Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. In Figure 2, the mixing effect on mass loss is only greater in the Sp + Ns treatment than in the Ck treatment. What could be the possible reason for this?
2. There are still some points that need to be elaborated in the research methods section, such as: How many times did it rain during the experiment? What range did the rainfall fall within? After the leaves were retrieved, cleaning with a brush alone might not be able to completely remove the adhering substances on the leaves.
3. Please provide the calculation formulas for quality loss， nitrogen/carbon release ?
4. Where does the formula for calculating NAT come from? do the values of O and P in the formula represent? How is P predicted? What model is used for the prediction? What model was used for prediction?
5. The cellulose and lignin concentrations of the litter were measured by the acid-detergent fiber method [40]. What roles do these two indicators play in this paper?
6. In both single-species and multi-species experiments, there was no significant difference in mass loss between the CK and RP treatments (Figure 1), but there was a significant difference in mass loss between the CK and IP treatments. Both are treatments related to water changes, with the same amount of water change, why does the response of mass loss vary?

Author Response

In Figure 2, the mixing effect on mass loss is only greater in than in the Ck treatment. What could be the possible reason for this?

Response: In Figure 2, the mixing effect on mass loss for the Sp + Ns treatment was significant; It does not mean that it is significantly different from the CK, but that the antagonistic effect is significant.

There are still some points that need to be elaborated in the research methods section, such as: How many times did it rain during the experiment? What range did the rainfall fall within? After the leaves were retrieved, cleaning with a brush alone might not be able to completely remove the adhering substances on the leaves.

Response: the times and range of rainfall has been added in the section of precipitation design in Line 267-268.

The revised sentences as follows:

“During the entire experimental period, there were 15 precipitation events with a total precipitation of 79.2 mm.”

Please provide the calculation formulas for quality loss, nitrogen/carbon release?

Response: the calculation formulas have been provided in Line 290-295.

Where does the formula for calculating NAT come from? do the values of O and P in the formula represent? How is P predicted? What model is used for the prediction? What model was used for prediction?

Response: According to the description in the results section, the author has revised the NAT to RME in the methodology. The corresponding calculation formula and references have also been updated in Line 296-300 in the revised manuscript.

The cellulose and lignin concentrations of the litter were measured by the acid-detergent fiber method [40]. What roles do these two indicators play in this paper?

Response: it was deleted in the revised paper.

In both single-species and multi-species experiments, there was no significant difference in mass loss between the CK and RP treatments (Figure 1), but there was a significant difference in mass loss between the CK and IP treatments. Both are treatments related to water changes, with the same amount of water change, why does the response of mass loss vary?

Response: the reason has been added in the discussion of revised paper in line 158-168.

Reviewer 2 Report

Comments and Suggestions for Authors

General comments

This manuscript addresses a relevant question. The interaction between altered precipitation and litter-mixture decomposition in arid desert systems is worth studying, and the experiment has the potential to contribute useful evidence from a system that is less represented than forests or mesic grasslands in this literature. The paper is also not especially insular in its citation base. It draws on studies from different regions and ecosystem types, so the contextualization is acceptable even if not especially strong or conceptually ambitious.

The manuscript nevertheless has a serious weakness at the level of analysis, and this affects how much confidence one can place in the results. The main issue is the use of repeated-measures ANOVA in what appears to be a destructive litterbag design. As described, litterbags were harvested after 6 and 12 months, which means that the same observational units were not measured repeatedly across time. Time alone does not create a repeated-measures structure. A repeated-measures framework would only be appropriate if responses were followed on the same experimental units across time and analyzed accordingly. The manuscript does not demonstrate that such a structure was implemented. As written, this raises a strong concern that independent litterbags harvested at different dates may have been treated as repeated observations, which would affect the validity of the inference. This point needs to be clarified decisively, and if the present analysis is not appropriate, the data need to be reanalyzed.

That concern becomes more important because the manuscript also contains internal inconsistencies that reduce confidence in how carefully the paper was assembled. The experiment is described as lasting one year, with sampling after 6 and 12 months, yet Figure 2 is captioned as showing results “during 3 years of decomposition.” That looks like carryover text rather than a simple typo. The precipitation-design section also contains language about reduced-radiation plots and polyester filters that does not fit cleanly with the rest of the experimental description. When a manuscript already has a potentially serious analytical problem, these kinds of assembly inconsistencies matter because they make it harder to trust that the design, analysis, and presentation are fully aligned.

The paper is on firmer ground when it stays close to the observed patterns. Increased precipitation generally enhanced mass loss and nitrogen release, and the different litter mixtures did not respond in the same way. That is useful. The discussion becomes less convincing when it moves quickly into explanations involving microbial abundance, enzyme activity, moisture-mediated microclimate improvement, or substrate-driven interactions without directly measuring those processes in this experiment. Those interpretations are not implausible, but they remain interpretations. At present, the discussion often speaks with more mechanistic confidence than the data can sustain. The manuscript would improve if the authors separated more clearly what they observed from what they infer from the literature.

There is also some looseness in how the hypotheses, results, and conclusions are connected. The paper states two clear hypotheses, but important parts of those predictions were not supported. Increased precipitation did not shift antagonistic effects to synergistic ones for mass loss, and the expectation that three-species mixtures would more often show positive mixing effects was not clearly borne out either. That is not a problem in itself. Unsupported hypotheses are perfectly acceptable. The issue is that the manuscript still tries to maintain a stronger framing than the results justify. It would read better and more honestly if the interpretation were rebuilt around what was actually found rather than around what was initially expected.

Another important issue is that the manuscript appears to arise from a recent sequence of closely related studies by the same research group using the same desert experimental platform, including identical site conditions, overlapping experimental periods, and very similar plot and litterbag designs. While this can reflect a legitimate research program, it also raises the question of how this study is analytically and experimentally distinct from the authors’ recent publications addressing closely related decomposition processes under climate manipulations. The manuscript would benefit from a clear statement specifying what is genuinely new in terms of experimental design, dataset, and analytical contribution, and whether any text, figures, sampling periods, plots, or measurements overlap with previously published work. This clarification is necessary to ensure that the manuscript represents a distinct and independent contribution rather than a partial segmentation of a single experimental platform.

