Influence of Soil Texture on Carbon Stocks in Deciduous and Coniferous Forest Biomass in the Forest-Steppe Zone of Oka–Don Plain

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study by Sheshnitsan et al. found that soil texture, particularly the total stock of silt and clay, significantly impacts the carbon stock in the biomass of coniferous and deciduous forest stands in the forest-steppe zone. Understanding these features will surely help to develop more effective forest management techniques in this zone, ensuring the long-term viability and productivity of forest ecosystems. Overall, the experiment is well-designed, and the presentation and write-up are excellent. There are a few concerns that may help the author improve the quality of his work.

·         Lines16-17 Rephrase the sentence, it's not clear

·         Lines 65-74 combine these paragraphs

·         Soil sampling and sample plot descriptions

·         Please mention the study area (Total area) with sampling intensity in M&M section.

Results

Figure 2a:

Table 3 (SOC and Texture) shows the varying sample sizes in each forest type; n= 16, 26, 5, 5, and 3. Is this the outcome of an ANOVA or multiple comparisons? (This concern is in each table/ Figure). You have two factors: forest type and soil depth. Please explain how you conducted statistical analysis using a different sample size and two factors. Furthermore, if you present mean with SD, why do you want to provide minimum and maximum values, as well as CV? I recommend that you give mean values and SD/SE with alphabets indicating significant differences. Readers will be able to more clearly comprehend your findings.

Figure 2a:

Correct the spellings @ y-axis; “Percent of total Dry weight”. Rather replace it with Dry weight (%age)

Again in the captions; Lines 217-218, is it the ANOVA or multiple comparison test?

Discussion:

 

Avoid stating results in the discussion section (Table 6); instead, justify or relate your key findings to past research. I propose that you provide essential tables and figures. You may move the figures/tables as supplementary details. Thank you and good luck.

Comments for author File: Comments.pdf

Author Response

All of the revisions of the manuscript were marked in green

 

Comments 1: Overall, the experiment is well-designed, and the presentation and write-up are excellent.

Response 1: Thank you very much for appreciating our work.

 

Comments 2: There are a few concerns that may help the author improve the quality of his work. Lines16-17 Rephrase the sentence, it's not clear

Response 2: Thank you for pointing this out. We agree with this comment. We rephrased the sentence to “The aim of the study was to assess the impact of soil texture on carbon stocks in the biomass of deciduous and coniferous tree stands of a forest-steppe ecotone.”

 

Comments 3: Lines 65-74 combine these paragraphs

Response 3: Agree. Two paragraphs were joined into one as recommended.

 

Comments 4: Soil sampling and sample plot descriptions. Please mention the study area (Total area) with sampling intensity in M&M section.

Response 4: Thank you for your suggestion. We added the total area of forests in the paragraph from subsection 2.1. Study area:

“The study focuses on representative forests of the Voronezh region, including pine forests grown on the sands of the floodplain terraces on the watershed of the Voronezh and Usman rivers (42.2 km², including 21.3 km² of deforested lands), as well as broadleaved forests (Upland Oak Forest) developed on the highly dissected right bank of the Voronezh River (24.5 km²) (Figure 1)”.

To assess the study area (Total area) with sampling intensity we pointed out in the subsection 2.2. Soil sampling and sample plot descriptions the following information:

“In order to ensure the most comprehensive data set was obtained, a minimum of one soil pit was established for every 15 hectares for total study area of about 850 ha.”

 

Comments 5: Results. Figure 2a: Table 3 (SOC and Texture) shows the varying sample sizes in each forest type; n= 16, 26, 5, 5, and 3. Is this the outcome of an ANOVA or multiple comparisons? (This concern is in each table/ Figure). You have two factors: forest type and soil depth. Please explain how you conducted statistical analysis using a different sample size and two factors.

Response 5: Thank you for pointing this out. We agree with the comments. Therefore, we replaced ANOVA with Student t-test throughout the manuscript.

We performed statistical analysis using both pairwise comparisons (t-test) and one-way ANOVA. To avoid any difficulties in perceiving the results of statistical analysis, we replaced ANOVA with Student t-test throughout the manuscript.

 

Comments 6: Furthermore, if you present mean with SD, why do you want to provide minimum and maximum values, as well as CV? I recommend that you give mean values and SD/SE with alphabets indicating significant differences. Readers will be able to more clearly comprehend your findings.

Response 6: Agree. We reduced the length of Table 3 in accordance with your recommendations.

 

Comments 7: Figure 2a: Correct the spellings @ y-axis; “Percent of total Dry weight”. Rather replace it with Dry weight (%age)

Response 7: Agree. We changed the name of y-axis in Figure 2a into “Dry weight, percentage”.

 

Comments 8: Again in the captions; Lines 217-218, is it the ANOVA or multiple comparison test?

Response 8: Agree. Corrected as stated in Response 5

 

Comments 9: Discussion: Avoid stating results in the discussion section (Table 6); instead, justify or relate your key findings to past research. I propose that you provide essential tables and figures. You may move the figures/tables as supplementary details. Thank you and good luck.

