Influence of Tall Fescue Ecotype on Biomass Production, Radiation Interception and Use Efficiency in Alfalfa-Based Pasture Mixtures

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,
This paper contains some interesting results, but it also requires corrections and additions. These are presented in the review below.

The Abstract states that the study was conducted over two years, but the years 2016-2018 are given. The paper presents results from the 2017-2018 period.

The Introduction is very short, taking up only one page.

The Experimental Design section should state that no fertilization was used during the study.

L100-105 At the end of the introduction, after stating the study objective, information regarding the study results is included.

L142-143 The share of species in the two-species mixtures is not clearly stated, whether it was in a 50%:50% ratio, and what the share of components in the three-component mixture was.

The Measurements section states that two parameters were assessed – Aerial Dry Matter and PAR. The remaining parameters were calculated. This seems to be a relatively small number of measurements during the study period. Furthermore, L 152-153 states that "Measurements began one year after sowing and covered eight regrowth periods (March 2017–May 2018)." Figures 3 and 4, where eight regrowth dates (measurements) are given, show the first date as late summer and the last as autumn 2nd year. This is unclear.

The Results contain errors in the figure numbering; there are two figures with the number 3. Furthermore, Figures 2 and 3 show the average values ​​for the entire study period (8 regrowths and 5 repetitions) for the sowing variants, which demonstrates an overgeneralization of the results. Figures 3 and 4, however, show all measurement dates (8 regrowths).

 

Comments on the Quality of English Language

The manuscript is written quite clearly.

Author Response

Comments 1: The English could be improved to more clearly express the research.

Response 1: We revised the English throughout the manuscript to improve clarity of the research

 

Comments 2: The Abstract states that the study was conducted over two years, but the years 2016-2018 are given. The paper presents results from the 2017-2018 period.

Response 2: We clarified that:

Line 28-30: We evaluated from March 2017 to May 2018 in the Pampas (Argentina) monocultures of alfalfa and tall fescue Mediterranean and Continental ecotypes, and their mixtures with a sowing ratio 1:1 under frequent defoliation without fertilization.

 

Comments 3: The Introduction is very short, taking up only one page.

Response 3: We expanded the Introduction section according this suggestion.

 

Comments 4: The Experimental Design section should state that no fertilization was used during the study.

Response 4: We stated that no fertilization was used.

Comments 5: Line 28-30: We evaluated from March 2017 to May 2018 in the Pampas (Argentina) monocultures of alfalfa and tall fescue Mediterranean and Continental ecotypes, and their mixtures with a sowing ratio 1:1 under frequent defoliation without fertilization.

Response 5: Line 149: Pastures were hand-sown in May 2016 without fertilization.

 

Comments 6: L100-105 At the end of the introduction, after stating the study objective, information regarding the study results is included.

Response 6: We decided to remove this information in order to improve the structure of the Information section.

 

Comments 7: L142-143 The share of species in the two-species mixtures is not clearly stated, whether it was in a 50%:50% ratio, and what the share of components in the three-component mixture was.

Response 7: We included it.

Line 28-30: We evaluated from March 2017 to May 2018 in the Pampas (Argentina) monocultures of alfalfa and tall fescue Mediterranean and Continental ecotypes, and their mixtures with a sowing ratio 1:1 under frequent defoliation without fertilization.

Line 141-143: In mixtures, grasses and legumes were sown in alternating rows spaced 17.5 cm apart at a 1:1 mixing ratio.

 

Comments 8: The Measurements section states that two parameters were assessed – Aerial Dry Matter and PAR. The remaining parameters were calculated. This seems to be a relatively small number of measurements during the study period. Furthermore, L 152-153 states that "Measurements began one year after sowing and covered eight regrowth periods (March 2017–May 2018)." Figures 3 and 4, where eight regrowth dates (measurements) are given, show the first date as late summer and the last as autumn 2nd year. This is unclear.
Response 8: We clarified. We included Table 2 with cuttings performed.

Line 184: Table 2. Cutting date and thermal time accumulation during the experimental period.

 

Also, we included that in each regrowth fPARi measurements were performed to show that the number of measurements during the experimental period was quite large.

Line 195-196: The number of measurements within each regrowth period ranged from three to six, de-pending on its duration.

 

Comments 9: The Results contain errors in the figure numbering; there are two figures with the number 3. Furthermore, Figures 2 and 3 show the average values ​​for the entire study period (8 regrowths and 5 repetitions) for the sowing variants, which demonstrates an overgeneralization of the results. Figures 3 and 4, however, show all measurement dates (8 regrowths).

Response 9: Thanks for these observations. We corrected it.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The work by Mattera et al. shows interesting results concerning about of Influence of Tall Fescue Ecotype on Biomass Production, Radiation Interception and Use Efficiency in Alfalfa-Based Pasture  Mixtures. It explores the typical, yet understudied, trade-off between Alfalfa monoculture and its mixture with the Mediterranean, winter‑active tall fescue ecotype. The report is well written and condensed, as well as technically appropriate.  However, before being able to recommend acceptance, I invite authors to address the following minor amendments.


Abstract. The authors could explain why your research topic is relevant and important, its broader implications, and how it contributes to existing knowledge and identify knowledge gaps, and illustrate how your research contributes to filling those gaps. Highlight what the hypothesis of the work carried out would be.

 

Introduction section need more literature review: To enhance the introduction section of a literature review, include introducing the topic, establishing the significance of the study, providing an overview of relevant literature, identifying knowledge gaps, and illustrating how your study advances knowledge. Start by briefly describing the subject and clearly state the area or field you are exploring. The references are very old; 80-90% are from 8 or 10 years ago, or even earlier. There are no references from the last 4 years. Remember, the introduction serves as a roadmap for readers, guiding them through your academic work.

Please correct the scientific name of alfalfa. Medicago sativa must be written in cursive. Line 87.

 

Materials and methods. My concern is that the work was conducted 10 years ago, between 2016 and 2018. Are the results likely not comparable now in 2026. In addition the author should explain the phenology or growth stage at which the samples were taken. Was harvest reached? And in that sense, at what growth stage was defoliation carried out?. This section should be improved to provide a clearer overview of the experiments.

I recommend including parameters like solar radiation and other climatic conditions for the identified sites, as well as the databases used to estimate Argentina's annual solar radiation data.

 

 

 

 

 

Results. Figure 1, the graph mentions that it is the average of five replicates, it is recommended to graph with error or deviation bar and separate the bars, in order to show the significant differences by species or group of plant.

The figure 3. A linear regression model (using R² to measure explained variability) could better explain differences in productivity among canopies based on radiation interception.

 

Discussion section needs improvement to offer a more comprehensive understanding of the research gaps addressed in your study. To improve the article, the authors could include a more detailed discussion on the practical applications of the research findings, particularly in relation to if the results help to a possible improvement in the selection of plants as forage for livestock.

Conclusion. Last but not least, a section conclusions should bring the reader into perspectives and novel follow up approaches to bridge the caveats of the present study.

Specifically, how could breeding strategies account when comparing mixtures and monocultures due to compensatory effects between fPAR and RUE.

Author Response

Comments 1: Abstract. The authors could explain why your research topic is relevant and important, its broader implications, and how it contributes to existing knowledge and identify knowledge gaps, and illustrate how your research contributes to filling those gaps. Highlight what the hypothesis of the work carried out would be.

Response 1: We included the research gap and relevance and the complete aim of the study:

Line 22-27: Ecotypic variation in tall fescue (Lolium arundinaceum (Schreb.) Darbysh.), with differences in phenology, may affect the performance of mixtures with alfalfa (Medicago sativa L.). However, the effects of ecotypic variation within mixtures remain largely unexplored. The aim of this study was to evaluate the aerial dry matter (ADM) production and radiation model components of alfalfa-tall fescue mixtures, with particular emphasis on their implications for radiation interception and radiation use efficiency (RUE) at the canopy level.

The hypothesis was included only in the introduction due to limited words in the abstract:

Line 100-102: The hypothesis was that the inclusion of tall fescue Mediterranean ecotype in the mixture with alfalfa increases aerial biomass production due to complementary growth cycles with increased fPAR_i and RUE during winter season.

 

Comments 2: Introduction section need more literature review: To enhance the introduction section of a literature review, include introducing the topic, establishing the significance of the study, providing an overview of relevant literature, identifying knowledge gaps, and illustrating how your study advances knowledge. Start by briefly describing the subject and clearly state the area or field you are exploring. The references are very old; 80-90% are from 8 or 10 years ago, or even earlier. There are no references from the last 4 years. Remember, the introduction serves as a roadmap for readers, guiding them through your academic work.

Response 2: We reordered the first paragraph providing an overview of relevant literature, identifying knowledge gaps, and illustrating how your study advances knowledge.

Line 43-74: In livestock grazing systems, perennial temperate pastures are a major component of the animal diet because they provide large quantities of high-quality forage at a relative low cost. Mixtures of grasses and legumes are a common combination due to their advantages, such as complementarity in forage production [1] and stability [2], biological nitrogen fixation [3] and reduction of bloat risk [4]. Together, these benefits make grass-legume mixtures a key component of sustainable forage-based livestock systems, but the success of mixtures largely depends on the combination of species and cultivars. However, there exists a lack of information on the topic and it is essential to identify the most productive mixtures and the mechanisms that determine their performance.

The Pampas region (Argentina), characterized by a temperate climate and fertile soils, is highly important for livestock production, sustaining approximately 19 million head in Buenos Aires Province (SAGyP). There is a consensus that mixtures of alfalfa (Medicago sativa L.) and grasses including tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) provide year-round production, reduces bloat risk, and improves forage quality [5,6]. On one hand, alfalfa is the most widely used forage species in Argentina and particularly in Pampas region due to its high productivity, nutritive value and adaptation to wide range of environments [7]. On the other hand, tall fescue is the most important perennial grass in this region. Unlike other temperate grasses, tall fescue exhibits a much broader ecological tolerance, including greater resistance to summer drought conditions [8-10]. This capacity to withstand a wider range of environmental stresses has contributed to its extensive use across diverse management systems.

The complementarity of grass-legume mixtures is influenced by both physiological and morphological traits [11]. Among the physiological traits, the growth cycle and its seasonal dynamics play a key role. In tall fescue, these traits vary between ecotypes: the Mediterranean ecotype grows more actively during winter, while the Continental ecotype exhibits higher growth during spring and summer [12,13]. Morphologically, the Mediterranean ecotype presents smaller plant size and a greater number of tillers compared to the Continental ecotype [14]. However, the potential effects of intraspecific variation, such as differences among ecotypes, remain largely unexplored. This knowledge gap is the focus of the present study, particularly regarding how these differences affect light interception and radiation use efficiency at the canopy level when tall fescue is grown in mixture with summer-growing legumes.

 

Comments 3: Please correct the scientific name of alfalfa. Medicago sativa must be written in cursive. Line 87.

Response 3: We have corrected the scientific name of alfalfa in Line 87. 

 

Comments 4: Materials and methods. My concern is that the work was conducted 10 years ago, between 2016 and 2018. Are the results likely not comparable now in 2026. In addition the author should explain the phenology or growth stage at which the samples were taken. Was harvest reached? And in that sense, at what growth stage was defoliation carried out?. This section should be improved to provide a clearer overview of the experiments.

Response 4: We include these requested aspects:

Line 134: The cultivars are still currently available on the market as forage species have a slow cultivar turnover.

Line 172-173: The phenology at harvest corresponded to pre-flowering to 10% flowering in alfalfa and three expanded leaves in tall fescue

 

Comments 5: I recommend including parameters like solar radiation and other climatic conditions for the identified sites, as well as the databases used to estimate Argentina's annual solar radiation data.

Response 5: We included it.