The English also remains well below publication standard. This is not just a matter of scattered errors. Problems of grammar, agreement, wording, and sentence construction occur throughout the manuscript, including the abstract, results, discussion, and methods. In too many places, the phrasing is awkward enough to slow reading or blur meaning. This will need a thorough revision.

Overall, I think the study may contain publishable data, but the manuscript in its current form is not reliable enough analytically or clear enough in presentation to support publication. The statistical issue is the central problem, and unless that is resolved convincingly, the rest of the interpretation remains on weak ground. I therefore recommend major revision.

Minor comments

L8–10: “The decomposition characteristics of mixed litters are different with the monospecific litters” needs rewriting.

L10: “how altered precipitation affect” should be “affects”.

L13–16: Subject–verb agreement in the abstract needs correction.

L41–54: The literature review is acceptable and not narrowly local, but the transition from the general decomposition literature to the specific ecological expectations for this desert shrub system could be sharper.

L72–86: The Results section contains repeated grammatical problems and several sentences need rewriting for clarity.

Figure 1 caption: “during 1 years of decomposition” should be corrected.

Figure 2 caption: “during 3 years of decomposition” appears inconsistent with the described experiment and must be corrected or explained.

L109–116 and L295–315: The statistical analysis needs clearer explanation, especially the experimental unit, replication structure, and justification for the repeated-measures approach.

L166–179: Statements about microbial activity and enzyme-related processes should be framed more cautiously unless directly measured.

L188–191: The sentence about phenolic compounds is difficult to follow and needs rewriting.

L203–205: “could not be unmatched by that on mass loss” is unclear.

L249–273: The precipitation-design section needs careful editing for clarity and internal consistency.

L312–314: The sentence describing the multi-way ANOVA is grammatically broken and should be rewritten entirely.

The reference list also contains formatting inconsistencies and needs editorial cleanup.

Comments on the Quality of English Language

The quality of English is below publication standard. Grammatical errors, awkward phrasing, and unclear sentence construction occur throughout the manuscript and often affect precision and readability. A thorough language revision is required.

Author Response

This manuscript addresses a relevant question. The interaction between altered precipitation and litter-mixture decomposition in arid desert systems is worth studying, and the experiment has the potential to contribute useful evidence from a system that is less represented than forests or mesic grasslands in this literature. The paper is also not especially insular in its citation base. It draws on studies from different regions and ecosystem types, so the contextualization is acceptable even if not especially strong or conceptually ambitious.

The manuscript nevertheless has a serious weakness at the level of analysis, and this affects how much confidence one can place in the results. The main issue is the use of repeated-measures ANOVA in what appears to be a destructive litterbag design. As described, litterbags were harvested after 6 and 12 months, which means that the same observational units were not measured repeatedly across time. Time alone does not create a repeated-measures structure. A repeated-measures framework would only be appropriate if responses were followed on the same experimental units across time and analyzed accordingly. The manuscript does not demonstrate that such a structure was implemented. As written, this raises a strong concern that independent litterbags harvested at different dates may have been treated as repeated observations, which would affect the validity of the inference. This point needs to be clarified decisively, and if the present analysis is not appropriate, the data need to be reanalyzed.

Response: Based on the comments from the reviewers, the authors have re-examined the analytical methods adopted in this study. Certain inappropriacies were identified in the original statistical approaches; accordingly, the relevant data were re-analyzed using a three-way analysis of variance (three-way ANOVA).

That concern becomes more important because the manuscript also contains internal inconsistencies that reduce confidence in how carefully the paper was assembled. The experiment is described as lasting one year, with sampling after 6 and 12 months, yet Figure 2 is captioned as showing results “during 3 years of decomposition.” That looks like carryover text rather than a simple typo. The precipitation-design section also contains language about reduced-radiation plots and polyester filters that does not fit cleanly with the rest of the experimental description. When a manuscript already has a potentially serious analytical problem, these kinds of assembly inconsistencies matter because they make it harder to trust that the design, analysis, and presentation are fully aligned.

Response: Due to the authors’ oversights, some irrelevant content was inadvertently included in the manuscript. All such errors have been revised in the updated manuscript

The paper is on firmer ground when it stays close to the observed patterns. Increased precipitation generally enhanced mass loss and nitrogen release, and the different litter mixtures did not respond in the same way. That is useful. The discussion becomes less convincing when it moves quickly into explanations involving microbial abundance, enzyme activity, moisture-mediated microclimate improvement, or substrate-driven interactions without directly measuring those processes in this experiment. Those interpretations are not implausible, but they remain interpretations. At present, the discussion often speaks with more mechanistic confidence than the data can sustain. The manuscript would improve if the authors separated more clearly what they observed from what they infer from the literature.

Response: Microbial diversity and related enzyme activities were measured in this study, but they were not presented in this paper; however, the relevant data can explain our results

There is also some looseness in how the hypotheses, results, and conclusions are connected. The paper states two clear hypotheses, but important parts of those predictions were not supported. Increased precipitation did not shift antagonistic effects to synergistic ones for mass loss, and the expectation that three-species mixtures would more often show positive mixing effects was not clearly borne out either. That is not a problem in itself. Unsupported hypotheses are perfectly acceptable. The issue is that the manuscript still tries to maintain a stronger framing than the results justify. It would read better and more honestly if the interpretation were rebuilt around what was actually found rather than around what was initially expected.

Response: According to the suggestions of the review experts, this part of the content has been revised in the discussion in line 192-206.

The revised sentences as follows:

“it just weakened the antagonistic effect, One primary reason is the short duration of the precipitation treatment, as increased precipitation may not significantly improve soil microorganism number and enzyme activity within 6 months of decomposition [29], which is consistent with findings in semi-arid shrublands where litter decomposition responses to precipitation change are often time-dependent and weak in short-term treatments [30]. Additionally, the persistence of antagonistic effects may be attributed to the chemical properties of the mixed litters[27,28], and previous studies have shown that drought or precipitation change-induced alterations in litter chemical traits can generate a "legacy effect" that sustains recalcitrant compound content during decomposition, thereby limiting the conversion of antagonistic effects to synergistic ones. Moreover, non-additive effects of litter mixing are jointly determined by litter chemical traits, climatic factors and decomposition stage [31]. Furthermore, meta-analyses have shown that synergistic effects of mixed litters are more likely to occur when soil fauna are present or litter quality is low, while antagonistic effects tend to persist when inhibitory secondary compounds (e.g., phenolic compounds) are abundant [32], which may further explain why increased precipitation failed to induce a shift to synergistic effects.”

