Acidity and Salinization of Soil Following the Application of Ashes from Biomass Combustion Under Different Crop Plant Species Cultivation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors   1 The article should justify why it was chosen to study ash with such a composition, which has more than twice the potassium concentration and relatively low sodium concentration. 2 It would be good to provide data on the amount of precipitation that fell during the field experiment and describe in more detail the conditions that led to greater leaching of alkaline elements, as it was a significant factor in reducing soil salinity in this experiment. 3. The expediency of citing literary source 26 is questionable.    

Author Response

Response to Reviewer 1 Comments

The authors are grateful for the contribution of the reviewer. Numerous errors were removed and various sections of the manuscript were improved.

 

Point 1: The article should justify why it was chosen to study ash with such a composition, which has more than twice the potassium concentration and relatively low sodium concentration

 

Response 1: The description has been changed throughout of manuscript to justify this issue (lines 94 - 98 and 107 – 113.

Lines 94-98: “The BAs used in the experiment was sourced from a combined heat and power plant that combusts forest and agricultural biomass. This BAs is distributed as a product for fertilizing agricultural land. However, its application is not subjected to monitoring. The BAs utilized in the experiment originated from burning forest and agricultural biomass in a fluidized bed furnace. Specifically, the BAs were generated from approximately 70% forest biomass and 30% agricultural biomass. The forest biomass consisted of a balanced mix of deciduous and coniferous trees (50/50), while the agricultural biomass included components such as cereal straw, sunflower husks, and willow. Throughout the entire experiment, BAs with consistent properties were employed”.

Lines 107-113: “The variants of the experiment differed in the dose of potassium fertilization; this component accounted for the largest proportion of the ash used in the experiment which is related to biomass combustion technology [27]”.

Point 2: It would be good to provide data on the amount of precipitation that fell during the field experiment and describe in more detail the conditions that led to greater leaching of alkaline elements, as it was a significant factor in reducing soil salinity in this experiment.

Response 2: Table S2 - Meteorological conditions during the study period (2019–2021) and the corresponding description of the weather conditions have been added to the Supplementary materials (Table S2). Weather conditions were also referenced in the discussion:

“According to the data presented in Table S2, the individual years of the experiment varied in this regard. In the second year of the study, there were the highest rainfall amounts, with an annual total of 792.4 mm. In contrast, the third year recorded the lowest rainfall total of 610.3 mm. As a result, the distribution of nutrients introduced into the soil with BAs could differ from year to year. In years with lower rainfall, the solubility of the constituents in BAs might have been lower compared to the second year of the experiment when there was higher precipitation. With more rainfall, it can be assumed that the solubility of the components in BAs was greatest, particularly concerning K. For this reason, a significant increase in K content in the soil after the application of BAs was generally not observed”.

Point 3: The expediency of citing literary source 26 is questionable.

Response 3: The nomenclature and methods for determining soil hydrolytic acidity (HAC), cation exchange capacity (CEC), total exchangeable bases (TEB), and others were taken from this work; therefore, it is necessary to cite this manuscript.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This paper delves into the impact of biomass combustion ashes (BAs) on soil acidity and salinity, particularly the mechanisms of pH and salinity changes under different plant cultivation conditions. To further enhance the quality and scientific rigor of the article, the following revisions are suggested:

1. When proprietary nouns (such as BAs and various elements) first appear in the article, please indicate their abbreviations and consistently use them in subsequent descriptions. Currently, there are multiple repeated descriptions in the article, which affect its brevity.
2. When mentioning the biomass ash handling situation in the EU in lines 42-43 “Energy production in the EU generates 11 million tons of waste materials per year, including sludge and ash from biomass combustion (BAs).”, it is recommended to supplement with the latest statistical data and reliable sources to enhance the timeliness and accuracy of the article.
3. The content in lines 130-140 seems inconsistent with the results and discussion section. It is suggested to reorganize the language or adjust it to the introduction section to maintain the coherence of the article structure.
4. There is an error in the title of Figure 2. Please correct it to ensure that readers can accurately understand the chart content.
5. In lines 199-204, the literature citation format is incorrect. Please unify the format and carefully check the entire article to ensure that all citations comply with the norms.
6. In lines 212-215, when mentioning " Considering the results of the present study and the conclusions of the cited authors...", please supplement with specific references for readers to consult and verify.
7. When discussing the changes in soil pH, HAC, EC, and salinity caused by BAs, the author only briefly describes the results but lacks a deep exploration of the possible biological and chemical mechanisms involved, as well as a detailed analysis of the potential impact on the growth of different crops. It is suggested to reduce the repeated description of the results and instead increase the discussion of the influence mechanisms, providing readers with more valuable insights.

