Responses of Soil Respiration to the Interactive Effects of Warming and Drought in Alfalfa Grassland on the Loess Plateau
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear,
The article analyzes the response of soil respiration to multiple factors, including warming, drought and their interaction, in the semi-arid grassland of the Loess Plateau in Northwest China.
To improve the quality of the article, I have the following suggestions:
1- The Chinese territory is very vast. A figure with the georeferenced location of the study area is extremely important.
2- The report on the method is interesting, but it would be crucial to include images of the 16 experimental plots that were assembled, for the reader to understand the dynamics of the experiment.
3- The article proposes an interesting analysis, however it does not demonstrate 1 single equation, which is necessary to analyze the robustness and safety of the measures.
4- Figure 1 shows the weather conditions only for the year of the experiment. It is very important to trace the climatology of the location (averages of more than 30 years) to assess whether we are not dealing with an atypical year, which could influence the conclusions of the results. It is very likely that there are meteorological stations from some national service in locations close to the experiment. In a complete absence of information, satellite data could be used.
5- In figure 2, it is extremely important to compare the LAI measured in situ with the satellite LAI (MODIS).
Author Response
Dear reviewer,
Thank you very much for your constructive comments and suggestions on our manuscript entitled “Responses of soil respiration to the interactive of warming and drought in alfalfa grassland on the Loess Plateau” (Agronomy-2692564).
We have revised the manuscript in accordance with the reviewers' comments. Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe paper “Responses of soil respiration to the interactive of warming and drought in alfalfa grassland on the Loess Plateau” written by Jiaxuan L and co-authors is dealing with a very important issue in functional ecology, the factors affecting soil respiration.
Soil respiration, is one of the largest carbon flux between the atmosphere and terrestrial ecosystems. In this respect, soil respiration, is an important regulator of the global carbon cycle and climate change. The study of how the increase of temperature and drought under climate change impact the soil carbon dynamic is crucial.
Rs is independently or synergistically regulated by several biotic and abiotic factors. The previous studies indicated that warming leads to increased, short term increase, no effect or negative effects on Rs in different grassland ecosystems. Similarly, drought can significantly inhibit Rs, but it can also stimulate Rs. The inconsistency of these responses might be caused by the interactions between biotic and abiotic factors.
The study area the Loess Plateau in China would be a perfect site to conduct this study (1.09–1.46 Pg C). Unfortunately, the Authors decided to perform an controlled experiment. The design and methods used in the experiment are very good. However, this paper need a separate chapter in discussion regarding the difference in the quality of obtained results between the experiment in a field under natural conditions and the controlled experiment.
Author Response
Dear reviewer,
Thank you very much for your constructive comments and suggestions on our manuscript entitled “Responses of soil respiration to the interactive of warming and drought in alfalfa grassland on the Loess Plateau” (Agronomy-2692564).
We have revised the manuscript in accordance with the reviewers' comments. Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsAbstract
The abstract has several shortcomings. First, it lacks specific data points and error margins, making it challenging to assess the statistical significance of the findings. Second, there is a lack of context regarding the global significance and implications of the study's results for addressing climate change. Furthermore, the summary does not provide essential methodological details about the experimental design, data collection methods, or data analysis procedures, which are crucial for scientific rigor and reproducibility. The absence of a discussion on potential limitations and uncertainties is a notable omission. The conclusions are somewhat generalized, without specific recommendations or policy implications. The method for simulating drought is mentioned but lacks details on its efficacy, which is a potential source of uncertainty. Visual representation of the data would enhance understanding. Finally, the study's duration is not clear, and it would be beneficial to discuss how this relates to the ecological processes being investigated.
Introduction
While the introduction provides context on the significance of global climate change and its potential impacts on the carbon cycle, it lacks a clear and specific research focus or objectives, leaving readers somewhat uncertain about the study's precise aims. Also this section introduces the relevance of soil respiration (Rs) and its response to climate change but doesn't provide a clear hypothesis or research questions, which are essential for guiding the study. It mentions the complexity of interactions between warming, drought, and other factors affecting Rs but doesn't outline the specific knowledge gaps or research contributions that the study aims to address. While the this section discusses the vulnerability of the Loess Plateau to climate change and the importance of studying Rs in this region, it could benefit from a more detailed explanation of why this particular area is of interest and how it relates to broader ecological and climate concerns.
MM section
There are several potential shortcomings in the described research methodology, based on the information provided:
Limited Generalizability: The study was conducted at a specific location with a unique set of environmental conditions (e.g., climate, soil type, and vegetation). This could limit the generalizability of the findings to broader contexts, as the results may not be applicable to different geographic areas.
