Double-Double Row Planting Mode at Deficit Irrigation Regime Increases Winter Wheat Yield and Water Use Efficiency in North China Plain
Round 1
Reviewer 1 Report
This research evaluates the impacts of different wheat sowing methods and irrigation regimes on wheat yield and water use efficiency (WUE).
Authors suggest that planting wheat in a “double-double row” (which is also known as the “twin-rows” method) and split-applying irrigation at GS34 and GS48 is the best strategy to improve yield and WUE in dryland wheat. However, results don’t seem to support such a statement as demonstrated in Table 6. Double-Double row and the furrow-ridge row seemed to have the same effect. Maybe authors can implement a discussion with economic or other management practices that would make one of those treatments more feasible than another. For example, which one of those practices would be easier and more profitable (greater amount of plants per unit area) for a producer to do in the region?
The study was well developed and provides a great amount of data with good quality figures. I like Figure 2; I think that is extremely important for understanding the sowing method treatment. Good job. However, the manuscript needs some reorganization to improve readability and focus on the subject. Thus, I highly recommend improving the clarity of the article. Some parts are difficult to understand, and some others are repetitive. If results are shown in the figure, there is no need to write the values down again in the text. Reducing the number of abbreviations would improve the clarity of the manuscript. Hence, I recommend major revisions before this article is considered for publication.
Comments:
Abstract
I am not sure I would call it a poor planting method.
I don’t think that is a novel strategy. There have been several other studies conducted with those planting methods (as stated in the introduction session). I would also suggest reorganizing the irrigation systems so the names W1, W2, and W3 are in order.
Please clearly state the objectives of the study. You may also explain in a little more detail the differences planting patterns based on row spacing.
I suggest showing the results of your main variables (yield, WUE) and a brief sentence of the treatments on the other variables such as soil water status and ETA.
Introduction
The content is good. However, some parts of the introduction sound like a discussion session. It is too specific and sometimes repetitive and hard to follow. In my opinion, is better to not abbreviate SWC, SWS, SWD. Remember that the Introduction is like a funnel, it starts broad and narrows down to your topic.
Line 30: Clarify “this area”
Line 32 – Please provide a citation for where that information about precipitation and ETA was taken from. It would also be good to include the values that are based on long-term averages.
Line 33. You may consider rewording this to something along those lines: “Precipitation is not enough for wheat to reach its full potential (or maximize yields) as demonstrated by irrigated studies”.
Materials and Methods
The experimental design is a split-plot design with irrigation as the main plot and sowing method as sub-plot. I don’t think you need to say it is a two-factor because that is implicit on a split-plot design. Please clarify the number of replications per experimental unit.
Was the plot structure placed between plots? When was the concrete plot structure installed? Any chance that could cause changes in soil physical properties and alter the treatment effects on soil water status. A picture of the structure and plot would be beneficial too.
Please, state the number of rows per plot for each treatment.
Line 122. The sentence refers to a “Prior to sowing” fertilizer rates. However, later, the authors mention that N was split applied with half of the 112 kg/ha applied as a top dressing. Adjust the N rate to avoid confusion. Also, in my opinion, there is no need to add a decimal case to the fertilizer rates.
Was the amount of corn stubble evenly distributed across treatments? How even was the stubble in the furrow-ridge treatment?
I recommend not abbreviate yield. Too many abbreviations make the paper hard to read.
Please, add an equation for Soil water content.
Equation 4. Include the meaning of ETa in the description.
Results
I would suggest for authors to use their results to explain the treatment effects on the main variables, which in this case seems to be yield and WUE. There is no need to list every single treatment effect if it was not “important” for the main message of the paper. The way it is, it adds too much complexity to the manuscript and it becomes hard to follow. I would recommend for authors to be more direct and straight to the point.
For example: “Evaluated the impact of planting method on SWC at multiples stages. The most important was X which resulted in an increase of Y” Something like this. If someone is interested in more detailed information they can go to the tables and graphs, which is very clear.
Line 171. What about treatment W3?
Again. Please clarify the soil water content term in materials and methods to avoid confusion by readers. Also, soil water content is shown as a %, clarify the unit. % of water per mass of dry soil?
Figure 4. I would recommend adding lines like in Figure 5.
Table 6. Correct the growth stage for irrigation treatment is different from previously mentioned. I think it should be GS34 instead of GS35, correct?
