Maize//Soybean Intercropping Improves Yield Stability and Sustainability in Red Soil under Different Phosphate Application Rates in Southwest China
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors,
You have done fairly good work in the field of the intercropping system (not, cropping pattern). However, I have found some areas which can be further improved.
1. Relate the intercropping system with cultivating sustainability in your introduction.
2. In the introduction, you did not mention the limitation of harvesting which is energy/ labor-intensive.
3. In the M&M segment as well as abstract, necessary queries are to be answered for describing the statistical design and layout adopted.
4. There are several indices to evaluate the efficiency of an intercropping system, however, you relied on LER and AYL. Why? Please mention. I suggest for inclusion of the ATER, RCC, Maize Equivalent Yield, and Aggressivity to assess the maize-soybean intercropping system's benefit properly.
5. Discussion part is to be strengthened.
6. After doing the above, automatically, the conclusion part will be improved.
All the best.
Reviewer.
Comments for author File: 
Comments.pdf
The English is good; however, needs editing.
Author Response
Dear Reviewers:
Thank you for spending your valuable time on our manuscript, we have carefully checked the full text as recommended by the reviewers, and major revise the manuscript according to every suggestion made by the reviewers. In order to ensure that the main idea can be maintained after the revision of the manuscript, we have systematically sorted out the manuscript. At the same time, we have also proofread the contents in the manuscript one by one (such as the paper format, references, etc.).
The following is an item-by-item reply to the suggestions of the reviewers.
For reviewers
We are very grateful to the reviewers for their careful revision of the PDF version of the manuscript, and we have deeply felt the professionalism and dedication of the reviewers.
Dear Authors,
You have done fairly good work in the field of the intercropping system (not, cropping pattern). However, I have found some areas which can be further improved.
- Relate the intercropping system with cultivating sustainability in your introduction.
Response 1: Thanks to the editor for the suggestion. We will go as far as possible to revise and improve the introductory section and link intercropping systems to fostering sustainability. Changes to the manuscript will be marked in blue.
- In the introduction, you did not mention the limitation of harvesting which is energy/ labor-intensive.
Response 2: Thanks to the reviewers for their suggestions, intercropping does have limitations such as harvesting, but it is undeniable that intercropping has many benefits to the extent that it has become a widespread cropping pattern, and we emphasized more on the study and description of intercropping on yield stability and sustainability in this study, so we did not highlight its limitations in the introduction.
- In the M&M segment as well as abstract, necessary queries are to be answered for describing the statistical design and layout adopted.
Response 3: Thank you again for the reviewer's suggestion, we will describe the statistical design and layout adopted according to your notes in the Materials and Methods section of the paper. We also checked the relevant parameters.
- There are several indices to evaluate the efficiency of an intercropping system, however, you relied on LER and AYL. Why? Please mention. I suggest for inclusion of the ATER, RCC, Maize Equivalent Yield, and Aggressivity to assess the maize-soybean intercropping system's benefit properly.
Response 4: Thank you very much for the reviewer's suggestion. We agree very much with the reviewer's suggestion to correctly assess the benefits of the maize-soybean intercropping system, but the fact that our study was mainly focused on exploring the effects of maize-soybean intercropping system on maize yield and stability, and that we did not design a monoculture soybean treatment throughout the design of the study, which resulted in our inability to assess the benefits of the maize-soybean intercropping system, we are very much regret that this resulted in our inability to assess the benefits of the maize-soybean monoculture system. However, we thank the reviewers for their very informative suggestions, which will be taken into account in subsequent studies.
- Discussion part is to be strengthened.
Response 5: We are very grateful to the reviewers for their suggestions, and we have systematically reviewed the whole text in response to the reviewers' suggestions and made appropriate improvements to the discussion section. Especially where the reviewers have marked.
- After doing the above, automatically, the conclusion part will be improved.
Response 6: Thank you, reviewer, your suggestions on the manuscript are valuable and informative. In particular, the annotations you made on the PDF version greatly helped me to revise the manuscript further. I will do my best to revise the manuscript. The results and conclusions sections were not adjusted because we did not make larger adjustments.
- Other areas of the manuscript marked for revision.
(1) To address those elements of the manuscript that are more commonly recommended for revision by the reviewers. For example, word errors, capitalisation errors, inappropriate descriptions in the Materials and Methods section, and so on.
Response (1): We are particularly grateful to the reviewers for their careful review of the manuscript, the advice you gave was very valuable and I fully agree with the review suggestions you made. We read the whole paper carefully, especially the places you marked. And we will revise it one by one according to your suggestions. Changes to the manuscript will be marked in blue.
