Review Reports - Biochar Improved Saline–Alkali Barrier and Sunflower Yield Under Drip Irrigation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The article presents a two-year field experiment evaluating whether the application of biochar, desulfurized gypsum and straw return, combined with drip irrigation, can improve saline-alkali soil properties and increase sunflower yield. This topic is important, as saline-alkali soils can be a serious threat to agricultural productivity and food security. The novelty of the study is moderate since the individual components were previously studied. However, its main value is in their integration within a two-year field experiment conducted under agricultural conditions and its results have direct practical applicability.

The introduction provides sufficient background on soil salinization as a global and regional problem. It presents knowledge gaps and cites relevant literature. The aim of the study is described well.

Materials and Methods. This section is well written. However, a few details can be added (listed below).

Overview of the experimental site.

The soil is described as “heavy sulfated saline-alkali soil.” However, perhaps, a formal classification could be added (class, subclass) using a chosen Classification System.

Mean annual temperature and rainfall are given, but the variability during the year should be presented as well as the differences between each of the experimental years.

Test materials.

Main chemical properties of sunflower straw should be added.

Experimental Design.

Three replicates per treatment is acceptable, but borderline low for field studies. It should be acknowledged as a limitation.

“A random square design was used in the experiments.” Fully randomized or blocked?

Application rates of biochar, gypsum and straw seem very high, the economic and logistical challenges should be discussed in the article.

Soil sampling and chemical analysis.

Sampling dates should be added.

Determination of sunflower yield

“15 representative sunflower plants”. What were exact selection criteria? It is unclear. How was yield extrapolated from 15 plants to t/ha? What was plants spatial distribution within plots?

Basic yield components such as head diameter, seed number and thousand-seed weight could be added.

Results and analysis.

This section is logically structured. Figures are clear, easy to understand and appropriately referenced in the text.

Discussion.

The main conclusions are directly supported by the presented results. Authors acknowledge main limitations of the study. Authors compare their results with both supportive and contradictory studies. However, some more recent studies should be cited, the amount of cited literature seems a bit brief.

The Conclusions are acceptable in the current form.

In-text citations should be uniformed throughout the manuscript (sometimes two forms are used, for example “by Zhang et al. (2020) & Zhao et al. (2016) [31,32]” and sometimes just one of them (for example “[23,24” vs. “Wang et al., 2020”.

Literature.

It is well picked with relatively new positions being cited, however, as I mentioned before, some more studies could be compared in the Discussion.

After the necessary revisions the article may be considered for publication.

Author Response

Reviewer 1

Materials and Methods.

1、The soil is described as “heavy sulfated saline-alkali soil.” However, perhaps, a formal classification could be added (class, subclass) using a chosen Classification System.

Response: According to the reviewer's comments, classify and describe the soil based on WRB. (Line-84)

2、Mean annual temperature and rainfall are given, but the variability during the year should be presented as well as the differences between each of the experimental years.

Response: According to the reviewer's comments, additional rainfall and temperature change charts have been added (Line-95). In the discussion section, the heavy rainfall in July has been changed to heavy rainfall in August. (Line-395)

Test materials.

3、Main chemical properties of sunflower straw should be added.

Response: According to the reviewer's comments, the chemical properties of sunflower straw have been added and supplemented.（Line-108-109）

Experimental Design.

4、It is acceptable to repeat each treatment three times, but for field research, this number of repetitions is slightly lower. It should be seen as a limitation.

Response: Thank you for the expert opinion. Although the study used three replicates, the experimental results showed good reproducibility.

5、“A random square design was used in the experiments.” Fully randomized or blocked?

Response: Based on the reviewer's comments, we have made the following modifications to the "Materials and Methods" section to more accurately describe our experimental design and statistical analysis. (Line 130-134)

6、Application rates of biochar, gypsum and straw seem very high, the economic and logistical challenges should be discussed in the article.

