Grazing Impacts on Soil Enzyme Activities Vary with Vegetation Types in the Forest-Steppe Ecotone of Northeastern China

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

Point-by-point response to Comments and Suggestions for Authors

Comments 1: In introduction, give some more information about bacterial and fungal enzymes and their role in soil, separately.

Response 1: Thank you for your valuable feedback. I have incorporated the relevant information into the introduction section. (line 47-54)

Comments 2: How long were samples stored at 4°C for soil enzyme activity determination?

Response 2: Thank you for bringing this to our attention. We concur with this feedback. Consequently, I've updated the description related to soil sampling and emphasized that “The determination of parameters for all refrigerated soil samples was completed within a span of 15 days."（line 149-158）

Comments 3: Table 1. Based on which parameters did you determine the soil type?

Response 3: Thank you for pointing this out. To illustrate this, I provided a detailed explanation in section 2.1: “Based on the soil classification method employed by the reference system for Chinese soils using the FAO World Reference Base for Soil Resources (WRB), the soil types in this region comprise Haplic Luvisols, Petric Calcisols, Luvic Kastanozems, Gleyic Sol-onchaks, Calcaric Regosols, Gleyic Chernozems, among others (the data is retrieved from the National Soil Information Service Platform of China, accessible at http://www.soilinfo.cn).” (line 126-132)

Comments 4: Add few more info about the correlation of soil type, plant species and environmental impact to soil enzymatic activity in discussion.

Response 4: Thank you for your input. I have included the relevant discussion in the "Discussion" section. (Line 436-450)

Comments 5: Add some future perspectives of research on this topic in conclusion.

Response 5: Thank you for your valuable feedback. We have revised the conclusion section accordingly. (Line 467-478)

Comments 6: Uniform the line spacing throughout the text body.

Response 6: Thank you for bringing this to my attention. I have standardized the line spacing across the entire text body.

4. Response to Comments on the Quality of English Language

Point 1: Minor editing of English language required.

Response 1: Thank you for your valuable feedback. I have made appropriate modifications to the English sentences.

Thank you for dedicating your time to review this manuscript. Below, you'll find detailed responses along with the corresponding revisions and corrections, highlighted in the resubmitted files.

Point-by-point response to Comments and Suggestions for Authors

Comments 1: The manuscript "Grazing impacts on soil enzyme activities vary with vegetation types in the forest-steppe ecotone of northeastern China" by Long Wang et al. aims to evaluate the soil enzyme activities in ecosystem subject to grazing and non-grazing, identifying the factors associated with the observed changes in these activities. This is a well-written, well-organized manuscript. However, some details can be improved to be published.

L98-109 – provide proper reference to the site description, as well as for the vegetation composition.

Response 1: Thank you for your valuable input. We have duly cited the respective data sources and references in their appropriate positions. (line 126-134)

Comments 2: L110 – Define what the authors mean by: "soil texture in the region is "good"; otherwise, remove. Soil types must also be specified using the World Reference Base (as in Table 1).

Response 2: Thank you for your professional advice. I have eliminated the statement "soil texture in the region is good" and amended the delineation of soil types: “Based on the soil classification method employed by the reference system for Chinese soils using the FAO World Reference Base for Soil Resources (WRB), the soil types in this region comprise Haplic Luvisols, Petric Calcisols, Luvic Kastanozems, Gleyic Sol-onchaks, Calcaric Regosols, Gleyic Chernozems, among others (the data is retrieved from the National Soil Information Service Platform of China, accessible at http://www.soilinfo.cn).” (line 126-132)

Comments 3: L132 – remove hyperlinks.

Response 3: Thank you for pointing this out. I have removed hyperlinks.

Comments 4: L137-145 – Where machines/software/chemicals are first mentioned, add the information of model, company, city, abbr of the state (only for Canada and USA), and country.

Response 4: Thank you for highlighting this. I have included the information regarding the laboratory instruments. You can find these additions in the updated manuscript. (line 163-170)

Comments 5: L146-154 – Add references for the enzyme activity protocols.

