Spatially Contrasting CO<sub>2</sub> Dynamics Driven by Green Manure Intercropping in Subtropical Tea Plantations

Liu, Shuo; Jin, Zeping; Chen, Ziyi; Li, Haolin; Fan, Zihan; Li, Shaohui; Fu, Haiwang; He, Wei; Zang, Kunpeng; Fang, Shuangxi; Yan, Peng

doi:10.5194/egusphere-2025-5065

Preprints

https://doi.org/10.5194/egusphere-2025-5065

Preprints

20 Nov 2025

| 20 Nov 2025

Spatially Contrasting CO₂ Dynamics Driven by Green Manure Intercropping in Subtropical Tea Plantations

Shuo Liu, Zeping Jin, Ziyi Chen, Haolin Li, Zihan Fan, Shaohui Li, Haiwang Fu, Wei He, Kunpeng Zang, Shuangxi Fang, and Peng Yan

Abstract. Tea plantations are important contributors to greenhouse gas emissions due to intensive fertilization and continuous cultivation. However, the mechanisms by which green manure intercropping regulates soil CO₂ dynamics in these systems remain poorly understood. We investigated how intercropping with Vulpia myuros (SM) and a legume–nonlegume mixture of Lolium perenne and Trifolium repens (HM) influenced spatial CO₂ flux dynamics compared with a no-intercropping control (CK) from tea rows and inter-row zones in a subtropical tea plantation. Distinct seasonal variations were observed, with CO₂ fluxes peaking in summer and autumn and declining in spring and winter. Average tea-row fluxes were 7.41 ± 0.45, 7.35 ± 0.44, and 8.12 ± 0.46 mg·m⁻²·min⁻¹ under SM, HM, and CK, respectively, indicating emission reductions with intercropping. In contrast, inter-row fluxes were higher under SM (10.83 ± 0.52 mg m⁻² min⁻¹) and HM (9.77 ± 0.54 mg m⁻² min⁻¹) than under CK (9.07 ± 0.44 mg m⁻² min⁻¹), demonstrating pronounced spatial contrasts. Diurnal patterns exhibited midday peaks (12:00–14:00), especially in spring and summer, and short-term CO₂ pulses were triggered by field operations such as fertilization and pruning. Notably, HM effectively suppressed fertilization-induced CO₂ pulses, revealing the mitigation potential of legume–nonlegume mixtures. Green manure increased soil organic carbon (6.4 %), lowered soil temperature (4.5 %), and enhanced porosity (4.2 %), collectively shaping CO₂ dynamics. Multivariate analysis identified soil organic carbon (SOC) and temperature as dominant flux drivers, and a potential SOC threshold was detected, beyond which CO₂ emissions accelerated. While intercropping reduced tea-row emissions by 7.1–7.9 % but increased inter-row emissions by 12.7–28.9 %, continuous intercropping significantly decreased overall inter-row emissions over time. These results highlight the spatially heterogeneous nature of carbon flux regulation and demonstrate the long-term potential of green manure intercropping as a climate-smart management strategy in perennial agroecosystems.

Received: 14 Oct 2025 – Discussion started: 20 Nov 2025

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Journal article(s) based on this preprint

10 Aug 2026

Spatially contrasting CO₂ dynamics driven by green manure intercropping in subtropical tea plantations

Shuo Liu, Zeping Jin, Ziyi Chen, Haolin Li, Zihan Fan, Shaohui Li, Haiwang Fu, Wei He, Kunpeng Zang, Shuangxi Fang, and Peng Yan

Biogeosciences, 23, 5497–5513, https://doi.org/10.5194/bg-23-5497-2026,https://doi.org/10.5194/bg-23-5497-2026, 2026

Short summary

Shuo Liu, Zeping Jin, Ziyi Chen, Haolin Li, Zihan Fan, Shaohui Li, Haiwang Fu, Wei He, Kunpeng Zang, Shuangxi Fang, and Peng Yan