When an interaction is significant there is no need to discuss main effects alone. Just focus on the interaction effects.
Line 334. Careful is advised with that statement. That’s not what is showing in Table 6. What are those data points? You might consider plotting the average of replications for each treatment.
In my opinion, yield and WUE are your main variables, and the other variables tested are your supporting variables that help to explain your treatment effects. I believe that keeping this in mind will help to improve the focus and clarity of the manuscript.
Good work.
Author Response
Comments and Suggestions for Authors
This research evaluates the impacts of different wheat sowing methods and irrigation regimes on wheat yield and water use efficiency (WUE).
Point 1: Authors suggest that planting wheat in a “double-double row” (which is also known as the “twin-rows” method) and split-applying irrigation at GS34 and GS48 is the best strategy to improve yield and WUE in dryland wheat. However, results don’t seem to support such a statement as demonstrated in Table 6. Double-Double row and the furrow-ridge row seemed to have the same effect. Maybe authors can implement a discussion with economic or other management practices that would make one of those treatments more feasible than another. For example, which one of those practices would be easier and more profitable (greater amount of plants per unit area) for a producer to do in the region?
Response 1: Line 442-449, Page 15: We discussed the advantages of DD over F. Under the relative high yield and WUE, DD would be easier and more profitable for a producer to do.Thanks for your suggestion.
Point 2: The study was well developed and provides a great amount of data with good quality figures. I like Figure 2; I think that is extremely important for understanding the sowing method treatment. Good job. However, the manuscript needs some reorganization to improve readability and focus on the subject. Thus, I highly recommend improving the clarity of the article. Some parts are difficult to understand, and some others are repetitive. If results are shown in the figure, there is no need to write the values down again in the text. Reducing the number of abbreviations would improve the clarity of the manuscript. Hence, I recommend major revisions before this article is considered for publication.
Response 2: The repetitive sentences between Lines 197–198, 199, Page 7; Line 226, Page 8; Lines 275, 280, 285, Page 10; Line 301, Page 11; Line 383, Page 14 have been deleted.
The abbreviation for soil water content, soil water storage and evapotranspiration have been deleted in the whole manuscript. I revised the manuscript carefully to improve it.
Comments:
Abstract
Point 3: I am not sure I would call it a poor planting method.
Response 3: Line 14–15, Page 1: I have revised the description for planting mode with adding row spacing.
Point 4: I don’t think that is a novel strategy. There have been several other studies conducted with those planting methods (as stated in the introduction session). I would also suggest reorganizing the irrigation systems so the names W1, W2, and W3 are in order.
Response 4: Line 12–17, Page 1: The water-saving technology consisted of double-double row or furrow-ridge row plantings with deficit irrigation had been researched before, and in the study, we want to explore the best planting mode for improving yield and water use efficiency, so it is not exact to think that was a novel strategy. I had exchanged it with “effective” and reorganized the sequence of irrigation names.
Point 5: Please clearly state the objectives of the study. You may also explain in a little more detail the differences planting patterns based on row spacing.
Response 5: Line 12–14, Page 1: The objectives of the study is to improving productivity and water use efficiency (WUE) under deficit irrigation, and I have added objective and the row spacing for different planting mode.
Point 6: I suggest showing the results of your main variables (yield, WUE) and a brief sentence of the treatments on the other variables such as soil water status and ETA.
Response 6: I have deleted the result of soil water depletion between Line 17, and added sentences in Lines 23–24, mainly showing the results of yield and WUE according to your suggestion. Thanks.
Introduction
Point 7: The content is good. However, some parts of the introduction sound like a discussion session. It is too specific and sometimes repetitive and hard to follow. In my opinion, is better to not abbreviate SWC, SWS, SWD. Remember that the Introduction is like a funnel, it starts broad and narrows down to your topic.
Response 7: The sentences between Lines 32–34, Page 1 were repeated with each other, and then I revised it to one sentence.
The sentences between Lines 67–68, Page 2 were repeated with before, and then I deleted them.
Another sentences in Lines 68, Page 2 with simplification were moved to the Line 43-50 according to your suggestion of “it starts broad and narrows down to your topic”.
The abbreviation SWC, SWS, SWD were exchanged with soil water content, soil water storage and soil water depletion.
Point 8: Line 30: Clarify “this area”
Response 8: Line 32, Page 1: This area is North China Plain. According to another reviewer’s suggestion, I have deleted the sentence.