Another important issue is that the manuscript appears to arise from a recent sequence of closely related studies by the same research group using the same desert experimental platform, including identical site conditions, overlapping experimental periods, and very similar plot and litterbag designs. While this can reflect a legitimate research program, it also raises the question of how this study is analytically and experimentally distinct from the authors’ recent publications addressing closely related decomposition processes under climate manipulations. The manuscript would benefit from a clear statement specifying what is genuinely new in terms of experimental design, dataset, and analytical contribution, and whether any text, figures, sampling periods, plots, or measurements overlap with previously published work. This clarification is necessary to ensure that the manuscript represents a distinct and independent contribution rather than a partial segmentation of a single experimental platform.

Response: The previously published studies from our research group on litter decomposition mainly focused on the effects of climate change on monospecific litter decomposition, and mixed litters were not involved. By contrast, the present study primarily investigates the differences in mixing effects and their divergent responses to precipitation during mixed litter decomposition. Therefore, this research is distinct from our prior studies in terms of experimental design, and the corresponding statistical analytical methods are also different.

The English also remains well below publication standard. This is not just a matter of scattered errors. Problems of grammar, agreement, wording, and sentence construction occur throughout the manuscript, including the abstract, results, discussion, and methods. In too many places, the phrasing is awkward enough to slow reading or blur meaning. This will need a thorough revision.

Overall, I think the study may contain publishable data, but the manuscript in its current form is not reliable enough analytically or clear enough in presentation to support publication. The statistical issue is the central problem, and unless that is resolved convincingly, the rest of the interpretation remains on weak ground. I therefore recommend major revision.

Minor comments

L8–10: “The decomposition characteristics of mixed litters are different with the monospecific litters” needs rewriting.

Response: this sentence has been revised in line 9-10.

The revised sentences as follows: “Mixed litters exhibit distinct decomposition characteristics compared with monospecific litters,”

L10: “how altered precipitation affect” should be “affects”.

Response: this sentence has been revised.

L13–16: Subject–verb agreement in the abstract needs correction.

Response: We have corrected all subject–verb agreement errors in the abstract.

L41–54: The literature review is acceptable and not narrowly local, but the transition from the general decomposition literature to the specific ecological expectations for this desert shrub system could be sharper.

Response: We have strengthened the logical transition from general litter decomposition theories to the specific ecological implications for desert shrub ecosystems in the revised manuscript.

L72–86: The Results section contains repeated grammatical problems and several sentences need rewriting for clarity.

Response: The results sections have been revised in the revised paper.

Figure 1 caption: “during 1 years of decomposition” should be corrected.

Response: this caption of figure 1 has been revised.

Figure 2 caption: “during 3 years of decomposition” appears inconsistent with the described experiment and must be corrected or explained.

Response: this caption has been revised.

 

L109–116 and L295–315: The statistical analysis needs clearer explanation, especially the experimental unit, replication structure, and justification for the repeated-measures approach.

Response: the experimental unit, replication structure have been revised in line 254-255, and another analysis method that is three-way ANOVA was use to analyze the data

L166–179: Statements about microbial activity and enzyme-related processes should be framed more cautiously unless directly measured.

Response: the microbial activity and enzyme-related processes were measured, but this was not presented in this paper.

L188–191: The sentence about phenolic compounds is difficult to follow and needs rewriting.

Response: this sentence has been revised.

 

L203–205: “could not be unmatched by that on mass loss” is unclear.

Response: this sentence has been revised in line 210-212.

L249–273: The precipitation-design section needs careful editing for clarity and internal consistency.

Response: this section has been edited.

 

L312–314: The sentence describing the multi-way ANOVA is grammatically broken and should be rewritten entirely.

Response: this sentence has been revised.

The reference list also contains formatting inconsistencies and needs editorial cleanup.

Response: the references have been revised.

Reviewer 3 Report

Comments and Suggestions for Authors

The aim of this study is to investigate the process of plant residue decomposition in relation to changes in precipitation, as this is essential for an accurate assessment of the organic matter balance in ecosystems. The experiment was conducted in the desert in northwest China. Three precipitation modes were simulated: natural precipitation (CK), as well as two variants with an increase and decrease in precipitation by 30% (IP) and a decrease in precipitation by 30% (RP). Fresh leaves of R. Soongorica (Rs), S. Passerine (Sp) and N. Sphaerocarpa (Ns) were collected in the desert in October 2022. Three pure litter (Rs, Sp and Ns) variants and four mixed-species litter variant (Rs+Sp, Rs+Ns, Sp+Ns, and Rs+Sp+Ns). 15 g of each litter (pure or mix) was placed into 10×10 cm litterbags (in total 252 bags). The duration of the experiment was 6 and 12 months. The dried samples were analyzed for the mass loss, the total organic C and the total N concentrations, the cellulose and lignin concentrations. Statistical Analysis of all results was conducted. At least some of the most important quantitative estimates obtained in the experiment should be given.

Abstract. An abstract should not be too abstract. Please add the most important quantitative characteristics you have gained in your experience.

Introduction, Materials and Methods are well written, clear and detailed.

2. Results and Analysis. It would be better to name this section as "Results".

Figure 1. The font size is too small, making it difficult to read the axis labels and numbers. I suggest starting the Y-axis at 20% instead 0. Probably, the drawing can be divided into two - according to the terms of 6 and 12 months.

Figures 2, 3 and 4 – the same notes. The font size is too small, making it difficult to read the axis labels and numbers.

The manuscript material is of scientific interest in general. But without a representation of the concentration of C, N, as well as the biochemical composition (cellulose and lignin content) of the initial plant residues and their compost, it is difficult for a specialist to accept only qualitative estimates.

The authors should provide the chemical characteristics of the studied litter and their compost to enhance the scientific significance of their manuscript.

It is also possible to advise the authors in their future experiments not only to simulate different water intake with irrigation, but also soil moisture (compost litter).