Response: Thank you for the reviewer's comments. We have added corresponding content to Line 109-121 in the article

Soil sampling and chemical analysis.

7、Sampling dates should be added.

Response: Thank you for the reviewer's comments and for adding the sampling time. (Line-200-202)

Determination of sunflower yield

8、“15 representative sunflower plants”. What were exact selection criteria? It is unclear. How was yield extrapolated from 15 plants to t/ha? What was plants spatial distribution within plots?

Response: Thank you for the reviewer's comments. We randomly selected fifteen plants and calculated the yield based on the known planting density per kilogram. Based on the average yield per plant of the fifteen plants, we can deduce the yield per hectare.

9、Basic yield components such as head diameter, seed number and thousand-seed weight could be added.

Response: Thank you for the reviewer's comments. We only included production in our statistics and did not include the aforementioned factors.

Discussion.

10、The main conclusions are directly supported by the presented results. Authors acknowledge main limitations of the study. Authors compare their results with both supportive and contradictory studies. However, some more recent studies should be cited, the amount of cited literature seems a bit brief.

Response: According to the reviewer's comments, citations of the latest literature have been added.

The Conclusions are acceptable in the current form.

11、In-text citations should be uniformed throughout the manuscript (sometimes two forms are used, for example “by Zhang et al. (2020) & Zhao et al. (2016) [31,32]” and sometimes just one of them (for example “[23,24” vs. “Wang et al., 2020”.

Response: Thank you for the reviewer's comments. We have standardized the citations throughout the text into numerical numbering format.

Literature

12、It is well picked with relatively new positions being cited, however, as I mentioned before, some more studies could be compared in the Discussion.

After the necessary revisions the article may be considered for publication.

Response: According to the reviewer's comments, we have added some literature citations in the discussion section to improve the content. (Line-442-451)