Comments on the Quality of English Language

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

Author Response

Response to Reviewer 2 Comments

The authors appreciate the reviewer's contributions. Numerous errors have been corrected, and various sections of the manuscript have been enhanced. All changes made throughout the manuscript are highlighted in yellow.

 

Point 1: When proprietary nouns (such as BAs and various elements) first appear in the article, please indicate their abbreviations and consistently use them in subsequent descriptions. Currently, there are multiple repeated descriptions in the article, which affect its brevity.

Response 1: Nomenclature has been standardized throughout the manuscript.

Point 2: When mentioning the biomass ash handling situation in the EU in lines 42-43 “Energy production in the EU generates 11 million tons of waste materials per year, including sludge and ash from biomass combustion (BAs).”, it is recommended to supplement with the latest statistical data and reliable sources to enhance the timeliness and accuracy of the article.

Response 2: The description has been modified according to the reviewer's comments. Appropriate citations have been added.

“Renewable energy sources represent cleaner alternatives to fossil fuels. In 2022, energy from renewable sources accounted for 23% of energy consumption in the European Union. In 2023, lawmakers increased the EU target for the share of renewable energy in gross energy consumption from 32% to 42.5% by 2030, aiming to reach 45% [1]. Biomass is currently the most commonly used alternative to fossil fuels for heat and energy production. Biomass is considered a carbon-neutral fuel, which can help reduce greenhouse gas emissions. However, the combustion of biomass generates large quantities of ash, currently estimated at about 50 Mt/year in Europe [2].”

Point 3: The content in lines 130-140 seems inconsistent with the results and discussion section. It is suggested to reorganize the language or adjust it to the introduction section to maintain the coherence of the article structure.

Response 3: This description, after editing, has been moved to the Introduction section. Please see lines: 72-79.

Point 4: There is an error in the title of Figure 2. Please correct it to ensure that readers can accurately understand the chart content.

Response 4: The error has been corrected: “Figure 2. Effect of ashes from biomass combustion on soil HAC under the cultivation of various crops species (mean±SE)”

Point 5: In lines 199-204, the literature citation format is incorrect. Please unify the format and carefully check the entire article to ensure that all citations comply with the norms.

Response 5: The literature citation format has been improved and standardized throughout the manuscript.

 

Point 6: In lines 212-215, when mentioning " Considering the results of the present study and the conclusions of the cited authors...", please supplement with specific references for readers to consult and verify.

Point 7: When discussing the changes in soil pH, HAC, EC, and salinity caused by BAs, the author only briefly describes the results but lacks a deep exploration of the possible biological and chemical mechanisms involved, as well as a detailed analysis of the potential impact on the growth of different crops. It is suggested to reduce the repeated description of the results and instead increase the discussion of the influence mechanisms, providing readers with more valuable insights.

Response 6 and 7: The Results and Discussion section has been extensively revamped. Redundant data descriptions have been eliminated, and the discussion on potential factors influencing the obtained results has been expanded. Please see the Results and Discussion section.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Journal: applied sciences

Title: Acidity and salinization of soil after application of ashes from biomass combustion

MS No. applsci-3260527

 

The authors conducted cultivation experiments and assessed the impact of BAs on changes in pH and salinity, and total forms of Ca, Mg, K, and Na of luvisol soil under the cultivation of various plant species.

 

Application of ashes from biomass combustion is a traditional topic no matter in view of salinization or fertilization of acidic soil. Thus, the novelty of this paper is not clear.

 

According to the design by authors, the same ash, same soil but different plant species, thus, the attention should be paid to different plant species. However, the reviewer did not find the reasons that the results for different plants varied. In addition, the authors emphasized that “One major issue is the considerable variability in the chemical composition of BAs, which results from factors such as the type, origin, and combustion temperature of the biomass”. However, only ONE ash was used in this paper (Table S1). Moreover, because the basic components of biomass were not known, we could induce why considerable variability in the chemical composition of led to different results. The objectives of this paper are not clear.

 

Title: “various plant species” should be included.