There are no conclusions in the manuscript. The conclusions must be completed.

Author Response

The aim of this study is to investigate the process of plant residue decomposition in relation to changes in precipitation, as this is essential for an accurate assessment of the organic matter balance in ecosystems. The experiment was conducted in the desert in northwest China. Three precipitation modes were simulated: natural precipitation (CK), as well as two variants with an increase and decrease in precipitation by 30% (IP) and a decrease in precipitation by 30% (RP). Fresh leaves of R. Soongorica (Rs), S. Passerine (Sp) and N. Sphaerocarpa (Ns) were collected in the desert in October 2022. Three pure litter (Rs, Sp and Ns) variants and four mixed-species litter variant (Rs+Sp, Rs+Ns, Sp+Ns, and Rs+Sp+Ns). 15 g of each litter (pure or mix) was placed into 10×10 cm litterbags (in total 252 bags). The duration of the experiment was 6 and 12 months. The dried samples were analyzed for the mass loss, the total organic C and the total N concentrations, the cellulose and lignin concentrations. Statistical Analysis of all results was conducted. At least some of the most important quantitative estimates obtained in the experiment should be given.

Abstract. An abstract should not be too abstract. Please add the most important quantitative characteristics you have gained in your experience.

Response: the abstract have been revised in line 9-24.

 

Results and Analysis. It would be better to name this section as "Results".

Response: it has been revised into “results”

Figure 1. The font size is too small, making it difficult to read the axis labels and numbers. I suggest starting the Y-axis at 20% instead 0. Probably, the drawing can be divided into two - according to the terms of 6 and 12 months.

Response: According to the reviewers' comments, Figure 1 has been revised.

Figures 2, 3 and 4 – the same notes. The font size is too small, making it difficult to read the axis labels and numbers.

Response: According to the reviewers' comments, Figures have been revised.

The manuscript material is of scientific interest in general. But without a representation of the concentration of C, N, as well as the biochemical composition (cellulose and lignin content) of the initial plant residues and their compost, it is difficult for a specialist to accept only qualitative estimates.

The authors should provide the chemical characteristics of the studied litter and their compost to enhance the scientific significance of their manuscript.

Response: the initial chemical characteristics have been added in line 274-275 of the revised paper.

It is also possible to advise the authors in their future experiments not only to simulate different water intake with irrigation, but also soil moisture (compost litter).

Response: Based on the reviewer’s suggestion, we will pay attention to the moisture content of the litter substrate in our future studies.

There are no conclusions in the manuscript. The conclusions must be completed.

Response: the conclusion has been added in line 314-325 of the revised paper.

 

Reviewer 4 Report

Comments and Suggestions for Authors

This manuscript addresses an important topic on the effects of precipitation on litter decomposition and mixing effects in arid ecosystems. The experimental approach is valuable, and the dataset appears promising. However, substantial revisions are required.

The main concern is the quality of the language, as numerous grammatical and syntactic errors hinder clarity and readability. A thorough professional English revision is necessary.

The conceptual framework needs strengthening. Key concepts such as non-additive effects and precipitation-driven processes in drylands are not sufficiently developed, and the hypotheses are not clearly mechanistic.

The experimental design and statistical analyses require clarification and improvement. In particular, replication and independence of plots should be explicitly described, and more robust statistical approaches (e.g., mixed-effects models, reporting of effect sizes) are recommended.

The Results section is overly descriptive, and figures need improved clarity. The Discussion lacks mechanistic interpretation and stronger integration with current literature. Additionally, conclusions should be better aligned with the results.

Finally, the reference list requires updating and formatting corrections.

Overall, the manuscript has potential but requires major revision before it can be considered for publication.

Comments on the Quality of English Language

The quality of English requires substantial improvement. The manuscript contains numerous grammatical, syntactic, and stylistic errors that hinder clarity and readability. Common issues include incorrect verb tense, missing articles, subject–verb disagreement, and awkward sentence construction. In several cases, sentences are difficult to interpret or ambiguous.

Additionally, the manuscript contains inconsistent and non-standard phrasing throughout, which further compromises clarity and diminishes its overall scientific rigor.

A thorough revision by a fluent English speaker or professional editing service is strongly recommended before further consideration for publication.

Author Response

This manuscript addresses an important topic on the effects of precipitation on litter decomposition and mixing effects in arid ecosystems. The experimental approach is valuable, and the dataset appears promising. However, substantial revisions are required.

The main concern is the quality of the language, as numerous grammatical and syntactic errors hinder clarity and readability. A thorough professional English revision is necessary.

Response: the language has been revised.

 

The conceptual framework needs strengthening. Key concepts such as non-additive effects and precipitation-driven processes in drylands are not sufficiently developed, and the hypotheses are not clearly mechanistic.

Response: these suggestions have been revised.

The experimental design and statistical analyses require clarification and improvement. In particular, replication and independence of plots should be explicitly described, and more robust statistical approaches (e.g., mixed-effects models, reporting of effect sizes) are recommended.

The Results section is overly descriptive, and figures need improved clarity. The Discussion lacks mechanistic interpretation and stronger integration with current literature. Additionally, conclusions should be better aligned with the results.

Response: The experimental design and statistical analyses have been revised in the material and methods have been revised, the results and figures have been improved and the section of discussions has been revised.

Finally, the reference list requires updating and formatting corrections.

Response: the references have been corrected.

Overall, the manuscript has potential but requires major revision before it can be considered for publication.

 

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript addresses a relevant question and the experiment could yield useful information on how precipitation change influences litter decomposition and mixing effects in an arid desert system. The main patterns are visible in the figures and some of the results are potentially interesting, especially the general promotion of mass loss and nitrogen release under increased precipitation and the tendency for two-species mixtures to show more antagonistic effects than the three-species mixture. The problem is that the paper is still not in publishable shape. The English remains very weak throughout, the presentation is often difficult to follow, and some parts of the analysis do not look secure enough to support the conclusions being drawn.

