatments (Duncan test, P< 0.05). So, the letters a and b mean the values are significantly different, while ab means insignificant differences with a or b. We have revised the manuscript to explain these differences in lines 447-503:

“Table 5. Effects of different cultivation layers on fresh weight, plant height, and plant width of lettuce.

Values are given as means±standard error (n = 3). Different letter superscripts after the standard error indicate significant differences between treatments (Duncan test, P< 0.05).

In the pure sunlight greenhouse experiment, the three lettuce yield indicators for each layer of the cultivation frame exhibited relatively consistent outcomes (see Table 5). The fresh weight, plant width, and height of lettuce decreased in the following order: upper layer > middle layer > outer side of the lower layer > inner side of the lower layer. This order is in line with expectations, as it is consistent with previous solar radiation simulation results. The differences in yield indicators among the layers of the cultivation frame were not pronounced. For instance, compared with lettuce grown in the upper layer, the average fresh weight per plant in the inner side of the lower layer, outer side of the lower layer, and middle layer were 82.9%, 89.0%, and 92.6% of the lettuces in the upper layer, respectively. The average plant height in these layers were 80.4%, 84.0%, and 90.2% of the upper layer. It is noteworthy that our cultivation experiment relied solely on natural sunlight and ambient scattered light within the greenhouse, without the use of artificial supplementary lighting. So, the remaining yield differences could be explained by the remaining differences in light intensity. As the better the light conditions, the more photosynthetic products there are, and the greater the fresh weight and plant height of lettuce. The insignificant difference in the plant width of lettuce may due to the improvement of light uniformity. These results emphasize the NLSCF's success in compensating the substantial differences in solar radiation among layers solely through harnessing natural light conditions. The results underscore the efficiency of the cultivation frame in creating a conducive environment for plant growth, effectively reducing the disparities in crop yields across different layers. The NLSCF's ability to optimize light distribution and enhance the overall performance of the cultivation system positions it as a promising solution for sustainable and efficient vertical farming practices.

Q20. Line 427; does ‘substance accumulation’ equate to ‘biomass production’?

R20: Yes, the phrase is now revised in Line 507: “The NLSCF improves interlayer light conditions, making the distribution of natural light more uniform, promoting biomass production, and consequently achieving yields in the middle and lower layers ranging from 82.9% to 92.6% of the upper layer.”

Q21. Line 445; change to ‘The novel optimization methods for the structure design of VF cultivation frames were explored.’

R21: We have revised the corresponding text (in lines 535-536): “The novel optimization methods for the structure design of VF cultivation frames were explored. This study employed the parametric modeling and light simulation techniques in the design and optimization of VF frames. The results revealed that……”

Q22.  Line 473; should ‘Patents’ be removed if there are none?

R22: Yes, we are sorry for the unnecessary word and have removed it.

We thank both reviewers for their insightful comments, which have greatly improved the quality of this manuscript.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

1. The abstract and conclusions must be consistent with the theme and methodology presented in the document's body.

2. The abstract and the conclusions must reflect the structure and flow of the document. This includes presenting the results in an order corresponding to how they were introduced and discussed in the body of the text.

3. The introduction needs a clear and precise articulation of the research objectives. It is necessary that the introduction explicitly defines the research objectives.

4. Absence of an explicitly formulated hypothesis. Including a well-formulated hypothesis based on existing literature is essential to establish the expectations and direction of the study.

5. Although the introduction reviews previous studies, a deeper contextualization and a more robust study justification are required. This involves a more detailed discussion of how the current research fits into the existing body of knowledge and what specific gaps it aims to address.

6. While using specific tools such as Grasshopper and Ladybug for light simulation is mentioned, it would be beneficial to provide more details on the choice of these tools, their specific configurations, and how they were integrated into the study.

7. It would be helpful to detail the experimental setup, including environmental conditions, growth parameters, and relevant controls or variables.

8. A crucial aspect in the Materials and Methods section is replicability. The description should be detailed and precise enough so other researchers can replicate the study under similar conditions.

9. Better integration of the described methods with the general objectives of the study is required, demonstrating how each method contributes explicitly to achieving these objectives.

10. The results should be compared and contrasted with findings from previous studies. This comparison helps to contextualize the results within the field of research and to highlight their relevance and originality.