Reviewer 2 Report

Comments and Suggestions for Authors

The abstract generalizes to “sustainable agriculture” in the Hetao Area without acknowledging the short duration (two years), single site, and lack of long‑term salt balance or drainage monitoring. Temper the claim and state limitations up front.
In saline/sodic fields, salinity varies across short distances; without blocking in both directions (row–column designs), randomization alone often leaves baseline imbalance and reduces precision. Replace “random square design” with a row–column (two‑way) blocked design or at minimum a randomized complete block design and analyze as randomized (keep block effects in the model).
With drip on 1000‑m² plots in saline soils, lateral movement of water and salts between adjacent plots can occur if plots lack perimeter bunds or buffer alleys. Specify bunding, buffer widths, and whether drainage is shared or isolated.
Soil properties were sampled after each irrigation and at multiple depths over two years, but the analysis plan does not treat time/depth/plot correlations properly. Multi‑year field trials should use mixed models with repeated‑measures structures (e.g., AR (1) or unstructured covariance) and plot‑level random effects. Avoid per‑time ANOVAs or averaging across years without modeling interactions.
n=3 per treatment is common in field agronomy, but with high spatial variance, precision is limited—especially when testing depth×year×treatment effects. Consider increasing replicates or using designs that boost precision (row–column blocking, spatial analysis).
Gypsum requirement (GR) calculation is opaque.
The manuscript shows an equation fragment that is hard to interpret and doesn’t reference standard GR methods tied to target ESP reduction, soil CEC, soil bulk density, depth, and gypsum purity. Report full GR calculations (inputs: initial ESP or SAR of the exchange complex—not just solution SAR—target ESP, CEC, depth, bulk density, purity), cite standard references (USDA/ASA/FAO), and provide a worked example for 45 t·ha⁻¹.
FGD gypsum can contain trace metals and radionuclides; USDA NRCS Code 333 specifies screening and maximum allowable concentrations. Add a table of impurity screening results for the gypsum lot used (metals, radionuclides) and reference the standard.
Biochar characterization is insufficient for mechanism inference. Please, provide proximate/ultimate analyses (ash, fixed C, volatiles), surface area/porosity, pH/EC of char, exchange capacity, and soluble salt content—because some biochars add alkalinity/salts depending on feedstock and pyrolysis conditions. Current table lacks surface properties and soluble salts, which are central to the hypothesized mechanisms.
Rates of 22.5–45 t·ha⁻¹ are heavy and expensive to implement at scale. Add a short cost‑benefit paragraph with local prices and logistics or acknowledge feasibility limitations.
The manuscript should report and discuss both ECw and SARw against FAO irrigation water quality guidelines and sunflower salt tolerance, plus the leaching requirement concept and infiltration hazard matrix (SAR×EC).
FAO/USDA guidance emphasizes salt balance, leaching requirement, and drainage for saline irrigation. Provide the seasonal leaching fraction, any drainage observations, or at least a salt‑balance estimate to support statements about desalination.
Ambiguous phrase “surface tension −20 kPa.” Likely meant soil water potential (matric potential) setpoint (−20 kPa) rather than “surface tension.” Rephrase for clarity and provide sensor type/placement and irrigation control protocol.
International standards recommend ECe and SAR from the saturated paste extract for plant‑relevant salinity diagnosis; 1:5 extracts are acceptable for screening only if calibrated to ECe. Here, the text mixes 1:5 and saturation extract language and it is unclear which extract was actually used for EC, pH, and SAR. This undermines comparability to thresholds (e.g., ECe ≥ 4 dS·m⁻¹ standard). Please, clearly state the exact extract used (prefer saturated paste extract), and if 1:5 was used, provide and cite an empirical conversion to ECe for this soil texture range, or re‑measure on saturation extracts.
The equation is typeset in a way that obscures parentheses and units.
Only SO₄²⁻ is tracked over time; Cl⁻ and HCO₃⁻/CO₃²⁻ are not, yet the site is described as sulfate‑ and chloride‑rich saline‑alkali soil. Add Cl⁻ and HCO₃⁻ tracking (and exchangeable sodium percentage, ESP), which are crucial for mechanistic inferences about gypsum vs straw vs biochar.
The text attributes effects to biochar adsorption of Na⁺ and gypsum Ca²⁺–Na⁺ exchange, but does not report ESP, hydraulic conductivity, aggregate stability, or infiltration rate—key mechanistic endpoints per classic saline/sodic diagnostics. Either temper mechanistic claims or add these measurements (at least ESP and Ksat).
EC increase at 15–30 cm under gypsum is plausible (SO₄²⁻ addition), but without salt‑balance/leaching data, it is unclear whether salts are being redistributed rather than removed. Discuss this using FAO leaching concepts and consider presenting profile salt stocks (kg·ha⁻¹) over depth.
Yield was estimated from 15 plants per plot then scaled to area; this is prone to sampling error and edge effects. Standard agronomic practice harvests a fixed area (e.g., 2–10 m² quadrat) or the whole plot for yield. Re‑harvest a defined internal strip/area (avoid borders) or (if impossible) report a validation comparing the 15‑plant method to area harvest.
The manuscript attributes 2020 yield reductions to “heavy rain in July,” but provides no meteorological data (rainfall totals, timing). Include daily/weekly rainfall and ET₀ time series and discuss interactions with treatments (e.g., straw’s barrier effect).

Comments on the Quality of English Language

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

Author Response

Reviewer 2

1、The abstract generalizes to “sustainable agriculture” in the Hetao Area without acknowledging the short duration (two years), single site, and lack of long‑term salt balance or drainage monitoring. Temper the claim and state limitations up front.

Response: According to the reviewer's comments, we have added clear limitations and future prospects at the end of the relevant paragraphs. (Line 19-23)

2、In saline/sodic fields, salinity varies across short distances; without blocking in both directions (row–column designs), randomization alone often leaves baseline imbalance and reduces precision. Replace “random square design” with a row–column (two‑way) blocked design or at minimum a randomized complete block design and analyze as randomized (keep block effects in the model).