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2025-5065', Anonymous Referee #1, 29 Dec 2025
Title: Spatially Contrasting CO₂ Dynamics Driven by Green Manure Intercropping in Subtropical Tea Plantations
Author(s): Shuo Liu et al.
MS No.: egusphere-2025-5065

General Comments
The manuscript presents valuable insights from a two-year measurement campaign of CO₂ fluxes in a tea plantation in China. The study compares plots subjected to different intercropping treatments, providing an interesting perspective by distinguishing emissions from tea rows and inter-row spaces. The discussion is comprehensive; however, additional experimental details would enhance the reader’s ability to interpret the results. Aside from this, I have only a few minor comments (see below). Overall, the paper falls within the scope of Biogeosciences and merits publication after these minor revisions are addressed.

Specific Comments
Abstract
Lines 28–31: These absolute values are difficult to interpret without broader context regarding tea plantation emissions. Readers will likely be more interested in relative changes compared to control plots, as mentioned in line 41. Please provide relative changes for the total flux as well (see comment on line 41).

Lines 32–33: Specify for which plots midday peaks occurred.

Line 41: The relative changes reported do not correspond to the values in lines 28–31. Be more precise which aggregates are shown and used for the relative changes.

Lines 40–45: This section is unclear. Tea-row and inter-row fluxes appear similar in magnitude (e.g., 8.12 CK (tea-row) vs. 9.07 CK (inter-row)). Tea-row emissions decrease by 7–8%, while inter-row emissions increase by 13–29%. How does this support the conclusion that intercropping is a climate-smart management strategy?

Add to the abstract: measurement method (flux chambers), campaign duration, and dataset size.

Experimental Setup (Lines 164 ff.)
Provide more details: plantation size, distances between plots and replicates, age of plantation and tea plants, etc.

Consider adding a schematic (with dimensions) to Figure 1. Clarify whether tea plants were inside the chambers.

According to lines 183–184, one measurement included four samples every 7 minutes: indicate when the first sample was taken after chamber closure and how long (overall) a single experiment took. How high were the CO2 concentrations at the end? Include an example showing the 4 measured CO2 concentrations over time (perhaps in the appendix) and illustrate how fluxes were calculated. Was a linear fit applied to the four data points? How linear was the CO₂ increase? How consistent were the three replicates? Were all six plots always sampled simultaneously? Did you ever observe decreases in CO2 concentrations? Figure 2 shows only positive fluxes.

Include an uncertainty analysis for flux determination.

Figure and Table Captions
Add a condensed explanation of your three letter codes to the different figure/table captions: Something like: CK = control, SM and HM = intercropping types, T = tea row, G = inter-row.

Results
Line 243: Explain what the uncertainties represent.

Line 245: Specify the significance level for “significantly higher.”

Figures and Tables
Figure 2: Clarify whether error bars indicate uncertainty of a single flux measurement or standard deviation across duplicates.

Table 1: Explain ± values and superscript letters.

Figure 2: Use a different color for precipitation vs. temperature. Confirm whether negative CO₂ fluxes were ever observed. Were tea plants present in the chambers?

Figure 3: Explain superscript letters and error bars. Add “T” for tea row and “G” for inter-row in the legend.

Results
Lines 354 ff.: The consistent differences in soil properties are surprising given the short distances. Provide more detail on plantation history and intercropping duration. When did the intercropping practices start?

Conclusions
Line 587 refers to the mitigation of carbon losses. Quantify overall CO₂ emission reductions when summing tea-row and inter-row fluxes for HM, SM, and CK. Data (e.g. in abstract, see my comment there) do not support it and Figure 3 suggest reductions only for HM in the second year. If mitigation exists, contextualize its potential impact at larger scales.