11. Any data or data collection methodology limitations should be discussed. This includes limitations in the precision of the measurements, possible biases in the data, or any factors that may have affected the results.

12. The results presented must be consistent with the objectives set out in the study. They should directly address the research questions and hypotheses raised in the previous sections of the paper.

13. The results section should highlight the relevance and applicability of the findings. This involves discussing how the results contribute to the field of study and their potential for practical applications or future research.

Comments on the Quality of English Language

Moderate editing of English language required

Author Response

Response to the Reviewers

Re: “Parametric Design and Genetic Algorithm Optimization of a Natural Light Stereoscopic Cultivation Frame”

We gratefully appreciate the editors and reviewers for their time spent making positive and constructive comments. In response to the concerns raised, we have revised the manuscript accordingly. Below we address each comment in turn. Reviewers’ comments are in bold, our responses are immediately below.

*************************

Reviewer: 3

Comments and Suggestions for Authors

*************************

1. The abstract and conclusions must be consistent with the theme and methodology presented in the document's body.

R1: We thank you for your kind comments and suggestions, which have promoted the manuscript from a holistic viewpoint. We have revised the abstract and conclusions to be fully consistent with the theme and methodology of the manuscript. Please see the revised abstract in lines 10-24: “Vertical farming (VF) is an emerging cultivation frame that maximizes total plant production. However, the high energy-consuming artificial light sources for plants growing in the lower and middle layers significantly affect the sustainability of current VF systems. To address the challenges of supplementary lighting energy consumption, this study explored and optimized the structural design of cultivation frames in VF using parametric modeling, light simulation platform, and genetic algorithms. The optimal structure was stereoscopic, including 4 groups of cultivation trough units in the lower layer, 2 groups in the middle layer, and 1 group in the upper layer, with a layer height of 685 mm and a spacing of 350 mm between the cultivation trough units. A field experiment demonstrated lettuce yields in the middle and lower layers at 82.9% to 92.6% of the upper layer. The proposed Natural Light Stereoscopic Cultivation Frame (NLSCF) for VF is demonstrated to be feasible through simulations and on-site lettuce cultivation experiments without supplementary lighting. These findings confirmed that the NLSCF could effectively reduce the energy consumption of supplemental lighting with the ensure of lettuce's regular growth. Moreover, the designing processes of the cultivation frame may elucidate further research on the enhancement of the sustainability and efficiency of VF systems.”

The conclusions (lines 535-545) are revised as follows: “The novel optimization methods for the structure design of VF cultivation frames were explored. By harnessing parametric modeling and light simulation techniques, our research has introduced innovative approaches to designing and optimizing VF frames. The pivotal findings underscore the remarkable capability of these methods to swiftly and precisely simulate light characteristics across diverse frame structures. Notably, parametric modeling emerges as a key facilitator, streamlining design modifications with unprecedented convenience. These innovative methods provide technical support for the construction of VF cultivation systems, effectively reducing the design costs and design cycle of VF. This paper's primary contributions lie in expanding the technical toolkit for VF design and catalyzing practical advancements that propel the field toward enhanced sustainability and cost-effectiveness.”

2. The abstract and the conclusions must reflect the structure and flow of the document. This includes presenting the results in an order corresponding to how they were introduced and discussed in the body of the text.

R2: We have revised the abstract and conclusions to reflect the structure and flow of the manuscript. As for the conclusion section, we rewrote and rearranged our key findings to improve the clarity and research significance. Please see details in R1 and in the revised manuscript.

3. The introduction needs a clear and precise articulation of the research objectives. It is necessary that the introduction explicitly defines the research objectives.

R3: We rewrote the paragraphs about the research objectives in the introduction section in lines 81-85: “This study is driven by the overarching objective of optimizing the structural design of VF cultivation frames to address the challenges of supplementary lighting energy consumption. Specifically, the research aim is to introduce the natural light stereoscopic cultivation frame (NLSCF) that not only reduces energy consumption but also enhances light distribution for optimal crop growth.”

4. Absence of an explicitly formulated hypothesis. Including a well-formulated hypothesis based on existing literature is essential to establish the expectations and direction of the study.

