Coupling of SWAT and EPIC Models to Investigate the Mutual Feedback Relationship between Vegetation and Soil Erosion, a Case Study in the Huangfuchuan Watershed, China

Round 1

Reviewer 1 Report

This manuscript presents an excellent study by coupling SWAT and EPIC models to investigate the relationship between vegetation and soil erosion in Huangfuchuan Watershed (China). The manuscript needs the minor revisions bellow :

Line 38 – 42 : The authors need to add references for examples :

·         https://doi.org/10.1016/j.geodrs.2022.e00543

·          https://doi.org/10.2136/sssaj1999.03615995006300020014x

 

Line 112 : In Materials and methods section the authors need to give more details about the vegetation monitoring using the NDVI presented in the results, and add the equation related to Moran's I index in the methodology.

Line 131 : The authors need to improve the resolution of Figure 1, and the presentation of the Map, for examples Meteorological stations localization in map.

Line 129 : The authors need to add the reference related to section « Annual average sediment inflow to the Yellow River is about 0.41 million tons. “ .

Line 136: The authors need to add the reference related to section « …soil type data from the Harmonized World 135 Soil Database (HWSD) v1.2 “.

Line 232: The authors need to improve the Figure 2, and draw the bottom border in Figure 2.

Line 276: The authors need to correct the unit used for runoff and use the international unit system

Line 321: The authors need to correct figure 4 and put the letter a and b in this figure.

Line 524 - 533: Rephrase this section, in bare soil there is more evaporation and more runoff compared to grassland, water content and infiltration is expected to be higher in grassland compared to bare soil.

Author Response

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Reviewer 2 Report

 

The authors present a novel and interesting approach to analyze the relationships between soil loss due to water erosion and changes in vegetation, combining the well-known SWAT and EPIC models.

As a case study they use the Huangfuchuan Watershed, on the Loess Plateau, China, one of the most eroded areas worldwide.

Both the methodology and the data used are consistent, well described and substantiated.

The results are very well treated, despite the breadth of the study area and the numerous information generated.

Although the results are predictable, their quantification for different scenarios provide an interesting value to the study, which allows directing future research using the methodological approach proposed in this work.

Just some small comments that can help improve the work:

- Bearing in mind that the rainfall regime in the study area is the cause of the high erosion rates, it is recommended to provide more information in this regard, for example "rain intensity", "extreme events" or "long series of days with rain” (chapter 2.1, pages 113 and following)

- In figure 1 (line 129-130), the rectangle of the study area on the DEM of the Yellow River is not clearly visible.

- The origin of the NDVI data presented in chapter 3.1 has not been presented. Any comments regarding the source of the data and their treatment would be appreciated.

- The nomenclature used in figure 8 (WYLD and SYLD), lines 440-441, have not been cited in the text or in the description of the figure. Although it seems clear, it is suggested to make a reference to them.

- Figure 10 (line 534) is missing, which is important since you can't see the results of N loss and P loss in four scenarios.

Author Response

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Reviewer 3 Report

This manuscript takes an interesting approach in investigating the mutual feedback relationship between vegetation and soil erosion through SWAT and EPIC models. The manuscript is well-structured and well-written. It is also a very interesting topic as it transfers the scales to be used to more manageable tools for making management decisions. However, I have several questions and suggestions to the authors that in my opinion should be addressed before a possible publication. My questions mainly focus on some issues related to the methodology used.

1st I consider it a mistake that the authors have not presented the data analysis methods, especially linear fitting used in this manuscript.

I suggest briefly discuss the statistical methods for graphics and also writing down the software.

Line 70. Add space between different scenarios.

Line 409. Add space between ofS2

Line 409. Add space between S4increased

Figure 11. describe the significance level and also write the statistical test used for this.

Brief the conclusion section

Author Response

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