The Role of Leaching in Soil Carbon, Nitrogen, and Phosphorus Distributions in Subalpine Coniferous Forests on Gongga Mountain, Southwest China
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear authors,
The research presented in this manuscript is very interesting, as it deals with element leaching in subalpine conifoerous forests of China. All sections are presented clearly. Introduction and Discussion are well written and give relatively detailed connections to other relevant works in this research sphere. My comments are mostly related to the quality of English, which can be improved (some of the noticed flaws are pointed out in the comments below), some small technical errors, and a few comments about the soil taxonomy, as well as laboratory methods and equipment used.
Lines 1-3: I’d suggest adding more precise location to the title.
Line 67: „attentions“ → „attention“ (it doesn't necessarily need to be changed, and is probably allright as such, but I'd still use singular in this particular case).
Line 71, 80, 99, 103 etc.: what is „Craib“?
Line 95: „relatively“ → „respectively“
Lines 96-97: I’d advise using soil taxonomy criteria suggested by WRB or FAO, „brown forest soil“ and „dark-brown forest soil“ is not descriptive enough to global readers.
Lines 104-107: Reformulate the sentence. Especially the part „which the spacing of each profile was larger than 10 m“
Lines 106-107: If possible, please state the reference to the taxonomy used. I’d suggest using the term „subsoil mineral“ (in order to match the „surface mineral“ A horizon) rather than „illuvial“ unless elluviation/illuviation is clearly present, together with an overlying E horizon. B horizons can occur not only through illuviation, but through modification of the underlying parent material (as it commonly occurs in Cambisols, where they are classified as Bv). For the A horizon, also consider using the term „organo-mineral“.
Line 111: „...horizons respectively“ → „horizons, respectively“
Line 122-123: Please state the make and model of the analyzer.
Line 139: „which were special at the S2 site“ – what does this mean? „Especially noticeable at S2 site“ or there are some other specifics? Please clarify; „highest“ → „the highest“
Lines 140 and 141: „lowest“ → „the lowest“
Line 144: „highest“ → „the highest“
Lines 148-149: reformulate „whereas Feox and Alox in B and C horizons exhibited significantly higher compared to other horizons (P < 0.05).“
Line 162: „a significantly decrease“ → reformulate
Lines 164-165: reformulate
Line 170: „lowest“ → „the lowest“
Line 187: not fully neccessary, but I’d advise formatting Figure 3 into a somewhat more readable manner. Some of the graphs, and especially numbers, are very small.
Line 224: See the comment for lines 96-97
Line 229: reformulate „compared with in soil leachate“
Line 233: „Piceacrassifolia“ → „Picea crassifolia”
Line 286: „was“ → „were”
Have a wonderful day, good luck and keep up the good work!
Comments on the Quality of English LanguageModerate editing of English in needed. Some sentences need to be reformulated. Specific comments can be found in the comments to authors.
Author Response
Comments 1: [Lines 1-3: I’d suggest adding more precise location to the title.].
Response 1: Thank you for pointing this out. We have made the change to the title to better reflect the focus of our study: “The Role of Leaching in Soil Carbon, Nitrogen, and Phosphorus Distributions in Subalpine Coniferous Forests on Mt. Gongga, Southwest China”. (Lines 2-4 of the revised manuscript)
Comments 2: [Line 67: „attentions“ → „attention“ (it doesn't necessarily need to be changed, and is probably allright as such, but I'd still use singular in this particular case).]
Response 2: We have modified the text to: “Therefore, it is important to focus on the influences of leaching on the altitudinal distributs of soil C, N, and P.” on lines 71-72 of the revised manuscript.
Comments 3: [Line 71, 80, 99, 103 etc.: what is „Craib“?]
Response 3: In accordance with the naming regulations outlined in the International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code, 2017), the complete scientific name of the plant species investigated in this study area is Abies fabri (Mast.) Craib.
Comments 4: [Line 95: „relatively“ → „respectively“]
Response 4: The correction has been made on line 99 of the revised manuscript.
Comments 5: [Lines 96-97: I’d advise using soil taxonomy criteria suggested by WRB or FAO, „brown forest soil“ and „dark-brown forest soil“ is not descriptive enough to global readers.]