R4: Yes, we have added the suggested research hypothesis to the manuscript in the introduction section in lines 75-80: “In light of these considerations, we make the assumptions that the innate structure of the cultivation frame in VF relates directly to the shading issues of its lower layers. By investigating the effect of the growing frame structure on the light conditions of the crop, it is possible to use a low cost to achieve higher yields. Light simulation and genetic algorithms become a feasible way to solve the shortage of light in the lower layer of the stereoscopic cultivation frame and to reduce the high energy consumption of the VF.”

5. Although the introduction reviews previous studies, a deeper contextualization and a more robust study justification are required. This involves a more detailed discussion of how the current research fits into the existing body of knowledge and what specific gaps it aims to address.

R5: We appreciate your suggestions and have enhanced the argumentation of the introduction from two perspectives. First, we have added an in-depth discussion paragraph that analyzes existing research from three points of view: current research concerns, research weaknesses, and current unresolved challenges. The content of the added paragraph is shown in lines 55-61: “Taken together, these studies highlight that optimizing cultivation frame structures presents a cost-effective strategy for increasing crop yields while mitigating energy consumption. Nevertheless, existing studies often employ pre-designed cultivation frame structures, leaving the complex influence of structural parameters, such as arrangement directions, layer height, and the number of cultivation trough units (CTU), on light distribution inadequately explored. Notably, challenges related to shading in the lower and middle layers of cultivation frames remain unresolved.”

Second, we added a paragraph about the research gaps in the introduction section in lines 75-80: “In light of these considerations, we make the assumptions that the innate structure of the cultivation frame in VF relates directly to the shading issues of its lower layers. By investigating the effect of the growing frame structure on the light conditions of the crop, it is possible to use a low cost to achieve higher yields. Light simulation and genetic algorithms become a feasible way to solve the shortage of light in the lower layer of the stereoscopic cultivation frame and to reduce the high energy consumption of the VF.”

6. 6. While using specific tools such as Grasshopper and Ladybug for light simulation is mentioned, it would be beneficial to provide more details on the choice of these tools, their specific configurations, and how they were integrated into the study.

R6: We have added the detailed information about the benefits and the specific configurations of Grasshopper and Ladybug in section 2.2.1 and 2.3. Please see the lines 120-XXX in the revised manuscript:

Section 2.2.1. in lines 122-129:

The software Grasshopper used in this study is a parametric modeling plug-in in the 3D modeling software Rhino. It uses program algorithms to generate parametric models and render 3D models in Rh. Designers can model, simulate, and analyze in a single software, saving time in iterative modeling. We used the Ladybug plug-in for light simulation analysis in Grasshopper, as it can simulate the sunshine duration and solar radiation, to which an object is exposed, as well as work with parametric design software. Grasshopper also has a multi-objective genetic algorithm solver, which can optimize multiple target values [31].”

Section 2.3 in lines 158-160：“The spacing between the CTUs (d) ranged from 0mm to 700 mm. After analyzing the modeling parameters of the cultivation frame, the complete model of each layer was constructed in Grasshopper, and the parameters were set as digital sliders. Taken together, Figure 4 summarizes the battery connection for the cultivation frame model in the Grasshopper.”

We have revised the original Figure 4 by supplementing the specific configurations of every unit types in the layers, to illustrate the battery connection diagram of the three cultivation layers in the parametric modeling. The revisions in lines 163 to 164 are as follows:

“Figure 4. The battery connection diagram of the model in Grasshopper.”

We have enhanced the integration among the basic blocks (i.e., the import of EPW meteorological data, the simulation of sunshine duration and solar radiation, and the result output models) in Ladybug in lines 166-184:

“2.4 Establishment of Light Simulation Platform

To simulate and analyze the sunshine duration and the solar radiation of the cultivation frame, we used the Ladybug plug-in to build a light simulation platform for the cultivation frame. The location of the light simulation was Beijing, China. Firstly, we obtained the EPW meteorological data file of Beijing from https://www.ladybug.tools/epwmap/, which contains the meteorological parameters of Beijing at any time of the year. Secondly, the standard EPW meteorological data file was imported into Ladybug to construct the light simulation platform of sunshine duration and solar radiation (Figure 5). To make the results of the study more generalizable, the winter solstice (December 21), which has the worst light conditions in a year, was chosen for the cultivated frame light simulation. The solar trajectory of the winter solstice from 6 am to 6 pm is shown in Fig. 6. After the construction of the lighting simulation platform is completed, the simulation object (lower or middle layer of the cultivation frame) and the shadings (upper layer and its two sides of the cultivation frame) are respectively connected to the Geometry and Context ends of the sunshine duration module and the solar radiation module for simulation. Finally, we exported the simulation results for further analysis.”