Line 119-122: Global solar radiation was estimated from the hours of sunlight registered daily at the meteorological station of INTA and for the year 2017 ranged between a minimum of 7.7 MJ day^-1 in July and a maximum of 24 MJ day^-1 in January.

 

Comments 6: Results. Figure 1, the graph mentions that it is the average of five replicates, it is recommended to graph with error or deviation bar and separate the bars, in order to show the significant differences by species or group of plant.
Response 6: We corrected and included significant differences by species.

Line 267-276: Figure 1.

 

Comments 7: Line 269: The figure 3. A linear regression model (using R² to measure explained variability) could better explain differences in productivity among canopies based on radiation interception.

Response 7: Line308: We included Table 3 to include R² and model parameters of the fitted models.

 

Comments 8: Discussion section needs improvement to offer a more comprehensive understanding of the research gaps addressed in your study. To improve the article, the authors could include a more detailed discussion on the practical applications of the research findings, particularly in relation to if the results help to a possible improvement in the selection of plants as forage for livestock.

Response 8: We included it.

Line 408-410: These results provide relevant information for the identification of highly productive mixtures that are comparable to alfalfa monoculture but also provide other benefit for the development of more sustainable livestock grazing systems.

Line 426-428: The identification of tall fescue Mediterranean ecotype with superior performance in the mixture suggests a potential for breeding this species/ecotype developing outstanding cultivars.

 

Comments 9: Conclusion. Last but not least, a section conclusions should bring the reader into perspectives and novel follow up approaches to bridge the caveats of the present study.

Specifically, how could breeding strategies account when comparing mixtures and monocultures due to compensatory effects between fPAR and RUE.

Response 9: We included it.

Line 426-428: The identification of tall fescue Mediterranean ecotype with superior performance in the mixture suggests a potential for breeding this species/ecotype developing outstanding cultivars

Line 504-507: In conclusion, the selection of companion grasses according to their compatibility with alfalfa can enhance the canopy efficiency of the mixture. Future research should focus on three areas: 1)- identifying outstanding Mediterranean cultivars that express the ecotypic advantage in winter season with increased radiation interception besides high radiation use efficiency,

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Specific comments

As a researcher in the field of agriculture, I am very interested in your work. I have read your article carefully and I see that you have done a lot of work on it.

However, if I understand your description correctly, this paper needs a major overhaul in terms of content and formatting, and the changes are as follows.

Abstract

1. Lack of core quantitative data support；
2. The description of the experimental treatment is not comprehensive enough.
3. It is recommended to state the specific researchobjectives more clearly in the abstract. Please revise.
4. The conclusion could more explicitlypoint out the practical implications of the study for grassland management and cultivar selection.
5. Line 26-29, you should add key management measures for the two-year trial and clearly state that this study is conducted without nitrogen fertilizer.
6. Line 27, it is recommended to clarify the full name of 'ADM 'when it first appeared ( Aerial Dry Matter ) and keep the full term consistent.
7. Line 28, a two-year field study ( 2016-2018 ), this expression is easy to misunderstand, please change the expression.
8. Lines 30-31 : ' Mediterranean ' and ' Continental ', as ecotypes, should be capitalized, but there is a case mix ( e.g., line 235 ' mediterranean ' ).
9. Line 31, delete “,”；
10. In the research background, it is mentioned that ' mixed grassland can improve the stability of forage productivity ', but the innovation points or knowledge gaps of this study are not clearly explained, and it is recommended to supplement.
11. Line 33-35: It was mentioned that ' alfalfa monoculture and mixed with Mediterranean tall fescue have the highest yield ', but no specific data support was given.
12. It was not mentioned whether the influence of the change of mixed sowing ratio on the results was considered.
13. Line 35, “its”should read “their”.
14. It is recommended to slightly quantify ' higher RUE ' in the results section, for example, ' especially in late winter, RUE significantly increases X% ' to enhance the accuracy of the results.
15. Abbreviations need to give a full name when they first appear in the full text. Please check the full text abbreviation usage specification.
16. Key experimental conditions are missing: the absence of nitrogen fertilization is not mentioned, which makes it impossible to explain the important background of the low productivity of tall fescue monocultures, and the rigor of the conclusions is insufficient.

Title

Keywords

17. Please check the requirements of the journal you intend to submit to; it is usually recommended that the first letter of each keyword be capitalized.
18. It is recommended to adjust the order of keywords according to the logic of "research object- research process-research type".

Introduction

19. Line 45, “[1,2,3,4,5]”should be changed “[1-5]”.
20. No reasonable hypotheses were proposed.
21. Line 80-95, The logic of the writing is somewhat confusing, and the content needs to be organized.
22. In line 92, the reference [18,19,20] should be changed to [18-20].
23. The practical value of the study's findings for local grassland production has not been explained in the last paragraph; it is recommended to supplement this content.
24. The agricultural system and climatic characteristics of the Pampas region could be briefly expanded upon to help readers understand the research background.
25. Some research hypotheses could be added at the end of the introduction. Please revise.
26. It is suggested to more clearly identify the research gaps in the introduction and highlight the innovation of this study.
27. It is suggested that the research blank or scientific problem should be clearly put forward at the beginning of the introduction, which is slightly broad at present.
28. The Monteith model is mentioned, but it is not explained why it applies to mixed seeding systems.
29. The tropical mixed sowing system is mentioned, but how is it comparable to the temperate system?
30. The agricultural production background of the Pampas region is mentioned, but it is not stated why the region was chosen.
31. The article did not explain why alfalfa was selected as the mixed seeding object.
32. No clear hypothesis was put forward in the research objectives.
33. The timeliness of the cited literatures is slightly weak, and the citation of relevant studies on radiation use efficiency of alfalfa-grass mixed sowing systems in the past 5 years is insufficient, which makes it difficult to reflect the latest research progress in this field and better highlight the innovation of this study.
34. It is recommended to streamline the general description of the advantages of mixed planting and more quickly focus on the research gap regarding the variable “ecotype”in mixed planting studies.
35. It is suggested that after the goal, the core scientific hypothesis of this paper should be clearly put forward, which will make the research orientation clearer.
36. Line 99-104 gives a summary of the main conclusions in advance, which is allowed in some journals. However, considering that this is a peer-reviewed version, it is recommended to move this part to the beginning of the discussion section or rewrite it as a short ' preview ' to avoid giving a conclusion when the reader has not yet seen the results of the method.
37. The research background is poorly integrated with regional production practices, resulting in an inadequate demonstration of the study’s practical application value.
38. No clear research hypothesis is proposed, and only the research objective is stated, leading to an incomplete research logic.
39. This sentence “In summary, our results indicate that differences”appears improperly at the end of the introduction, should be moved to the conclusion or deleted.

Materials and Methods

40. The proportion of seeds sown in a mixed manner has not been specified.
41. The names and versions of the software used for data visualization must be clearly stated.
42. The seeding ratio of the mixed treatments in Section 2.2 has not been clearly specified; it is recommended to supplement this detail.
43. The monitoring dates have not been clearly specified in Section 2.3.2; it is recommended to supplement this information.
44. It is recommended to supplement detailed information on the soil type, climatic conditions, and planting density of the experimental site.
45. A schematic diagram of the experimental design could be included to aid reader comprehension.
46. The experimental design description is slightly lengthy. It is recommended to present the processing combination in the form of a table to improve readability.
47. Line 109-110, two years of data are not representative for perennial forage. It is recommended to discuss in the text the possible impact of interannual climate variability on the data.
48. Line 119, please ensure consistent spacing between numbers and units/symbols.
49. Line 152-162,The separation method and quantification standard of weeds and senescent tissues in the experiment are not specified, and the weed control measures under different treatments are also not mentioned, which may interfere with the determination results of aerial dry matter (ADM), lacking the explanation of experimental error control.
50. Line 155, It is recommended to explain the calculation base temperature and cumulative starting point of ' degree days '.
51. The experimental design (e.g., randomized block, number of replicates) was not explained.
52. It was recommended to add seeding rate, row spacing, seeding method and fertilization management (especially nitrogen fertilizer) and irrigation water management.
53. It is recommended to add a formula to express more clearly.
54. In the mixed sowing plot, how to accurately separate the biomass of alfalfa and tall fescue, whether by manual sorting or other methods, needs to be described in detail.
55. Statistical analysis software and model selection were not described.
56. Line 164-178,The description of the calculation process for accumulated intercepted photosynthetically active radiation (APAR) is overly complex and would be more straightforward if replaced with a calculation formula. Additionally, the specific method for linear interpolation of the daily fraction of intercepted photosynthetically active radiation (fPARi) and the corresponding error control measures are not specified, which is likely to arouse readers' doubts about the reliability of the calculation results.
57. Line 167, BAR-RAD, not “BAR-RAD”.
58. In line 174, ' fPARi ' is currently used directly and is not described when it first appears ( it should be defined in lines 165-168 ).
59. Line 175, The formula ' RUE was calculated as... ' should be listed separately and the unit should be explained.
60. The experimental design part lacks key information. Please supplement the soil type, basic fertility (such as organic matter, N, P, K content) and whether fertilization is applied before sowing. This is crucial to explain the low yield of tall fescue monoculture (due to lack of nitrogen fertilizer).
61. The specific variety names of the tested materials should be clearly stated.
62. Please specify the specific cutting threshold (e.g., when alfalfa height reaches X cm or X accumulated temperature) and stubble height. This is crucial for understanding why alfalfa is dominant in mixed sowing.
63. The measurement method of radiation interception (fPAR) needs to be described in more detail. For example, what type of linear optical quantum sensor is used? What time of day does the measurement take place? How many points are measured in each cell? How are measurements taken above and below the canopy?
64. It is recommended to explain the rationale for adopting an establishment coefficient of 0.6 and supplement supporting literature or empirical data.
65. The mixing ratio is not stated, and it is recommended to supplement whether it is 1:1.