The most serious technical problem is Table 1. The degrees of freedom reported for the mixing-effects ANOVA do not match the factor structure described in the manuscript. If precipitation has three levels, species composition has four mixture levels, and sampling date has two levels, then for the mixing-effects analysis the dfs should be: P = 2, C = 3, D = 1, P × C = 6, C × D = 3, P × D = 2, and P × C × D = 6. But the table reports C × D = 6, P × D = 3, and P × C × D = 2. Those are not small formatting slips. They suggest either that the wrong model has been reported, the dfs have been entered incorrectly, or the analysis is not being described consistently with the design. This needs to be checked carefully and corrected. Until it is, the reader cannot have much confidence in the statistical backbone of the manuscript.

The discussion also still runs ahead of the data in places. The paper repeatedly explains its results in terms of microbial abundance, microbial activity, enzyme activity, and soil water responses, but those variables are not presented as measured outcomes in the study as currently described. These mechanisms may be reasonable interpretations, but they should be stated as possible explanations supported by previous work, not as if they were shown directly here. The same applies to parts of the hypothesis discussion. At present the paper says the first hypothesis is supported, then partly inconsistent, then not supported in some respects, but without handling that very cleanly. The manuscript would be stronger if it stated more directly which predictions were supported and which were not, and then discussed why.

A further problem is that the manuscript still needs major language revision. This is not just a matter of smoothing a few sentences. The writing is frequently ungrammatical and sometimes unclear enough to obscure meaning. That affects the Introduction, the Results, and especially the Discussion. The paper also uses terminology imprecisely in places, which makes the presentation sound weaker than the experiment itself may deserve.

So the review should stay focused on those real problems: The experiment may be useful,t he main patterns are potentially publishable, but the manuscript still has serious issues in language, statistical reporting, and interpretive discipline, with the ANOVA table being the clearest concrete technical problem that must be fixed.

In short, the statistical analysis still needs to be clarified and corrected, especially where the ANOVA presentation does not align cleanly with the stated design, and the discussion still needs to be tightened so that mechanistic explanation does not go beyond what was actually measured and shown in this study. Until those two points are addressed, the manuscript still has too much uncertainty in its analytical foundation and interpretation to justify a lighter recommendation.

 

Comments on the Quality of English Language

The quality of English is still below publication standard. Grammatical errors, awkward phrasing, and unclear sentence construction occur throughout the manuscript and often affect precision and readability. A thorough language revision is required.

Author Response

The manuscript addresses a relevant question and the experiment could yield useful information on how precipitation change influences litter decomposition and mixing effects in an arid desert system. The main patterns are visible in the figures and some of the results are potentially interesting, especially the general promotion of mass loss and nitrogen release under increased precipitation and the tendency for two-species mixtures to show more antagonistic effects than the three-species mixture. The problem is that the paper is still not in publishable shape. The English remains very weak throughout, the presentation is often difficult to follow, and some parts of the analysis do not look secure enough to support the conclusions being drawn.

The most serious technical problem is Table 1. The degrees of freedom reported for the mixing-effects ANOVA do not match the factor structure described in the manuscript. If precipitation has three levels, species composition has four mixture levels, and sampling date has two levels, then for the mixing-effects analysis the dfs should be: P = 2, C = 3, D = 1, P × C = 6, C × D = 3, P × D = 2, and P × C × D = 6. But the table reports C × D = 6, P × D = 3, and P × C × D = 2. Those are not small formatting slips. They suggest either that the wrong model has been reported, the dfs have been entered incorrectly, or the analysis is not being described consistently with the design. This needs to be checked carefully and corrected. Until it is, the reader cannot have much confidence in the statistical backbone of the manuscript.

Response: Thank you very much for the reviewer’s comment on this issue. The authors have carefully checked the relevant content and made corrections. The correct dfs as follows: P = 2, C = 3, D = 1, P × C = 6, C × D = 3, P × D = 2, and P × C × D = 6.

The discussion also still runs ahead of the data in places. The paper repeatedly explains its results in terms of microbial abundance, microbial activity, enzyme activity, and soil water responses, but those variables are not presented as measured outcomes in the study as currently described. These mechanisms may be reasonable interpretations, but they should be stated as possible explanations supported by previous work, not as if they were shown directly here. The same applies to parts of the hypothesis discussion. At present the paper says the first hypothesis is supported, then partly inconsistent, then not supported in some respects, but without handling that very cleanly. The manuscript would be stronger if it stated more directly which predictions were supported and which were not, and then discussed why.

Response: The discussion section of the manuscript has been revised in accordance with the reviewers’ comments, and the data on soil moisture and soil enzyme activities have been provided in the appendix.

A further problem is that the manuscript still needs major language revision. This is not just a matter of smoothing a few sentences. The writing is frequently ungrammatical and sometimes unclear enough to obscure meaning. That affects the Introduction, the Results, and especially the Discussion. The paper also uses terminology imprecisely in places, which makes the presentation sound weaker than the experiment itself may deserve.

Response: The manuscript has been revised for grammar and other linguistic issues by relevant professionals.

So the review should stay focused on those real problems: The experiment may be useful, the main patterns are potentially publishable, but the manuscript still has serious issues in language, statistical reporting, and interpretive discipline, with the ANOVA table being the clearest concrete technical problem that must be fixed.

Response: the issues in language, statistical reporting, and interpretive discipline have been revised in revised paper, meanwhile the table about ANOVA also has been revised.

In short, the statistical analysis still needs to be clarified and corrected, especially where the ANOVA presentation does not align cleanly with the stated design, and the discussion still needs to be tightened so that mechanistic explanation does not go beyond what was actually measured and shown in this study. Until those two points are addressed, the manuscript still has too much uncertainty in its analytical foundation and interpretation to justify a lighter recommendation.

Response: In accordance with the reviewers’ comments, the authors have revised the above‑mentioned two issues.

 Comments on the Quality of English Language

The quality of English is still below publication standard. Grammatical errors, awkward phrasing, and unclear sentence construction occur throughout the manuscript and often affect precision and readability. A thorough language revision is required.

Response: The manuscript has been revised for grammar and other linguistic issues by relevant professionals.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have corrected the manuscript according to all the comments of the reviewer, both in the text and in the list of references.

I believe that the article is now more clear for the reader and can be submitted for publication.

Author Response

The authors have corrected the manuscript according to all the comments of the reviewer, both in the text and in the list of references.

I believe that the article is now more clear for the reader and can be submitted for publication.