Response 5: In order to provide a clear description to all readers, we have used two soil classification criteria. According to the China soil classification system, the soil types are identified as brown forest soil at elevations of 2600-2800 m, and dark-brown forest soil at elevations of 2800-3200 m [26]. Additionally, based on the world reference base (WRB) for soil resources [27], the soil types are classified as Cambisols at the 2628 m site and Luvisols at the 2781 and 3044 m site, as illustrated in Figure 1. (Lines 100-104 of the revised manuscript)
Comments 6: [Lines 104-107: Reformulate the sentence. Especially the part „which the spacing of each profile was larger than 10 m“]
Response 6: This statement was modified as: “Each site included six randomly selected soil profiles with a slope less than 30° and profiles spaced at intervals greater than 10 m. These profiles were classified into five horizons, including OL, O, A, B, and C horizons (Figure 1).” (Lines 111-113 of the revised manuscript)
Comments 7: [Lines 106-107: If possible, please state the reference to the taxonomy used. I’d suggest using the term „subsoil mineral“ (in order to match the „surface mineral“ A horizon) rather than „illuvial“ unless elluviation/illuviation is clearly present, together with an overlying E horizon. B horizons can occur not only through illuviation, but through modification of the underlying parent material (as it commonly occurs in Cambisols, where they are classified as Bv). For the A horizon, also consider using the term „organo-mineral“.]
Response 7: We have added two references (e.g. [28] and [29]) to the taxonomy used. In order to facilitate the readers’ understanding, the statement was change to: “These profiles were categorized into five horizons, including OL, O, A, B, and C horizons (Figure 1). The OL horizon represented the litter layer, primarily composed of fermented and shredded litter [28]. The O horizon contained soils with a brown color and humified organic matter. The A horizon comprised organic mineral soils with a dark brown color. The B horizon consisted of soils with illuvial and/or eluvial materials. The C horizon represented the soil parent materials [29].” (Lines 112-118 of the revised manuscript)
Comments 8: [Line 111: „...horizons respectively“ → „horizons, respectively“]
Response 8: This statement was modified as: “Subsequently, soil temperature was monitored using Hygrochron temperature logger iButtons (Maxim DS 1923, USA) embedded in the O, A, and B horizons, with a sampling interval of 1 hour for continuous monitoring.” (Lines 120-121 of the revised manuscript)
Comments 9: [Line 122-123: Please state the make and model of the analyzer.]
Response 9 The concentrations of C and N were acquired using an element analyzer (Vario ISOTOPE cube, Elementar, Germany). (Lines 132-134 of the revised manuscript)
Comments 10: [Line 139: „which were special at the S2 site“ – what does this mean? „Especially noticeable at S2 site“ or there are some other specifics? Please clarify; „highest“ → „the highest“]
Response 10: The reference to 'special' at the S2 site pertains to soil properties including Mois., pH, Feox, Alox, MBC, MBN, MBP, Clit, Nlit and Plit. These properties were observed to exhibit higher or lower values at the S2 site in comparison to the S1 and S3 sites, as detailed further below. In order to clarify the ambiguity, the statement modified to “......, which were particularly noticeable at the S2 site. ” (Line 161 of the revised manuscript)
We added “the” in front of “highest”. Moreover, the full text of the revised manuscript was examined, ensuring the use of "the" before the superlative of all adjectives.
Comments 11: [Lines 140 and 141: „lowest“ → „the lowest“]
Response 11: We have corrected. (Line 162 and 163 of the revised manuscript)
Comments 12: [Line 144: „highest“ → „the highest“]
Response 12: We have corrected. (Line 167 of the revised manuscript)
Comments 13: [Lines 148-149: reformulate „whereas Feox and Alox in B and C horizons exhibited significantly higher compared to other horizons (P < 0.05).“]
Response 13: The statement was modified to “Concentrations of Feox and Alox were found to be the lowest in O horizons, while they were the highest in B horizons compared to other horizons (P < 0.05).” (Lines 171-173 of the revised manuscript)
Comments 14: [Line 162: „a significantly decrease“ → reformulate]
Response 14: The “significantly” was corrected to “significant”. (Line 187 of the revised manuscript)
Comments 15: [Lines 164-165: reformulate]
Response 15: The statement was changed to: “ In the A horizons, there were no significant differences in the concentrations of C and P, as well as in the atomic ratios of C:P, among the sampling sites (P > 0.05). ” (Lines 189-191 of the revised manuscript)
Comments 16: [Line 170: „lowest“ → „the lowest“]
Response 16: We have corrected. (Line 195 of the revised manuscript)
Comments 17: [Line 187: not fully neccessary, but I’d advise formatting Figure 3 into a somewhat more readable manner. Some of the graphs, and especially numbers, are very small.]