Results

66. The units of ADM in Figure 1 are inconsistent with those stated in the figure caption.
67. Figure 1 does not recommend the use of stacked bar charts.
68. Line 197, “Efficiency”not “Effieciency”.
69. The data analysis was too simplistic and failed to uncover the underlying relationships.
70. The abbreviations such as "AA-TFC" and "AA-TFM" in the figures have not been clearly corresponding to their treatment names in the legends; it is recommended to supplement these annotations.
71. The second Figure 3 in the text should actually be Figure 4; the numbering needs to be corrected.
72. The results section should focus on describing the data and avoid prematurely introducing discussion content.
73. Line 206,' 82 % lower yield ' suggests giving absolute values at the same time, so that readers can understand the actual difference..
74. All fonts in Figure 1 should use new Roman fonts.
75. Line 212-218,The ordinate of Figure 1 is labeled with the unit of kg DM ha⁻¹, while the unit in the chart title is marked as g DM m⁻²without unit unification, which is likely to lead to misinterpretation of the data by readers. In addition, the "Other" component in the figure is not clearly explained, resulting in incomplete content labeling.
76. Line 214, “(ADM; g DM m^-2)”should be changed “(ADM; g m^-2)”.
77. Line 216, “its”should read “their”.
78. Line 219-221, the visual description of the chart trends is too fragmented.
79. Line 225, “compensate”should read “compensated”
80. In the correct order, the last two figures 3, 4 should be changed to figure 4, 5.
81. In Figure 4, a, b, h are not marked with significant letters, please change
82. 1 No error bar.
83. Some graphs in Figure 4 are not marked significant.
84. There are two figures in the article 3, is this a picture ?
85. When describing the significant interaction of ' treatment × growth period ', the statistics of the interaction effect (F value, P value) should be reported first, and then multiple comparisons should be made in different periods to avoid losing the overall sense by only listing the results of individual comparisons in each period.
86. Line 237, The definition of ' saturation ' should be explained for fPAR reached saturation ' ( e.g.fPAR > 0.95 ).
87. Line 246,the correlation curve between fPARi and accumulated temperature in Figure 3 is not marked with the coefficient of determination (R²) of the fitting model, which cannot directly reflect the fitting effect of the model. Nor is the quantitative analysis of the differences in fPARi saturation values under different treatments conducted, only described in words, resulting in insufficient depth of result analysis.
88. Line 263-269,the seasonal APARs results figure is incorrectly marked as Figure 3, which causes duplicate numbering with the fPARi figure (originally Figure 3).
89. Figure 1 (page 6) clearly shows the difference in total biomass. It is suggested that in the result text, in addition to indicating the percentage difference, it is also clear that there is no significant difference between AA and AA-TFm treatments, but both are significantly higher than AA-TFc treatment, which is one of the core findings.
90. It is suggested that the model fitting parameters and statistical comparison of each treatment should be given in the result part or supplementary material.
91. Please correct the figure and note number.
92. The connection between the data and ecotypic characteristics is lacking; the experimental results are not correlated with the phenological and morphological differences of tall fescue, resulting in a superficial interpretation of the findings.
93. In Figure 1, the horizontal axis summarizes whether it is more appropriate to use planting patterns.
94. It is recommended to adjust the distance between ( a ) and ( b ) in Figure 2 and Monocultures and Mixtures, where the distance is too large, please adjust.
95. Figure 3 appears twice, it is recommended to check the picture number.
96. The title of Figure 3 is ' fPARi along eight regrowth periods ', but the note also says ' Values are the average of five replicates ', and different symbols represent different treatments, but there is no clear illustration.
97. In Figure 4, a,b and h lack significance and are recommended to be supplemented.
98. The title of Figure 4 ( APARs ) is incorrectly numbered, and the text is called ' Figure 4 ', but the picture is marked as ' Figure 3 ' ( confused with the previous fPARi diagram ).
99. Figure 5 ( Seasonal RUEs ) also has a numbering error, the image is marked as ' Figure 4 ', but the text should be cited as Figure 5.

Discussion

100. The discussion was not thorough enough and lacked logical coherence.
101. The references provided are too few and the content is too thin.
102. The reasons for the similarities and differences between the findings of this study and those of relevant studies have not been clarified; it is recommended to supplement this analysis.
103. Annual differences and their underlying causes have not been analyzed; it is recommended to supplement this part of the content.
104. More recent relevant studies could be cited to broaden and deepen the discussion.
105. Future research directions could be pointed out in the discussion, such as suggesting studies on ecotype performance under different nitrogen levels or exploring other grass-legume combinations.
106. The discussion should avoid simply repeating the results, focusing instead on explanation and interpretation. Please revise.
107. Line 312, The ' frequent defoliation restricts LAI expansion ' can further explain why this is beneficial to alfalfa.
108. The discussion mentioned that nitrogen may affect the growth of tall fescue through alfalfa transfer (lines 323-324). This is an important point, but the discussion is shallow.
109. Line 325, 'RUE partially compensated for lower interception ' should indicate the degree of compensation ( such as percentage ).
110. Line 330-332, The citation format is incorrect.
111. Line 342-344, 'Mediterranean ecotype did not fully express its expected advantage ' should explain possible reasons ( such as alfalfa dominance ).
112. When discussing the high yield of alfalfa monoculture, we should combine the specific data measured in this study (such as the measured extinction coefficient k value and leaf inclination angle) to demonstrate its canopy structure advantage, rather than just citing previous literature.
113. In view of the phenomenon that the Mediterranean RUE did not fully show the expected advantage in late winter, more specific mechanism speculation should be put forward.
114. Specific research directions should be put forward when looking forward to future research.
115. There is an imbalance in the combination of old and new references. Most studies on the compensation effect of radiation use efficiency cite literatures before 2000, and the latest research progress in this field in the past 10 years is not integrated into the discussion, resulting in insufficient timeliness and cutting-edge nature of the conclusions.
116. The discussion section lacks an in-depth discussion of the corresponding mechanisms.
117. Due to having only two years of data, when discussing “over-yielding”, the possible limitations must be acknowledged.
118. It is recommended to further discuss why high-frequency mowing will 'favorable radiation interception alfalfa over tall fescue '? Is it because the regeneration of alfalfa is fast, or its canopy structure (pianophile) can restore light interception faster after mowing? This can be discussed in conjunction with the dynamic data of leaf area index (LAI) (if not shown in this article, it can be mentioned).
119. Comparisons with previous studies only address the similarities and differences in results without analyzing the causes of such discrepancies, leading to poor research relevance and systematicity.
120. In the discussion, it is suggested that the distance between paragraphs and paragraphs is too large to adjust.

Conclusions

121. Line 350, Missing spaces.
122. The conclusion is somewhat rough and fails to provide a comprehensive summary of the entire text.
123. The breakthroughs of this study have not been clearly defined in the conclusions; it is recommended to supplement the core innovations.
124. The limitations of the study have not been specified; it is recommended to supplement the relevant content.
125. The application potential of the Mediterranean ecotype in grassland management could be more clearly stated.
126. The conclusion could reiterate that this study is the first to reveal the regulatory mechanism of tall fescue ecotypes on radiation use, emphasizing the innovative aspects of the research.
127. The conclusion should not appear new information that has not been fully discussed above, such as the difference in nitrogen competition between ecotypes.
128. The limitations of the study are not explained, and the conclusions can briefly mention the shortcomings of the study.
129. The suggestions for future research directions are too general. Only "screening excellent Mediterranean cultivars and optimizing management practices" are mentioned, and the specific research contents are not specified.
130. The promotion cost and economic benefits of the alfalfa-Mediterranean tall fescue mixed sowing system in actual agricultural production are not analyzed,and there is a lack of economic feasibility demonstration, which is not conducive to the technological transformation and field application of research results.
131. The expression is overly general, failing to refine the core research findings, highlight the innovative points, and include a conclusive summary of the key experimental data.
132. Suggestions for future research are vague; only "screening varieties and optimizing management" are mentioned, without specifying concrete research directions.
133. The specific application value of the research conclusions for temperate forage mixed sward systems is not clarified, and the integration with actual production practices is inadequate.

Abbreviations

References

134. Reference 4, The authors use ";" to separate each other
135. Reference 6, 10, 21, 29, 33, all of these are incorrect.
136. Reference 14, The year does not need to be enclosed in parentheses.
137. Reference 14, please keep consistent with other formats, such as year font thickening, please modify.
138. Reference 14 The author list uses the “&” symbol, which is inconsistent with other reference formats and is recommended to be unified.
139. It is recommended that the reference font be the same. Please modify it.
140. Line 388, “N2O emissions”should be modified “N₂O emissions”.
141. The 10th reference year appears twice, please check and modify it.
142. The year of publication of the 14th reference is not in the right place.
143. The formatting of some literatures is non-standard, such as the journal names of some foreign literatures are not in italics, the annotation positions of volume and issue numbers are not unified, and some literatures lack key information such as place of publication and publisher, which is not in line with the formatting specifications of references for academic papers.
144. It is recommended that authors check whether the format of all references meets journal requirements (e.g., whether journal names should be abbreviated).
145. Formatting is inconsistent, with discrepancies in author name abbreviations, journal title annotations and the placement of publication years.
146. The journal name is recommended to be unified as a full name or standard abbreviation.

 

Author Response

Review 3

Abstract

Comments 1:

Lack of core quantitative data support；

Response 1: We included data support for key findings.

Line 31-32: ADM was higher in alfalfa monoculture and its mixture with the Mediterranean than the mixture with the Continental ecotype (+20%; 3225 kg ha^-1).

Line 32:34: Alfalfa monoculture exhibited the highest radiation interception whereas the mixture with the Mediterranean ecotype fully compensated interception reduction with RUE increase (≈10%)

 

Comments 2:

The description of the experimental treatment is not comprehensive enough.

Response 2: We expanded the description of the experimental treatments.

Line 28-30: We evaluated from March 2017 to May 2018 in the Pampas (Argentina) monocultures of alfalfa and tall fescue Mediterranean and Continental ecotypes, and their mixtures with a sowing ratio 1:1 under frequent defoliation without fertilization.

 

Comments 3:

It is recommended to state the specific research objectives more clearly in the abstract. Please revise.

Response 3: We have revised the abstract to state the specific research objectives more clearly and explicitly.

Line 24-27: The aim of this study was to evaluate the aerial dry matter (ADM) production and radiation model components of alfalfa-tall fescue mixtures, with particular emphasis on their implications for radiation interception and radiation use efficiency (RUE) at the canopy level.

 

Comments 4:

The conclusion could more explicitly point out the practical implications of the study for grassland management and cultivar selection.

Response 4: We pointed out.

Line 36-38: These findings highlight the potential of Mediterranean tall fescue ecotype and the importance of species/ecotype selection for grassland productivity.

 

Comments 5:

Line 26-29, you should add key management measures for the two-year trial and clearly state that this study is conducted without nitrogen fertilizer.

Response 5: We clearly stated.

Line 28-30 We evaluated from March 2017 to May 2018 in the Pampas (Argentina) monocultures of alfalfa and tall fescue Mediterranean and Continental ecotypes, and their mixtures with a sowing ratio 1:1 under frequent defoliation without fertilization.

 

Comments 6:

Line 27, it is recommended to clarify the full name of 'ADM 'when it first appeared ( Aerial Dry Matter ) and keep the full term consistent.

Response 6: Done. It was included in Line 25.

 

Comments 7:

Line 28, a two-year field study ( 2016-2018 ), this expression is easy to misunderstand, please change the expression.

Response 7: We changed the expression.

Line 28-30: We evaluated from March 2017 to May 2018 in the Pampas (Argentina) monocultures of alfalfa and tall fescue Mediterranean and Continental ecotypes, and their mixtures with a sowing ratio 1:1 under frequent defoliation without fertilization.

 

Comments 8:

Lines 30-31 : ' Mediterranean ' and ' Continental ', as ecotypes, should be capitalized, but there is a case mix ( e.g., line 235 ' mediterranean ' ).

Response 8: We corrected this mistake.

 

Comments 9:

Line 31, delete “,”；

Response 9: It was deleted.

 

Comments 10:

In the research background, it is mentioned that ' mixed grassland can improve the stability of forage productivity ', but the innovation points or knowledge gaps of this study are not clearly explained, and it is recommended to supplement.

Response 10: It was included.

Line 22-24: Ecotypic variation in tall fescue (Lolium arundinaceum (Schreb.) Darbysh.), with differences in phenology, may affect the performance of mixtures with alfalfa (Medicago sativa L.). However, the effects of ecotypic variation within mixtures remain largely unexplored.

 

Comments 11:

Line 33-35: It was mentioned that ' alfalfa monoculture and mixed with Mediterranean tall fescue have the highest yield ', but no specific data support was given.

Response 11: It was included.

Line 30-32: Aerial dry matter (ADM) was higher in alfalfa monoculture and mixture with the Mediterranean ecotype than the mixture with the Continental ecotype (+20%; 3225 kg ha^-1).

 

Comments 12:

It was not mentioned whether the influence of the change of mixed sowing ratio on the results was considered.

Response 12: We included the mixed sowing ratio used.

Line 28-30: We evaluated from March 2017 to May 2018 in the Pampas (Argentina) monocultures of alfalfa and tall fescue Mediterranean and Continental ecotypes, and their mixtures with a sowing ratio 1:1 under frequent defoliation without fertilization.

 

Comments 13:

Line 35, “its”should read “their”.

Response 13: We changed it.

 

Comments 14:

It is recommended to slightly quantify ' higher RUE ' in the results section, for example, ' especially in late winter, RUE significantly increases X% ' to enhance the accuracy of the results.

Response 14: We included it.