Add general considerations on intercropping: benefits and drawbacks (costs, labor, temperature effects, soil compaction, aeration, etc.). Large-scale adoption depends on whether benefits outweigh additional costs.
Citation: https://doi.org/10.5194/egusphere-2025-5065-RC1
- AC1: 'Reply on RC1', shuo liu, 16 Jan 2026
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5065/egusphere-2025-5065-AC1-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2025-5065-AC1
- AC2: 'Reply on RC1', shuo liu, 16 Jan 2026
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5065/egusphere-2025-5065-AC2-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2025-5065-AC2
RC2:
'Comment on egusphere-2025-5065', Anonymous Referee #2, 03 Jan 2026

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5065/egusphere-2025-5065-RC2-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2025-5065-RC2
- AC3: 'Reply on RC2', shuo liu, 16 Jan 2026
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5065/egusphere-2025-5065-AC3-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2025-5065-AC3
RC3:
'Comment on egusphere-2025-5065', Anonymous Referee #3, 26 Jan 2026

This manuscript examines how green manure intercropping with grasses and grass–legume mixtures influences spatial and temporal patterns of soil CO2 fluxes in a subtropical tea plantation, with a focus on contrasts between tea-row and inter-row zones. The dataset appears extensive, and the field effort is clearly substantial. However, based on the current framing in the introduction, the broader scientific importance and implications of the study would benefit from further clarification and strengthening before the manuscript is ready for publication.
The introduction places the study within the context of greenhouse gas emissions, but this framing would benefit from greater conceptual precision. In agricultural systems, soil CO2 fluxes are not necessarily equivalent to net GHG emissions, as their climatic relevance depends strongly on C origin. CO2 derived from root respiration or recent plant inputs is part of the short-term carbon cycle rather than a net climatic forcing. Clarifying whether the measured CO2 fluxes represent autotrophic respiration, heterotrophic respiration, or their combination would greatly improve interpretation of the results and help align the study more clearly with its stated climate relevance. In addition, although N2O emissions are mentioned in the introduction, they are not included in the study, and refining the scope of the introduction to better match the measurements would improve coherence.
The motivation for the study currently appears to rest primarily on the limited number of prior studies examining soil CO2 dynamics in tea plantations with green manure intercropping. While this system-specific focus is valuable, the manuscript would be strengthened by more clearly articulated scientific questions and testable hypotheses that highlight the underlying processes or mechanisms being investigated. As written, the study is largely descriptive, and the novelty would be clearer if the authors explicitly stated what new conceptual or mechanistic insights are expected beyond documenting spatial and temporal flux patterns. Similarly, the role of green manure would benefit from clearer definition and context. It is not always clear whether green manure refers to cover crops or other intercropping practices, and relevant literature on how green manure influences soil C cycling could be more fully integrated. Statements regarding green manure introducing soil disturbance would also benefit from additional explanation or supporting evidence.
The Materials and Methods section would benefit from substantially more detail to allow readers to fully evaluate the experimental design and reproduce the study. Important information that should be clarified includes the timing of green manure planting and termination, planting rates, termination methods, plot layout and size, the presence of buffer zones between treatments, and whether chamber bases included vegetation. The rationale for diurnal monitoring, as well as how diurnal and seasonal variations were calculated, also needs to be more clearly explained. Several methodological aspects would benefit from clarification, including gas sampling and storage procedures, flux calculation methods, whether fresh soil was used for total C and N analyses, and the distinction between injected gas and carrier gas. In addition, management activities such as fertilization, grass cutting or termination, and tea pruning are discussed in the Results and Discussion but should be more fully described in the Methods.
The discussion is logically structured, but it would benefit from deeper engagement with underlying mechanisms and clearer links back to explicit hypotheses. Terms such as “human management” would be clearer if they were more precisely defined and contextualized, including what conditions are being compared before and after management interventions. Additional clarification on how high-frequency flux measurements were aggregated or transformed to generate the reported temporal patterns would also strengthen interpretation. Overall, the main take-home message and the broader contribution of the study would be clearer with a more analytical and mechanism-focused discussion rather than a primarily descriptive one. Overall, the dataset has potential, but the manuscript would benefit from conceptual reframing, clearer hypotheses, improved methodological transparency, and a more mechanistically grounded discussion. Addressing these points would substantially strengthen the scientific clarity and impact of the study.

