Effects of Nitrogen Application on Crop Production and Nitrogen Use in Rice–Wheat Rotation
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsIn general, a very interesting study. There is a lot of data, and some times is hard to follow.
Main issues:
Experimental design. Not clear how the experiment was implemented in the field. It needs to be clear if: 1) every plot receive the same treatment the two years; 2) there were 30 plots per replicate, therefore there were five plots for every level of N in rice; 3) the two replicates were per treatment, independent to the subsampling described in lines 111-118.
Data analysis. Data were analyzed as a three factor combination (Rice fertilization, Wheat fertilization, year). However, I see it more as a series of experiments or even repeated measurements. Rice planted on June 2022 affected wheat sown in November (and the following crops), but not viceversa. In 2023, rice planted in June was affected by previous treatments, and affected the following crop. Same did happen with wheat sown in November 2023, that did not affect previous crops of rice.
Mean separation test. Authors used LSD for multiple means separation. It is a good method for pairwise comparisons.
Tables and figures. Revise order and appropriate reference in the text. There is no order on how figures are referenced in the text. For example, first figure referenced in text is Fig 9, and it is the last in the manuscript. The same with other figures. Figures are too pixelated. Table 3 is either out of place or not needed. Several other tables have serious issues.
Mean separation. Not clear how the mean separation was performed in the tables, and it needs to be revised carefully. From the text, I understand that the mean separation in the tables was done per column, however it is confusing. Some cases a literal is missing (a, c, d, and missing b), some others group b is larger than group a (descending order). See notes in the tables.
Figure 1. Data of 2022, 2023 or average?
Table 3. Wrong or is it table 4?
180. First figure cited in text is Figure 9?
Table 4. Main issues.
a) Interaction Rice and Wheat treatments does not make sense, since "rice treatments" were applied before wheat treatments both in 2022 and 2023. Can be done the interaction between Wheat 2022 and Rice 2023.
b) Mean separation (in addition to what I said before about LSD method) needs to be carefully revised. In te text I marked only some cases, as examples. Panicle number; W0-2023: group b is missing; W300: a: 289, 285, 260, b: 295, 186, How is it possible?
c) Placing the ANOVA p-values for the main sources of variation (I guess: Rice Wheat, Year, and interactions) makes the table larger and confusing.
Minor issues: Referred in the text as table 3. It is a large table. I suggest putting the p-values in another table or supplementary data.
Figure 5 is pixelated, hard to understand
Table 5.
Mean separation needs to be carefully revised, as described for table 4. Examples: R0W0 for rice amylose content 2023 values with literal a are: 14, 11 and 10, while for b 11 and 12, and c, it is 11; and for R0W180 values for a (11, 12); b (10, 11, and 13), and c?
Put P-values in a separate table.
Interaction "Rice" x "Wheat" is ok in this case if the .
Tables 6.
Issues with mean separation as previously described.
Table 7. When was the N accumulation measured?
Conclusions. May vary if data is reanalyzed as suggested.
Line 103. What does "long-term positioning experiment" mean?
105. Table 2. Units.
111-112 Parameters measured on 4-m2 plots?
117-118 Needs editing.
148 Are kg ha-1 the units for St in Table 2?
166-167 Move the note as a foot-table note.
187-188 Indicate the treatments.
195-196 Editting
206 See note
208-209 See note
276 Table 5?
Comments for author File: 
Comments.pdf
Author Response
Comments 1: Experimental design. Not clear how the experiment was implemented in the field. It needs to be clear if: 1) every plot received the same treatment the two years; 2) there were 30 plots per replicate, therefore there were five plots for every level of N in rice; 3) the two replicates were per treatment, independent to the subsampling described in lines 111-118.