(2) Clarification on the description of spacing and density in the Materials and Methods section.
Response (2): We thank the reviewers for their careful review of the manuscript. In the present study rows and plants spacing was 50 cm × 25 cm in both monoculture and intercropping and there was a 25 cm margin on both sides of the rows and plants, hence our plot area was 24 m2 (4 m × 6 m) and we again calculated that the planting density was 7500 plants/ha, which we have corrected in the manuscript.
(3) In figure 3: Is it not an abrupt increase of PLERY with P0 in 2021? AYL also reached to its peak in 2021 with P0.
Response (3): Thanks to the reviewer's reminder, we verified the original data and calculation steps again, and checked all the records of planting years in detail, and I am sure that our data and calculations are correct, and our previous study also reported that maize was the dominant crop in maize-soybean intercropping system (Zhou et al., 2023). Over the course of our long-term locational trials, there was an overall trend of lower yields in the P0 treatment crops with increasing planting years, and the greater the differences between the single intercrops, especially in years with poor environmental conditions. In addition, pLERY and AYL were higher than the other treatments in 2021 in our study, which may be related to lower rainfall in 2021.
(4) In 4.1: Recast the sentence ‘Consistent with the research results of Wang et al. [34] and Xu et al. [35]. Although intercropping and P application had significant effects on maize yields, there were significant differences between different P application rates and were also affected by the planting years [15,36].’
Response (4): Thanks to the reviewers, we have revised the sentences mentioned by the reviewers. They are as follows: Consistent with the findings of Wang et al. [34] and Xu et al. [35], although intercropping and P application had a significant effect on maize yield, significant differences existed between different P application rates, and were also affected by planting year [15,36].
(5) In 4.3: There are many examples and research findings on maize-soybean intercropping system. Please find the same and include in the article.
Response (5): Thanks to the reviewers, we have replaced the examples and research results of maize-soybean intercropping systems in this section.
(6) In 4.4: please polish the english and cite reference.
Response (6): We thank the reviewers for their suggestions, and we have touched up the section in English and added the appropriate references according to the reviewers' suggestions. Follow: On the one hand, the optimum amount of P fertilizer obtained from many years of P fertilizer experiment is related to the continuous decline of P supply capacity and the effect and efficiency of continuous application of each P fertilizer treatment. On the other hand, the optimum amount of P fertilizer is related to crop absorption and the fixation and release of phosphorus in the soil [60,61].
(7) in the experiment, there was not major variation among management. Can you please mention why it has been mentioned? I suggest to delete the prase.
Response (7): Thanks to the reviewer, I couldn't agree more with the suggestion you made and we have removed the description here.
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Authors,
In my opinion, the topics of the field research undertaken are timely and interesting. Despite the many benefits of intercropping with legumes, this scheme is not intensively spread. Thus, I consider any research presenting the benefits of intercropping to be relevant and useful to modern agronomy. As for the content of the manuscript, I have a few comments and suggestions. Unfortunately, the text does not include line numbers so this is a bit of an impediment to providing suggestions. In addition, in my opinion, part of the manuscript needs clarification:
Introduction
In my opinion, it is generally well written. It adequately introduces the subject of intercropping and briefly outlines the benefits that arise from it. I would suggest a minor addition of economic considerations due to higher and more stable yields and less use of mineral fertilizers. This all leads to an increase in the level of profitability of the crop. In addition, I would suggest emphasizing the relevance of P fertilization for crop plants.
Materials and Methods
I believe that this section needs some additions and clarifications.
Section 2.2:
From the remainder of the manuscript, I infer that seeding for all years of field research was conducted in the same field immediately after each other? If so, this should be included in this section.
Why was the object with the soybean monoculture not used as a reference complement. This would have allowed a more accurate determination of the benefits of intercropping
Describe the soybean planting scheme similarly to what was done for corn. According to the description, I understand that the planting density for corn when grown with soybeans was about 37500 plants per hectare? Or was it a different scheme?
Were the soybeans inoculated before sowing?
Section 2.3
What about the harvesting of soybeans? Was its yield not analyzed? I understand that the authors focused on corn, however, in my opinion, for a full evaluation of the benefits of intercropping, it would have been good to present soybean yields as well.
Results
Section 3.1
Would it be possible for the authors to present corn yields depending on the seeding pattern of both monoculture and intercropping? If I understand the planting scheme from the Materials and Methods section correctly, half as much corn was sown in intercropping so the results given seem inadequate. However, it is possible that the seeding was implemented differently and soybeans were only an addition to the corn rows. Please clarify
Section 3.2
I suggest checking the calculation of pLERA values, only partial LER was calculated and the values obtained are often higher than those reported in the literature for total LER.