Line 32-34: Alfalfa monoculture exhibited the highest radiation interception, whereas the mixture with the Mediterranean ecotype compensated for reduced interception through increased RUE (≈10%).

 

Comments 15:

Abbreviations need to give a full name when they first appear in the full text. Please check the full text abbreviation usage specification.

Response 15: We revised it.

 

Comments 16:

Key experimental conditions are missing: the absence of nitrogen fertilization is not mentioned, which makes it impossible to explain the important background of the low productivity of tall fescue monocultures, and the rigor of the conclusions is insufficient.

Response 16: We included.

Line 28-30: We evaluated from March 2017 to May 2018 in the Pampas (Argentina) monocultures of alfalfa and tall fescue Mediterranean and Continental ecotypes, and their mixtures with a sowing ratio 1:1 under frequent defoliation without fertilization.

Title

Keywords

Comments 17:

Please check the requirements of the journal you intend to submit to; it is usually recommended that the first letter of each keyword be capitalized.

Response 17: We checked the requirements and published paper and keywords are not capitalized.

 

Comments 18:

It is recommended to adjust the order of keywords according to the logic of "research object- research process-research type".

Response 18: We adjusted the order according to the recommendation

Line 39-40: Keywords: grass-legume mixtures; temperate grasses; dry matter production; seasonality.

 

Introduction

Comments 19:

Line 45, “[1,2,3,4,5]”should be changed “[1-5]”.

Response 19: We changed it.

 

Comments 20:

No reasonable hypotheses were proposed.

Response 20: We included the hypothesis.

Line 100-102: The hypothesis was that the inclusion of tall fescue Mediterranean ecotype in the mixture with alfalfa increases aerial biomass production due to complementary growth cycles with increased fPAR_i and RUE during winter season.

 

Comments 21:

Line 80-95, The logic of the writing is somewhat confusing, and the content needs to be organized.

Response 21: We reorganized the content; the description of the Pampas region and the importance of the species/ecotypes was moved at the beginning of the introduction (Line 52-74), while the description of the radiation model components and the mechanisms associated was moved together with the radiation model description, as a separate paragraph (Line 75-96).

 

Comments 22:

In line 92, the reference [18,19,20] should be changed to [18-20].

Response 22: It was changed.

 

Comments 23:

The practical value of the study's findings for local grassland production has not been explained in the last paragraph; it is recommended to supplement this content.

Response 23: It was added.

Line 102-105: The practical value of the study's findings for the Pampas region grassland production is that we provide information to identify better adapted options of grass-legume mixtures that efficiently uses radiation to enhance forage production for grazing livestock systems.

 

Comments 24:

The agricultural system and climatic characteristics of the Pampas region could be briefly expanded upon to help readers understand the research background.

Response 24: We included it.

Line 52-54: The Pampas region (Argentina), characterized by a temperate climate and fertile soils, is highly important for livestock production, sustaining approximately 19 million head in Buenos Aires Province (SAGyP).

 

Comments 25:

Some research hypotheses could be added at the end of the introduction. Please revise.

Response 25: We included the hypothesis.

Line 100-102: The hypothesis was that the inclusion of tall fescue Mediterranean ecotype in the mixture with alfalfa increases aerial biomass production due to complementary growth cycles with increased fPAR_i and RUE during winter season.

 

Comments 26:

 

It is suggested to more clearly identify the research gaps in the introduction and highlight the innovation of this study.

Response 26: It was included.

Line 49-51: However, there exists a lack of information on the topic and it is essential to identify the most productive mixtures and the mechanisms that determine their performance.

Line 70-74: However, the potential effects of intraspecific variation, such as differences among ecotypes, remain largely unexplored. This knowledge gap is the focus of the present study, particularly regarding how these differences affect light interception and radiation use efficiency at the canopy level when tall fescue is grown in mixture with summer-growing legumes.

 

Comments 27:

It is suggested that the research blank or scientific problem should be clearly put forward at the beginning of the introduction, which is slightly broad at present.

Response 27: It was moved at the beginning of the introduction after the description of tall fescue ecotypes and better detailed.

Line 49-51: However, there exists a lack of information on the topic and it is essential to identify the most productive mixtures and the mechanisms that determine their performance.

Line 70-74: However, the potential effects of intraspecific variation, such as differences among ecotypes, remain largely unexplored. This knowledge gap is the focus of the present study, particularly regarding how these differences affect light interception and radiation use efficiency at the canopy level when tall fescue is grown in mixture with summer-growing legumes.

 

Comments 28:

The Monteith model is mentioned, but it is not explained why it applies to mixed seeding systems.

Response 28: We explained it.

Line 80-83: This approach can be applied to mixed seeding systems because the inclusion of different tall fescue ecotypes may modify radiation model components through different growth seasonal dynamics and different structural attributes.

 

Comments 29:

The tropical mixed sowing system is mentioned, but how is it comparable to the temperate system?

Response 29: We eliminated that comparison in order to avoid potential confusion and ensure a clear focus on the temperate system under study.

 

Comments 30:

The agricultural production background of the Pampas region is mentioned, but it is not stated why the region was chosen.

Response 30: We stated the importance of the region.

Line 52-54: The Pampas region (Argentina), characterized by a temperate climate and fertile soils, is highly important for livestock production, sustaining approximately 19 million head in Buenos Aires Province (SAGyP).

 

Comments 31:

The article did not explain why alfalfa was selected as the mixed seeding object.

Response 31: We included it.

Line 57-59: On one hand, alfalfa is the most widely used forage species in Argentina and particularly in Pampas region due to its high productivity, nutritive value and adaptation to wide range of environments [7].

 

Comments 32:

No clear hypothesis was put forward in the research objectives.

Response 32: We included the hypothesis.

Line 100-102: The hypothesis was that the inclusion of tall fescue Mediterranean ecotype in the mixture with alfalfa increases aerial biomass production due to complementary growth cycles with increased fPAR_i and RUE during winter season.

 

Comments 33:

The timeliness of the cited literatures is slightly weak, and the citation of relevant studies on radiation use efficiency of alfalfa-grass mixed sowing systems in the past 5 years is insufficient, which makes it difficult to reflect the latest research progress in this field and better highlight the innovation of this study.

Response 33: We modified the timeliness of cited literature and introduce newer studies to show the latest progress research.

Line 43-47: Mixtures of grasses and legumes are a common combination due to their advantages, such as complementarity in forage production [1] and stability [2], biological nitrogen fixation [3] and reduction of bloat risk [4].

Line 84-96: Previous studies have shown that interactions among species and management within a mixture can modify radiation model components. In a mixture of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.) under different nitrogen levels total biomass production was similar between treatments due to compensatory effects between fPAR_i and RUE [19]. Furthermore, total biomass in various species mixtures combination was not associated with changes in radiation model components but with asynchronous growth cycles among species [20]. Without N fertilization, mixtures of alfalfa and tall fescue increased productivity in comparison to tall fescue monocultures due to a higher RUE [21]. Conversely, when mixtures and tall fescue monocultures were fertilized with N the RUE and productivity equal those of the mixtures [21], or even increased [22]. These contrasting results indicate that the net effect of mixtures on aerial biomass production relative to monocultures is context dependent, with species phenology playing a key role in radiation-driven processes.

 

Comments 34:

It is recommended to streamline the general description of the advantages of mixed planting and more quickly focus on the research gap regarding the variable “ecotype” in mixed planting studies.

Response 34: We reordered the text according to the recommendation of the reviewer.

Line 43-74: In livestock grazing systems, perennial temperate pastures are a major component of the animal diet because they provide large quantities of high-quality forage at a relative low cost. Mixtures of grasses and legumes are a common combination due to their advantages, such as complementarity in forage production [1] and stability [2], biological nitrogen fixation [3] and reduction of bloat risk [4]. Together, these benefits make grass-legume mixtures a key component of sustainable forage-based livestock systems, but the success of mixtures largely depends on the combination of species and cultivars. However, there exists a lack of information on the topic and it is essential to identify the most productive mixtures and the mechanisms that determine their performance.

The Pampas region (Argentina), characterized by a temperate climate and fertile soils, is highly important for livestock production, sustaining approximately 19 million head in Buenos Aires Province (SAGyP). There is a consensus that mixtures of alfalfa (Medicago sativa L.) and grasses including tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) provide year-round production, reduces bloat risk, and improves forage quality [5,6]. On one hand, alfalfa is the most widely used forage species in Argentina and particularly in Pampas region due to its high productivity, nutritive value and adaptation to wide range of environments [7]. On the other hand, tall fescue is the most important perennial grass in this region. Unlike other temperate grasses, tall fescue exhibits a much broader ecological tolerance, including greater resistance to summer drought conditions [8-10]. This capacity to withstand a wider range of environmental stresses has contributed to its extensive use across diverse management systems.

The complementarity of grass-legume mixtures is influenced by both physiological and morphological traits [11]. Among the physiological traits, the growth cycle and its seasonal dynamics play a key role. In tall fescue, these traits vary between ecotypes: the Mediterranean ecotype grows more actively during winter, while the Continental ecotype exhibits higher growth during spring and summer [12,13]. Morphologically, the Mediterranean ecotype presents smaller plant size and a greater number of tillers compared to the Continental ecotype [14]. However, the potential effects of intraspecific variation, such as differences among ecotypes, remain largely unexplored. This knowledge gap is the focus of the present study, particularly regarding how these differences affect light interception and radiation use efficiency at the canopy level when tall fescue is grown in mixture with summer-growing legumes.

 

Comments 35:

It is suggested that after the goal, the core scientific hypothesis of this paper should be clearly put forward, which will make the research orientation clearer.

Response 35: We included the hypothesis.

Line 100-102: The hypothesis was that the inclusion of tall fescue Mediterranean ecotype in the mixture with alfalfa increases aerial biomass production due to complementary growth cycles with increased fPAR_i and RUE during winter season.

 

Comments 36:

Line 99-104 gives a summary of the main conclusions in advance, which is allowed in some journals. However, considering that this is a peer-reviewed version, it is recommended to move this part to the beginning of the discussion section or rewrite it as a short ' preview ' to avoid giving a conclusion when the reader has not yet seen the results of the method.

Response 36: It was eliminated from the introduction.

 

Comments 37:

The research background is poorly integrated with regional production practices, resulting in an inadequate demonstration of the study’s practical application value.

Response 37: We included.

Line 102-105: The practical value of the study's findings for the Pampas region grassland production is that we provide information to identify better adapted options of grass-legume mixtures that efficiently uses radiation to enhance forage production for grazing livestock systems.

 

Comments 38:

No clear research hypothesis is proposed, and only the research objective is stated, leading to an incomplete research logic.

Response 38: We included the hypothesis.

Line 100-102: The hypothesis was that the inclusion of tall fescue Mediterranean ecotype in the mixture with alfalfa increases aerial biomass production due to complementary growth cycles with increased fPAR_i and RUE during winter season.

 

Comments 39:

This sentence “In summary, our results indicate that differences” appears improperly at the end of the introduction, should be moved to the conclusion or deleted.

Response 39: It was deleted.

Materials and Methods

 

Comments 40:

The proportion of seeds sown in a mixed manner has not been specified.

Response 40: It was included.

Line 141-143: In mixtures, grasses and legumes were sown in alternating rows spaced 17.5 cm apart at a 1:1 mixing ratio.

 

Comments 41:

The names and versions of the software used for data visualization must be clearly stated.

Response 41: It was clearly stated.

Line 236-237: Data visualization and analysis were performed with R Core Team.

 

Comments 42:

The seeding ratio of the mixed treatments in Section 2.2 has not been clearly specified; it is recommended to supplement this detail.

Response 42: It was included.

Line 141-143: In mixtures, grasses and legumes were sown in alternating rows spaced 17.5 cm apart at a 1:1 mixing ratio.