“Figure 5. The description of solar radiation analysis and sunshine duration analysis in Ladybug.”

7. It would be helpful to detail the experimental setup, including environmental conditions, growth parameters, and relevant controls or variables.

R7: We have added the advised details into section 2.7 in lines 259-274: “The experimental procedure was as follows. Seedlings were nursed on March 4th of 2023, and when seedlings had 3 leaves and 1 heart on March 25th, seedlings with the same growth conditions were selected for planting. All layers used identical irrigation conditions and nutrient solution during the planting period, and the temperature of the glasshouse was controlled between 18-25 degrees. Plants were sampled and tested from the same location on the north side of the cultivation frame after 40 days of growth. The sampling layers were in order of upper, middle, inner and outer lower layers. In accordance to Lei et al[38]. experiences in lettuce yield and quality, the indicators of design effectiveness include plant height (length from the base of the stem to the tallest part of the plant) and plant width (the widest part of the canopy) obtained by measuring live samples from the field, as well as the fresh weight of single plants (with roots removed) determined by taking samples in freshness and measuring in laboratory. Measuring equipment were electronic scales (range 0-500g, accuracy 0.001g) and straightedge (range 50cm, accuracy 1mm). The lettuce fresh weight measurements were retained with 2 valid digits and plant width and height were retained with 1 valid digit. The average yield of five lettuces was calculated at each measurement and repeated three times (Fig. 8b).

Figure 8. Cultivation experiment. (a) Planting effect of NLSCF. (b) Lettuce fresh weight measurement. The total length of the cultivation frame was 20 m. The spacing between the middle CTU was 350 mm, the height of all layers was 685 mm, and the height of the lower layer from the ground was 400 mm. The ground of the greenhouse installation site was hardened and leveled to ensure the stability of the cultivation frame installation and the stability of drainage from cultivation troughs. Pipeline installation was arranged at both ends of the cultivation frame and buried underground to prevent the pipes from interfering with the movement of cultivation boards. The operational aisle width was set to 500 mm to ensure sufficient operational space while minimizing the use of aisle space resources.

8. A crucial aspect in the Materials and Methods section is replicability. The description should be detailed and precise enough so other researchers can replicate the study under similar conditions.

R8: We have thoroughly revised and meticulously restructured the Materials and Methods sections to further improve the clarity and reproducibility. We added sufficiently detailed explanations to Figure 4, and removed redundant details and enhanced the clarity of the Figures 5 and 7. In addition, we added and refined the content descriptions in Sections 2.1, 2.6, and 2.7 to make the study's methods more reproducible. Please see the revised manuscript in lines 97-119, 211-283 for specific modifications.

9. Better integration of the described methods with the general objectives of the study is required, demonstrating how each method contributes explicitly to achieving these objectives.

R9: This is a great point! We are sorry for our ambiguous expressions, and have reviewed the methods and the objectives in section 2.1. Please see the revised descriptions and the new Figure 1 in lines 104-119:

“The research outline is shown in Figure 1. In the first stage, we analyzed the design requirements of the cultivation frame, including the structure of the CTU and the structure of the cultivation frame. In the second stage of conducting light simulation of the cultivation frame, we established the parameter model and light simulation platform for each layer of cultivation frames in Grasshopper and Ladybug. In the third stage, we designed the structure of the cultivation frames. We used Ladybug to simulate and analysis the lighting of the cultivation frame, including the simulation analysis of the direction of the cultivation frame arrangement, the influence of the structure of the cultivation frame on the solar radiation of the middle and lower layers, and the calculation of the number of CTUs in each layer. The fourth stage was to optimize the structural parameters of the cultivation frame using genetic algorithms. The fifth stage is to verify the feasibility of the design, and a lettuce cultivation experiment was used for verification. Through the above series of research processes, the design and optimization of the structural parameters were finally completed to meet the design requirements of the NLSCF.

