Critical Factors Affecting Water and Nitrogen Losses from Sloping Farmland during the Snowmelt Process
, Jifeng Zhang 1,†, Jingwei Wu 1,*, Chenyao Guo 1, Chengeng Li 2, Yawen Liu 1, Rui Zhang 1 and Hang Zhao 1
Round 1
Reviewer 1 Report
Interesting research results for science and agricultural practice. I appreciate that this is field research. I included my comments in the text of the manuscript (pdf). After corrections, I recommend publishing the manuscript in the journal Agronomy. First of all, the Material and Methods chapter and the References section should be corrected Do tables and figures have to be placed in the "Discussion" section? What conclusions should be drawn from the research and measures to counteract the described phenomena should be applied.
Comments for author File: 
Comments.pdf
Author Response
January 13, 2023
Dear Editor:
We are submitting a revision of the manuscript, titled “Critical factors affecting water and nitrogen losses from sloping farmland during the snowmelt process” (Manuscript Number: agronomy-2151652) to Agronomy. We greatly appreciate the editor’s constructive comments and suggestions, which help to improve the quality of our paper. Following the comments and suggestions, we have made corresponding changes of the manuscript. The affiliated contents are detailed point-by-point responses to the comments of the reviewers.
We hope that now the manuscript is acceptable for publication in Agronomy. Thank you for your consideration on the manuscript.
Best regards.
Jingwei Wu, Ph.D.
Professor
CC: Qiang Zhao, Jifeng Zhang, Chenyao Guo,
Chengeng Li, Yawen Liu, Rui Zhang, Hang Zhao
Comments from Reviewer #1:
General Evaluation:
Interesting research results for science and agricultural practice. I appreciate that this is field research. I included my comments in the text of the manuscript (pdf). After corrections, I recommend publishing the manuscript in the journal Agronomy. First of all, the Material and Methods chapter and the References section should be corrected. Do tables and figures have to be placed in the "Discussion" section? What conclusions should be drawn from the research and measures to counteract the described phenomena should be applied.
Response: We thank the reviewer for his/her positive evaluation of the manuscript. Material and Methods chapter and the References section have been corrected according to the reviewer’s suggestions. The tables and figures in ‘Discussion’ section are most supporting data, which are used to analyze and explain the conclusions obtained from ‘Results’ section. These data are not systematic, and if they are placed in the ‘Results’ section, the logic of the whole paper is not smooth. Therefore, we placed them in the ‘Discussion’ section just where they were needed. In addition, in this study we just explored the water and nitrogen export processes from a 0.8 m × 7.0 m sloping farmland. The relationship between the conclusions in this study to the water and nitrogen export processes from hill and watershed scale sloping farmland are still unclear, which is the content of our next study. Only when we make a clearly understand of the relationship between the processes of water and nitrogen production in sloping farmland at the scale of plot, hill and watershed, can we effectively formulate measures to counteract disadvantage phenomena and guide practice. Therefore, we didn’t discuss it in this paper.
The manuscript has also been revised to address the review comments in the PDF manuscript, and below is the detailed response to the comments.
- Add ‘Nitrogen leaching’ in keywords.
Response: We thank the reviewer for his/her suggestion. However, in this study we did not focus on nitrogen leaching because of the existing of frozen soil, which greatly reduced the infiltration of snowmelt water. Thus, we did not add ‘nitrogen leaching’ as a keyword in this study.
- The labeled form of references in lines 74-84 should be modified.
Response: We thank the reviewer for his/her suggestion, and have modified the manuscript, please see lines 72-81.
For instance, Harms et al [39] found that slope aspect had a major influence on soil temperature and moisture, and south-facing slopes produced the earliest snowmelt but yielded the least amount of runoff. Qiu et al [40] conducted a simulated slope snowmelt experiment, and found that the snow melting rate exhibited a positive correlation with slope gradient and length. Hinckley et al [41] discovered that snowmelt events that occurred on south-facing slopes quickly transported soil nitrogen into aquatic systems compared with north-facing slopes. Zhao et al [5] conducted a watershed monitoring experiment in an agricultural watershed, and found that nitrogen was mostly flushed into rivers by water from steeper areas (> 6°), and lower slope areas (< 2°) along the river consumed snowmelt water and nitrogen through depression and retention storage. (Lines 72-81)
- Lines 92-94: What is the research hypothesis of this study?
Response: The research hypothesis of this study is that slope, soil water content, and snow water equivalents are major factors affecting the processed of runoff and nitrogen loss from sloping farmland during the snowmelt period. We did not explicitly show the hypotheses because of we feel that it may duplication with the experimental description and research objectives (lines 89 to 94).
- Line 101: Do you have weather conditions from your local weather station?
Response: We thank the reviewer for his/her reminding, and have added the information of local weather station. Please see lines 136-138.