Point 9: Line 32: Please provide a citation for where that information about precipitation and ETA was taken from. It would also be good to include the values that are based on long-term averages.
Response 9: Line 33–34, Page 1: I have added the long-term average of precipitation and citation for them.
Point 10: Line 33. You may consider rewording this to something along those lines: “Precipitation is not enough for wheat to reach its full potential (or maximize yields) as demonstrated by irrigated studies”.
Response 10: Line 35, Page 1: I have replaced the sentence according to your suggestion.
Materials and Methods
Point 11: The experimental design is a split-plot design with irrigation as the main plot and sowing method as sub-plot. I don’t think you need to say it is a two-factor because that is implicit on a split-plot design. Please clarify the number of replications per experimental unit.
Response 11: Line 115, Page 3: Yes, you are right. Split-plot design is implicit a two-factor, so I delete “two-factor”. I have stated the three replications per experimental unit.
Point 12: Was the plot structure placed between plots? When was the concrete plot structure installed? Any chance that could cause changes in soil physical properties and alter the treatment effects on soil water status. A picture of the structure and plot would be beneficial too.
Response 12: Line 130–131, Page 4: Yes, they are. Figure 3 were added that the plot structure placed between plots. Long years before, we installed the concrete plot structure, and we planted maize and wheat in this plot for many years, which couldn’t change the soil physical properties and alter the treatment effects on soil water status.
Point 13: Please, state the number of rows per plot for each treatment.
Response 13: Line 128–129, Page 4: Each plot has 10 rows of wheat for U and F, 30 rows of wheat for DD.
Point 14: Line 122. The sentence refers to a “Prior to sowing” fertilizer rates. However, later, the authors mention that N was split applied with half of the 112 kg/ha applied as a top dressing. Adjust the N rate to avoid confusion. Also, in my opinion, there is no need to add a decimal case to the fertilizer rates.
Response 14: Line 133, Page 4: Sorry, the 112.5 kg/ha is half of total N, and then the describe for the amount of top-dressing is wrong. I have revised it and deleted the decimal case to the fertilizer rates.
Point 15: Was the amount of corn stubble evenly distributed across treatments? How even was the stubble in the furrow-ridge treatment?
Response 15: The stubble of corn and wheat are removed from each plot, and then straw don’t be returned to field.
Point 16: I recommend not abbreviate yield. Too many abbreviations make the paper hard to read.
Response 16: Line 172–173, Page 6: Equation 4, I have exchanged the abbreviate of Y and ETa with yield and Evapotranspiration according to your suggestion.
Point 17: Please, add an equation for Soil water content.
Response 17: Line 151–152, Page 5: A local field-calibrated CNC503B Neutron Moisture Probe was used to monitor soil water content, which directly output the data of volumetric water content. We just set the parameters for the Neutron Moisture Probe, so there was no equation for soil water content.
Point 18: Equation 4. Include the meaning of ETa in the description.
Response 18: Line 173–174, Page 6: I have added the meaning of ETa in the description.
Results
Point 19: I would suggest for authors to use their results to explain the treatment effects on the main variables, which in this case seems to be yield and WUE. There is no need to list every single treatment effect if it was not “important” for the main message of the paper. The way it is, it adds too much complexity to the manuscript and it becomes hard to follow. I would recommend for authors to be more direct and straight to the point.
For example: “Evaluated the impact of planting method on SWC at multiples stages. The most important was X which resulted in an increase of Y” Something like this. If someone is interested in more detailed information they can go to the tables and graphs, which is very clear.
Response 19: The sentences between Lines 197–198, 199, Page 7; Line 226, Page 8; Lines 275, 280, Page 10; Line 301, Page 11; Line 383, Page 14 have been deleted as they were not “important” for the main message of the pape.
The sentence between Lines 285–286, Page 10 was improper here as they were not result, so I removed it to discussion in Line 411-415, Page 14.
Line 198, Page 6; 257–258, Page 9: I have revised the sentence according to your suggestion.
Point 20: Line 171. What about treatment W3?
Response 20: Line 183-184, Page 6: Soil water content in W3 hardly decreased in the middle soil layer.
Point 21: Again. Please clarify the soil water content term in materials and methods to avoid confusion by readers. Also, soil water content is shown as a %, clarify the unit. % of water per mass of dry soil?