Citation: https://doi.org/10.5194/egusphere-2025-5065-RC3
- AC4: 'Reply on RC3', shuo liu, 22 Feb 2026
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5065/egusphere-2025-5065-AC4-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2025-5065-AC4

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload

ED: Reconsider after major revisions (22 Feb 2026) by Paul Stoy

AR by shuo liu on behalf of the Authors (09 Mar 2026) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (10 Mar 2026) by Paul Stoy

RR by Anonymous Referee #3 (31 Mar 2026)

Suggestions for revision or reasons for rejection

I appreciate the effort that went into revising this manuscript, but I have to be honest that I am still not convinced by the revision. In its current form, I do not think the study is suitable for publication. My main concern remains unchanged: I am not convinced that this study actually addresses greenhouse gas (GHG) emissions, even though the manuscript is framed that way throughout.
The CO2 measured here represents total ecosystem respiration, not GHG emissions in the sense relevant to atmospheric forcing. As described in the methods, the flux reflects the gross exchange (not net exchange) of CO2 from the system, which includes plant respiration, residue/litter fall decomposition, and soil respiration. CO2 derived from plant biomass originates from photosynthesis and is part of the biogenic carbon cycle, so it should not be interpreted as a net GHG source. Because the chambers are dark, photosynthesis is excluded, meaning the measurements do not represent net ecosystem exchange. Under this setup, I do not see how the CO2 fluxes can be interpreted as GHG emissions at the ecosystem level. This is a fundamental issue, and I strongly recommend removing any discussion or framing related to GHG emissions, as the experimental design cannot support those discussions and conclusions.
Beyond this central issue, I also have concerns about the experimental design and statistical analysis. The CO2 measurements include multiple sources, not just soil respiration, and this is not consistently acknowledged in the interpretation. The statistical approach is also not well aligned with the structure of the data. If fluxes were measured repeatedly over time, then a repeated measures framework would be more appropriate than a simple ANOVA. The study involves multiple factors, including treatment type, spatial position (tree row versus inter-row), and observation period, yet only a two-way ANOVA is described (lines 256). It is not clear whether interactions among these factors were tested. If significant interactions were present, then the statistical analysis that was used to generate stats results in Table 2; Figures 3, 5, and 6 would no longer be appropriate. In several places where comparisons are discussed, particularly between tree rows and inter-rows, it is unclear how the statistical analyses were actually conducted.
I also find the results and discussion difficult to follow due to internal inconsistencies and unclear logic. It is often not clear whether the discussion refers to inter-row, tree row, or the entire system. There are places where statements directly contradict each other (e.g., lines 480–481 versus lines 520–522), and in many cases it is not clear whether differences are statistically significant (most often no significant difference showed between the discussed treatments based on the figures and tables). The explanation of negative CO2 fluxes is problematic (lines 474–476). Even under low temperature conditions, respiration should approach zero but not become negative unless there are measurement issues or a true sink such as photosynthesis or methanogenesis, neither of which applies here given the dark chamber and oxic conditions. Some interpretations also needs evidence to support, such as attributing increases in CO2 after pruning to soil temperature needs temperature data to support (line 382). It is also not clear whether differences among green manure types (HM versus SM) are consistently evaluated.
There are also several points where the interpretation is not convincing. For example, the discussion of nitrate (lines 577–580) suggests that higher biomass reduces nitrate losses via runoff or leaching, but that does not explain higher NO3- concentrations in soil. These are different processes, and the reasoning does not hold. Similarly, the logic around GHG mitigation, SOC thresholds, and C/N ratios is often unclear or introduced without sufficient context (lines 583–595). The reported increase in soil C:N ratio from around 10.5 (baseline) to approximately 17 within two years (lines 606–607) is difficult to accept for an established system and needs strong justification.
In terms of clarity and presentation, many statements need clearer linkage to figures and tables, and statistical significance should be explicitly stated. It is often unclear whether reported values represent means, cumulative emissions, or single time points. Some methodological details are also missing, such as whether chamber bases were kept in the same locations across sampling events and years. Some of the conclusions, particularly those related to agronomic benefits and economic implications, feel overstated relative to the data presented (lines 643–645). There are also instances where differences are discussed but appear not to be statistically significant based on the tables.
There are also specific technical concerns that need attention. In Table 1, SOC appears higher than TC in most treatments, which is not physically consistent and raises concerns about how SOC was calculated. Given that soil pH is below 4.5, it is also unclear whether reporting both TC and SOC is necessary. In Figure 2, graphical elements such as green arrows are missing or misaligned. In Figure 3, it is not clear whether there are significant differences in annual CO₂ emissions at the ecosystem level. In Figure 6, only a single data point is shown despite monthly sampling, and it is not clear which year the data represent.
Overall, the manuscript has substantial conceptual, methodological, and interpretive issues. The central framing around GHG emissions is not supported by the experimental design, and there are multiple inconsistencies throughout the results and discussion. For these reasons, I do not recommend publication in its current form.