Figure 3 The Figure caption shows the abbreviations MM and IM which are missing in the Figure. I suggest correcting the description.
Discussion
“The LER value of this study was higher than 1 in all treatments, indicating that the maize//soybean intercropping pattern still showed yield advantages, meanwhile, the yield advantages of intercropping maize were affected by P application and changed with the planting years.” - In the results section, partial LER rather than total LER is given.
References
There is double numbering, this should be corrected.
Good luck
Author Response
Dear Authors,
In my opinion, the topics of the field research undertaken are timely and interesting. Despite the many benefits of intercropping with legumes, this scheme is not intensively spread. Thus, I consider any research presenting the benefits of intercropping to be relevant and useful to modern agronomy. As for the content of the manuscript, I have a few comments and suggestions. Unfortunately, the text does not include line numbers so this is a bit of an impediment to providing suggestions. In addition, in my opinion, part of the manuscript needs clarification:
Dear Reviewers:
I apologize for the inconvenience caused by the lack of line numbers in the manuscript for your review, and thank you even more for your valuable time in reviewing the manuscript. We have carefully checked the full text as recommended by the reviewers, and major revise the manuscript according to every suggestion made by the reviewers. In order to ensure that the main idea can be maintained after the revision of the manuscript, we have systematically sorted out the manuscript. At the same time, we have also proofread the contents in the manuscript one by one (such as the paper format, references, etc.).
The following is an item-by-item reply to the suggestions of the reviewers.
Introduction
- In my opinion, it is generally well written. It adequately introduces the subject of intercropping and briefly outlines the benefits that arise from it. I would suggest a minor addition of economic considerations due to higher and more stable yields and less use of mineral fertilizers. This all leads to an increase in the level of profitability of the crop. In addition, I would suggest emphasizing the relevance of P fertilization for crop plants.
Response 1: We would like to thank the reviewers for their valuable time and high evaluation of the manuscript. Your suggestions will help us to further improve the quality of our manuscript and we strongly agree with them!
As mentioned by the reviewer, intercropping can lead to high yields and reduce the use of mineral fertilizers and maintain yield stability better. Based on the cost of fertilizers spent in the same year, intercropping maize would certainly be more profitable than monocropping maize. However, since this study is a dynamic process with fluctuations in fertilizer prices and crop prices from year to year, the information related to economic benefits is not reflected in the manuscript.
In addition, this paper emphasizes the maize-soybean intercropping to improve maize yield and yield stability under different levels of phosphorus application, and focuses more on the advantage of corn-soybean intercropping over maize monocropping in terms of yield and inter-annual variability and response to phosphorus application, which is important to the crop, and the reviewer's suggestion is very meaningful. We have emphasized the relevance of phosphorus fertilization to crop plants at appropriate places in the manuscript as suggested by the reviewers.
Materials and Methods
- I believe that this section needs some additions and clarifications.
Response 2: Thanks to the reviewers, we synthesized the suggestions of the two reviewers on the Materials and Methods section and reorganized them to revise, supplement and improve the experimental design and planting system. We have marked the changes and additions in blue.
Section 2.2:
- From the remainder of the manuscript, I infer that seeding for all years of field research was conducted in the same field immediately after each other? If so, this should be included in this section.
Response 3: Many thanks to the reviewer for the suggestion that this study is a long-term localization experiment, conducted in the same plot, which I have added in the Materials and Methods section.
- Why was the object with the soybean monoculture not used as a reference complement. This would have allowed a more accurate determination of the benefits of intercropping
Response 4: Thank you very much for the reviewer's suggestion, I agree very much with the reviewer's suggestion to correctly assess the benefits of maize-soybean intercropping system, but the fact that our study was mainly focused on investigating the effect of maize-soybean intercropping system on maize yield and stability, and that we did not design the monocropping soybean treatment throughout the whole design of the study, which resulted in the inability of assessing the benefits of the maize-soybean monocropping system is very unfortunate for us. However, we thank the reviewers for their very informative suggestions, which will be taken into account in subsequent studies.
- Describe the soybean planting scheme similarly to what was done for corn. According to the description, I understand that the planting density for corn when grown with soybeans was about 37500 plants per hectare? Or was it a different scheme?