 

Comments 43:

The monitoring dates have not been clearly specified in Section 2.3.2; it is recommended to supplement this information.

Response 43: It was added the information in the Table 2.

Line 184. Table 2. Cutting date and thermal time accumulation during the experimental period.

 

Comments 44:

It is recommended to supplement detailed information on the soil type, climatic conditions, and planting density of the experimental site.

Response 44: It was better detailed.

Line 108-124: The experiment was carried out from May 2016 to May 2018 at the INTA Experimental Station (Pergamino, Buenos Aires, Argentina). Ecologically, this region is part of the Rio de la Plata grasslands [23] one of the largest subhumid grassland regions in the world [24]. This vast ecological area is subdivided into five sub-regions [23], where the study site is located within the ecological sub-region denominated the Rolling Pampas. The area is dominated by Typic Argiudoll soils, as due to this soil type, most of this region has historically transitioned from native grassland to arable annual crops and sown pasture rotations [25], where the length of each land-use has changed over the decades [26]. This subregion has a temperate climate with a mean annual temperature of 16.6 °C. Average monthly temperatures range from 9.8 °C in July to 23.3 °C in January. Long-term (1967–2017) mean annual precipitation is 986 mm. The experimental site exceeded this average, reaching 1148 mm in 2016, 1115 mm in 2017 and 1100 mm in 2018. Global solar radiation was estimated from the hours of sunlight registered daily at the meteorological station of INTA and for the year 2017 ranged between a minimum of 7.7 MJ day^-1 in July and a maximum of 24 MJ day^-1 in January. The experimental site soil was a Typic Argiudoll (Pergamino series) with 2.9 % organic matter (Walkley–Black method), pH 6.0 (in water), and 24.7 ppm extractable phosphorus (Bray and Kurtz I).  

 

Line 138-148: All pastures were sown at a target density of 300 seedlings m⁻², using an establishment coefficient based on empirical data of 0.6 to account for potential losses that represent according to Equation 1 a density of 21.3, 13.4 and 8.9 kg ha^-1 for alfalfa and tall fescue Continental and Mediterranean ecotype, respectively. In mixtures, grasses and legumes were sown in alternating rows spaced 17.5 cm apart at a 1:1 mixing ratio. For treatments including both tall fescue ecotypes, their seeds were thoroughly mixed prior sowing to ensure co-occurrence within the same rows. This procedure was applied in both alfalfa-tall fescue pastures and tall fescue mixtures.

 

 (1)

 

 

Comments 45:

A schematic diagram of the experimental design could be included to aid reader comprehension.

Response 45: We have provided additional detail in the Materials and Methods section, as well as in Tables 1 and 2 to clarify the experimental design and improve reader comprehension.

 

Comments 46:

The experimental design description is slightly lengthy. It is recommended to present the processing combination in the form of a table to improve readability.

Response 46: We included Table 1 to improve readability and excluded the experimental design description from the text.

Line 159-166.

 

Comments 47:

Line 109-110, two years of data are not representative for perennial forage. It is recommended to discuss in the text the possible impact of interannual climate variability on the data.

Response 47: We included in the discussion.

Line 403-408: Precipitations during the experiment were favorable for growth, so species could express their productive potential. The impact of interannual climate variability on the data can modify relationships between species components of the mixtures. Thus, the results obtained may be extrapolated cautiously to normal or above normal precipitation conditions and so dataset was limited for an over-yielding analysis of perennial pastures.

 

Comments 48:

Line 119, please ensure consistent spacing between numbers and units/symbols.

Response 48: We included a space between 2.9 %.

 

Comments 49:

Line 152-162, The separation method and quantification standard of weeds and senescent tissues in the experiment are not specified, and the weed control measures under different treatments are also not mentioned, which may interfere with the determination results of aerial dry matter (ADM), lacking the explanation of experimental error control.

Response 49: We have revised lines 152-162 to clarify the separation and quantification methods, as well as weed control and experimental error management.

Line 179-182: In mixed canopies, samples were manually separated by component (alfalfa and tall fescue). Fresh weight was recorded, and subsamples were oven dried at 60 °C for 48 h to determine dry matter content. When present, weeds or senescent material were separated and quantified (consider in another component named others).

 

Comments 50:

Line 155, It is recommended to explain the calculation base temperature and cumulative starting point of ' degree days '.

Response 50: We included.

Line 170-172: Measurements began one year after sowing and included eight regrowth periods (March 2017–May 2018) (Table 2). During spring and summer, the cutting defoliation threshold was applied every 450 ± 50-degree days to avoid leaf senescence [27,28] considering a base temperature of 5° C.

 

Comments 51:

The experimental design (e.g., randomized block, number of replicates) was not explained.

Response 51: It is now explained.

Line 135-136: The experimental design was a randomized complete block design with five replicates to account for variability in slope gradient in the experimental site.

 

Comments 52:

It was recommended to add seeding rate, row spacing, seeding method and fertilization management (especially nitrogen fertilizer) and irrigation water management.

Response 52: We included it.

Line 149-157: Pastures were hand-sown in May 2016 without fertilization. The seedbed was prepared by disk plowing followed by tine harrowing to ensure a fine and uniform surface for sowing. After seeding pre-emergence herbicide Flumetsulam was applied at a dose of 0.5 l ha^-1 to control weeds during the establishment phase. A sprinkler irrigation system was used during the establishment phase to maintain adequate soil moisture, applying five irrigations totaling 55 mm between May and September 2016, and two additional irrigations (24 mm) in the first spring. Occasional irrigations were also applied in late spring and summer of the second year to prevent drought stress. No pests or diseases were detected during the experimental period.

 

Comments 53:

It is recommended to add a formula to express more clearly.

Response 53: We added it.

Line 147:

 (1)

 

Comments 54:

In the mixed sowing plot, how to accurately separate the biomass of alfalfa and tall fescue, whether by manual sorting or other methods, needs to be described in detail.

Response 54: We added it.

Line 179-182: In mixed canopies, samples were manually separated by component (alfalfa and tall fescue). Fresh weight was recorded, and subsamples were oven dried at 60 °C for 48 h to determine dry matter content. When present, weeds or senescent material were separated and quantified (consider in another component named others).

 

Comments 55:

Statistical analysis software and model selection were not described.

Response 55: We corrected this part of the manuscript, and now it was clearly stated.

Line 234-251: Non-linear two-phase models with a plateau were selected and fitted to fPAR_i versus degree-day accumulation according to usual radiation interception patterns to represent the timing of radiation interception saturation [31]. Data visualization and analysis were performed with R Core Team. Linear-plateau models were fitted individually for each of the treatments using segmented multiple linear regression. The mathematical model was:

 

 (5)

 

where α represents the intercept, β_1 the linear slope up to the breakpoint γ, and the maximum plateau defined as β_1×γ.

For each treatment, a grid search of 20 equidistant points within the degree days sum range (excluding 10% extremes) identified the optimal γ value that minimized the Akaike Information Criterion (AIC). Model fit was assessed using R², AIC, BIC, and RMSE [32]. Maximum plateaus (β₁×γ) and linear slope (β₁) were compared among treatments using 95% confidence intervals derived from sample variance. Treatments with overlapping intervals were deemed statistically equal [33].

 

Comments 56:

Line 164-178,The description of the calculation process for accumulated intercepted photosynthetically active radiation (APAR) is overly complex and would be more straightforward if replaced with a calculation formula. Additionally, the specific method for linear interpolation of the daily fraction of intercepted photosynthetically active radiation (fPARi) and the corresponding error control measures are not specified, which is likely to arouse readers' doubts about the reliability of the calculation results.

Response 56: We have revised it to improve clarity and overall wording.

Line 196-210: The fraction of intercepted PAR (fPAR_i) was calculated according to Eq. 2. Daily fPAR_i values were linearly interpolated between measurement dates according to Eq. 3. Accumulated intercepted PAR (APAR) for each regrowth period and total was obtained according to Eq. 4. Incident PAR was derived from global solar radiation recorded at the INTA EEA Pergamino weather station using a conversion factor of 0.45 [30]. Seasonal radiation use efficiency (RUE_s) was then calculated according to Eq. 5.

 

                                   (2)

 

where fPAR_i is the fraction of intercepted PAR and fPAR_t is the fraction of transmitted PAR,

 

                      (3)

 

where fPAR_i1 is the first measurement and fPAR_i2 is the second measurement and fPAR_ix represents the previous day of the day estimated,

 

 

Comments 57:

Line 167, BAR-RAD, not “BAR-RAD”.

Response 57: We included it.

Line 190-193: On clear days between 12:00 and 14:00 h, incident and transmitted photosynthetically active radiation (PAR) were measured using photon flux ceptometer BAR-RAD 50 (Cavadevices, Buenos Aires, Argentina) that uses a method that integrates the photon flux received in 50 cm.

 

Comments 58:

In line 174, ' fPARi ' is currently used directly and is not described when it first appears (it should be defined in lines 165-168 ).

Response 58: It is now defined the first time it appears.

Line 196.

 

Comments 59:

Line 175, The formula ' RUE was calculated as... ' should be listed separately and the unit should be explained.

Response 59: It was now included.

Line 214-220: where APAR_t (MJ m^-2) is total for all the experimental period and APAR_s is seasonal for each regrowth,

 

                                                      (5)

 

where RUE_g (g DM MJ^-1) is global for all the experimental period and RUE_s is seasonal for each regrowth.

 

Comments 60:

The experimental design part lacks key information. Please supplement the soil type, basic fertility (such as organic matter, N, P, K content) and whether fertilization is applied before sowing. This is crucial to explain the low yield of tall fescue monoculture (due to lack of nitrogen fertilizer).

Response 60: We have included the soil analysis results from the experimental site.

Line 122-124: The experimental site soil was a Typic Argiudoll (Pergamino series) with 2.9 % organic matter (Walkley–Black method), pH 6.0 (in water), and 24.7 ppm extractable phosphorus (Bray and Kurtz I). 

 

Comments 61:

The specific variety names of the tested materials should be clearly stated.

Response 61: It was included.

Line 127-135: The alfalfa (Medicago sativa L.) cultivar was ‘Barpal 9242’ (Barenbrug–Palaversich S.A., Pergamino, Argentina; fall dormancy 9). Seeds were coated and inoculated with Sinorhizobium meliloti (thousand-seed weight = 4 g; germination = 94%). Two tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) cultivars were used: ‘Palenque Plus INTA’ (Picasso S.A., Buenos Aires, Argentina; Continental ecotype; thousand-seed weight = 2.5 g; 93% germination) and ‘Flecha’ (Gentos S.A., Pergamino, Argentina; Mediterranean ecotype; thousand-seed weight = 1.5 g; 84% germination). Both tall fescue cultivars were uncoated. The cultivars are still currently available on the market as forage species have a slow cultivar turnover.

 

Comments 62:

Please specify the specific cutting threshold (e.g., when alfalfa height reaches X cm or X accumulated temperature) and stubble height. This is crucial for understanding why alfalfa is dominant in mixed sowing.

Response 62: It was included.

Line 170-179: During spring and summer, the cutting defoliation threshold was applied every 450 ± 50-degree days to avoid leaf senescence [27,28] considering a base temperature of 5° C. The phenology at harvest corresponded to pre-flowering to 10% flowering in alfalfa and three expanded leaves in tall fescue. In autumn, cuts were performed at higher degree days sum (above 700-degree days) to allow carbohydrate reserve replenishment, since excessive defoliation can reduce partitioning to below-ground organs and decrease photosynthetic capacity [29]. Aerial dry matter (ADM) production was determined at all harvests. Herbage was clipped manually from a 1 m² quadrat located at the plot center, cutting at 5 cm height. After sampling, all plots were uniformed to a 5 cm stubble height.