3、With drip on 1000‑m² plots in saline soils, lateral movement of water and salts between adjacent plots can occur if plots lack perimeter bunds or buffer alleys. Specify bunding, buffer widths, and whether drainage is shared or isolated.

Response: According to the reviewer's comments, we have added the following content in the "Materials and Methods" section to clearly explain the measures taken to prevent cross contamination. (Line 130-138)

4、Soil properties were sampled after each irrigation and at multiple depths over two years, but the analysis plan does not treat time/depth/plot correlations properly. Multi‑year field trials should use mixed models with repeated‑measures structures (e.g., AR (1) or unstructured covariance) and plot‑level random effects. Avoid per‑time ANOVAs or averaging across years without modeling interactions.

Response: Thank you for the reviewer's comments. I have optimized and explained the sampling method based on them. (Line 195-202)

5、n=3 per treatment is common in field agronomy, but with high spatial variance, precision is limited—especially when testing depth×year×treatment effects. Consider increasing replicates or using designs that boost precision (row–column blocking, spatial analysis).

Response: Thank you for the expert opinion. Although the study used three replicates, the experimental results showed good reproducibility.

6、Gypsum requirement (GR) calculation is opaque.

Response: Thank you for the expert's opinion. Please refer to Line 166-170 for detailed information on the demand for gypsum.

7、FGD gypsum can contain trace metals and radionuclides; USDA NRCS Code 333 specifies screening and maximum allowable concentrations. Add a table of impurity screening results for the gypsum lot used (metals, radionuclides) and reference the standard.

Response: Thank you for providing this important and professional opinion. We fully agree that ensuring the environmental safety of agricultural amendments, especially industrial by-products such as desulfurization gypsum, is crucial. This content was added to the text. (Line 186-193)

8、Biochar characterization is insufficient for mechanism inference. Please, provide proximate/ultimate analyses (ash, fixed C, volatiles), surface area/porosity, pH/EC of char, exchange capacity, and soluble salt content—because some biochars add alkalinity/salts depending on feedstock and pyrolysis conditions. Current table lacks surface properties and soluble salts, which are central to the hypothesized mechanisms.

Response: Thank you for the reviewer's comments. We have made supplements to the corresponding content. (Line 107-108)

9、Rates of 22.5–45 t·ha⁻¹ are heavy and expensive to implement at scale. Add a short cost‑benefit paragraph with local prices and logistics or acknowledge feasibility limitations.

Response: Thank you for the reviewer's comments. We have added corresponding content to Line 108-123 in the article.

10、The manuscript should report and discuss both ECw and SARw against FAO irrigation water quality guidelines and sunflower salt tolerance, plus the leaching requirement concept and infiltration hazard matrix (SAR×EC).

Response: Thank you for the reviewer's comments. According to the standards for agricultural irrigation water in China (query irrigation water standards), the irrigation water and soil related data are listed in Table 1, and the soil types are classified. (Line 90-94)

11、FAO/USDA guidance emphasizes salt balance, leaching requirement, and drainage for saline irrigation. Provide the seasonal leaching fraction, any drainage observations, or at least a salt‑balance estimate to support statements about desalination.

Response: In our research methodology, we provided detailed explanations on irrigation frequency and irrigation water volume, and supplemented monthly precipitation data. (Line 96-97)

12、Ambiguous phrase “surface tension −20 kPa.” Likely meant soil water potential (matric potential) setpoint (−20 kPa) rather than “surface tension.” Rephrase for clarity and provide sensor type/placement and irrigation control protocol.