 

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript addresses an important topic concerning how altered precipitation regimes influence litter decomposition and non-additive litter-mixing effects in arid desert ecosystems. The study is relevant to dryland ecology and climate-change research, and the experimental approach is generally appropriate. The dataset has potential value for understanding nutrient cycling processes under changing precipitation regimes. However, the manuscript still requires substantial revision before it can be considered for publication.

Major comments:

1. The manuscript requires extensive English language revision. Numerous grammatical, syntactic, and stylistic problems reduce readability and obscure the scientific message. Many sentences are awkwardly constructed, verb tenses are inconsistent, and terminology varies throughout the manuscript. Professional language editing is strongly recommended.
2. The Introduction should be more concise and conceptually focused. Several ideas are repetitive, particularly regarding precipitation effects on decomposition and non-additive litter interactions. The authors should better emphasize the ecological significance of decomposition processes in arid systems and more clearly explain the mechanisms expected to drive litter-mixture effects under altered precipitation.
3. The hypotheses should be reformulated more mechanistically. Currently, they are largely descriptive. The manuscript would benefit from explicitly linking predictions to microbial activity, litter chemistry, nutrient transfer, or moisture-mediated decomposition processes. A clearer, more mechanistic hypothesis could be: We hypothesized that increased precipitation would enhance litter mass loss and nutrient release by alleviating moisture limitation on decomposition, but that non-additive litter-mixing effects would remain constrained by litter chemical composition. Therefore, increased precipitation was expected to reduce the strength of antagonistic effects without necessarily converting them into synergistic effects. We further hypothesized that three-species mixtures would exhibit weaker antagonistic effects than two-species mixtures due to greater chemical complementarity among litter types.
4. The Discussion is overly repetitive and frequently restates the Results rather than synthesizing ecological implications. The authors should substantially condense the Discussion and focus more strongly on the mechanisms underlying persistent antagonistic effects in mixed litters.
5. Several mechanistic interpretations are speculative and not directly supported by the data. For example, statements regarding increased microbial activity or improved moisture conditions in litter mixtures should be presented more cautiously unless microbial or litter-moisture measurements were conducted.
6. The manuscript’s strongest contribution appears to be the finding that increased precipitation weakened antagonistic litter interactions but did not fully shift them toward synergistic effects. This suggests that litter chemical traits may exert stronger controls over decomposition dynamics than precipitation alone in these desert systems. This conceptual point should be emphasized more clearly throughout the Discussion and Conclusions.
7. Statistical reporting could be improved. The ANOVA tables should include clearer formatting, and exact P-values should be reported where possible. Consistent terminology should also be used throughout the manuscript (e.g., “mixing effects,” “non-additive effects,” or “mixture effects”).
8. Some references are duplicated or inconsistently formatted, and the bibliography requires careful revision to comply with journal style.

Minor comments:

1. Revise awkward expressions such as “the decomposition of mixed litter will occurred significant mixing effects.”
2. Replace “sampling data” with “sampling date.”
3. Standardize species names and abbreviations throughout the manuscript.
4. Improve figure readability by enlarging labels and simplifying captions where possible.
5. Clarify whether the ±30% precipitation manipulation reflects historical interannual variability or projected climate scenarios.

Comments on the Quality of English Language

The manuscript requires substantial English language revision before it can be considered for publication. Although the overall scientific content is understandable, the text contains frequent grammatical, syntactic, and stylistic errors that significantly affect readability and clarity.

Common issues include incorrect verb tenses and subject–verb agreement, awkward sentence construction, misuse of articles and prepositions, inconsistent terminology, and unclear or repetitive phrasing.

Several sentences are difficult to follow and occasionally obscure the intended scientific meaning. Examples include expressions such as “the decomposition of mixed litter will occurred significant mixing effects,” which require major rewriting.

In addition, terminology should be standardized throughout the manuscript (e.g., “mixing effects,” “mixture effects,” and “non-additive effects”), and some sections—particularly the Introduction and Discussion—would benefit from clearer and more concise writing.

I strongly recommend professional English editing by a fluent scientific English speaker or a specialized editing service prior to resubmission.

Author Response

The manuscript addresses an important topic concerning how altered precipitation regimes influence litter decomposition and non-additive litter-mixing effects in arid desert ecosystems. The study is relevant to dryland ecology and climate-change research, and the experimental approach is generally appropriate. The dataset has potential value for understanding nutrient cycling processes under changing precipitation regimes. However, the manuscript still requires substantial revision before it can be considered for publication.

Major comments:

The manuscript requires extensive English language revision. Numerous grammatical, syntactic, and stylistic problems reduce readability and obscure the scientific message. Many sentences are awkwardly constructed, verb tenses are inconsistent, and terminology varies throughout the manuscript. Professional language editing is strongly recommended.

Response: The manuscript has been revised for grammar and other linguistic issues by relevant professionals.

The Introduction should be more concise and conceptually focused. Several ideas are repetitive, particularly regarding precipitation effects on decomposition and non-additive litter interactions. The authors should better emphasize the ecological significance of decomposition processes in arid systems and more clearly explain the mechanisms expected to drive litter-mixture effects under altered precipitation.

Response: the introduction has been revised.

The hypotheses should be reformulated more mechanistically. Currently, they are largely descriptive. The manuscript would benefit from explicitly linking predictions to microbial activity, litter chemistry, nutrient transfer, or moisture-mediated decomposition processes. A clearer, more mechanistic hypothesis could be: We hypothesized that increased precipitation would enhance litter mass loss and nutrient release by alleviating moisture limitation on decomposition, but that non-additive litter-mixing effects would remain constrained by litter chemical composition. Therefore, increased precipitation was expected to reduce the strength of antagonistic effects without necessarily converting them into synergistic effects. We further hypothesized that three-species mixtures would exhibit weaker antagonistic effects than two-species mixtures due to greater chemical complementarity among litter types.

Response: according to the suggestion of reviewer, the hypotheses have been reformulated in the revised paper.

The Discussion is overly repetitive and frequently restates the Results rather than synthesizing ecological implications. The authors should substantially condense the Discussion and focus more strongly on the mechanisms underlying persistent antagonistic effects in mixed litters.