 

Comments 63:

The measurement method of radiation interception (fPAR) needs to be described in more detail. For example, what type of linear optical quantum sensor is used? What time of day does the measurement take place? How many points are measured in each cell? How are measurements taken above and below the canopy?

Response 63: It has been described in greater detail.

Line 189-195: Radiation interception was monitored periodically throughout the eight regrowth periods. On clear days between 12:00 and 14:00 h, incident and transmitted photosynthetically active radiation (PAR) were measured using photon flux ceptometer BAR-RAD 50 (Cavadevices, Buenos Aires, Argentina) that uses a method that integrates the photon flux received in 50 cm. Five readings per plot were taken at ground level below the canopy and one reading above the canopy, perpendicular and centered relative to sowing rows. The number of measurements within each regrowth period ranged from three to six, depending on its duration.

 

Comments 64:

It is recommended to explain the rationale for adopting an establishment coefficient of 0.6 and supplement supporting literature or empirical data.

Response 64: We included it.

Line 138-141: All pastures were sown at a target density of 300 seedlings m⁻², using an establishment coefficient based on empirical data of 0.6 to account for potential losses that represent according to Equation 1 a density of 21.3, 13.4 and 8.9 kg ha^-1 for alfalfa and tall fescue Continental and Mediterranean ecotype, respectively.  

 

Comments 65:

The mixing ratio is not stated, and it is recommended to supplement whether it is 1:1.

Response 65: It was now stated.

Line 141-143: In mixtures, grasses and legumes were sown in alternating rows spaced 17.5 cm apart at a 1:1 mixing ratio.

Results

 

Comments 66:

The units of ADM in Figure 1 are inconsistent with those stated in the figure caption.

Response 66: We corrected it.

 

Comments 67:

Figure 1 does not recommend the use of stacked bar charts.

Response 67: We changed it.

 

Comments 68:

Line 197, “Efficiency”not “Effieciency”.

Response 68: We corrected.

 

Comments 69:

The data analysis was too simplistic and failed to uncover the underlying relationships.

Response 69: We expanded the results of radiation model components.

Line 277-286: The alfalfa monoculture canopy captured the highest amount of radiation (Figure 2.a), this level of accumulation of APAR_t was significantly higher than in all other canopies including grasses. Mixtures of alfalfa with the presence of tall fescue Mediterranean ecotype (AA-TFm and AA-TFc-TFm) were significantly higher than the mixture of alfalfa with tall fescue Continental ecotype (AA-TFc). Tall fescue monocultures had significantly lower APAR_t.

The mixture of alfalfa and tall fescue Mediterranean ecotype had higher RUE_g than the alfalfa monoculture (Figure 2.b), whereas mixtures of alfalfa and tall fescue did not differ between them. Tall fescue monocultures had significant lower RUE_g, with the lowest RUE_g in tall fescue Mediterranean ecotype.

We expanded the analysis of fPARi

Line 297-320: The greatest APAR accumulation in the alfalfa monoculture was associated to its rapid attainment of high fPAR_i values (Figure 3). Furthermore, tall fescue ecotype strongly influenced canopy light interception in mixtures. Mixtures with tall fescue Mediterranean ecotype showed faster fPAR_i progression than those including the Continental ecotype. This was evidenced by the parameter beta of the fitted models, which represents the slope of the relationship between fPAR_i and degree day accumulation that was similar between alfalfa monoculture and the mixture of alfalfa and tall fescue Mediterranean ecotype (Table 3) and higher than the mixtures with the tall fescue Continental ecotype. Tall fescue monocultures and their mixture had the lowest beta parameter, representing a slow fPAR_i progression.

 

Table 3. Linear-plateau model’s parameters and fit developed for each treatment to represent fPAR_i progression to degree days (°) sum.

 

	Parameter		Model fit
Treatment	Beta	Plateau	AIC	R2	RMSE
AA	0.0034 a	0.9567 a	-78.25	0.67	0.174
TFc	0.0007 c	0.3826 b	-71.45	0.60	0.086
TFm	0.0008 c	0.4601 b	-59.85	0.62	0.099
AA-TFm	0.0025 ab	0.8848 a	-75.43	0.74	0.143
AA-TFc-TFm	0.0022 b	0.848 a	-70.82	0.76	0.134
AA-TFc	0.0021 b	0.7962 a	-70.1	0.75	0.129
TFc-TFm	0.0008 c	0.4307 b	-65.43	0.63	0.092

 

According to the fitted non-linear models, fPAR_i reached saturation (i.e. stabilization) similarly in alfalfa monoculture and mixtures of alfalfa and tall fescue, but significantly higher than tall fescue monoculture and the mixture of tall fescue ecotypes. Alfalfa monocultures reached critical interception (fPAR_i = 0.95), indicative of a fully closed canopy in three regrowth periods (late summer, autumn, and spring) (data not shown), while mixtures reached the saturation in a lower fPAR_i value according to tall fescue ecotype. The mixtures with Mediterranean ecotype were closest to alfalfa saturation value. Besides, the tall fescue monocultures and their mixtures never reached the critical threshold of 0.95, and the fPAR_i stabilization occurred after in the regrowth.

 

Comments 70:

The abbreviations such as "AA-TFC" and "AA-TFM" in the figures have not been clearly corresponding to their treatment names in the legends; it is recommended to supplement these annotations.

Response 70: We now include abbreviations in all figures legends.

 

Comments 71:

The second Figure 3 in the text should actually be Figure 4; the numbering needs to be corrected.

Response 71: We corrected it.

 

Comments 72:

The results section should focus on describing the data and avoid prematurely introducing discussion content.

Response 72: We deleted all introducing discussion content:

ADM differences among treatments were highly associated with APAR_t and in a less but significant proportion with RUE_g (Figure 2).

On this end, the similar level of aerial biomass between the alfalfa monoculture and its combination with the Mediterranean ecotype indicates that the mixture exhibited a higher RUE_g value (Figure 2.b) that compensated for the lower APAR_t. All the other canopy types lower forage productivity, were majorly the consequence of lower APAR_t.

 

Comments 73:

Line 206,' 82 % lower yield ' suggests giving absolute values at the same time, so that readers can understand the actual difference.

Response 73: We detailed it.

The combination of both tall fescue ecotypes and tall fescue monocultures showed ADM values approximately 75% lower than the maximum observed (-11705 kg ha^-1).

 

Comments 74:

All fonts in Figure 1 should use new Roman fonts.

Response 74: We changed it in all figures.

 

Comments 75:

Line 212-218, The ordinate of Figure 1 is labeled with the unit of kg DM ha⁻¹, while the unit in the chart title is marked as g DM m⁻²without unit unification, which is likely to lead to misinterpretation of the data by readers. In addition, the "Other" component in the figure is not clearly explained, resulting in incomplete content labeling.

Response 75: We corrected it.

Other component was also explained in materials and methods section.

Line 181-182: When present, weeds or senescent material were separated and quantified (consider in another component named others).

 

Comments 76:

Line 214, “(ADM; g DM m^-2)”should be changed “(ADM; g m^-2)”.

Response 76: It was changed.

 

Comments 77:

Line 216, “its”should read “their”.

Response 77: It was changed.

 

Comments 78:

Line 219-221, the visual description of the chart trends is too fragmented.

Response 78: It was better explained.

Line 277-286: The alfalfa monoculture canopy captured the highest amount of radiation (Figure 2.a), this level of accumulation of APAR_t was significantly higher than in all other canopies including grasses. Mixtures of alfalfa with the presence of tall fescue Mediterranean ecotype (AA-TFm and AA-TFc-TFm) were significantly higher than the mixture of alfalfa with tall fescue Continental ecotype (AA-TFc). Tall fescue monocultures had significantly lower APAR_t.

The mixture of alfalfa and tall fescue Mediterranean ecotype had higher RUE_g than the alfalfa monoculture (Figure 2.b), whereas mixtures of alfalfa and tall fescue did not differ between them. Tall fescue monocultures had significant lower RUE_g, with the lowest RUE_g in tall fescue Mediterranean ecotype.

 

Comments 79:

Line 225, “compensate”should read “compensated”

Response 79: It was changed.

 

Comments 80:

In the correct order, the last two figures 3, 4 should be changed to figure 4, 5.

Response 80: It was changed.

 

Comments 81:

In Figure 4, a, b, h are not marked with significant letters, please change

Response 81: They were now included.

 

Comments 82:

1 No error bar.

Response 82: It was included.

 

Comments 83:

Some graphs in Figure 4 are not marked significant.

Response 83: They were included.

 

Comments 84:

There are two figures in the article 3, is this a picture ?

Response 84: We changed the figure. It is now only one picture.

 

Comments 85:

When describing the significant interaction of ' treatment × growth period ', the statistics of the interaction effect (F value, P value) should be reported first, and then multiple comparisons should be made in different periods to avoid losing the overall sense by only listing the results of individual comparisons in each period.

Response 85: F value was included, it is reported first.

Line 340-341: A strong treatment × regrowth period interaction (F value = 2.72, p < 0.0001) indicated that APAR_s varied seasonally among canopies (Figure 4).

Line 372-373: A significant treatment × regrowth period interaction (F value = 10.36, p < 0.0001) confirmed temporal variability (Figure 5).

 

Comments 86:

Line 237, The definition of ' saturation ' should be explained for fPAR reached saturation ' ( e.g.fPAR > 0.95 ).

Response 86: It was better detailed.

Line 312-314: According to the fitted non-linear models, fPAR_i reached saturation (i.e. stabilization) similarly in alfalfa monoculture and mixtures of alfalfa and tall fescue, but significantly higher than tall fescue monoculture and the mixture of tall fescue ecotypes.

 

Comments 87:

Line 246, the correlation curve between fPARi and accumulated temperature in Figure 3 is not marked with the coefficient of determination (R²) of the fitting model, which cannot directly reflect the fitting effect of the model. Nor is the quantitative analysis of the differences in fPARi saturation values under different treatments conducted, only described in words, resulting in insufficient depth of result analysis.

Response 87: We developed a model presented in Table 3, including its parameters and the fit for each.

Line 308-311: Table 3. Linear-plateau model’s parameters and fit developed for each treatment to represent fPAR_i progression to degree days (° C) sum.

 

Comments 88:

Line 263-269, the seasonal APARs results figure is incorrectly marked as Figure 3, which causes duplicate numbering with the fPARi figure (originally Figure 3).

Response 88: We corrected it.

 

Comments 89:

Figure 1 (page 6) clearly shows the difference in total biomass. It is suggested that in the result text, in addition to indicating the percentage difference, it is also clear that there is no significant difference between AA and AA-TFm treatments, but both are significantly higher than AA-TFc treatment, which is one of the core findings.

Response 89: It was included.

Line 255-259: Total accumulated aerial dry matter (ADM) was highest in the alfalfa monoculture (AA) and in the mixture of alfalfa with the Mediterranean ecotype (AA-TFm) without significant difference between them, but both were significantly higher than the mixtures of alfalfa with the Continental ecotype (AA-TFc), and the mixture of both tall fescue ecotypes (TFc-TFm) (p < 0.0001; Figure 1).

 

Comments 90:

It is suggested that the model fitting parameters and statistical comparison of each treatment should be given in the result part or supplementary material.

Response 90: We developed a model presented in Table 3, including its parameters and the fit for each.

Line 308-311: Table 3. Linear-plateau model’s parameters and fit developed for each treatment to represent fPAR_i progression to degree days (° C) sum.

 

Comments 91:

Please correct the figure and note number.

Response 91: We corrected it.

 

Comments 92:

The connection between the data and ecotypic characteristics is lacking; the experimental results are not correlated with the phenological and morphological differences of tall fescue, resulting in a superficial interpretation of the findings.

Response 92: As we did not have phenological and morphological measurements we based on literature (Line 66-70).