The air temperature was monitored at the Shuangyang weather station located 5.9 km northwest of the experimental plot. (Lines 136-138)
- Line 104: In which laboratory the soil analysis was performed.
Response: We have added the information in lines 151-153.
These soil and water physical or chemical analysises were performed in state key laboratory of water resources and hydropower engineering science, Wuhan University. (Lines 151-153)
- Line 112: Were any agrotechnical treatments performed after corn harvest?
Response: The farmland were left idle after the corn harvest, and agrotechnical treatments were performed in spring when frozen soil have melted.
- Some format problems: Lines 95, 96, 98, 105, 168, 218.
Response: We are very grateful to the reviewers for their meticulous modifications. We have made modifications to the marked places and other similar mistakes in the paper.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Major comments
- Add some studies/references about the present study highlighting research gaps, which necessitated conducting this trial.
Minor comments
- Line 18: soil water content (SWC) treatment, but in Line 90: water treatment (high and low). Please clarify
- Line 105 please provide the reference for the method
- Line 143 please add the specification of the power sampling drill
- Line 144 please describe the oven-drying method and reference
- Line 145 please explain the method how do you measure soil ammonium nitrogen and nitrate nitrogen content
- Line 159 please provide the company and country for the SPSSS 17 program
- Add reference for data visualization software /program
- Line 373 – 378 repetitions of results
Author Response
January 13, 2023
Dear Editor:
We are submitting a revision of the manuscript, titled “Critical factors affecting water and nitrogen losses from sloping farmland during the snowmelt process” (Manuscript Number: agronomy-2151652) to Agronomy. We greatly appreciate the editor’s constructive comments and suggestions, which help to improve the quality of our paper. Following the comments and suggestions, we have made corresponding changes of the manuscript. The affiliated contents are detailed point-by-point responses to the comments of the reviewers.
We hope that now the manuscript is acceptable for publication in Agronomy. Thank you for your consideration on the manuscript.
Best regards.
Jingwei Wu, Ph.D.
Professor
CC: Qiang Zhao, Jifeng Zhang, Chenyao Guo,
Chengeng Li, Yawen Liu, Rui Zhang, Hang Zhao
Comments from Reviewer #2:
- Add some studies/references about the present study highlighting research gaps, which necessitated conducting this trial.
Response: We thank the reviewer for his/her suggestion, and have added some references in lines 81-85.
However, these studies were mostly conducted at the watershed or hill scale, and the influencing factors were unmanageable [5, 39, 41]. Thus, their conclusions were mostly gained from qualitative analysis, lacking quantitative and statistical results [40, 41]. （Lines 81-85）
- Line 18: soil water content (SWC) treatment, but in Line 90: water treatment (high and low). Please clarify
Response: We are sorry to have confused the reviewer, and we have modified ‘water treatment’ in line 90 into ‘soil water content (SWC)’. Please see line 88.
- Line 105 please provide the reference for the method
Response: We have added the reference for the method. Please see lines 104 and 478
Bao, S.D. Soil Agrochemical Analysis (third edition). China Agriculture Press, Beijing. 2000. (Lines 478)
- Line 143 please add the specification of the power sampling drill
Response: We thank the reviewer for his/her reminding, and have added the diameter of the drill, please see line 141.
These soil samples were collected using a power sampling drill (5cm diameter)… （Line 141）
- Line 144 please describe the oven-drying method and reference
Response: We have added the reference for the method. Please see lines 143 and 478.
Bao, S.D. Soil Agrochemical Analysis (third edition). China Agriculture Press Beijing. 2000. (Lines 478)
- Line 145 please explain the method how do you measure soil ammonium nitrogen and nitrate nitrogen content.
Response: We have added the method to measure soil ammonium nitrogen and nitrate nitrogen content, please see lines 149-151.
The NH4+-N and NO3--N concentrations of water and soil extraction were measured using a CleverChem 200 automatic continuous analyzer (DeChem-Tech. GmbH, Hamburg, Germany). (Lines 149-151)
- Line 159 please provide the company and country for the SPSSS 17 program
Response: We thank the reviewer for his/her suggestion, and have added the company and country for the SPSS 17 program, please see line 158-159.
Principal component regression analysis was conducted using SPSS 17 (IBM, New York, America). (Lines 158-159)
- Add reference for data visualization software /program
Response: We thank the reviewer for his/her suggestion, and have added the information of software /program for data visualization, please see line 159-160.
The figures were prepared using Origin 2021 (Origin Lab, Northampton, America). (Lines 159-160)
- Line 373 – 378 repetitions of results
Response: We have modified the ‘Conclusion’ section that repeats with the results, please see lines 371-373.
Higher snow depth delayed the occurrence of snowmelt and enhanced the yields of water and nitrogen. The generation of nitrogen was advanced compared with that of water induced by the preferential production of nitrogen during the snowmelt process. (Lines 371-373)
Author Response File: Author Response.docx