Response 1: Thank you for pointing this out. We agree with all these comments and have revised as requested. Firstly, this experiment was a long-term field trial conducted over multiple years, initiated in 2019, using a rice–wheat rotation system. The experiment consisted of 30 treatments, combined with six nitrogen rates in rice season and five nitrogen rates in wheat season. Each treatment was independent combination of a specific nitrogen rate in rice season and another nitrogen rate in wheat season, and each treatment was repeated twice in the field, thus a total of 60 plots were formed. Secondly, the sampling methods for wheat have been revised, line 105-107.
Comments 2: Data analysis. Data were analyzed as a three factor combination (Rice fertilization, Wheat fertilization, year). However, I see it more as a series of experiments or even repeated measurements. Rice planted on June 2022 affected wheat sown in November (and the following crops), but not vice versa. In 2023, rice planted in June was affected by previous treatments and affected the following crop. Same did happen with wheat sown in November 2023, that did not affect previous crops of rice.
Response 2: Thank you for pointing this out. We agree with all these comments. The data were analyzed as a three factor combination (Rice fertilization, Wheat fertilization, year) previously. As the results failed to reflect the interactions between rice or wheat yield and previous or current nitrogen rate, we deleted this data analysis.
Comments 3: Mean separation test. Authors used LSD for multiple means separation. It is a good method for pairwise comparisons.
Response 3: Thank you for pointing this out. We agree with all these comments. Therefore, I made a mistake in writing. All the original data were analyzed by Duncan and all previous LSD analyses have been analyzed by Duncan.
Comments 4: Tables and figures. Revise order and appropriate reference in the text. There is no order on how figures are referenced in the text. For example, the first figure referenced in text is Fig 9, and it is the last in the manuscript. The same with other figures. Figures are too pixelated. Table 3 is either out of place or not needed. Several other tables have serious issues.
Response 4: Thank you for pointing this out. We agree with all these comments. Therefore, we rearranged the order of the charts so that they were in the right place.
Comments 5: Mean separation. Not clear how the mean separation was performed in the tables, and it needs to be revised carefully. From the text, I understand that the mean separation in the tables was done per column, however it is confusing. Some cases a literal is missing (a, c, d, and missing b), some others group b is larger than group a (descending order). See notes on the tables.
Response 5: Thank you for pointing this out. We agree with all these comments. Therefore, all comparisons are reannotated in the table.
Comments 6: Figure 1. Data of 2022, 2023 or average.
Response 6: Thank you for pointing this out. We agree with all these comments. The rice yield was an average across 2022 and 2023, we have revised in the text.
Comments 7: Table 3. Wrong or is it table 4.
Response 7: Thank you for pointing this out. We agree with all these comments. Therefore, it's Table 3, but in the wrong order. We rearranged the order of the table.
Comments 8: 180. First figure cited in text is Figure 9.
Response 8: Thank you for pointing this out. We agree with all these comments. There was a mistake when uploaded the file, maybe a wrong file or any other, which caused all the tables to be in the wrong order. Now the modification has been completed.
Comments 9: Table 4. Main issues. a) Interaction Rice and Wheat treatments does not make sense, since "rice treatments" were applied before wheat treatments both in 2022 and 2023. Can be done the interaction between Wheat 2022 and Rice 2023. b) Mean separation (in addition to what I said before about LSD method) needs to be carefully revised. In the text I marked only some cases, as examples. Panicle number; W0-2023: group b is missing; W300: a: 289, 285, 260, b: 295, 186, How is it possible? c) Placing the ANOVA p-values for the main sources of variation (I guess: Rice Wheat, Year, and interactions) makes the table larger and confusing.
Response 9: Thank you for pointing this out. We agree with all these comments. Therefore, we made the following changes. a) As the interaction turned to be quiet confusing, we have deleted this analysis. b) Data paste error. c) Table has been split (updated text in the manuscript if necessary).
Comments 10: Minor issues: Referred in the text as table 3. It is a large table. I suggest putting the p-values in another table or supplementary data.
Response 10: Thank you for pointing this out. We agree with all these comments. Therefore, we divided this chart into two (updated text in the manuscript if necessary).