Response 17: A brief background on how the Random Forest model was applied on page 4, lines 146-155 of the revised manuscript. Moreover, annotations have been added below Figure 3 (page 8, lines 213-220 of the revised manuscript) and Figure 4 (page 9, lines 229-236 of the revised manuscript). To improve legibility, we increased the font size of the letters in Figure 3 and Figure 4. Furthermore, we added letter labels (e.g. Figure 3a to Figure 3l) to the pictures in Figure 3 and Figure 4 for enhanced precision. Additionally, we redrew Figure 3 and Figure 4 to ensure better coordination.
Comments 18: [Line 224: See the comment for lines 96-97]
Response 18: This statement was developed and modified as “Previous research in this area has reported substantial leaching in Cambisols (2628 m) and Luvisols (2781 m and 3044 m) soil, resulting in the rapid migration of soil solutes [21-22].” (Lines 261-263 of the revised manuscript)
Comments 19: [Line 229: reformulate „compared with in soil leachate“]
Response 19: This statement was developed and modified as “Additionally, concentrations of C and N in rainfall were notably lower compared to those in soil leachate (CO32- at 35.3 mg∙L-1, HCO32- at 367.5 mg∙L-1, N at 3.9 mg∙L-1) based on data from the 3000 m meteorological station at Mt. Gongga.” (Lines 268-271 of the revised manuscript)
Comments 20: [Line 233: „Piceacrassifolia“ → „Picea crassifolia”]
Response 20: The correction has been made on line 273 of the revised manuscript.
Comments 21: [Line 286: „was“ → „were”]
Response 21: The correction has been made on line 321 of the revised manuscript.
Comments 22: Moderate editing of English in needed. Some sentences need to be reformulated. Specific comments can be found in the comments to authors.
Response 22: Thank you for pointing this out. We conducted a thorough review for English errors and the changes were highlighted in red in the revised manuscript.
Special thanks to you for your good comments.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe study addresses gaps in understanding how leaching processes shape nutrient distribution in mountainous ecosystems, specifically in subalpine coniferous forests, and underscores its importance for ecological research, conservation efforts, and sustainable resource management. This study aligns with the Forest journal by advancing knowledge on forest ecosystem dynamics, particularly in relation to nutrient cycling and environmental influences, thereby contributing to the journal's mission of publishing high-quality research on forest science and management.
The abstract effectively meets the criteria for a strong abstract by offering a concise overview of the research issue, outlining the methodology and key findings, and underscoring the broader implications of the study. It serves as an engaging entry point for readers by succinctly encapsulating the essence of the research.
The authors adeptly outlined the background of their research, encompassing the research problem, their study hypothesis, and specific objectives. They provided clear explanations of the procedures and data collection methods, offering insights into the significance of their findings within the results and discussion sections, supported by relevant references. Furthermore, they presented a succinct conclusion, including recommendations for future research directions, while adhering to the guidelines for referencing.
Comments
· Figure 1 would benefit from improved labeling in the legend for sampling sites. For example, the legend for sampling site was either covered (S3) or not visible (S1 and S2). The symbols (^, #, *) used in the map legend also require definitions. Furthermore, the caption should include the country where Mt. Gongga is located to aid readers unfamiliar with its geographical context.
· In the Data Analysis section (Line 129), the authors need to specify the statistical test used for mean separation or comparison of means.
· I recommend including a brief background on how the Random Forest model was applied to investigate the effects of edaphic properties on the concentrations of C, N, P, and the stoichiometry of C:N
· Table 1 and Table 3 should use numerical headers and column labels instead of letters to avoid confusion with letters used in statistical mean separation.