Response: We have made corrections to the expression of surface tension in our research methodology. (Line-157)

13、International standards recommend ECe and SAR from the saturated paste extract for plant‑relevant salinity diagnosis; 1:5 extracts are acceptable for screening only if calibrated to ECe. Here, the text mixes 1:5 and saturation extract language and it is unclear which extract was actually used for EC, pH, and SAR. This undermines comparability to thresholds (e.g., ECe ≥ 4 dS·m⁻¹ standard). Please, clearly state the exact extract used (prefer saturated paste extract), and if 1:5 was used, provide and cite an empirical conversion to ECe for this soil texture range, or re‑measure on saturation extracts.

Response: According to the reviewer's comments, the statement of using deionized water to extract soil for the determination of EC and SAR has been unified. (Line204-214)

14、The equation is typeset in a way that obscures parentheses and units.

Response: The layout of the equation has been revised and changed.

15、Only SO₄²⁻ is tracked over time; Cl⁻ and HCO₃⁻/CO₃²⁻ are not, yet the site is described as sulfate‑ and chloride‑rich saline‑alkali soil. Add Cl⁻ and HCO₃⁻ tracking (and exchangeable sodium percentage, ESP), which are crucial for mechanistic inferences about gypsum vs straw vs biochar.

Response: In this study, desulfurization gypsum was mainly added, so the changes in sulfate ions in different soil layers were quite drastic. Therefore, the ion content of desulfurization gypsum in the soil was mainly detected. Subsequent experiments will detect other ions to improve the understanding of ion migration and distribution in soil under different improvement conditions.

16、The text attributes effects to biochar adsorption of Na⁺ and gypsum Ca²⁺–Na⁺ exchange, but does not report ESP, hydraulic conductivity, aggregate stability, or infiltration rate—key mechanistic endpoints per classic saline/sodic diagnostics. Either temper mechanistic claims or add these measurements (at least ESP and Ksat).

Response: Relevant literature was cited to provide explanations for this section. (Line 489-504)

17、EC increase at 15–30 cm under gypsum is plausible (SO₄²⁻ addition), but without salt‑balance/leaching data, it is unclear whether salts are being redistributed rather than removed. Discuss this using FAO leaching concepts and consider presenting profile salt stocks (kg·ha⁻¹) over depth.

Response: According to the reviewer's comments, we have added some references to illustrate that increasing irrigation and leaching effects lead to the migration of salt to deeper layers, increasing the salt content below the soil surface. (Line-489-504)

18、Yield was estimated from 15 plants per plot then scaled to area; this is prone to sampling error and edge effects. Standard agronomic practice harvests a fixed area (e.g., 2–10 m² quadrat) or the whole plot for yield. Re‑harvest a defined internal strip/area (avoid borders) or (if impossible) report a validation comparing the 15‑plant method to area harvest.

Response: As per the first suggestion, the determination of yield per hectare with a planting density of 3.3 × 10 ⁴ plants was repeated three times, and the results showed good reproducibility.

19、The manuscript attributes 2020 yield reductions to “heavy rain in July,” but provides no meteorological data (rainfall totals, timing). Include daily/weekly rainfall and ET₀ time series and discuss interactions with treatments (e.g., straw’s barrier effect).

Response: According to the reviewer's comments, the description of rainfall conditions has been revised, and Line-399 provides corresponding meteorological data. (Line-96-97)

Reviewer 3 Report

Comments and Suggestions for Authors

Dear authors,

The manuscript "Biochar improved saline-alkali barrier and sunflower yield under drip irrigation" addresses an important and current topic regarding the improvement of saline soils. The study conducted in Hetao Region has scientific and applicable relevance, but certain aspects of the presentation of information in the manuscript require clarification or improvement. My recommendations are attached.

Best regard!

Comments for author File: Comments.pdf

Author Response

Avoid using keywords that are part of the article title

Response: According to the reviewer's comments, the keywords have been modified. (Line 24-25)

2、Standardize the spelling of the word desulfurized or de-sulfurized;

Response: Unified and standardized the word 'desulfurized'.

3、In the Materials and Methods section, item 2.1 should include a map showing the location of the experimental area;

Response: According to the reviewer's comments, additional map photos of Hangjinhou Banner have been added (Line-89).

