Scale Effects on the Reduction of Drainage Water and Nitrogen and Phosphorus Loads in Hilly Irrigation Areas
, Baokun Xu 1,2, Fengli Liu 1,2 and Haolong Fu 1,2Round 1
Reviewer 1 Report
The research is interesting and presents valuable results, however, the article needs to be refined.
The given methods do not allow to recreate of the experiment - the methods should be supplemented with the necessary data (details in the comments).
There is a lack of statistical calculations and visualization of results in this area.
It is necessary to develop the discussion! Conclusions are correct, but very poorly or not at all compared with the results of other authors or even previous results from the same object.
Table editing is required (details in the comments).
Consistently use in the methodology, text, tables and graphs the names or chemical formulas of the compounds that have been analyzed (N-NO3 or NO3-, N-NH4 or NH4+) is necessary. Nitrates are not the same as nitrate nitrogen etc. Maybe you calculated forms eg. N-NO3 to NO3-, if yes, you should write it in the methodology.
References must be adapted to editorial requirements.
Comments for author File: 
Comments.pdf
Author Response
Reviewer 1
Comments and Suggestions for Authors
The research is interesting and presents valuable results, however, the article needs to be refined.
The given methods do not allow to recreate of the experiment - the methods should be supplemented with the necessary data (details in the comments).
There is a lack of statistical calculations and visualization of results in this area.
It is necessary to develop the discussion! Conclusions are correct, but very poorly or not at all compared with the results of other authors or even previous results from the same object.
Table editing is required (details in the comments).
Consistently use in the methodology, text, tables and graphs the names or chemical formulas of the compounds that have been analyzed (N-NO3 or NO3-, N-NH4 or NH4+) is necessary. Nitrates are not the same as nitrate nitrogen etc. Maybe you calculated forms eg. N-NO3 to NO3-, if yes, you should write it in the methodology.
References must be adapted to editorial requirements.
Answer 1:
Thank you very much for your positive comments. We have carefully gone through the comments and suggestions and made efforts to address all the concerns raised by the reviewer. We hope all the revisions have satisfactorily addressed the comments.
We will first respond to the overall comments of the reviewers here, and specific modification suggestions will be replied to one by one.
This study has a large scale and is not suitable for repeated experiments, but we set up three parallel samples when testing the samples to ensure the reliability of the results. The revised manuscript has made modifications to the repeated expression of figures and tables, as well as the accuracy of table data. The writing of nitrate nitrogen and ammonia nitrogen has been modified. The references have been rearranged according to the requirements of the journal. In the discussion section, the conclusions of this article were compared with similar studies conducted in the same experimental area, Zhejiang Province in China, as well as Japan and Egypt. The on-site test results were also compared with the model simulation results.
Line 15-19
this sentence seems to be too extensive, please share
Answer: Thank you very much for pointing this out. We have shared this sentence. (See Line 15-20).
Line 53-55
Lack of the year of publication (Cui et al)-its better to use: For example, Cui et al., (2018) used the improved (...) - without quoting at the end of the sentence
Answer: Thank you for your careful reading. The kind suggestion has been adopted. (The sentence have been corrected as “Cui et al. (2018) used the improved SWAT model to study the water cycle process in the irrigated area of Tongjiqiao Reservoir in Zhejiang Province.” See Line 55-57).
Line 55-58
quoting (Gosain et al., 2005), please reformat as in the comment above (quoting without abbreviations of the author's name)
Answer: Thank you for your careful reading. The kind suggestion has been adopted. (The sentence have been corrected as “Gosain et al. (2005) applied the SWAT model to study the spatial-temporal variation characteristics of groundwater regression caused by irrigation in Pslleru Basin, India, and predicted the runoff of the basin without human intervention (reservoir management and irrigation).” See Line 57-60).
Line 55-59
Please reformat the sentences to make them consistent
Answer: Thank you very much for your comments. We have reformated the sentences as “Gosain et al. (2005) also evaluated the influence of irrigation and other human activities on regional water balance.” See Line 60-62.
Line 59-61
Please reformat the sentences to make them consistent
Answer: Thank you very much for your comments. We have reformated the sentences as “Cui et al. (2006) belived that reclaimed water and reuse existed in the water cycle process of irrigated areas due to irrigation and rainfall.” See Line 62-63.