Hide

ED: Reconsider after major revisions (04 Apr 2026) by Paul Stoy

AR by shuo liu on behalf of the Authors (03 May 2026) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (08 May 2026) by Paul Stoy

RR by Anonymous Referee #1 (20 May 2026)

ED: Publish as is (17 Jun 2026) by Paul Stoy

AR by shuo liu on behalf of the Authors (18 Jun 2026) Manuscript

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2025-5065', Anonymous Referee #1, 29 Dec 2025
Title: Spatially Contrasting CO₂ Dynamics Driven by Green Manure Intercropping in Subtropical Tea Plantations
Author(s): Shuo Liu et al.
MS No.: egusphere-2025-5065

General Comments
The manuscript presents valuable insights from a two-year measurement campaign of CO₂ fluxes in a tea plantation in China. The study compares plots subjected to different intercropping treatments, providing an interesting perspective by distinguishing emissions from tea rows and inter-row spaces. The discussion is comprehensive; however, additional experimental details would enhance the reader’s ability to interpret the results. Aside from this, I have only a few minor comments (see below). Overall, the paper falls within the scope of Biogeosciences and merits publication after these minor revisions are addressed.

Specific Comments
Abstract
Lines 28–31: These absolute values are difficult to interpret without broader context regarding tea plantation emissions. Readers will likely be more interested in relative changes compared to control plots, as mentioned in line 41. Please provide relative changes for the total flux as well (see comment on line 41).

Lines 32–33: Specify for which plots midday peaks occurred.

Line 41: The relative changes reported do not correspond to the values in lines 28–31. Be more precise which aggregates are shown and used for the relative changes.

Lines 40–45: This section is unclear. Tea-row and inter-row fluxes appear similar in magnitude (e.g., 8.12 CK (tea-row) vs. 9.07 CK (inter-row)). Tea-row emissions decrease by 7–8%, while inter-row emissions increase by 13–29%. How does this support the conclusion that intercropping is a climate-smart management strategy?

Add to the abstract: measurement method (flux chambers), campaign duration, and dataset size.

Experimental Setup (Lines 164 ff.)
Provide more details: plantation size, distances between plots and replicates, age of plantation and tea plants, etc.

Consider adding a schematic (with dimensions) to Figure 1. Clarify whether tea plants were inside the chambers.

According to lines 183–184, one measurement included four samples every 7 minutes: indicate when the first sample was taken after chamber closure and how long (overall) a single experiment took. How high were the CO2 concentrations at the end? Include an example showing the 4 measured CO2 concentrations over time (perhaps in the appendix) and illustrate how fluxes were calculated. Was a linear fit applied to the four data points? How linear was the CO₂ increase? How consistent were the three replicates? Were all six plots always sampled simultaneously? Did you ever observe decreases in CO2 concentrations? Figure 2 shows only positive fluxes.