Figure 1. Design optimization flow chart.”

10. The results should be compared and contrasted with findings from previous studies. This comparison helps to contextualize the results within the field of research and to highlight their relevance and originality.

R10: We thank the reviewer for the kind advice. We agree that it is beneficial to compare the results of this study with the results of previous studies, so we supplemented the results with multiple units that are consistent with the results of Fang et al. and Chen et al. for direct comparison. The revised manuscript in lines 453-460 is as follows: “The spacing between CTUs is 348 mm, the layer height is 685 mm, the maximum average solar radiation on the outer side of the lower layer is 1.26 kWh·m^-2 (i.e., DLI ≈ 9.07 mol·m^-2·day^-1), on the inner side is 1.13 kWh·m^-2 (i.e., DLI ≈ 8.14 mol·m^-2·day^-1), and in the middle layer is 1.66 kWh·m^-2 (i.e., DLI ≈ 11.95 mol·m^-2·day^-1). The solar radiation on the inner and outer sides of the lower layer and the middle layer are 60.6%, 54.3%, and 79.8% of those on the upper layer, respectively. For convenience in subsequent design, d is set to 350 mm, and L is set to 685 mm. Therefore, the optimized design of the NLSCF is shown in Figure 17.”

and in lines 464 to 472 : “For example, Fang et al.[42] found that the DLIs of the middle and lower layers in a stereoscopic cultivation frame were only 1.30 and 1.26 mol·m-2·day-1, far lower than the result of this study, 11.95 and 8.61 mol·m^-2·day^-1. Chen et al.[24] studied the light-temperature effect of A-shape cultivation frames for strawberries, measuring that the photosynthetically active radiation in the middle and lower layers was only from 56.9%, and from 39.3% of those in the upper layer on average, 22.9% and 18.2% lower than the present study. The NLSCF significantly increased the solar radiation of the lower and middle layers, making it possible to investigate the effects of natural lighting on lettuce yield and quality.”

11. Any data or data collection methodology limitations should be discussed. This includes limitations in the precision of the measurements, possible biases in the data, or any factors that may have affected the results.

R11: We added the discussion of research limitation in lines 524 to 533: “The study has several potential limitations. Due to the research purpose of designing a natural light cultivation frame for VF, variability in plant responses to various light qualities and spectrums was not fully considered. Moreover, while providing practical insights, the cultivation experiment may have inherent variability due to real-world conditions. Factors such as other crop types, temperature variations, nutrient distribution, and other environmental conditions in the glass greenhouse might introduce variations in lettuce growth. By acknowledging these limitations, the study ensures transparency regarding potential sources of error or bias, contributing to a more comprehensive interpretation of the results and recommendations. Future research could delve deeper into these limitations, refining methodologies for more robust outcomes.”

12. The results presented must be consistent with the objectives set out in the study. They should directly address the research questions and hypotheses raised in the previous sections of the paper.

R12: We thoroughly revised the result section to address the proposed objectives and research questions respectively. To be specific, we validated the hypothesis that whether the lower layer of a cultivation frame arranged in a north-south direction is able to obtain periodic light in section 3.1. We performed shading analysis and mechanism design of the cultivation frame, and optimized the structural parameters of the frame in sections 3.2, 3.3, and 3.4. We also verified the proposed hypothesis through cultivation experiments in section 3.5. Please see the revised manuscript for details.

13. The results section should highlight the relevance and applicability of the findings. This involves discussing how the results contribute to the field of study and their potential for practical applications or future research.

R13: We have highlighted the relevance applicability of research findings in the conclusion section in lines 538-545: “The pivotal findings underscore the remarkable capability of these methods to swiftly and precisely simulate light characteristics across diverse frame structures. Notably, parametric modeling emerges as a key facilitator, streamlining design modifications with unprecedented convenience. These innovative methods provide technical support for the construction of VF cultivation systems, effectively reducing the design costs and design cycle of VF. This paper's primary contributions lie in expanding the technical toolkit for VF design and catalyzing practical advancements that propel the field toward enhanced sustainability and cost-effectiveness.”