4、Item 2.3 should include a graphic illustration of the experimental design; In Figure 2, it is soil bulk and not dulk;

Response: According to the reviewer's comments, the content has been supplemented. (Line 140-141).Change dulk to bulk （Line 272-274）

5、Figures 3a and 3b are the same as figures 2a and 2b, with the same typing error! Given the repetition, I recommend keeping only the figure 3, as it is better for illustrating the variations in properties comparatively.

Response: According to the reviewer's comments, we have removed Figure 2 and corrected the errors in the image.

6、On page 11, the citation “(Wang et al., 2020)” is outside the citation norms and was not included in the references.

Response: The reference format in the article has been uniformly adjusted

7、In the references, the year should be in bold.

Response: According to the reviewer's comments, change the year of all references to bold.

8、The references should be corrected, specifically regarding the way authors' names are presented: Surname followed by the initials of their first names.

Response: Correct the presentation of names in the references.

9、In the references, I strongly recommend including the DOI of the publications.

Response: Supplemented the reference DOI.

Regarding the content:

10、-In the materials and methods, I believe they could also include the implementation costs of the treatments for each experimental plot and whether the gain in agricultural production obtained compensated for the costs of the treatments. This is to estimate the implementation costs in large agricultural areas. In this aspect, the authors point out the limitation due to the high implementation costs of these measures. However, could such costs be reduced by scale and also by the growth in sunflower production?

Response: Thank you for the reviewer's comments. We have added corresponding content to lines 109-124 in the article.

11、In the materials and methods, I believe they could also have adopted mixed management, such as: 1) Drip irrigation coupled with biochar and desulfurized gypsum; 2) Drip irrigation coupled with biochar and straw return and other combinations.

Response: According to the reviewer's comments, it is very valuable for the treatment of saline alkali soil and agricultural yield increase in the local area. We have added follow-up experimental suggestions in the discussion. (Line 539-547)

12、In the discussions, the article lacks an item that addresses the limitations of the study and the prospects for the use of these treatments in areas intended for agricultural production. Because the success of the experimental plots in improving the conditions of salinized and alkalized soils and agricultural production will only be effective if it can be used more widely.

Response: According to the reviewer's comments, we have provided additional explanations for the above content in both the discussion and abstract. (Line 19-23) (Line 539-547)

13、The discussions should better develop the issue of the study's limitation due to saturated soil caused by heavy rain in July 2020, which would explain the lower production that year. Because it seems that the treatments were not effective under these saturated soil conditions and, therefore, comparisons with the following year (2021) should be made with great care or perhaps even ignored. Because it is not possible to consider that the higher production in 2021 resulted from the continuous effect of the treatments.

The study's conclusions should not be generic for the entire study period, but should be considered year by year. Because, even with the rainy event, in the first year, production increased compared to drip irrigation in all three treatments.

Response: Correct the above discussion content. (Line 531-543)

Reviewer 4 Report

Comments and Suggestions for Authors

Review of article ID agronomy-4108508: “Biochar improved saline-alkali barrier and sunflower yield under drip irrigation”, submitted to the journal Agronomy.

Special Issue: Advances in Soil Remediation Techniques for Degraded Land

The article aims to evaluate how to improve sunflower productivity in an arid region, based on the performance of different management alternatives, such as biochar, dehydrated gypsum, and straw, in saline and alkaline soils with drip irrigation.

The field experiment was conducted in Sandaoqiao, Hetao Region, Inner Mongolia, China, from May to October 2020 and 2021, with the following treatments: drip irrigation alone; drip irrigation coupled with biochar; drip irrigation coupled with desulfurized gypsum; and drip irrigation coupled with straw returning. Each 25 x 40 m experimental plot was replicated 3 times, using a randomized square design. The results were subjected to statistical analysis with a degree of significance.

The article should be subjected to careful review for possible publication.