Include an uncertainty analysis for flux determination.

Figure and Table Captions
Add a condensed explanation of your three letter codes to the different figure/table captions: Something like: CK = control, SM and HM = intercropping types, T = tea row, G = inter-row.

Results
Line 243: Explain what the uncertainties represent.

Line 245: Specify the significance level for “significantly higher.”

Figures and Tables
Figure 2: Clarify whether error bars indicate uncertainty of a single flux measurement or standard deviation across duplicates.

Table 1: Explain ± values and superscript letters.

Figure 2: Use a different color for precipitation vs. temperature. Confirm whether negative CO₂ fluxes were ever observed. Were tea plants present in the chambers?

Figure 3: Explain superscript letters and error bars. Add “T” for tea row and “G” for inter-row in the legend.

Results
Lines 354 ff.: The consistent differences in soil properties are surprising given the short distances. Provide more detail on plantation history and intercropping duration. When did the intercropping practices start?

Conclusions
Line 587 refers to the mitigation of carbon losses. Quantify overall CO₂ emission reductions when summing tea-row and inter-row fluxes for HM, SM, and CK. Data (e.g. in abstract, see my comment there) do not support it and Figure 3 suggest reductions only for HM in the second year. If mitigation exists, contextualize its potential impact at larger scales.

Add general considerations on intercropping: benefits and drawbacks (costs, labor, temperature effects, soil compaction, aeration, etc.). Large-scale adoption depends on whether benefits outweigh additional costs.
Citation: https://doi.org/10.5194/egusphere-2025-5065-RC1
- AC1: 'Reply on RC1', shuo liu, 16 Jan 2026
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5065/egusphere-2025-5065-AC1-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2025-5065-AC1
- AC2: 'Reply on RC1', shuo liu, 16 Jan 2026
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5065/egusphere-2025-5065-AC2-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2025-5065-AC2
RC2:
'Comment on egusphere-2025-5065', Anonymous Referee #2, 03 Jan 2026

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5065/egusphere-2025-5065-RC2-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2025-5065-RC2
- AC3: 'Reply on RC2', shuo liu, 16 Jan 2026
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5065/egusphere-2025-5065-AC3-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2025-5065-AC3
RC3:
'Comment on egusphere-2025-5065', Anonymous Referee #3, 26 Jan 2026

This manuscript examines how green manure intercropping with grasses and grass–legume mixtures influences spatial and temporal patterns of soil CO2 fluxes in a subtropical tea plantation, with a focus on contrasts between tea-row and inter-row zones. The dataset appears extensive, and the field effort is clearly substantial. However, based on the current framing in the introduction, the broader scientific importance and implications of the study would benefit from further clarification and strengthening before the manuscript is ready for publication.
The introduction places the study within the context of greenhouse gas emissions, but this framing would benefit from greater conceptual precision. In agricultural systems, soil CO2 fluxes are not necessarily equivalent to net GHG emissions, as their climatic relevance depends strongly on C origin. CO2 derived from root respiration or recent plant inputs is part of the short-term carbon cycle rather than a net climatic forcing. Clarifying whether the measured CO2 fluxes represent autotrophic respiration, heterotrophic respiration, or their combination would greatly improve interpretation of the results and help align the study more clearly with its stated climate relevance. In addition, although N2O emissions are mentioned in the introduction, they are not included in the study, and refining the scope of the introduction to better match the measurements would improve coherence.
The motivation for the study currently appears to rest primarily on the limited number of prior studies examining soil CO2 dynamics in tea plantations with green manure intercropping. While this system-specific focus is valuable, the manuscript would be strengthened by more clearly articulated scientific questions and testable hypotheses that highlight the underlying processes or mechanisms being investigated. As written, the study is largely descriptive, and the novelty would be clearer if the authors explicitly stated what new conceptual or mechanistic insights are expected beyond documenting spatial and temporal flux patterns. Similarly, the role of green manure would benefit from clearer definition and context. It is not always clear whether green manure refers to cover crops or other intercropping practices, and relevant literature on how green manure influences soil C cycling could be more fully integrated. Statements regarding green manure introducing soil disturbance would also benefit from additional explanation or supporting evidence.
The Materials and Methods section would benefit from substantially more detail to allow readers to fully evaluate the experimental design and reproduce the study. Important information that should be clarified includes the timing of green manure planting and termination, planting rates, termination methods, plot layout and size, the presence of buffer zones between treatments, and whether chamber bases included vegetation. The rationale for diurnal monitoring, as well as how diurnal and seasonal variations were calculated, also needs to be more clearly explained. Several methodological aspects would benefit from clarification, including gas sampling and storage procedures, flux calculation methods, whether fresh soil was used for total C and N analyses, and the distinction between injected gas and carrier gas. In addition, management activities such as fertilization, grass cutting or termination, and tea pruning are discussed in the Results and Discussion but should be more fully described in the Methods.
The discussion is logically structured, but it would benefit from deeper engagement with underlying mechanisms and clearer links back to explicit hypotheses. Terms such as “human management” would be clearer if they were more precisely defined and contextualized, including what conditions are being compared before and after management interventions. Additional clarification on how high-frequency flux measurements were aggregated or transformed to generate the reported temporal patterns would also strengthen interpretation. Overall, the main take-home message and the broader contribution of the study would be clearer with a more analytical and mechanism-focused discussion rather than a primarily descriptive one. Overall, the dataset has potential, but the manuscript would benefit from conceptual reframing, clearer hypotheses, improved methodological transparency, and a more mechanistically grounded discussion. Addressing these points would substantially strengthen the scientific clarity and impact of the study.