Response 5: Thank you for pointing this out. I have incorporated the references for the enzyme activity protocols. They are “Chen, Y.; Wei, T.; Sha, G.; Zhu, Q.; Liu, Z.; Ren, K.; Yang, C. Soil enzyme activities of typical plant communities after vege-tation restoration on the Loess Plateau, China. Appl. Soil Ecol. 2022, 170, 104292. doi: 10.1016/j.apsoil.2021.104292; Zhang, C.; Liu, G.; Xue, S.; Song, Z. Rhizosphere soil microbial activity under different vegetation types on the Loess Plateau, China. Geoderma 2011, 161, 115-125. doi: 10.1016/j.geoderma.2010.12.003.” (line 174-183)

Comments 6: L167-168 – Specify the specific function used for PCA-MLR.

Response 6: Thank you for your valuable feedback. I have provided a detailed description of the specific steps of PCA-MLR used in this study, along with the formulas applied. (line 196-207)

Comments 7: Table 2, Figure 7 - Which would be the ecological interpretation of PC3-PC5? Although the authors associated the relative contribution of their variables to an ordination axis of the principal components analysis, there is no clear explanation for this selection. How did the authors decide to name them "PC1 (soil nutrient factor), PC2 (soil mineralization factor), PC3 (microbial biomass carbon factor), PC4 (microbial biomass nitrogen factor) and PC5 (grazing factor) “? It is not mentioned in Table 2 because certain variables are in bold. The explanation given in L256-265 needs to be sufficiently clear and supported since the negative contributions are not considered and are also contributing to the ordination. Also, check the RELATIVE contribution of MBC on PC3.

Response 7: Thank you for your careful review and valuable feedback. As a result, I have made corresponding modifications and improvements. I have provided further explanations and referenced literature for each principal component (line 303-314). I included a note below Table 2 to explain the bold (line 337-338). Additionally, I greatly appreciate you pointing out a technical error. Upon verification, the RELATIVE contribution of MBC on PC3 is confirmed to be "0.864." (line 334)

Comments 8: The PCA analyses (Table 2, Fig. 7) must be thoroughly justified and supported; otherwise, modify the associated discussion. Besides, models like principal component analysis may have limitations, potentially leading to the loss of valuable information when the input data aren't correctly transformed to satisfy normality and equal variance prerequisites. Consequently, their application may need to be revised. On the other hand, nonmetric multidimensional scaling (NMS) serves as an unconstrained ordination method, not making any assumptions about data distribution, offering an alternative approach.

Response 8: Thank you very much for your valuable input. We conducted tests for normality and homogeneity of variance on the data used for principal component analysis, with detailed explanations provided in "2.4 Statistical analysis" (line 186-189). Additionally, regarding the nonmetric multidimensional scaling (NMS) method you mentioned, we have given it significant attention and study, which will be highly insightful for our future research.

Response to Comments on the Quality of English Language

Point 1: English language fine. No issues detected

Thank you for dedicating your time to review this manuscript. Below, you'll find detailed responses along with the corresponding revisions and corrections, highlighted in the resubmitted files.

Point-by-point response to Comments and Suggestions for Authors

Comments 1: Lines 17-23: The presentation of the key findings of experimental results should be improved and data regarding the mainly measured indicators should be presented.

Response 1: Thank you for bringing this to my attention. I concur with the feedback. As a result, I have enhanced the results section and provided data concerning the primarily measured indicators. (line 19-26)

Comments 2: Line 27: keywords are already stated in the title. Please consider changing the keywords list and use synonyms.

Response 2: Agree. Thank you for bringing this to my attention. I have updated the keywords to: "grazing effects; catalase; urease; cellulase; microbial biomass" (line 29)

Comments 3: The manuscript is full of abbreviations; I suggest to include a list of abbreviations after the keywords.

Response 3: Thank you for your suggestion. I have now added a list of abbreviations following the keywords. (line 31-32)

Comments 4: To provide a good reflection of this study, the authors should address these questions in the conclusion section (What is the novelty of this work? - What can be done after this study or suggestions should be made? - What are the future prospectives?).

Response 4: Thank you for your valuable feedback. We have revised the conclusion section accordingly. (line 467-478)

Response to Comments on the Quality of English Language

Point 1: Minor corrections.

Response 1: Thank you for your valuable feedback. I have made appropriate modifications to the English sentences.