Several mechanistic interpretations are speculative and not directly supported by the data. For example, statements regarding increased microbial activity or improved moisture conditions in litter mixtures should be presented more cautiously unless microbial or litter-moisture measurements were conducted.

Response: The discussion section has been condensed and revised in accordance with all reviewers’ comments

The manuscript’s strongest contribution appears to be the finding that increased precipitation weakened antagonistic litter interactions but did not fully shift them toward synergistic effects. This suggests that litter chemical traits may exert stronger controls over decomposition dynamics than precipitation alone in these desert systems. This conceptual point should be emphasized more clearly throughout the Discussion and Conclusions.

Response: according to the suggestion of reviewer, the conceptual point has been revised.

Statistical reporting could be improved. The ANOVA tables should include clearer formatting, and exact P-values should be reported where possible. Consistent terminology should also be used throughout the manuscript (e.g., “mixing effects,” “non-additive effects,” or “mixture effects”).

Some references are duplicated or inconsistently formatted, and the bibliography requires careful revision to comply with journal style.

Response: according to the suggestion of reviewer, the ANOVA table has been revised.

Minor comments:

Revise awkward expressions such as “the decomposition of mixed litter will occurred significant mixing effects.”

Response: it has been revised

Replace “sampling data” with “sampling date.”

Response: according to the suggestion of reviewer, “sampling data” has been replaced with “sampling date.”

Standardize species names and abbreviations throughout the manuscript.

Response: they have been revised throughout the manuscript.

Improve figure readability by enlarging labels and simplifying captions where possible.

Response: the figures have been improved.

Clarify whether the ±30% precipitation manipulation reflects historical interannual variability or projected climate scenarios.

Response: Based on the analysis of meteorological data from the past 50 years in the study area, the precipitation fluctuation range varied within ±30% (Zhang et al. 2018). Consequently, three precipitation treatments were designed: natural precipitation (CK), 30% increased precipitation (IP), and 30% reduced precipitation (RP). In other words, the ±30% precipitation manipulation reflects historical interannual variability

Comments on the Quality of English Language

The manuscript requires substantial English language revision before it can be considered for publication. Although the overall scientific content is understandable, the text contains frequent grammatical, syntactic, and stylistic errors that significantly affect readability and clarity.

Common issues include incorrect verb tenses and subject–verb agreement, awkward sentence construction, misuse of articles and prepositions, inconsistent terminology, and unclear or repetitive phrasing.

Several sentences are difficult to follow and occasionally obscure the intended scientific meaning. Examples include expressions such as “the decomposition of mixed litter will occurred significant mixing effects,” which require major rewriting.

In addition, terminology should be standardized throughout the manuscript (e.g., “mixing effects,” “mixture effects,” and “non-additive effects”), and some sections—particularly the Introduction and Discussion—would benefit from clearer and more concise writing.

I strongly recommend professional English editing by a fluent scientific English speaker or a specialized editing service prior to resubmission.

Response: The manuscript has been revised for grammar and other linguistic issues by relevant professionals.

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

Major comments

1. The statistical analysis still needs to be checked carefully because Table 1 is not fully reliable as presented. The degrees of freedom are now much more plausible than in the previous version, especially in the mixing-effects section, but at least one line still appears internally inconsistent. In the mixing-effects part of Table 1, the P × D term for mass loss is reported as F = 10.39 yet marked ns with p = .732, which cannot be correct. Either the F-value, the significance label, or the p-value has been entered incorrectly. Given that this table is the analytical backbone of the paper, all entries should be rechecked carefully before the manuscript can be considered final.
2. The discussion is improved, but it still sometimes moves too quickly from the observed patterns to mechanistic explanation. The revised text is more careful than before and now explicitly says that soil enzyme activity was not directly measured in the main experiment. That is a step forward. However, the manuscript still leans on explanations involving enzyme activity and moisture-mediated microbial processes as though they were close to being demonstrated, whereas the main evidence shown here is decomposition response plus supplementary soil moisture and cellulase figures. These explanations are plausible, but they should remain clearly framed as interpretations supported by previous work and by the supplementary patterns, not as mechanisms established directly in this experiment.
3. The argument about litter chemical traits as the dominant regulators of decomposition is reasonable, but it is still stronger than the evidence directly presented. The revised manuscript now does a better job of stating that precipitation weakened antagonistic interactions without fully shifting them, and that this pattern is consistent with a strong role of litter chemical properties. That is fine as an interpretation. But the paper still ends by asserting rather firmly that litter chemical traits, rather than precipitation alone, are the dominant regulators of decomposition dynamics in these desert ecosystems. Since litter chemistry was characterized only in initial bulk terms and not tracked through decomposition, and since some of the mechanistic intermediates are inferred rather than measured, that final claim should be softened slightly. The data support an important role for litter traits; they do not fully establish dominance in a strong causal sense.
4. The conclusions are better focused than before, but they are still somewhat stronger than necessary in the final lines. The manuscript now has a clearer main message, which is that increased precipitation altered decomposition rates but did not fundamentally overturn the antagonistic structure of most mixing interactions. That is a good result. The last sentences of the conclusion would be stronger if they stayed at that level rather than extending to a broader statement about dominant controls in future climate-change scenarios.

Minor comments

The title is improved, but “Regulate Litter Mixing Decomposition Effects on Desert Arid Regions” is still awkward English and should be revised.

Line 70: “plays as an important role” should be corrected.

Line 80: “two-species mixture” should be plural for parallel structure.

Table 1: spacing and notation should be standardized throughout, including “species composition(C)” and p-value formatting.

Figure 1 caption: “monocultures and mixtures litter” should be revised.

Line 120: “the Rs+Ns mixture” is fine, but the surrounding sentence would read more clearly if abbreviations were used more consistently throughout the paragraph.

Figure 2 caption: “during 1 years of decomposition” should be corrected.

Line 141: “S. passerine” should be checked for consistency with the species name used elsewhere.

Line 186: “antagonistic ay persist” should be corrected.

Lines 203–206: “Synergistic interaction are” and “antagonistic interactions tent to persist” both need correction.

Line 270: the methods say the litter was collected fresh and then “air-dried at 65°C,” which is contradictory phrasing. This should be rewritten.

Line 280: “After 6 and 12 of decomposition” is missing “months.”