We thank both reviewers for their insightful comments, which have greatly improved the quality of this manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The author is recommended to comparare the existing approach to the state-of-the-art .There are many papers found relavant to the same context .Why Fresh Weight （g）, Plant width （cm）, Plant height along with differnt layers ? Expected to update in the section 3.5. Lettuce Cultivation Experiment.

Comments on the Quality of English Language

ok

Author Response

Re: “Parametric Design and Genetic Algorithm Optimization of a Natural Light Stereoscopic Cultivation Frame”

We gratefully appreciate the editors and reviewers for their time spent making positive and constructive comments. In response to the concerns raised, we have revised the manuscript accordingly. Below we address each comment in turn. Reviewers’ comments are in bold, our responses are immediately below.

*************************

Reviewer: 1
Comments and Suggestions for Authors

*************************

1. The author is recommended to comparare the existing approach to the state-of-the-art. There are many papers found relavant to the same context .Why Fresh Weight （g）, Plant width （cm）, Plant height along with differnt layers ? Expected to update in the section 3.5. Lettuce Cultivation Experiment.

R1: We thank the reviewer for the kind suggestions, which have promoted the manuscript from a methodological perspective. We have added a comparison and outlook on the methodology between this study and existing cutting-edge research. Please see lines 502-511 in section 3.5 Lettuce Cultivation Experiment:

“This experiment validates the NLSCF improves interlayer light conditions, making the distribution of natural light more uniform, promoting biomass production, and consequently achieving yields in the middle and lower layers ranging from 82.9% to 92.6% of the upper layer. The optimized structure of the NLSCF could meet the normal growth requirements of lettuce. Compared with previous studies that optimized the LED light recipes using the design of experiments (DoE) methodology[42] and the Taguchi method [43], this study harnessed innovative computer simulation and modeling techniques, including parametric modeling, light simulation techniques, and genetic algorithm methods, to assess the impact of different design parameters on the lighting distribution and to utilize the cost-efficient natural light in a better way.

Secondly, we agree that more challenges in vertical agriculture could be addressed by utilizing the state-of-the-art approach. Apart from the computer simulation and model simulation used in this study, other cutting-edge methods, such as advanced lighting technology, Internet of Things (IoT) and sensing technology, and artificial intelligence, are also worth exploring. Therefore, we have revised our research prospect in the hope of exploring these critical issues in the future (Please see lines 533-536). “Future research could delve deeper into these limitations, exploring the use of cutting-edge research methods, such as advanced lighting technology, the Internet of Things (IoT) and sensing technology, and artificial intelligence, for more robust and fully-considered outcomes.”

Thirdly, we have added explanations on the differences in these lettuce yield indicators at various layers in lines 481-501 in section 3.5 Lettuce Cultivation Experiment: “In the pure sunlight greenhouse experiment, the three lettuce yield indicators for each layer of the cultivation frame exhibited relatively consistent outcomes (see Table 5). The fresh weight, plant width, and height of lettuce decreased in the following order: upper layer > middle layer > outer side of the lower layer > inner side of the lower layer. This order is in line with expectations, as it is consistent with previous solar radiation simulation results. The differences in yield indicators among the layers of the cultivation frame were not pronounced. For instance, compared with lettuce grown in the upper layer, the average fresh weight per plant in the inner side of the lower layer, the outer side of the lower layer, and middle layer were 82.9%, 89.0%, and 92.6% of the lettuces in the upper layer, respectively. The average plant heights in these layers were 80.4%, 84.0%, and 90.2% of the upper layer. It is noteworthy that our cultivation experiment relied solely on natural sunlight and ambient scattered light within the greenhouse, without the use of artificial supplementary lighting. So, the remaining yield differences could be explained by the remaining differences in light intensity. As the better the light conditions, the more photosynthetic products there are, and the greater the fresh weight and plant height of lettuce. The insignificant difference in the plant width of lettuce may be due to the improvement of light uniformity. These results emphasize the NLSCF's success in compensating for substantial differences in solar radiation among layers solely through harnessing natural light conditions. The results underscore the efficiency of the cultivation frame in creating a conducive environment for plant growth, effectively reducing the disparities in crop yields across different layers. ”

Author Response File: Author Response.pdf