· Figure 3 requires additional information to assist readers in interpreting the data. If details about the values will be provided in the Random Forest model procedure (comments 3), an explanation is necessary, including clarification on the interpretation of negative and positive numbers.
· The manuscript's English is generally sound, but I recommend a thorough review for errors. For instance, commas are needed before "respectively" in Line 111 and Line 124.
Comments on the Quality of English LanguageThe manuscript's English is generally sound, but I recommend a thorough review for errors. For instance, commas are needed before "respectively" in Line 111 and Line 124.
Author Response
Comments 1: [Figure 1 would benefit from improved labeling in the legend for sampling sites. For example, the legend for sampling site was either covered (S3) or not visible (S1 and S2). The symbols (^, #, *) used in the map legend also require definitions. Furthermore, the caption should include the country where Mt. Gongga is located to aid readers unfamiliar with its geographical context.]
Response 1: Thank you for pointing this out. We agree with this comment. Therefore, the legend for sampling sites in Figure 1 has been improved with better labeling. The symbols used in the map were also redefined in the revised manuscript. To ensure clarity, three image formats (EMF, BMP, and JPG) have been redrawn and submitted in the “Figures, Graphics, Images” section. Additionally, we have included the country where Mt. Gongga is located in the caption on page 2, line 92 of the revised manuscript.
Comment 2: [In the Data Analysis section (Line 129), the authors need to specify the statistical test used for mean separation or comparison of means.]
Response 2: Soil properties were compared among different sampling sites using a one-way analysis of variance (ANOVA). If the variables showed homogeneity, Ryan-Einot-Gabriel-Welsch F (R) post hoc tests were conducted; otherwise, Tamhane's post hoc tests were applied. Statistical significance was determined at P < 0.05. (Lines 144-146 of the revised manuscript)
Comment 3: [I recommend including a brief background on how the Random Forest model was applied to investigate the effects of edaphic properties on the concentrations of C, N, P, and the stoichiometry of C:N]
Response 3: A random forest model was conducted for each horizon to rank the impacts of soil properties on the concentrations of C, N, and P and C:N:P stoichiometry. The random forest model employed the increase in mean squared error (%IncMSE) as the criterion for assessing the importance of soil properties. %IncMSE values can be positive or negative. A positive value signifies a more pronounced positive effect on the predicted variables, encompassing the concentrations of C, N, and P, as well as C:N:P stoichiometry. Conversely, a negative %IncMSE indicates that removing this soil property does not notably escalate the mean squared error, suggesting a limited impact on the predicted variables. (Lines 146-155 of the revised manuscript)
Comment 4: [Table 1 and Table 3 should use numerical headers and column labels instead of letters to avoid confusion with letters used in statistical mean separation.].
Response 4: Numerical headers and column labels have been used in Table 1 (page 5-6, lines 174-180 of the revised manuscript) and Table 3 (page 14, lines 317-318 of the revised manuscript).
Comment 5: [Figure 3 requires additional information to assist readers in interpreting the data. If details about the values will be provided in the Random Forest model procedure (comments 3), an explanation is necessary, including clarification on the interpretation of negative and positive numbers.]
Response 5: A brief background on how the Random Forest model was applied on page 4, lines 147-154 of the revised manuscript. Moreover, annotations have been added below Figure 3 (page 8, lines 213-220 of the revised manuscript) and Figure 4 (page 9, lines 229-236 of the revised manuscript). To improve legibility, we increased the font size of the letters in Figure 3 and Figure 4. Furthermore, we added letter labels (e.g. Figure 3a to Figure 3l) to the pictures in Figure 3 and Figure 4 for enhanced precision. Additionally, we redrew Figure 3 and Figure 4 to ensure better coordination.
Comment 6: [The manuscript's English is generally sound, but I recommend a thorough review for errors. For instance, commas are needed before "respectively" in Line 111 and Line 124.]
Response 6: The above statements were corrected in line 121 and line 135 of the revised manuscript. Moreover, we also conducted a thorough review for English errors and the changes were highlighted in red in the revised manuscript.