Line 62-65
quoting like in comment to line 53-55
Answer: Thank you very much for your comments. We have reformated the sentences as “Schulze. (2000) found significant differences in water movement in irrigated areas at different spatial and temporal scales. Loeve et al. (2004) studied the water productivity at different scales in the Zhanghe irrigated area and found that, influenced by the reuse of irrigation backwater, the water productivity based on irrigation water consumption was lowest at the channel scale and highest at the irrigated area scale.” See Line 64-69.
Figure 1
Figure is difficult to read, it may be worth enlarging the scale of the field and the ditch in a new window in the same figure (upper left corner). Can the contrast be increased? (only water reservoirs are clearly visible). Perhaps it is worth considering developing a map with the use of the catchment area (fields, forests, meadows, surface waters: reservoirs, a network of ditches, canals, etc.). In the context of moving loads (distances of the drop from the measurement points), this is important. It is also worth noting water facilities (although larger gates or weirs)
Answer: Thank you very much for your careful read. We set up the test site according to the river system in the irrigation area and installed the measuring devices. The test site is located at the same location as the water conservancy facilities in the irrigation area. According to the need, the scale of the ditch was enlarged. See Figure 1.
Line 153
Installed instead install; which model of HOBO water level logger was installed?
Answer: Thank you very much for your careful read. The kind suggestion have been adopted. See line 168.
Line 153-156
If the flow was determined based on a water level curve, for each location it was necessary to determine the flows corresponding to a given water level, how was the flow measurement done? Previously established flow-by-state curves for the location of HOBO? Please clarify. How are other balance sheet items determined? (evapotranspiration, infiltration) How to collect seepage water? Was it water infiltrating into the ground? Please explain in the text
Answer: Thank you very much for your careful read. The kind suggestion have been adopted. See line 172-180. According to the discharge mode of monitoring points, such as wide crest weir discharge or culvert pipe overflow, and the water level measured by the upstream and downstream HOBO (U20L-04) water level gauge, the hydraulic formula is used to calculate the water amount.
The deep seepage water was collected by a PVC pipe like “7”. See line 186-191. Field surface water samples were taken directly from the surface. See line 192-194.
Line 159-165
Only 52 samples were collected from the five observation points? Please specify in detail the research period and how many times precipitation occurred after which water tests were carried out on the first, third, fifth, seventh and ninth day.
(by the way, graph 3 shows that precipitation occurred at least 5 times in the period, i.e. at least 4 additional collections X 5 rainfall x 5 points = 100 samples)
Answer: Thank you very much for your careful read. I did miscalculate the total number of samples. We have a total of 5 sampling sites, each site samples 51 times, a total of 255 samples. Thank you for your serious reminding. See line 195.
The sampling began on May 20th and ended on September 26th, with rain occurring on June 3rd, June 20th, July 21st, July 26th and August 12th. It is not possible to take 5 samples consecutively after each rainfall. When the rainfall is not heavy enough or the interval between two rainfalls is long, the samples may only be taken on the first and third days after the rainfall. So it's not five times as many samples as it rains. See Table 1.
Line 161
These are actually written ordinal numbers?
Answer: Thank you very much for your careful read. These are written ordinal numbers. We have revised them. See line 183.
Line 164
Please specify the exact period in which the measurements were made, specify the model of the analyzer
Answer: Thank you very much for your careful read. We have added the sampling time and the model of the analyzer. See in line 197 and table 1.
Line 175
Statistical analysis of the results seems to be necessary to confirm the strength of the dependencies you are writing about, choose an analysis adapted to the number of results you have
Answer: Thank you very much for your careful read. We performed a statistical analysis of the concentration data using standard deviation. It's not easy to replicate these large-scale experiments and we can't find another test site with the same conditions at the same time. We did not obtain parallel sample data, so we could not carry out statistical analysis and calculate significance indicators. However, we will continue to carry out the same experiment in 2023, in order to get the change law of drainage and nitrogen and phosphorus load at different scales at different hydrologic year. We have changed the statement. See in line 208-209.
It is better to present statistical results than to duplicate the same results in tables and graphs
Answer: Thank you very much for your careful read. We have improved the tables and remove some graphs (eg.Figures 2, 5, 9d, 10b,12).