In terms of structure, the article is well organized and without major typing or writing problems. Observations were made in the form of comments in the attached file. Thus, the authors should pay sufficient attention to the following aspects:

- Avoid using keywords that are part of the article title;

- Standardize the spelling of the word desulfurized or de-sulfurized;

- In the Materials and Methods section, item 2.1 should include a map showing the location of the experimental area;

- Item 2.3 should include a graphic illustration of the experimental design;

- In Figure 2, it is soil bulk and not dulk;

- Figures 3a and 3b are the same as figures 2a and 2b, with the same typing error! Given the repetition, I recommend keeping only the figure 3, as it is better for illustrating the variations in properties comparatively.

- On page 11, the citation “(Wang et al., 2020)” is outside the citation norms and was not included in the references.

- In the references, the year should be in bold.

- The references should be corrected, specifically regarding the way authors' names are presented: Surname followed by the initials of their first names.

In the references, I strongly recommend including the DOI of the publications.

Regarding the content:

- In the materials and methods, I believe they could also include the implementation costs of the treatments for each experimental plot and whether the gain in agricultural production obtained compensated for the costs of the treatments. This is to estimate the implementation costs in large agricultural areas. In this aspect, the authors point out the limitation due to the high implementation costs of these measures. However, could such costs be reduced by scale and also by the growth in sunflower production?

- In the materials and methods, I believe they could also have adopted mixed management, such as: 1) Drip irrigation coupled with biochar and desulfurized gypsum; 2) Drip irrigation coupled with biochar and straw return and other combinations.

- In the discussions, the article lacks an item that addresses the limitations of the study and the prospects for the use of these treatments in areas intended for agricultural production. Because the success of the experimental plots in improving the conditions of salinized and alkalized soils and agricultural production will only be effective if it can be used more widely.

- The discussions should better develop the issue of the study's limitation due to saturated soil caused by heavy rain in July 2020, which would explain the lower production that year. Because it seems that the treatments were not effective under these saturated soil conditions and, therefore, comparisons with the following year (2021) should be made with great care or perhaps even ignored. Because it is not possible to consider that the higher production in 2021 resulted from the continuous effect of the treatments.

- The study's conclusions should not be generic for the entire study period, but should be considered year by year. Because, even with the rainy event, in the first year, production increased compared to drip irrigation in all three treatments.

Comments for author File: Comments.pdf

Author Response

Avoid using keywords that are part of the article title

Response: According to the reviewer's comments, the keywords have been modified. (Line 24-25)

2、Standardize the spelling of the word desulfurized or de-sulfurized;

Response: Unified and standardized the word 'desulfurized'.

3、In the Materials and Methods section, item 2.1 should include a map showing the location of the experimental area;

Response: According to the reviewer's comments, additional map photos of Hangjinhou Banner have been added (Line-89).

4、Item 2.3 should include a graphic illustration of the experimental design; In Figure 2, it is soil bulk and not dulk;

Response: According to the reviewer's comments, the content has been supplemented. (Line 140-141).Change dulk to bulk （Line 272-274）

Response: According to the reviewer's comments, we have removed Figure 2 and corrected the errors in the image.

6、On page 11, the citation “(Wang et al., 2020)” is outside the citation norms and was not included in the references.

Response: The reference format in the article has been uniformly adjusted

7、In the references, the year should be in bold.

Response: According to the reviewer's comments, change the year of all references to bold.

8、The references should be corrected, specifically regarding the way authors' names are presented: Surname followed by the initials of their first names.

Response: Correct the presentation of names in the references.

9、In the references, I strongly recommend including the DOI of the publications.

Response: Supplemented the reference DOI.

Regarding the content:

Response: Thank you for the reviewer's comments. We have added corresponding content to lines 109-124 in the article.