L18-21, what kind of biomass used should be indicated.

L37, the significance of this study should be pointed out.

L64-66, 76-77, such being the case, why were the corresponding experiments not designed?

L63-75, various plant species was not concerned, It is not reasonable.

L77-81, the content on various plant species should be included.

L87-88, as mentioned above, the basic components of biomass should be given.

L93, Table S1, more information about the ash should be added, such as carbonate (K2CO3, CaCO3).

L95 and Table 1, in general, the unit for CEC is cmol/kg.

L125, only 70% HClO4 is sufficient for digestion of soil?

L125-126, another Section should be designed in order to illustrate the methods in detail.

L130-149, the descriptions do not belong to “Results and discussion”, but background.

L169-173 and the following texts, the reasons that the results for different plants are too farfetched.

 

In view of the above, the paper should be rejected.

Author Response

Response to Reviewer 3 Comments

The authors appreciate the reviewer's contributions. Numerous errors have been corrected, and various sections of the manuscript have been enhanced. All changes made throughout the manuscript are highlighted in yellow.

Point 1: Application of ashes from biomass combustion is a traditional topic no matter in view of salinization or fertilization of acidic soil. Thus, the novelty of this paper is not clear.

Point 2: According to the design by authors, the same ash, same soil but different plant species, thus, the attention should be paid to different plant species. However, the reviewer did not find the reasons that the results for different plants varied. In addition, the authors emphasized that “One major issue is the considerable variability in the chemical composition of BAs, which results from factors such as the type, origin, and combustion temperature of the biomass”. However, only ONE ash was used in this paper (Table S1). Moreover, because the basic components of biomass were not known, we could induce why considerable variability in the chemical composition of led to different results. The objectives of this paper are not clear.

 

Response 1 and 2: We agree that the application of ashes from biomass combustion is a well-established topic in the literature, addressing both salinization and the fertilization of acidic soils. However, it is essential to consider specific factors that influence this impact, such as soil type, climatic conditions, and others. Our research was conducted under field conditions over a three-year period. In these conditions, certain changes may be challenging to observe; nonetheless, such experiments are crucial for accurately assessing the effects of BAs on the environment.

Our objective was to focus on particular aspects of BAs usage, particularly their effects on different plant species. We believe that the diversity of plant responses to BAs can provide valuable insights into existing knowledge on this subject.

We acknowledge that only one type of ash was used in this study and that the differences in results for various plant species warrant further explanation, even though they were generally minor. We have thoroughly revised the Results and Discussion section to explore the potential reasons for the observed results in greater detail. The decision to use a single type of ash with a consistent composition was intentional, given the potentially variable compositions of such materials. Utilizing ash with even slight differences in chemical composition would complicate drawing meaningful conclusions.

The selected ash is sourced from a local combined heat and power plant and possesses consistently comparable properties due to the uniformity in biomass feedstock. Its favorable chemical composition makes it an attractive substitute for farmers, who often use it in place of other fertilizers, such as calcium-magnesium or potassium products. However, the application of this BAs to soils is not further monitored, underscoring the significance of our research.

Furthermore, we wish to emphasize that the aspects discussed in this paper represent only a part of a larger body of ongoing research in this area, which includes investigating the effects of these materials on soil nutrient levels, organic matter properties, and physical characteristics. This research will be subjected to another manuscript. We believe that our study makes a significant contribution to understanding this topic.

Action taken: according to Reviewer 3 comments, numerous improvements throughout the manuscript were provided, especially in Introduction and Results and Discussion sections.

 

Point 3: Title: “various plant species” should be included.

 

Response 3: The title of the manuscript has been changed: “Acidity and Salinization of Soil Following the Application of Ashes from Biomass Combustion Under Different Crop Plant Species Cultivation”

Point 4: L18-21, what kind of biomass used should be indicated.

Point 5: L37, the significance of this study should be pointed out.

Response 4 and 5: Additional description has been added: “The BAs used in the experiment was sourced from a combined heat and power plant that combusts forest and agricultural biomass. This BAs is distributed as a product for fertilizing agricultural land. However, its application is not subjected to further monitoring”.

Point 6: L64-66, 76-77, such being the case, why were the corresponding experiments not designed?

Response 6: In these lines offer general information supported by relevant citations. As explained in Section 1, the study utilized a single type of ash consistently over the three years of research. The focus of the study was on the impact of BAs on soil conditions, while the technological aspects of ash production were not analyzed.