Line 179-180
"graph" and "table" in the plural
Answer: Thank you very much for your careful read. See in line 215.
Line 194-196
The total share of evapotranspiration in these phases was 47% of the total, it does not give 25% each, it may be better to write that evapotranspiration in (...) phases was 47%
Answer: Thank you very much for your careful read. We have revised them. See line 227-228.
Line 207
Please enter a valid percentage of precipitation
Answer: Thank you very much for your careful read. We have revised it. See line 231.
Table 1 and Figure 2
The table contains very important information but the graph contain the same information please amend the table accordingly or delete the graph.
Answer: Thank you very much for your careful read. We have deleted the Figure 2.
Please make the table in accordance with the journal guidelines (editorial guidelines).
First column in the Table 1 (irrigation share in growth stages) contains the total sum of percentage share-101%
Answer: Thank you very much for your careful read. We have revised them. See Table 2.
Consistently use in the methodology, text, tables and graphs the names or chemical formulas of the compounds that have been analyzed (N-NO3 or NO3-, N-NH4 or NH4+). Nitrates is not the same as nitrate nitrogen etc. Maybe you calculated forms eg. N-NO3 to NO3-, if yes, you should wite it in the Methodology
Answer: Thank you very much for your careful read. We have delete the graph 2 and amended the table. The infirmation in the tables was modified.
Nitrates was not use the abbreviation “NN”, insteaded by “NO3-_ N”. Ammonium was not use the abbreviation “AN”, insteaded by “NH4+_ N”, see the manuscript.
Figure 3
Why the graphs show different precipitation sums in the analyzed period?
Figure 4
Why the graphs show different precipitation sums in the analyzed period?
Answer: Thank you very much for your careful read. Rainfall is same in the all figures. However, when the rainfall is small, no drainage will be generated on the field surface, so no water sample can be taken from the field surface. In the drawing, although there is rain on some days, it is not shown on the map because there is no sample point. We have revised the Figure 3 and Figure 4. See the manuscript.
Line 254-257
the percentages given are correct? (seepages)
Answer: Thank you very much for your careful read. We have checked and modified them. See line 291-293.
Line 257-259 and Table 2
Use chemical formula of nitrate nitrogen instead NN, the same to ammonia nitrogen
Answer: Thank you very much for your careful read. We have modified them. Nitrates was not use the abbreviation“NN”, instead of “NO3-_ N ”. Ammonium was not use the abbreviation “AN”, instead of “NH4+_ N”. See line 294-295 and Table 3.
Line 274
You have not performed/presented statistical analysis, you cannot write about significant correlation
Answer: Thank you very much for your careful read. It's not easy to replicate these large-scale experiments and we can't find another test site with the same conditions at the same time. We did not obtain parallel sample data, so we could not carry out statistical analysis and calculate significance indicators. We have changed the statement. See line 302-303.
Table 2
some load percentages are wrong, please correct
Answer: Thank you very much for your careful read. We have checked and modified them. See table 3.
Please make the table in accordance with the journal guidelines (editorial guidelines).
Answer: Thank you very much for your careful read. We have modified the table. See table 3.
Table 3
some load percentages are wrong, please correct
Answer: Thank you very much for your careful read. We have checked and modified them. See table 4.
Please make the table in accordance with the journal guidelines (editorial guidelines).
Please correct the Excel tables in terms of editorial (according to the editorial guidelines) and take care appropriate rounding of the given numbers (the number of places at the decimal point), and then the appropriate values expressed in % share of the correct sums of percentages
Answer: Thank you very much for your careful read. We have checked and modified them. See table 4.
Line 323
what fertilizers were used in the field and when - should be given in the material and methods
Answer: Thank you very much for your careful read. We have added the date, type and amount of fertilizer in the materials and methods. See in the chapter of 2.2.1.
Line 333
Is it really only the Yangshudang Reservoir that has reduced the concentration of nitrates in the catchment scale? whether dilution with waters from land not used for agriculture had any significance. Unfortunately, we do not know what area in the catchment area is occupied by rice cultivation and what by other uses (especially non-agricultural).
Answer: Thank you very much for your careful read. As for the types of land use in the test area, I have supplemented in the materials and methods, see in the paper for details. The test area is located in the Zhanghe Irrigation District, which has a designed irrigation area of 173,000 hectares and is an important rice producing area in Hubei Province. The main land use type is cultivated land, and the main crop is middle rice. There is very little off-farm water consumption in this area, and the dilution of nitrogen is negligible.