Response: According to the reviewer's comments, we have provided additional explanations for the above content in both the discussion and abstract. (Line 19-23) (Line 539-547)

Response: Correct the above discussion content. (Line 531-543)

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for your reply to all my comments. In my opinion the manuscript was sufficiently improved as missing information was added, issues were corrected and the number of cited literature was increased.

The article can be considered for the publication in the current form.

Author Response

Thank you for your suggestions on improving the quality of this article

Reviewer 2 Report

Comments and Suggestions for Authors

Authors are instructed to ensure that all revisions are clearly and distinctly marked, with newly introduced changes explicitly highlighted.

Author Response

Thank you for your suggestions on improving the quality of this article

Reviewer 4 Report

Comments and Suggestions for Authors

Review of article ID agronomy-4108508-v2: “Biochar improved saline-alkali barrier and sunflower yield under drip irrigation”, submitted to the journal Agronomy.

Special Issue: Advances in Soil Remediation Techniques for Degraded Land

The authors met a good part of the recommendations made by this reviewer. And many of them were not adequately met, considering the criteria for publication in the journal Agronomy.

Regarding the format:

The location map of the study area was included (figure 1), however with details that are difficult to visualize.

Figure 2 on the annual variation of temperature and precipitation was included, but without proper citation and contextualization in the study.

An illustration of the experimental design was included, with a title containing an acronym not identified in the article. The illustration also does not present the figure caption, which, therefore, should be figure 3.

Figure 1 of version v1 remains as figure 1.

Figure 2 of version v1 was duly excluded.

Figures 3, 4, 5, and 6 in version v1 retain the same numbering.

These numbering errors in the figures make the article difficult to understand.

Citations in the article should be corrected, avoiding superscripts.

In the first paragraph of the discussion, Wang was cited, but shouldn't it be Wang et al.? However, it doesn't correspond to reference 21, but rather to 20! In the first paragraph of the discussion, Wang was cited, but shouldn't it be Wang et al.? However, it doesn't correspond to reference 21, but rather to 20!

The references should be reviewed again, because despite the corrections made, they do not fully comply with the standard: There is a publication year without bolding; journal name without italics, and references without the DOI.

Thus, in general, in this v2 the authors supplemented the content as suggested. However, the formatting, even more confusing than v1, makes it difficult to understand the content.

Comments for author File: Comments.pdf

Author Response

Thank you for your suggestions on improving the quality of this article

1、The location map of the study area was included (figure 1), however with details that are difficult to visualize.

Response: We have optimized Figure 1 based on the reviewer's suggestions to enhance its readability. Line 84-85

2、Figure 2 on the annual variation of temperature and precipitation was included, but without proper citation and contextualization in the study.

Response: We have made the following modifications to the main text of the manuscript. Line 78-81

3、An illustration of the experimental design was included, with a title containing an acronym not identified in the article. The illustration also does not present the figure caption, which, therefore, should be figure 3.

Response: According to expert opinions, the illustrations in the article have been supplemented and explained. Line 117-121

4、Figure 1 of version v1 remains as figure 1.Figure 2 of version v1 was duly excluded.Figures 3, 4, 5, and 6 in version v1 retain the same numbering. These numbering errors in the figures make the article difficult to understand.

Response: Corrected the incorrect numbering in the text.

5、Citations in the article should be corrected, avoiding superscripts.

Response: Correct incorrect references in the text.

6、In the first paragraph of the discussion, Wang was cited, but shouldn't it be Wang et al.? However, it doesn't correspond to reference 21, but rather to 20! In the first paragraph of the discussion, Wang was cited, but shouldn't it be Wang et al.? However, it doesn't3 correspond to reference 21, but rather to 20!

Response: Corrected incorrect references.

7、The references should be reviewed again, because despite the corrections made, they do not fully comply with the standard: There is a publication year without bolding; journal name without italics, and references without the DOI.

Thus, in general, in this v2 the authors supplemented the content as suggested. However, the formatting, even more confusing than v1, makes it difficult to understand the content.

Response: Corrections have been made to the references