Response 9: Thank you for pointing this out. We agree with this comment. We have moved Table 6 to Appendix A and added a reference with research results that support our findings.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript entitled by “Influence of soil texture on carbon stocks in deciduous and coniferous forest biomass in the forest-steppe zone of Oka-Don plain” shows an interesting result which suggests that soil texture can profoundly affect tree stands and the carbon stocks in tree biomass, as well as soil organic carbon stock. However, the discussion regarding the reasons why soil fine particles can determine the carbon stock of tree stand requires further strengthening. For example, how’s the influences of soil nutrients, soil depth, soil mineralogy, soil bulk density, soil water holding capacity?

 

Besides, is it possible to show the distributions of soil sample sites and different forest type area in the Figure 1? What’s the meanings of the index in the Table 1 and the site index in the Table 2? I also suggest to remove the Table 6 to the previous context, because it is perplexing to understand the meanings of some forest types such as PfBAOp-C and PfBAOp-CD.

Author Response

All of the revisions of the manuscript were marked in blue

 

Comments 1: However, the discussion regarding the reasons why soil fine particles can determine the carbon stock of tree stand requires further strengthening. For example, how’s the influences of soil nutrients, soil depth, soil mineralogy, soil bulk density, soil water holding capacity?

Response 1: Thank you for pointing this out. We agree with this comment. We added to the Discussion the following paragraphs and references:

Devi (2021) [42] suggested that loamy soils, comprising 40% sand, 40% silt and 20% clay, are conducive to tree growth due to the favorable properties of these mineral particles. The growth rates of trees on loam soils are typically higher than those on sandy loam or clay soils. These observations reflect the enhanced fertility and moisture retention capacity of loam [43]. Additionally, a study of mixed-species plantations on loam soils demonstrated superior survival rates of trees compared to other soil types [44].

The results of the studies demonstrated that forests with sandy soils had lower carbon stocks than those with loamy soils [42]. However, other studies indicated that the influence of tree diversity on forest productivity was more amplified in sandy soils, where resources are limited, and a greater species diversity can more effectively occupy different niches than in loamy soils, where competition for resources may be less intense due to the higher availability of nutrients [45, 46]. This indicates that the interrelationship between soil texture, tree diversity, and productivity may be dependent on the specific characteristics of the forest ecosystem. Although present study results demonstrate that soil texture predicts forest productivity in forest-steppe regions, additional factors such as climate, topography, and management practices that may also affect forest carbon stocks need to be considered.

42. Devi, A. S. Influence of Trees and Associated Variables on Soil Organic Carbon: A Review. Journal of Ecology and Environment 2021, 45 (1), 5. https://doi.org/10.1186/s41610-021-00180-3.
43. Heineman, K. D.; Jensen, E.; Shapland, A.; Bogenrief, B.; Tan, S.; Rebarber, R.; Russo, S. E. The Effects of Belowground Resources on Aboveground Allometric Growth in Bornean Tree Species. Forest Ecology and Management 2011, 261 (11), 1820–1832. https://doi.org/10.1016/j.foreco.2011.02.005.
44. Cao, S.; Chen, L.; Xu, C.; Liu, Z. Impact of Three Soil Types on Afforestation in China’s Loess Plateau: Growth and Survival of Six Tree Species and Their Effects on Soil Properties. Landscape and Urban Planning 2007, 83 (2–3), 208–217. https://doi.org/10.1016/j.landurbplan.2007.04.006.
45. Huang, Y.; Ma, Y.; Zhao, K.; Niklaus, P. A.; Schmid, B.; He, J.-S. Positive Effects of Tree Species Diversity on Litterfall Quantity and Quality along a Secondary Successional Chronosequence in a Subtropical Forest. Journal of Plant Ecology 2017, 10 (1), 28–35. https://doi.org/10.1093/jpe/rtw115.
46. Mensah, S.; Noulèkoun, F.; Dimobe, K.; Seifert, T.; Glèlè Kakaï, R. Climate and Soil Effects on Tree Species Diversity and Aboveground Carbon Patterns in Semi-Arid Tree Savannas. Sci Rep 2023, 13 (1), 11509. https://doi.org/10.1038/s41598-023-38225-3.

 

Comments 2: Besides, is it possible to show the distributions of soil sample sites and different forest type area in the Figure 1?

Response 2: Thank you for pointing this out. We have completely rearranged Figure 1 and indicated all sample plots and soil pit locations. A modified figure is available in the revised manuscript.

 

Comments 3: What’s the meanings of the index in the Table 1 and the site index in the Table 2?

Response 3: Index in Table 1 denotes the forest type (trophotope) labelling according to Alekseev and Pogrebnyak classification.

Site index in Table 2 is the dimensionless indicator of productivity of forest stands; it is defined by average age and average height of a tree stand.

 

Comments 4: I also suggest to remove the Table 6 to the previous context, because it is perplexing to understand the meanings of some forest types such as PfBAOp-C and PfBAOp-CD.

Response 4: Thank you for pointing this out. We agree with this comment. We moved Table 6 to Appendix A

Author Response File: Author Response.pdf