Figures 7, 8, 9, 10
Spelling mistakes in charts (legend, axis) - omissions and lowercase and uppercase letters
Answer: Thank you very much for your careful read. We have checked and modified them. Change the first letter to uppercase in the legend, the “waershed” was modified to “watershed”. See Figures 7, 8, 9, 10.
Line 351-352
You have not performed/presented statistical analysis, you cannot write about significant correlation
Answer: Thank you very much for your careful read. It's not easy to replicate these large-scale experiments and we can't find another test site with the same conditions at the same time. We did not obtain parallel sample data, so we could not carry out statistical analysis and calculate significance indicators. We have changed the statement. See line 383-385.
Line 354-360
I don't understand - in general throughout the growth period? The graphs 9a,b,c show the division into growth phases and graph 9d shows other load values (relative percentage to field scale)
Answer: Thank you very much for your careful read. After consideration, we think 9d has little meaning and relevance to the content expressed in Section 3.6.1, so this figure has been deleted in the revision.
Line 364
You have not performed/presented statistical analysis, you cannot write about significant correlation
Answer: Thank you very much for your careful read. It's not easy to replicate these large-scale experiments and we can't find another test site with the same conditions at the same time. We did not obtain parallel sample data, so we could not carry out statistical analysis and calculate significance indicators. We have changed the statement. See line 404-406.
Line 370-372
The graph 10b shows other load values (relative percentage to field scale)
Answer: Thank you very much for your careful read. After consideration, we think 10b has little meaning and relevance to the content expressed in Section 3.6.1, so this figure has been deleted in the revision.
Chapter discussion
It is necessary to develop the discussion! Conclusions are correct, but very poorly or not at all compared with the results of other authors or even previous results from the same object.
Answer: Thank you very much for your careful read. According to the opinions of reviewers, the discussion is compared with the results of Gao Yang, Yang Baolin, He Jun, Takehide, Fleifle and Wu, et al., see line 450-455, 470-477,505-508.
References
The list of references is not adapted to the editorial requirements
Lack position 16 in the text
Answer: Thank you very much for your careful read. The reference is adapted in the line 90.
Lack position 24 in the text
Answer: Thank you very much for your careful read. The reference is adapted in the line 50.
Lack position 27 in the text
Answer: Thank you very much for your careful read. The reference is adapted in the line 84.
Lack Takehide et al. 2006 in references
Answer: Thank you very much for your careful read. There was a spelling mistake of the author’s name in the manuscript, it shouled be Takeda in line 120. The reference is listed 31.
Lack position 30 in the text
Answer: Thank you very much for your careful read. Positopn 30 was the “Takehide et al. 2006” in the manuscript.
Lack Yang et al. 2016 in references
Answer: Thank you very much for your careful read. The reference is position 30 and is adapted in the line 84.
Author Response File: Author Response.pdf
Reviewer 2 Report
Unfortunately, my decision is that the manuscript in its present form, due to serious flaws, should be REJECTED,
Such a decision was mostly influenced by chapters: 3. Results; and 4. Discussion of the reviewed manuscript.
Although the collected data and conducted research have a potential to be a solid basis for a scientific paper, they have not been adequately utilized. The systematization and presentation of the acquired results demand a considerably more thorough analysis. In other words, they require the use of relevant analytical methods, including statistics, which would contribute to defining and explaining the observed topic. This includes statistical argumentation and confirmation of validity and significance of the presented results and conclusions. The results and their interpretation have to be based on concrete parameters. The presented charts and tables do illustrate the results, but on their own they are not enough for a scientific paper. The relationship and correlations between parameters have to be corroborated in an adequate manner.
Moreover, the presented tables require a better design. The percentages in these tables are not always correctly calculated: not only rounding up the numbers (in all tables), but significant mistakes were also observed (eg. in Tables 2 and 3).
The same data has been presented both in tables and charts, eg. Table 1 and Fig. 2, Table 4 and Fig 5 etc.
The manuscript is overburdened with charts, and some of them are not particularly clear and intuitive. Only the necessary and most important ones should be kept. Some results should be presented and interpreted in a different manner.