Response 21: Line 151–152, Page 5: The soil volumetrici water content (m3/m3, %) was monitored using a local field-calibrated CNC503B Neutron Moisture Probe (Super Energy Nuclear Technology, Ltd., Beijing, China).
Point 22: Figure 4. I would recommend adding lines like in Figure 5.
Response 22: I have added the line in Figure 4.
Point 23: Table 6. Correct the growth stage for irrigation treatment is different from previously mentioned. I think it should be GS34 instead of GS35, correct?
Response 23: Table 6. Sorry, it is correct that the time for irrigation should be GS34, and I have corrected it and other errors in legend or footnote of other Figures and Tables. Tanks.
Point 24: When an interaction is significant there is no need to discuss main effects alone. Just focus on the interaction effects.
Response 24: The sentence between Line 285–286, Page 10 was deleted, because we mainly discuss main effects caused by interaction of years and planting mode.
Point 25: Line 334. Careful is advised with that statement. That’s not what is showing in Table 6. What are those data points? You might consider plotting the average of replications for each treatment.
Response 25: The sentence in Line 342, Page 12 of “High yield might require more
evapotranspiration” can be get from Figure 6, but the statement “but with the increase of the water requirement did not improve wheat WUE” is summarized from Table 6. So it is not exact here. I have deleted it. We also used the average of replications for each treatment to plot the Figure 6 in Line 346, Page 13.
Point 26: In my opinion, yield and WUE are your main variables, and the other variables tested are your supporting variables that help to explain your treatment effects. I believe that keeping this in mind will help to improve the focus and clarity of the manuscript.
Response 26: Based on your suggestion, I have revised the manuscript with the main variables (yield and WUE) especially in the discussion.
Good work.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Review of Agronomy_887734 “Double-Double Row Planting Mode at Deficit Irrigation Regime Increases Winter Wheat Yield and Water Use Efficiency in North China Plain”
This study investigated the interactive effect of planting methods and irrigation regimes on grain yield, soil water depletion, evapotranspiration and water use efficiency of winter wheat in a semiarid region over two growing seasons. The author concluded that combination of double-double row planting mode and split application of 50 mm irrigation water each at jointing and heading stages is a good cultivation practice for water-saving technology. The experiments were properly designed, and Materials and Methods section is concisely written. However, in the introduction authors failed to develop a clear knowledge gap with sufficient background and is not well written. The flow of information was poor with repetition of the same information (please see the specific comments for details). The same is true for the discussion part. The authors failed to discuss the mechanism of yield improvement, water savings and improving water use efficiency instead heavily repeated the results with merely justifying their findings with existing literature. I recommend that the paper not be considered for publication in Agronomy as its current form. However, may be considered after major modification and restructuring the introduction and discussion sections.
Other comments:
- The Abstract is results dominated.
- Keywords: “Water use efficiency” and “yield” are mentioned in the title therefore better to remove form the keywords.
- Line 29: replace “where” with “which”
- Lines 29 - 35: The whole section here is repeating the same information that “crop yield in semiarid regions are primarily limited by water availability”. Concise this section avoiding duplication of the same information by different sentences.
- Lines 59 - 60: “Plants with high WUE may be expected to show relatively high productivity under water-limited conditions” Not sure whether the authors are addressing the WUE as a genotypic trait here. If so, this sentence needs to be deleted as not relevant with the overall study.
- Line 74: Missing “.”
- Line 75: replace “wary” with “vary”.
- Line 85 - 87: These sentences are repetition from the earlier paragraphs and do not suit here as authors needs wrap up the Introduction rather than using very basic introductory sentences at this stage.
- Lines 127 – 129: The authors reported Zadok scale without citing the original source.
- Lines 131 – 132: Treatment sequence in the figure title is not matching with the schematic diagram.
- Lines 118 – 120: Use of complex sentences made it harder for the reader to get clear messages.
- 400 – 401: Its pure results not discussion, delete this.
- Lines 427 – 435: Just repetition of results not leading to any mechanism for discussion.
- Lines 343 – 344: Is this a meaningful sentence?
- I strongly recommend proof reading for improving readability of the manuscript.