Citation: https://doi.org/10.5194/egusphere-2025-5065-RC3
- AC4: 'Reply on RC3', shuo liu, 22 Feb 2026
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-5065/egusphere-2025-5065-AC4-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2025-5065-AC4

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload

ED: Reconsider after major revisions (22 Feb 2026) by Paul Stoy

AR by shuo liu on behalf of the Authors (09 Mar 2026) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (10 Mar 2026) by Paul Stoy

RR by Anonymous Referee #3 (31 Mar 2026)

Suggestions for revision or reasons for rejection

Hide

ED: Reconsider after major revisions (04 Apr 2026) by Paul Stoy

AR by shuo liu on behalf of the Authors (03 May 2026) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (08 May 2026) by Paul Stoy

RR by Anonymous Referee #1 (20 May 2026)

ED: Publish as is (17 Jun 2026) by Paul Stoy

AR by shuo liu on behalf of the Authors (18 Jun 2026) Manuscript

Journal article(s) based on this preprint

10 Aug 2026

Spatially contrasting CO₂ dynamics driven by green manure intercropping in subtropical tea plantations

Shuo Liu, Zeping Jin, Ziyi Chen, Haolin Li, Zihan Fan, Shaohui Li, Haiwang Fu, Wei He, Kunpeng Zang, Shuangxi Fang, and Peng Yan

Biogeosciences, 23, 5497–5513, https://doi.org/10.5194/bg-23-5497-2026,https://doi.org/10.5194/bg-23-5497-2026, 2026

Short summary

Shuo Liu, Zeping Jin, Ziyi Chen, Haolin Li, Zihan Fan, Shaohui Li, Haiwang Fu, Wei He, Kunpeng Zang, Shuangxi Fang, and Peng Yan

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We studied how planting green manure between tea rows affects carbon dioxide release from tea fields. Mixing legume and grass species improved soil health, reduced emissions from tea rows, and stabilized carbon over time. Although inter-row areas released more carbon, overall emissions declined with continued intercropping. This shows that green manure can make tea farming more climate-friendly and sustainable.


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Spatially Contrasting CO2 Dynamics Driven by Green Manure Intercropping in Subtropical Tea Plantations

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Spatially Contrasting CO₂ Dynamics Driven by Green Manure Intercropping in Subtropical Tea Plantations