The discussion should provide a summary of the main findings and the most important results of the manuscript in the context of the broader scientific literature, as well as addressing any limitations of the study or results that conflict with other published work. Along those lines, new results and charts should not be presented in this chapter.
Because of the aforementioned, the manuscript in its current form can not be accepted for publishing.
I encourage the authors to significantly upgrade the concept and approach of the manuscript, to conduct further analyses, improve the presentation and interpretation of the results along with an appropriate discussion, and re-submit the manuscript in this or a different journal.
Author Response
Reviewer 2
Comments and Suggestions for Authors
Unfortunately, my decision is that the manuscript in its present form, due to serious flaws, should be REJECTED,
Such a decision was mostly influenced by chapters: 3. Results; and 4. Discussion of the reviewed manuscript.
Although the collected data and conducted research have a potential to be a solid basis for a scientific paper, they have not been adequately utilized. The systematization and presentation of the acquired results demand a considerably more thorough analysis. In other words, they require the use of relevant analytical methods, including statistics, which would contribute to defining and explaining the observed topic. This includes statistical argumentation and confirmation of validity and significance of the presented results and conclusions. The results and their interpretation have to be based on concrete parameters. The presented charts and tables do illustrate the results, but on their own they are not enough for a scientific paper. The relationship and correlations between parameters have to be corroborated in an adequate manner.
Answer: Thank you very much for your careful read. This study has a large scale and is not suitable for repeated experiments, but we set up three parallel samples when testing the samples to ensure the reliability of the results. In the discussion section, the conclusions of this article were compared with similar studies conducted in the same experimental area, Zhejiang Province in China, as well as Japan and Egypt. The on-site test results were also compared with the model simulation results.
Moreover, the presented tables require a better design. The percentages in these tables are not always correctly calculated: not only rounding up the numbers (in all tables), but significant mistakes were also observed (eg. in Tables 2 and 3).
Answer: Thank you very much for your careful read. We have checked and modified all the tables.
The same data has been presented both in tables and charts, eg. Table 1 and Fig. 2, Table 4 and Fig 5 etc.
The manuscript is overburdened with charts, and some of them are not particularly clear and intuitive. Only the necessary and most important ones should be kept. Some results should be presented and interpreted in a different manner.
Answer: Thank you very much for your careful read. The revised manuscript has made modifications to the repeated expression of figures and tables, as well as the accuracy of table data. We have removed the Figures 2, 5, 9d, 10b, 12.
The discussion should provide a summary of the main findings and the most important results of the manuscript in the context of the broader scientific literature, as well as addressing any limitations of the study or results that conflict with other published work. Along those lines, new results and charts should not be presented in this chapter.
Answer: Thank you very much for your careful read. We have refined the discussion. Compared with similar research results. We deleted the figure 12. In the discussion, the conclusions of this article were compared with similar studies conducted in the same experimental area, Zhejiang Province in China, as well as Japan and Egypt. The on-site test results were also compared with the model simulation results.
The main purpose of this study was to explore the change rules in drainage volume and nitrogen and phosphorus at different scales, as well as the reasons for these phenomena. At present, through on-site monitoring experiments, we have only obtained the change rules in drainage volume and nitrogen and phosphorus load at different scales. These conclusions were consistent with previous research results in this region and other similar regions, such as Tongjiqiao irrigation area in Zhejiang province in China, Japan, Egpyt. However, due to the large area of the study region (43.3 km2)and the existence of many uncontrollable factors, we cannot analyze the mechanism of scale effects in detail based solely on monitoring data. This article only provides a simple generalization of the mode of irrigation return flows within the project area, and the research results are only applicable to the research area of this article. Subsequent research needs to select appropriate models, calibrate models, and set scenarios based on on-site monitoring data to make the research results more informative.
Because of the aforementioned, the manuscript in its current form can not be accepted for publishing.
I encourage the authors to significantly upgrade the concept and approach of the manuscript, to conduct further analyses, improve the presentation and interpretation of the results along with an appropriate discussion, and re-submit the manuscript in this or a different journal.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The authors accepted the reviewer's suggestions and significantly improved the manuscript. I think the paper Scale Effects on The Reduction of Drainage Water and Nitrogen and Phosphorus Loads in Hilly Irrigation Areas can be now published in Agronomy journal.
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