Author Response
Comments and Suggestions for Authors
Review of Agronomy_887734 “Double-Double Row Planting Mode at Deficit Irrigation Regime Increases Winter Wheat Yield and Water Use Efficiency in North China Plain”
Point 1: This study investigated the interactive effect of planting methods and irrigation regimes on grain yield, soil water depletion, evapotranspiration and water use efficiency of winter wheat in a semiarid region over two growing seasons. The author concluded that combination of double-double row planting mode and split application of 50 mm irrigation water each at jointing and heading stages is a good cultivation practice for water-saving technology. The experiments were properly designed, and Materials and Methods section is concisely written. However, in the introduction authors failed to develop a clear knowledge gap with sufficient background and is not well written. The flow of information was poor with repetition of the same information (please see the specific comments for details). The same is true for the discussion part. The authors failed to discuss the mechanism of yield improvement, water savings and improving water use efficiency instead heavily repeated the results with merely justifying their findings with existing literature. I recommend that the paper not be considered for publication in Agronomy as its current form. However, may be considered after major modification and restructuring the introduction and discussion sections.
Response 1:
Introduce: The repetitive sentences between Line 67–68, Page 2 was deleted it
which was repeated with before.
Discussion: the repetitive sentences between Line 363, Page 13; Line 383, 386, 403–404, Page 14; Line 449–450, Page 15 were deleted.
On the basis of above revised, I also improved carefully the discussion.
Other comments:
Point 2: The Abstract is results dominated.
Response 2: The grain yield and WUE are dominated in the abstract, so I deleted the sentence in Line 17 and added the sentence in Line 23-24.
Point 3: Keywords: “Water use efficiency” and “yield” are mentioned in the title therefore better to remove form the keywords.
Response 3: Line 27, Page 1: Thank you for your suggestion. I have removed “Water use efficiency” and “yield” from keywords.
Point 4: Line 29: replace “where” with “which”
Response 4: Line 31, Page 1: “where” is replaced with “which”.
Point 5: Lines 29–35: The whole section here is repeating the same information that “crop yield in semiarid regions are primarily limited by water availability”. Concise this section avoiding duplication of the same information by different sentences.
Response 5: Lines 32–39, Page 1: I have made the three sentences to one sentence, and added other sentences to clary the current status for water conditions.
Point 6: Lines 59–60: “Plants with high WUE may be expected to show relatively high productivity under water-limited conditions” Not sure whether the authors are addressing the WUE as a genotypic trait here. If so, this sentence needs to be deleted as not relevant with the overall study.
Response 6: Lines 45–46, Page 2: The WUE is not a genotypic trait here, and we address that “the plants on the basis of improving WUE may be expected to show relatively high productivity”. I have revised it according to your suggestion.
Point 7: Line 74: Missing “.”
Response 7: Line 79, Page 2: I have added the “.”
Point 8: Line 75: replace “wary” with “vary”.
Response 8: Line 79, Page 2: “wary” have been replaced with “vary”. Thanks.
Point 9: Line 85–87: These sentences are repetition from the earlier paragraphs and do not suit here as authors needs wrap up the Introduction rather than using very basic introductory sentences at this stage.
Response 9: Line 90–92, Page 2: I have deleted the sentence, and added another concluding sentence according to your suggestion.
Point 10: Lines 127–129: The authors reported Zadok scale without citing the original source.
Response 10: Lines 135, Page 4: I have added the reference of [28].
Point 11: Lines 131–132: Treatment sequence in the figure title is not matching with the schematic diagram.
Response 11: Lines 139–140, Page 4: Sorry, the sequence of b and c is reversed in the title, and I have revised it. Thanks.
Point 12: Lines 118–120: Use of complex sentences made it harder for the reader to get clear messages.
Response 12: Lines 126–127, Page 4: The sentence is mainly introduced plant density and dates for sowing and harvest of winter wheat, and I have revised it.
Point 13: Lines 400–401: Its pure results not discussion, delete this.
Response 13: The sentences between Lines 403–404, Page 14 were deleted according to your suggestion. Thanks.
Point 14: Lines 427–435: Just repetition of results not leading to any mechanism for discussion.
Response 14: The sentences between Lines 449–450, Page 15 were deleted as they were repeated with results, and added another discussion for yield and WUE caused by planting pattern in Lines 442–449, Page 15.
Point 15: Lines 343–344: Is this a meaningful sentence?
Response 15: Lines 350, Page 13: It just confirmed that precipitation in our experimental site was normal in the North China Plain and less than evapotranspiration, so additional irrigation was needed to satisfy growth of plants. I have deleted them.
I strongly recommend proof reading for improving readability of the manuscript.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The manuscript is been revised following my earlier comments and I am happy with the improvements done by the authors.