 

Comments 93:

In Figure 1, the horizontal axis summarizes whether it is more appropriate to use planting patterns.

Response 93: We consider that treatments are more appropriate to reflect differences between mixtures and monocultures.

 

Comments 94:

It is recommended to adjust the distance between ( a ) and ( b ) in Figure 2 and Monocultures and Mixtures, where the distance is too large, please adjust.

Response 94: We used the distance provided in the template of the journal.

 

Comments 95:

Figure 3 appears twice, it is recommended to check the picture number.

Response 95: We corrected it.

 

Comments 96:

The title of Figure 3 is ' fPARi along eight regrowth periods ', but the note also says ' Values are the average of five replicates ', and different symbols represent different treatments, but there is no clear illustration.

Response 96: We included it.

Line 337-338: Values are the average of five replicates and different symbols represent different treatments.

 

Comments 97:

In Figure 4, a,b and h lack significance and are recommended to be supplemented.

Response 97: We added it.

 

Comments 98:

The title of Figure 4 ( APARs ) is incorrectly numbered, and the text is called ' Figure 4 ', but the picture is marked as ' Figure 3 ' ( confused with the previous fPARi diagram ).

Response 98: We corrected it.

 

Comments 99:

Figure 5 ( Seasonal RUEs ) also has a numbering error, the image is marked as ' Figure 4 ', but the text should be cited as Figure 5

Response 99: We corrected it.

Discussion

 

Comments 100:

The discussion was not thorough enough and lacked logical coherence.

Response 100: We have reorganized and expanded the Discussion to improve its depth and logical coherence.

We now improve the discussion about the importance of radiation interception. First, the mechanisms in alfalfa monoculture, second the mechanisms in the mixtures with alfalfa, and last the monocultures of tall fescue and their mixtures. Check Lines 394-438.

 

Comments 101:

The references provided are too few and the content is too thin.

Response 101: We provided more references.

19 references now and previously were 16.

 

Comments 102:

The reasons for the similarities and differences between the findings of this study and those of relevant studies have not been clarified; it is recommended to supplement this analysis.

Response 102: We supplemented the recommended analysis.

Line 444-455: This coincides with a recent study where N fertilized tall fescue Continental ecotype monoculture had the highest RUE, the mixture of alfalfa and tall fescue intermediate and alfalfa monoculture the lowest [22]. The authors interpret that decreasing RUE was due to a greater partition to belowground structures in alfalfa. In our work, mixtures with alfalfa involving the Mediterranean ecotype, as well as those including both ecotypes, effectively compensated for reduced APAR_t through increased RUE_g, resulting in comparable total ADM. In this sense, our results agree with previous reports on white clover and perennial ryegrass mixtures where a compensation between radiation model under different N fertilization treatments result in similar total ADM [19]. Under low N, white clover intercepted more radiation through vertical dominance in the canopy, whereas under high N level reduced the vertical dominance but increased EUR due to an increased photosynthetic efficiency of partially shaded clover leaves.

Line 460-465: Another work on diverse mixtures [20] did not find an association between total ADM production and radiative model components and the highest production of the mixtures were due to an increased asynchrony in growth cycles of the species. The cause of the divergence may be that species growth cycles were less overlapping that in our study due to species identity (i.e. red clover instead of alfalfa).

Line 471-476: Previous studies in the region [5] have shown growth cycle complementarity between Mediterranean tall fescue and alfalfa cultivars of intermediate dormancy (group 6), less winter-active than the cultivar used here (group 9). It is likely that the extended growth cycle of highly winter-active alfalfa restricted temporal complementarity between species under the temperate conditions of the Pampas region.

 

Comments 103:

Annual differences and their underlying causes have not been analyzed; it is recommended to supplement this part of the content.

Response 103: We included it.

Line 394-403: Total ADM production (Figure 1) indicated that alfalfa monoculture and its mixture with tall fescue Mediterranean ecotype achieved the highest productive potential. Regarding the alfalfa monoculture, its high ADM is consistent with its well-known yield potential on fertile soils [7,34]. Furthermore, our results indicate that maximum productivity was associated with greater radiation interception driven by alfalfa growth, both in monocultures and mixtures. Alfalfa forms a more planophilous canopy with a higher light extinction coefficient (k) [35] than tall fescue [36], and exhibits leaf angle variation within the canopy [37] and leaflet movement following solar position [38]. These canopy traits enhance radiation capture, as reflected in the steeper fPAR_i–degree-day slope and earlier canopy closure.

 

Comments 104:

More recent relevant studies could be cited to broaden and deepen the discussion.

Response 104: We add recent relevant studies to improve the discussion

Line 444-447: This coincides with a recent study where N fertilized tall fescue Continental ecotype monoculture had the highest RUE, the mixture of alfalfa and tall fescue intermediate and alfalfa monoculture the lowest [22]. The authors interpret that decreasing RUE was due to a greater partition to belowground structures in alfalfa.

 

Line 433-438: Furthermore, the maintenance or increase of tall fescue ADM in combination with alfalfa compared with their monocultures suggests a better nutritional status of tall fescue, possibly due to nitrogen transfer from alfalfa residues. Tall fescue plants mixed with alfalfa had a higher nutrition index and a different isotopic composition ¹⁵N in comparison with tall fescue plants growing alone confirming the contribution of the legume to the grass nutrition [43].            

 

Comments 105:

Future research directions could be pointed out in the discussion, such as suggesting studies on ecotype performance under different nitrogen levels or exploring other grass-legume combinations.

Response 105: We included it.

Line 476-480: Future research should clarify this limitation and explore management in addition genetic options to enhance the tall fescue contribution in mixtures as N fertilization in autumn-winter to promote grass outcompete the legume according to its greater response to N (42) and favored ADM trough and increase in both radiation model components.

 

Comments 106:

The discussion should avoid simply repeating the results, focusing instead on explanation and interpretation. Please revise.

Response 106: We introduce in each paragraph sentences to explain and interpret results.

Line 408-410: These results provide relevant information for the identification of highly productive mixtures that are comparable to alfalfa monoculture but also provide other benefit for the development of more sustainable livestock grazing systems.

Line 426-428: The identification of tall fescue Mediterranean ecotype with superior performance in the mixture suggests a potential for breeding this species/ecotype developing outstanding cultivars.

 

Comments 107:

Line 312, The ' frequent defoliation restricts LAI expansion ' can further explain why this is beneficial to alfalfa.

Response 107: We included it.

Line 419-426: The high cutting frequency used in our study, as defined by a low thermal time between harvests, probably favored radiation interception of alfalfa over tall fescue, as the latter’s erectophile leaves can maintain high LAI with limited self-shading [40], yet frequent defoliation restricts LAI expansion. Conversely, alfalfa canopy features previously described determine a rapid LAI recovery after cutting with a higher radiation interception than tall fescue. Nonetheless, such management is also recommended for tall fescue, promoting shorter, younger leaves and maintaining high forage quality [41].

 

Comments 108:

The discussion mentioned that nitrogen may affect the growth of tall fescue through alfalfa transfer (lines 323-324). This is an important point, but the discussion is shallow.

Response 108: We detailed better.

Line 429-438: Finally, tall fescue monocultures and the mixture of both ecotypes produced substantially lower ADM than alfalfa monoculture and the alfalfa-tall fescue mixtures. It should be emphasized that this experiment was conducted without nitrogen fertilization, which likely constrained tall fescue growth, a species with a well-documented response to N supply in the region [42]. Furthermore, the maintenance or increase of tall fescue ADM in combination with alfalfa compared with their monocultures suggests a better nutritional status of tall fescue, possibly due to nitrogen transfer from alfalfa residues. Tall fescue plants mixed with alfalfa had a higher nutrition index and a different isotopic composition ¹⁵N in comparison with tall fescue plants growing alone confirming the contribution of the legume to the grass nutrition [43].   

 

Comments 109:

Line 325, 'RUE partially compensated for lower interception ' should indicate the degree of compensation (such as percentage).

Response 109: We included it.

Line 441-444: Global radiation use efficiency (RUE_g) was higher in alfalfa-tall fescue Mediterranean mixtures and compensated for lower interception (Figure 2.b, ≈ 10%), particularly during late winter, when favorable temperature conditions enhanced seasonal radiation use efficiency (RUE_s) (Figure 5.d).

 

Comments 110:

Line 330-332, The citation format is incorrect.

Response 110: We corrected it.

 

Comments 111:

Line 342-344, 'Mediterranean ecotype did not fully express its expected advantage ' should explain possible reasons (such as alfalfa dominance).

Response 111: We included it.

Line 468-471: Under these conditions, the Mediterranean ecotype did not fully express its expected advantage in winter (i.e. higher fPAR_i), probably because alfalfa maintained canopy dominance, where alfalfa structural canopy characteristics would have outcompeted tall fescue.

 

Comments 112:

When discussing the high yield of alfalfa monoculture, we should combine the specific data measured in this study (such as the measured extinction coefficient k value and leaf inclination angle) to demonstrate its canopy structure advantage, rather than just citing previous literature.

Response 112: It would be interesting but we do not have measured those variables. We have therefore revised the Discussion to avoid any overinterpretation and to base our conclusions strictly on the data collected.

 

Comments 113:

In view of the phenomenon that the Mediterranean RUE did not fully show the expected advantage in late winter, more specific mechanism speculation should be put forward.

Response 113: We included it.

Line 468-471: Under these conditions, the Mediterranean ecotype did not fully express its expected advantage in winter (i.e. higher fPAR_i), probably because alfalfa maintained canopy dominance, where alfalfa structural canopy characteristics would have outcompeted tall fescue.

 

Comments 114:

Specific research directions should be put forward when looking forward to future research.

Response 114: We included it.

Line 476-480: Future research should clarify this limitation and explore management in addition genetic options to enhance the tall fescue contribution in mixtures as N fertilization in autumn-winter to promote grass outcompete the legume according to its greater response to N (42) and favored ADM trough and increase in both radiation model components.

 

Comments 115:

There is an imbalance in the combination of old and new references. Most studies on the compensation effect of radiation use efficiency cite literatures before 2000, and the latest research progress in this field in the past 10 years is not integrated into the discussion, resulting in insufficient timeliness and cutting-edge nature of the conclusions.

Response 115: We included recent references to improve the discussion.

 

Comments 116:

The discussion section lacks an in-depth discussion of the corresponding mechanisms.

Response 116: We add discussion of the corresponding mechanisms throughout the text.

 

Comments 117:

Due to having only two years of data, when discussing “over-yielding”, the possible limitations must be acknowledged.

Response 117: We included it.

Line 404-410: The impact of interannual climate variability on the data can modify relationships between species components of the mixtures. Thus, the results obtained may be extrapolated cautiously to normal or above normal precipitation conditions and so dataset was limited for an over-yielding analysis of perennial pastures. These results provide relevant information for the identification of highly productive mixtures that are comparable to alfalfa monoculture but also provide other benefit for the development of more sustainable livestock grazing systems.

 

Comments 118:

It is recommended to further discuss why high-frequency mowing will 'favorable radiation interception alfalfa over tall fescue '? Is it because the regeneration of alfalfa is fast, or its canopy structure (pianophile) can restore light interception faster after mowing? This can be discussed in conjunction with the dynamic data of leaf area index (LAI) (if not shown in this article, it can be mentioned).

Response 118: It was included.

Line 419-426: The high cutting frequency used in our study, as defined by a low thermal time between harvests, probably favored radiation interception of alfalfa over tall fescue, as the latter’s erectophile leaves can maintain high LAI with limited self-shading [40], yet frequent defoliation restricts LAI expansion. Conversely, alfalfa canopy features previously described determine a rapid LAI recovery after cutting with a higher radiation interception than tall fescue. Nonetheless, such management is also recommended for tall fescue, promoting shorter, younger leaves and maintaining high forage quality [41].