 

Point 7: L63-75, various plant species was not concerned, It is not reasonable.

Response 7: In these lines offer general information supported by relevant citations.

Point 8: L77-81, the content on various plant species should be included.

Response 8: Proper description has been added: “The BAs used in the experiment was sourced from a combined heat and power plant that combusts forest and agricultural biomass. This BAs is distributed as a product for fertilizing agricultural land. However, its application is not subjected to monitoring. Therefore, the conducted research analyzed the impact of BAs with a consistent composition, applied uniformly over three years, on selected properties of Haplic luvisol soil (pH, hydrolytic acidity (HAC), electrical conductivity (EC), and the concentration of Ca, Mg, K, and Na). The effects of BAs application were also examined in relation to different cultivated crop plants—spring barley, winter oilseed rape, and potatoes—which further may modified soil properties”.

Point 9: L87-88, as mentioned above, the basic components of biomass should be given.

Response 9: Additional description has been added: “The BAs utilized in the experiment originated from burning forest and agricultural biomass in a fluidized bed furnace. Specifically, the BAs were generated from approximately 70% forest biomass and 30% agricultural biomass. The forest biomass consisted of a balanced mix of deciduous and coniferous trees (50/50), while the agricultural biomass included components such as cereal straw, sunflower husks, and willow”.

Point 10: L93, Table S1, more information about the ash should be added, such as carbonate (K2CO3, CaCO3).

Response 10: In our studies, only the elemental composition of BAs was analyzed. Indeed, in subsequent studies it would be worthwhile to also provide the content of individual compounds.

Point 11: L95 and Table 1, in general, the unit for CEC is cmol/kg.

Response 11: The units have been corrected.

 

Point 12: L125, only 70% HClO4 is sufficient for digestion of soil?

Response 12: The 70% HClO4 is sufficient and proper for soil digestion as pointed out in  citing literature [position no 33].

Point 13: L125-126, another Section should be designed in order to illustrate the methods in detail.

Response 13: The presented manuscript provides a continuous description of the research methodology used in the experiment. In our opinion, this description contains all the necessary information.

Point 14: L169-173 and the following texts, the reasons that the results for different plants are too farfetched.

Response 14: The entire Results and Discussion section has been thoroughly revised. Potential causes of the results obtained have been explained in detail. Please see the Results and Discussion section.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Although the author has made revisions based on previous review comments and the manuscript quality has improved, there are still significant deficiencies in writing norms. For example, there is no need to unnecessarily capitalize the initial letter for non-specific nouns (such as "Haplic luvisol soil"). There are both grammatical errors and word spelling mistakes. Furthermore, the image quality is extremely poor, far from meeting the required 300dpi standard, with the numbers in the figures being completely illegible. The author must submit separate high-resolution images, or else bear the consequences.

Comments on the Quality of English Language

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

Author Response

Response to Reviewer 2 Comments

The authors appreciate the reviewer's contributions. Numerous errors have been corrected. All changes made throughout the manuscript are highlighted in “marked manuscript”.

Point 1: Although the author has made revisions based on previous review comments and the manuscript quality has improved, there are still significant deficiencies in writing norms. For example, there is no need to unnecessarily capitalize the initial letter for non-specific nouns (such as "Haplic luvisol soil"). There are both grammatical errors and word spelling mistakes. Furthermore, the image quality is extremely poor, far from meeting the required 300dpi standard, with the numbers in the figures being completely illegible. The author must submit separate high-resolution images, or else bear the consequences.

Response 1: The manuscript has undergone thorough linguistic proofreading, and typographical and stylistic errors have been corrected. All figures included in the manuscript have been enhanced in terms of quality. Additionally, the figures have been sent as separate files.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This is a revised paper. 

Although the reviewer suggested the rejection for this paper, going through the responses by authors and the revision version of paper, the reviewer thinks that the revision is substaintial and OK at large.

The paper could be accepted.

Author Response

Response to Reviewer 3 Comments

Although the reviewer suggested the rejection for this paper, going through the responses by authors and the revision version of paper, the reviewer thinks that the revision is substaintial and OK at large.

The paper could be accepted.

The authors are grateful for the contribution of the reviewer process and the positive evaluation of the manuscript.

Author Response File: Author Response.pdf