Long-Term (1990–2013) Changes and Spatial Variations of Cropland Runoff across China

Round 1

Reviewer 1 Report

This manuscript combined the SCS-CN method and geostatistical techniques to quantify long-term (1990-2013) and regional variations of cropland runoff derived from rainfall and irrigation across the diverse landscapes and climates in China. It is concluded that the SCS-CN method was suited for cropland runoff estimation in China, and the inverse distance weighting method achieved the highest accuracy for prediction of cropland runoff depth. Estimated cropland runoff depth gradually increased from the drier northwest inland region to the wetter southeast coastal region. During the study period, estimated cropland runoff depth showed no significant trends, whereas cropland runoff volume and irrigation-contributed percentage showed a significant decreased trend owing to implementation of water-saving irrigation technologies. These results will be valuable to research scientists and policymakers on agricultural water management in China. Although some issues still exist in the current form of manuscript, data were well collected and the manuscript was well organized in high performance. Therefore, I recommend it can be accepted with a minor revision.

 

Specific comments:

Line 72: Abbreviations should be added after the “National Engineering Handbook”.

Line 76-77: Change “….Midwestern regional bias [e.g., Romanian River Basins and Southeastern Arizona]” to “….Midwestern regional bias, e.g., Romanian River Basins  and Southeastern Arizona”.

Line 253: Change “…. [i.e., EC, CC, SC and SWC [57]]” to “…. {i.e., EC, CC, SC and SWC [57]}”.

Line 277: Change “…. low agricultural water-use efficiency (0.30±0.23 from 2000 to 2015, [35]…” to “…. low agricultural water-use efficiency {0.30±0.23 from 2000 to 2015, [35]}…”.

Line 279-280: Change “…. (0.63±0.13 from 2000 to 2015, [35] in the NC region (the major grain production area in China [62]…” to “…. {0.63±0.13 from 2000 to 2015[35]}in the NC region {the major grain production area in China [62]}…”.

 

Table 1: “Fujian” should be distributed in “Eastern China”.

Figure 3: Explain what the smaller map map-frame in the lower left corner represents.

Figure 6: Explain what the smaller map map-frame of each figure in the lower right corner represents.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

-          What novelty you added in this article as SCS-CN is very common and widely applied methods in runoff analysis?

-          Page 3: Please check Figure and Table number. Also please follow the correct format of reference.

-          Please add the reference for Table 1

-          Section 2.3 (Statistical Analysis) need to describe properly.

-          Can you please figure 7 (it showed p>0.05 but the figure description mentioned p<0.05)

-          Figures number are not following the numbering and it is confusing that what actually authors wants to explain.

-          Line 394 “suitable estimate” – can you please explain this? What do you mean by suitable estimate?

-          I would like to read this article again after correcting the figure number.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Thanks for the update.

A minor query, can you please explain the lower R-square and NSE value?

Author Response

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Author Response File: Author Response.docx