 

Comments 119:

Comparisons with previous studies only address the similarities and differences in results without analyzing the causes of such discrepancies, leading to poor research relevance and systematicity.

Response 119: We included the interpretation of the causes of such discrepancies.

Line 444-455: This coincides with a recent study where N fertilized tall fescue Continental ecotype monoculture had the highest RUE, the mixture of alfalfa and tall fescue intermediate and alfalfa monoculture the lowest [22]. The authors interpret that decreasing RUE was due to a greater partition to belowground structures in alfalfa. In our work, mixtures with alfalfa involving the Mediterranean ecotype, as well as those including both ecotypes, effectively compensated for reduced APAR_t through increased RUE_g, resulting in comparable total ADM. In this sense, our results agree with previous reports on white clover and perennial ryegrass mixtures where a compensation between radiation model under different N fertilization treatments result in similar total ADM [19]. Under low N, white clover intercepted more radiation through vertical dominance in the canopy, whereas under high N level reduced the vertical dominance but increased EUR due to an increased photosynthetic efficiency of partially shaded clover leaves.

Line 460-465: Another work on diverse mixtures [20] did not find an association between total ADM production and radiative model components and the highest production of the mixtures were due to an increased asynchrony in growth cycles of the species. The cause of the divergence may be that species growth cycles were less overlapping that in our study due to species identity (i.e. red clover instead of alfalfa).

Line 471-476: Previous studies in the region [5] have shown growth cycle complementarity between Mediterranean tall fescue and alfalfa cultivars of intermediate dormancy (group 6), less winter-active than the cultivar used here (group 9). It is likely that the extended growth cycle of highly winter-active alfalfa restricted temporal complementarity between species under the temperate conditions of the Pampas region.

 

Comments 120:

In the discussion, it is suggested that the distance between paragraphs and paragraphs is too large to adjust.

Response 120: We use the template of the journal.

Conclusions

Comments 121:

Line 350, Missing spaces.

Response 121: We corrected it.

 

Comments 122:

The conclusion is somewhat rough and fails to provide a comprehensive summary of the entire text.

Response 122: We intended to provide a comprehensive summary.

Line 494-497: In summary, our results demonstrate that ecotypic variation in tall fescue has a decisive influence on the performance of alfalfa-tall fescue mixtures, to a greater extent through morphological mechanisms (i.e. radiation interception) and to a lesser extent through physiological ones (i.e. radiation use efficiency).

Line 504-505: In conclusion, the selection of companion grasses according to their compatibility with alfalfa can enhance the canopy efficiency of the mixture.

 

Comments 123:

The breakthroughs of this study have not been clearly defined in the conclusions; it is recommended to supplement the core innovations.

Response 123: We included it.

Line 482-483: This study is the first to disentangle the effects of tall fescue ecotypes in the mixtures on radiation use.

Line 498-499: The identification of suitable species/ecotype for designing successful grass-legume mixtures represent an innovation to develop sustainable grassland production systems.

 

Comments 124:

The limitations of the study have not been specified; it is recommended to supplement the relevant content.

Response 124: We included.

Line 510-511: 3)- evaluate these canopies along different years to account for climate interannual variability.

 

Comments 125:

The application potential of the Mediterranean ecotype in grassland management could be more clearly stated.

Response 125: We included.

Line 500-503: The mixtures of alfalfa with Mediterranean tall fescue therefore represent a recommended productive option for temperate grassland that combine highest productivity with the well-known benefits of mixed swards. These findings highlight the potential of these associations that would require the dissemination across productive systems.

 

Comments 126:

The conclusion could reiterate that this study is the first to reveal the regulatory mechanism of tall fescue ecotypes on radiation use, emphasizing the innovative aspects of the research.

Response 126: We included it.

Line 482-483: This study is the first to disentangle the effects of tall fescue ecotypes in the mixtures on radiation use.

 

Comments 127:

The conclusion should not appear new information that has not been fully discussed above, such as the difference in nitrogen competition between ecotypes.

Response 127: We revised it.

 

Comments 128:

The limitations of the study are not explained, and the conclusions can briefly mention the shortcomings of the study.

Response 128: We included as future research areas.

Line 505-511: Future research should focus on three areas: 1)- identifying outstanding Mediterranean cultivars that express the ecotypic advantage in winter season with increased radiation interception besides high radiation use efficiency, 2)- refining management practices, such as defoliation regimes and nitrogen supply strategies that favored tall fescue growth during winter, to maximize these positive interactions, and 3)- evaluate these canopies along different years to account for climate interannual variability.

 

Comments 129:

The suggestions for future research directions are too general. Only "screening excellent Mediterranean cultivars and optimizing management practices" are mentioned, and the specific research contents are not specified.

Response 129: We expanded it.

Line 505-511: Future research should focus on three areas: 1)- identifying outstanding Mediterranean cultivars that express the ecotypic advantage in winter season with increased radiation interception besides high radiation use efficiency, 2)- refining management practices, such as defoliation regimes and nitrogen supply strategies that favored tall fescue growth during winter, to maximize these positive interactions, and 3)- evaluate these canopies along different years to account for climate interannual variability.

 

Comments 130:

The promotion cost and economic benefits of the alfalfa-Mediterranean tall fescue mixed sowing system in actual agricultural production are not analyzed, and there is a lack of economic feasibility demonstration, which is not conducive to the technological transformation and field application of research results.

Response 130: Although is very interesting the comment, the focus of our work was related to forage production and ecophysiology of temperate grasslands, in addition we do not have the academic knowledge for fulfill this requirement.

 

Comments 131:

The expression is overly general, failing to refine the core research findings, highlight the innovative points, and include a conclusive summary of the key experimental data.

Response 131: We included it.

Line 482-483: This study is the first to disentangle the effects of tall fescue ecotypes in the mixtures on radiation use.

Line 494-497: In summary, our results demonstrate that ecotypic variation in tall fescue has a decisive influence on the performance of alfalfa-tall fescue mixtures, to a greater extent through morphological mechanisms (i.e. radiation interception) and to a lesser extent through physiological ones (i.e. radiation use efficiency).

 

Line 498-499: The identification of suitable species/ecotype for designing successful grass-legume mixtures represent an innovation to develop sustainable grassland production systems.

 

Comments 132:

Suggestions for future research are vague; only "screening varieties and optimizing management" are mentioned, without specifying concrete research directions.

Response 132: We expanded it.

Line 505-511: Future research should focus on three areas: 1)- identifying outstanding Mediterranean cultivars that express the ecotypic advantage in winter season with increased radiation interception besides high radiation use efficiency, 2)- refining management practices, such as defoliation regimes and nitrogen supply strategies that favored tall fescue growth during winter, to maximize these positive interactions, and 3)- evaluate these canopies along different years to account for climate interannual variability.

 

Comments 133:

The specific application value of the research conclusions for temperate forage mixed sward systems is not clarified, and the integration with actual production practices is inadequate.

Response 133: We included it.

Line 498-503: The identification of suitable species/ecotype for designing successful grass-legume mixtures represent an innovation to develop sustainable grassland production systems. The mixtures of alfalfa with Mediterranean tall fescue therefore represent a recommended productive option for temperate grassland that combine highest productivity with the well-known benefits of mixed swards. These findings highlight the potential of these associations that would require the dissemination across productive systems.

 

Abbreviations

References

Comments 134:

Reference 4, The authors use ";" to separate each other

Response 134: We corrected it.

 

Comments 135:

Reference 6, 10, 21, 29, 33, all of these are incorrect.

Response 135: We corrected it.

 

Comments136:

Reference 14, The year does not need to be enclosed in parentheses.

Response 136: We corrected it.

 

Comments 137:

Reference 14, please keep consistent with other formats, such as year font thickening, please modify.

Response 137: We corrected it.

 

Comments 138:

Reference 14 The author list uses the “&” symbol, which is inconsistent with other reference formats and is recommended to be unified.

Response 138: We corrected it.

 

Comments 139:

It is recommended that the reference font be the same. Please modify it.

Response 139: We corrected it.

 

Comments 140:

Line 388, “N2O emissions”should be modified “N₂O emissions”.

Response 140: We corrected it.

 

Comments 141:

The 10th reference year appears twice, please check and modify it.

Response 141: We corrected it.

 

Comments 142:

The year of publication of the 14th reference is not in the right place.

Response 142: We corrected it.

 

Comments 143:

The formatting of some literatures is non-standard, such as the journal names of some foreign literatures are not in italics, the annotation positions of volume and issue numbers are not unified, and some literatures lack key information such as place of publication and publisher, which is not in line with the formatting specifications of references for academic papers.

Response 143: We corrected it.

 

Comments 144:

It is recommended that authors check whether the format of all references meets journal requirements (e.g., whether journal names should be abbreviated).

Response 144: We checked it.

 

Comments 145:

Formatting is inconsistent, with discrepancies in author name abbreviations, journal title annotations and the placement of publication years.

Response 145: We corrected it.

 

Comments 146:

The journal name is recommended to be unified as a full name or standard abbreviation.

Response 146: We corrected it.

 

 

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

First of all, I would like to express my gratitude for the opportunity to participate in the review of this manuscript.

The topic of the research is timely, as the production of high-quality feed is a prerequisite for successful animal husbandry.

The Abstract section adequately summarizes the results of the research and focuses on results that can be used in practice.

In the Introduction section, the authors present the significance and background of the topic in detail.

In the Materials and methods section, the definition and determination methods of the parameters studied are adequately documented.

Two questions arose in connection with this section:

Was it necessary to protect against diseases and pests, and if so, what pests occurred and what methods were used to protect against them?

How many times were radiation interception measurements taken during the development of one regrowth period? This is a very important question because the representativeness of the measured values depends on it.

In the Results section, the interpretation of the results is clear and logical, and the conclusions drawn are statistically verified.

The only comment I have on this section is that in subsection 3.3, Figure 3 would be correct instead of Figure 4, and in subsection 3.4. Figure 4 would be correct instead of Figure 5.

The Discussion section evaluates the results at an appropriate level and compares them critically with the work of other researchers.

The only error here is in subsection 4.2, where Figure 4 would be correct instead of Figure 5.

The language of the manuscript is logical and easy to follow, its findings are accurate and useful in practice.

Author Response

Comments 1:

Was it necessary to protect against diseases and pests, and if so, what pests occurred and what methods were used to protect against them?

Response 1: We included it.

Line 156-157: No pests or diseases were detected during the experimental period.

Comments 2:

How many times were radiation interception measurements taken during the development of one regrowth period? This is a very important question because the representativeness of the measured values depends on it.

Response 2: We included it.

Line 195-196: The number of measurements within each regrowth period ranged from three to six, depending on its duration.

Comments 3:

The only comment I have on this section is that in subsection 3.3, Figure 3 would be correct instead of Figure 4, and in subsection 3.4. Figure 4 would be correct instead of Figure 5.

Response 3: We corrected it.

Comments 4: The only error here is in subsection 4.2, where Figure 4 would be correct instead of Figure 5.

Response 4: We corrected it.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,
The suggested corrections and additions have been incorporated into the work. As a result, the work in its current form is methodologically sound and has gained a more scientific aspect.
The work can be accepted in its current form.

Kind regards,

Reviewer 2 Report

Comments and Suggestions for Authors

I have reviewed the revised manuscript titled “Influence of Tall Fescue Ecotype on Biomass Production, Radiation Interception, and Use Efficiency in Alfalfa-Based Pasture Mixtures” by Mattera et al. In this second revision, the authors provide a more detailed explanation of the data analysis. The manuscript is well written, concise, and can be recommended for acceptance.

Reviewer 3 Report

Comments and Suggestions for Authors

I have carefully reviewed the manuscript and recommend accept.