Special thanks to you for your good comments.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors of the article studied the leaching of elements in mountain systems and the distribution of these elements in soil horizons for several altitude levels. The work was performed at a high scientific degree and is of interest from the point of view of studying the distribution of substances in soils under the influence of various environmental factors. I noticed a few minor points (given below) that need editing, but in general there are no serious comments on the text of the work.
Figure 1: Sign the soil types presented.
Lines 122-123: "The concentrations of C and N were determined using the element analyzer" here you must specify the method or characteristics of the device.
Lines 226-228: "Moreover, lower pH values in A horizons and higher concentrations of Feox and Alox in B horizons (Table 1) indicated significant loss of alkaline particles in this region" you need to provide a link confirming the existence of such a pattern.
Lines 147-149: possibly a repeat of lines 141-142. In general, the idea is not very clearly expressed, you need to systematize the data by horizons, sites or properties.
Section conclusions: also add a mark on the correspondence of the degree of leaching of elements from the upper soil horizons to the site and its height. At least in the simplest version, X (xxx m) > Y (yyy m) > Z (zzz m).
Author Response
Comment 1:[Figure 1: Sign the soil types presented.]
Response 1: In order to provide a clear description to all readers, we have used two soil classification criteria. According to the China soil classification system, the soil types are identified as brown forest soil at elevations of 2600-2800 m, and dark-brown forest soil at elevations of 2800-3200 m [26]. Additionally, based on the world reference base (WRB) for soil resources [27], the soil types are classified as Cambisols at the 2628 m site and Luvisols at the 2781 and 3044 m site, as illustrated in Figure 1. (Lines 100-104 of the revised manuscript)
Comment 2:[Lines 122-123: "The concentrations of C and N were determined using the element analyzer" here you must specify the method or characteristics of the device.]
Response 2: The concentrations of C and N were acquired using an element analyzer (Vario ISOTOPE cube, Elementar, Germany). (Lines 132-134 of the revised manuscript)Agree. The concentrations of C and N were acquired using an element analyzer (Vario ISOTOPE cube, Elementar, Germany). (Lines 132-134 of the revised manuscript)
Comment 3:[Lines 226-228: "Moreover, lower pH values in A horizons and higher concentrations of Feox and Alox in B horizons (Table 1) indicated significant loss of alkaline particles in this region" you need to provide a link confirming the existence of such a pattern.]
Response 3: This statement was developed and modified as: “Moreover, the pH in the A horizon was observed to be the lowest among the four horizons (Table 1), which was attributed to the intense leaching of alkaline particles [34-35]. The concentrations of Feox and Alox were found to be the lowest in the O horizon and the highest in the B horizon (P < 0.05; Table 1)”. (Lines 264-268 of the revised manuscript)
Comment 4:[Lines 147-149: possibly a repeat of lines 141-142. In general, the idea is not very clearly expressed, you need to systematize the data by horizons, sites or properties.]
Response 4: To avoid misunderstandings, we modified Lines 147-149 from the perspective of horizons. The corrected statement was that “By comparing the average values of each soil property among horizons, it was noted that the average pH value in the A horizon was the lowest among the four horizons, with a measurement of 4.6 ± 0.1. Concentrations of Feox and Alox were found to be the lowest in O horizons, while they were the highest in B horizons compared to other horizons (P < 0.05).” (Lines 169-173 of the revised manuscript)
Comment 5:[Section conclusions: also add a mark on the correspondence of the degree of leaching of elements from the upper soil horizons to the site and its height. At least in the simplest version, X (xxx m) > Y (yyy m) > Z (zzz m).]
Response 5: The correspondence of the leaching degree of elements has been added to the statement ”Furthermore, the leaching degree of C, N, and P from the O to B horizon at the 2781 m site followed the sequence C > N > P.” (Lines 353-354 of the revised manuscript)
Special thanks to you for your good comments.
Reviewer 4 Report
Comments and Suggestions for AuthorsThe manuscript relevant fo the Forests. The main idea is rather itemized description C,N,P and their ratio of subalpic plateau in the Tibetan montane. But the title of the manuscript need correct. I guess "Shaping...gradients"not a very good name for manuscript. In the articles discussed change C,N, P and their ratio depend on altitude and biological factors but not a gradients. Additional minor comments in the text of manuscript in attach file.