Response 5: Thank you very much for the reviewer's suggestion, only maize-soybean intercropping and maize monocropping were designed in this study, maize and soybean were sown at the same time, and the row spacing of maize-soybean intercropping and maize monocropping was the same, maize-soybean intercropping was based on monocropping maize by replacing half of the maize with soybeans according to the ratio of 1:1, that is, the planting density of maize in monocropping was 75,000 plants/ha, and the planting density of maize in maize-soybean intercropping was 37,500 plants/ha, which we have added to clarify in the Materials and Methods section of the manuscript. In other words, the planting density of corn in monoculture is 75000 plants/ha, and that of maize-soybean intercropping is 37,500 plants/ha, which has been clarified in the Materials and Methods section of the manuscript.
- Were the soybeans inoculated before sowing?
Response 6: Soybeans were not inoculated prior to planting.
Section 2.3
- What about the harvesting of soybeans? Was its yield not analyzed? I understand that the authors focused on corn, however, in my opinion, for a full evaluation of the benefits of intercropping, it would have been good to present soybean yields as well.
Response 7: Many thanks to the reviewers for their advice, and it were unfortunate that the monoculture soybean treatment was not designed throughout the study design, which prevented us from evaluating the benefits of the maize-soybean monoculture system. Our study focused on the effects of maize-soybean intercropping systems on maize yield and stability, and the reviewer's suggestion to correctly assess the benefits of maize-soybean intercropping systems reminds us that we may want to consider monoculture soybeans in our subsequent work, as well as considering the benefits of maize-soybean intercropping systems. We remain grateful to the reviewers for their very informative suggestions, and we will take them into account in our subsequent research.
Results
Section 3.1
- Would it be possible for the authors to present corn yields depending on the seeding pattern of both monoculture and intercropping? If I understand the planting scheme from the Materials and Methods section correctly, half as much corn was sown in intercropping so the results given seem inadequate. However, it is possible that the seeding was implemented differently and soybeans were only an addition to the corn rows. Please clarify
Response 8: Indeed, intercropped maize is sown at half the seeding rate of monoculture maize, and monoculture maize is planted according to the planting pattern of replacing 2 rows of soybeans with 2 rows of maize at intervals to form a maize-soybean intercropping pattern, and we measure intercropped maize yield statistics by dividing maize yield per unit area of maize-soybean intercropping treatments by the proportion of maize in the maize-soybean intercropping system.
Section 3.2
- I suggest checking the calculation of pLERA values, only partial LER was calculated and the values obtained are often higher than those reported in the literature for total LER.
Response 9: Thanks to the reviewer's reminder, we verified the original data and calculation steps again, and checked all the records of planting years in detail, and I am sure that our data and calculations are correct, and our previous study also reported that maize was the dominant crop in maize-soybean intercropping system (Zhou et al., 2023). Over the course of our long-term locational trials, there was an overall trend of lower yields in the P0 treatment crops with increasing planting years, and the greater the differences between the single intercrops, especially in years with poor environmental conditions. In addition, pLERY and AYL were higher than the other treatments in 2021 in our study, which may be related to lower rainfall in 2021.
- Figure 3 The Figure caption shows the abbreviations MM and IM which are missing in the Figure. I suggest correcting the description.
Response 10: The figure 3 does not relate to monoculture and intercropping maize, therefore, there is no need to add legends for monocrops and intercrops. In addition, we have made some adjustments to the chart titles.
Discussion
- “The LER value of this study was higher than 1 in all treatments, indicating that the maize//soybean intercropping pattern still showed yield advantages, meanwhile, the yield advantages of intercropping maize were affected by P application and changed with the planting years.” - In the results section, partial LER rather than total LER is given.
Response 11: Indeed, our study was unable to calculate the total LER due to the lack of a single-crop soybean design, however, the partial LER of maize is greater than 1, thus intercropping maize is advantageous. Thanks to the reviewer's suggestion, and we will add the relevant design in our subsequent studies.
References
- There is double numbering, this should be corrected.
Response 12: Thanks to the reviewers, we have adjusted and corrected the numbering of the manuscript's references, and based on the revisions to the manuscript we have reorganized the order in which the manuscript's references are cited.
Good luck
Response: Once again, we would like to thank the reviewing experts for spending your valuable time on our paper and making suggestions of practical significance. We couldn't agree more with the expert's suggestions and have done our best to revise them.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsIt's fine with me.
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Authors,
thank you very much for your detailed response to the comments I sent and for all the changes to the manuscript.
It is no less surprising to me to receive higher maize yields with 50% less sowing. The authors have provided as supplementary materials a detailed table of results with confirmation of this. Thank you.
I have no further comments on the manuscript.