Small Sample Size: The experiment employed only 16 experimental plots (4 treatments with 4 replicates each) with a relatively small plot area of 16 square meters. This limited sample size might not capture the full range of variability in the system, potentially affecting the robustness of the conclusions.
Short Study Period: The research period is not explicitly mentioned, but it appears that data collection was conducted over a limited time frame during the growing season. This short study period may not account for seasonal variations and long-term trends in soil respiration and other ecological processes.
Lack of Control for Confounding Variables: The study focuses on the effects of warming and drought on soil respiration, but it does not mention whether other variables that could confound the results (e.g., nutrient levels, vegetation type, or microbial communities) were controlled for or monitored. Failure to control for these factors can make it challenging to attribute observed changes solely to warming and drought.
Measurement Timing: The study mentions that soil respiration measurements were carried out between 9:00 and 11:00 a.m. This timing might not capture diurnal variations in soil respiration, as rates can fluctuate throughout the day.
Treatment Implementation: While the description of the warming and drought treatments is provided, the efficacy and uniformity of these treatments are not discussed. The effectiveness of the methods used to simulate warming and drought conditions is crucial for drawing accurate conclusions.
Data Analysis and Statistical Methods: While the analysis techniques are mentioned, specific details about the statistical tests, assumptions, and the reasoning behind choosing these methods are not provided. Transparent and appropriate data analysis is essential for the validity of the study.
Unclear Data Presentation: The study mentions several variables (e.g., Ts, VWC, LAI, and Rs) without presenting the results or the relationships between these variables. Clear data presentation is essential for understanding the research findings.
Lack of Discussion on Limitations: The materials and methods section does not include a discussion of the potential limitations of the study. Identifying and addressing these limitations is important for the interpretation of results and conclusions.
To address these shortcomings, it's important to carefully design the research methodology, consider potential limitations, and provide a clear and detailed account of the methods, data collection, and analysis procedures in the research paper.
Results
Result can be improved.
Discussion
The discussion section presents several noteworthy findings, such as the variation in soil respiration (Rs) throughout the growing season. It highlights the relatively high values of Rs in the study, potentially attributed to the high root density and aboveground biomass in the artificial grassland, but doesn't delve into the ecological implications of this variation. The impact of warming on Rs is explored, emphasizing the increase in Rs under warming conditions due to elevated aboveground biomass and the input of organic carbon. However, the lack of statistical significance in the results is mentioned but not thoroughly explained, leaving room for a more in-depth discussion of why the warming effect might not be as pronounced as expected. The effect of drought on Rs is addressed, with a focus on its reduction due to limited water availability, which aligns with previous research in semi-arid ecosystems. Still, a more comprehensive discussion could include potential feedback loops or secondary effects resulting from decreased Rs under drought conditions. The most notable aspect of the discussion is the interactive effect of warming and drought on Rs. This interaction leads to a decrease in Rs, emphasizing the importance of considering multiple climate change factors simultaneously. However, the section lacks a comprehensive exploration of the mechanisms behind this interaction and the broader implications for carbon cycling. The impact of environmental and biotic factors on Rs is discussed, particularly the role of temperature, soil water content, and aboveground biomass. While the relationships between these factors and Rs are highlighted, a more detailed analysis of their interplay and how they collectively influence soil respiration would enhance the discussion. Overall, the discussion section provides valuable insights into the study's findings, but it could benefit from a more extensive exploration of the ecological implications and mechanisms driving these effects, as well as addressing potential limitations and connections to existing research.
Conclusion
The conclusion effectively summarizes the key findings, emphasizing the contrasting effects of warming and drought on soil respiration, as well as their significant interactive impact. However, it lacks an in-depth exploration of the ecological implications and potential consequences of these effects, leaving a gap in understanding. Additionally, while the importance of various regulating factors like soil temperature, water content, and vegetation characteristics is acknowledged, the conclusion could benefit from suggesting specific recommendations for land management and restoration efforts in response to these findings. Finally, it mentions the need for future investigations but doesn't elaborate on the specific research questions or areas that should be prioritized, limiting the guidance for future studies.
I believe that due to these shortcomings, this manuscript is not suitable for publication.
Comments on the Quality of English LanguageMinor editing of English language required.
Author Response
Dear reviewer,
Thank you very much for your constructive comments and suggestions on our manuscript entitled “Responses of soil respiration to the interactive of warming and drought in alfalfa grassland on the Loess Plateau” (Agronomy-2692564).
We have revised the manuscript in accordance with the reviewers' comments. Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsAccept in present form.
Comments on the Quality of English LanguageAccept in present form.