Comments for author File: 
Comments.pdf
Author Response
Comment 1: [The manuscript relevant fo the Forests. The main idea is rather itemized description C,N,P and their ratio of subalpic plateau in the Tibetan montane. But the title of the manuscript need correct. I guess "Shaping...gradients"not a very good name for manuscript. In the articles discussed change C,N, P and their ratio depend on altitude and biological factors but not a gradients. Additional minor comments in the text of manuscript in attach file.]
Response 1: Thank you for pointing this out. We have made the change to the title to better reflect the focus of our study: “The Role of Leaching in Soil Carbon, Nitrogen, and Phosphorus Distributions in Subalpine Coniferous Forests on Mt. Gongga, Southwest China”. (Lines 2-4 of the revised manuscript).
Comment 2: [In the Chemical Analysis section (Line 115). How were samples crashed?]
Response 2: Samples of OL horizons were air-dried and then ground passing through a sieve (< 0.075 mm) before analysis. (Lines 125-126 of the revised manuscript)
Comment 3: [In the Impacts of soil properties on the C, N, and P concentrations section (Line 180). It is not clean. If in O horizont P concentrations were mesured like as Plit it could not be used like a P-determinant. Or it means influence only variations in the P mesure?]
Response 3: The concentration of P in litters (Plit) in the OL (fermented/shredded litter) horizon was determined by digesting with a HNO3-HClO4 solution. Below the OL horizon was the O (humified litter) horizon, where P was digested with a H2SO4-HClO4 solution. Therefore, P concentrations in the O horizon differ from Plit, and Plit can serve as a P-determinant from the aspect of plant litters for assessing the effects on C, N, and P concentrations. In order to specify the chemical analysis method more clearly, the Soil Sampling section was changed to “These profiles were categorized into five horizons, including OL, O, A, B, and C horizons (Figure 1). The OL horizon represented the litter layer, primarily composed of fermented and shredded litter [28]. The O horizon contained soils with a brown color and humified organic matter. The A horizon comprised organic mineral soils with a dark brown color. The B horizon consisted of soils with illuvial and/or eluvial materials. The C horizon represented the soil parent materials [29]. Sampling began with plant litter in the OL horizons, followed by a hierarchical collection of soil samples from the C to O horizons based on soil occurrence. ” (Lines 112-119 of the revised manuscript)
Moreover, the Chemical Analysis section was changed to “In OL horizons, concentrations of P represented the contents of P in litters (Plit) and were determined by digesting with a HNO3-HClO4 solution. In the other four horizons, P was digested with a H2SO4-HClO4 solution.” (Lines 136-139 of the revised manuscript)
Comment 4: [Figure 3. Too small letters of Y-axis.]
Response 4: To improve legibility, we increased the font size of the Y-axis letters in Figure 3 and Figure 4. Furthermore, we added letter labels (e.g. Figure 3a to Figure 3l) to the pictures in Figure 3 and Figure 4 for enhanced precision. Additionally, we redrew Figure 3 and Figure 4 to ensure better coordination.
Comment 5: [Figure 4. Too small letters of Y-axis.]
Response 5: To improve legibility, we increased the font size of the Y-axis letters in Figure 3 and Figure 4. Furthermore, we added letter labels (e.g. Figure 3a to Figure 3l) to the pictures in Figure 3 and Figure 4 for enhanced precision. Additionally, we redrew Figure 3 and Figure 4 to ensure better coordination.
Comment 6: [In the Leaching effects on soil C:N:P stoichiometry section (Line 287), the statement “......except for C:N ratios in the O horizon” is not clean.]
Response 6: The ambiguous statement was changed to “The C:N ratios in the O horizon were primarily influenced by Plit concentrations (Figure 4a), indicating that the spatial distribution of soil C:N ratios in the subalpine coniferous forest was primarily influenced by litter return, consistent with previous studies by Chen et al. and Li et al. [8-9].” (Lines 321-324)
Special thanks to you for your good comments.