The supplementary figures are useful because they at least show the moisture and cellulase patterns invoked in the discussion, but they should be integrated a little more cleanly into the interpretation. Right now they are doing important support work somewhat from the side rather than being explicitly framed as supplementary evidence.

Comments on the Quality of English Language

The English has improved substantially compared with the previous version. The manuscript is now readable and the argument is easier to follow. However, it still needs a careful final language edit because there are recurring grammatical slips, awkward phrases, and a few sentences where the wording remains rough enough to distract from the scientific content

Author Response

1. The statistical analysis still needs to be checked carefully because Table 1 is not fully reliable as presented. The degrees of freedom are now much more plausible than in the previous version, especially in the mixing-effects section, but at least one line still appears internally inconsistent. In the mixing-effects part of Table 1, the P × D term for mass loss is reported as F = 10.39yet marked nswith p = .732, which cannot be correct. Either the F-value, the significance label, or the p-value has been entered incorrectly. Given that this table is the analytical backbone of the paper, all entries should be rechecked carefully before the manuscript can be considered final.

Response：We have carefully verified all statistical data in accordance with the reviewer’s comments and found individual entry errors, which have been corrected in this revised manuscript.

2. The discussion is improved, but it still sometimes moves too quickly from the observed patterns to mechanistic explanation. The revised text is more careful than before and now explicitly says that soil enzyme activity was not directly measured in the main experiment. That is a step forward. However, the manuscript still leans on explanations involving enzyme activity and moisture-mediated microbial processes as though they were close to being demonstrated, whereas the main evidence shown here is decomposition response plus supplementary soil moisture and cellulase figures. These explanations are plausible, but they should remain clearly framed as interpretations supported by previous work and by the supplementary patterns, not as mechanisms established directly in this experiment.

Response：We have revised the discussion to optimize logical reasoning, and repeatedly clarified that soil enzyme activity was not directly measured in our main experiment. In addition, all inferences about enzyme activity and moisture-regulated microbial processes are now clearly stated as reasonable interpretations based on our supplementary data and previous studies, instead of mechanisms confirmed by this work.

3. The argument about litter chemical traits as the dominant regulators of decomposition is reasonable, but it is still stronger than the evidence directly presented. The revised manuscript now does a better job of stating that precipitation weakened antagonistic interactions without fully shifting them, and that this pattern is consistent with a strong role of litter chemical properties. That is fine as an interpretation. But the paper still ends by asserting rather firmly that litter chemical traits, rather than precipitation alone, are the dominant regulators of decomposition dynamics in these desert ecosystems. Since litter chemistry was characterized only in initial bulk terms and not tracked through decomposition, and since some of the mechanistic intermediates are inferred rather than measured, that final claim should be softened slightly. The data support an important role for litter traits; they do not fully establish dominance in a strong causal sense.

Response：According to the reviewer’s suggestions, we have carefully revised the discussion, the influence of litter traits is attenuated, and their dominant role is no longer emphasized.

4. The conclusions are better focused than before, but they are still somewhat stronger than necessary in the final lines. The manuscript now has a clearer main message, which is that increased precipitation altered decomposition rates but did not fundamentally overturn the antagonistic structure of most mixing interactions. That is a good result. The last sentences of the conclusion would be stronger if they stayed at that level rather than extending to a broader statement about dominant controls in future climate-change scenarios.

Response：According to the reviewer’s suggestions, we have carefully revised the conclusion section and deleted the broader statement about dominant controls in future climate-change scenarios.

Minor comments

The title is improved, but “Regulate Litter Mixing Decomposition Effects on Desert Arid Regions” is still awkward English and should be revised.

Response：The tile has been revised.

Line 70: “plays as an important role” should be corrected.

Response ：This sentence has been revised in this revised paper.

Line 80: “two-species mixture” should be plural for parallel structure.

Response：According to the suggestion of the reviewer, this sentence has been revised in this revised paper.

Table 1: spacing and notation should be standardized throughout, including “species composition(C)” and p-value formatting.

Response ：According to the suggestion of the reviewer, the spacing and notation has be standardized throughout the revised paper.

Figure 1 caption: “monocultures and mixtures litter” should be revised.

Response： This caption has been revised.

Line 120: “the Rs+Ns mixture” is fine, but the surrounding sentence would read more clearly if abbreviations were used more consistently throughout the paragraph.

Response：The full species names are presented at first occurrence, and abbreviations are used in the next paragraphs.

Figure 2 caption: “during 1 years of decomposition” should be corrected.

Response：This caption has been revised.

Line 141: “S. passerine” should be checked for consistency with the species name used elsewhere.

Response： This species name have been checked and revised throughout the text.

Line 186: “antagonistic ay persist” should be corrected.

Response：This sentence has been revised

Lines 203–206: “Synergistic interaction are” and “antagonistic interactions tent to persist” both need correction.

Response：This sentence has been revised

Line 270: the methods say the litter was collected fresh and then “air-dried at 65°C,” which is contradictory phrasing. This should be rewritten.

Response：A sentence was accidentally deleted during grammatical revision. It has been restored and revised after careful inspection.

Line 280: “After 6 and 12 of decomposition” is missing “months.”

Response：”months” has been added in the revised paper.

The supplementary figures are useful because they at least show the moisture and cellulase patterns invoked in the discussion, but they should be integrated a little more cleanly into the interpretation. Right now they are doing important support work somewhat from the side rather than being explicitly framed as supplementary evidence.

Comments on the Quality of English Language

The English has improved substantially compared with the previous version. The manuscript is now readable and the argument is easier to follow. However, it still needs a careful final language edit because there are recurring grammatical slips, awkward phrases, and a few sentences where the wording remains rough enough to distract from the scientific content

Response：In accordance with the reviewers' comments, the authors have further checked and revised grammatical errors throughout the manuscript.

 

 

Round 4

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for the improvements.

Please check a few remaining issues:

Results still point to “Figure 2e–f” for carbon release where that appears to belong to Figure 1; table heading still says “Decompostion”.

Author Response

Please check a few remaining issues:

Results still point to “Figure 2e–f” for carbon release where that appears to belong to Figure 1; table heading still says “Decompostion”.

Response: These issues have been corrected in the revised paper.