Comments 11: Figure 5 is pixelated, hard to understand.
Response 11: Thank you for pointing this out. We agree with all these comments. Therefore, the resolution has been changed (updated text in the manuscript if necessary).
Comments 12: Table 5. Mean separation needs to be carefully revised, as described for table 4. Examples: R0W0 for rice amylose content 2023 values with literal a are: 14, 11 and 10, while for b 11 and 12, and c, it is 11; and for R0W180 values for a (11, 12); b (10, 11, and 13), and c?
Put P-values in a separate table.
Response 12: Thank you for pointing this out. We agree with all these comments. Therefore, the comparison methods have been recemented below the table, and we divide the rice and wheat into two.
Comments 13: Tables 6. Issues with mean separation as previously described.
Response 13: Thank you for pointing this out. We agree with all these comments. Therefore, analyzing methods were changed to Duncan (updated text in the manuscript if necessary).
Comments 14: Table 7. When was the N accumulation measured.
Response 14: Thank you for pointing this out. We agree with all these comments. Therefore, we added nitrogen measurement to crop maturity.
Comments 15: Conclusions. May vary if data is reanalyzed as suggested.
Response 15: Thank you for pointing this out. We agree with all these comments. Therefore, we re-added the impact of later crops on previous crops to the discussion, line 515-517.
Comments 16: Line 103. What does "long-term positioning experiment" mean?
Response 16: Thank you for pointing this out. We agree with all these comments. This experiment was a long-term field trial, each treatment was maintained and conducted continuously in a fixed trial field for many years. We have rephrased in the text.
Comments 17: 105. Table 2. Units.
Response 17: Thank you for pointing this out. We agree with all these comments. Therefore, We reworked the table and added units (updated text in the manuscript if necessary).
Comments 18: 111-112 Parameters measured on 4-m2 plots?
Response 18: Thank you for pointing this out. We agree with all these comments. Therefore, the paragraph was redundant, so we condensed it to make it easier to understand, line 115-118.
Comments 19: 117-118 Needs editing.
Response 19: Thank you for pointing this out. We agree with all these comments. Therefore, We added a paragraph. One thousand grains were counted from 50 panicles and weighed to obtain a thousand grain weight, line 118-119.
Comments 20: 148 Are kg ha-1 the units for St in Table 2.
Response 20: Thank you for pointing this out. We agree with all these comments. All soil nitrogen storage’s units are kg ha-1.
Comments 21:166-167 Move the note as a foot-table note.
Response 21: Thank you for pointing this out. We agree with all these comments. That was a typographical error. We moved all the notes to the correct position.
Comments 22:187-188 Indicate the treatments.
Response 22: Thank you for pointing this out. We added processing inside, line 198-199.
Comments 23: 195-196 Editing.
Response 23: Thank you for pointing this out. We have re-edited the passage, line 208-210.
Comments 24: 206 See note.
Response 24: Thank you for pointing this out. We have re-edited the figure title.
Comments 25: 208-209 See note.
Response 25: Thank you for pointing this out. We can move it to where it belongs.
Comments 26: 276 Table 5.
Response 26: Thank you for pointing this out. We have reordered the tables and charts so that Table 5 in the original is now Table 5.
Reviewer 2 Report
Comments and Suggestions for AuthorsDear Autors
Your manuscript is interesting because it shows the effect of different doses of Nitrogen on soil N budget. Maintaining good physicochemical properties of the soil during the growing season is a challenge for farmers. Considering the management of plant fertilization (mainly nitrogen), excessive or insufficient use of organic and mineral fertilizers can directly affect soil fertility, leading to nutrient loss through leaching or volatilization. The authors indicate that when nitrogen doses during the season ranged from 0 to 240 kg ha⁻¹, residual nitrogen from the previous season significantly contributed to improved yields for subsequent crops.
The layout of the articles became standard for research papers. I don’t feel qualified to judge about The English language an style. However, I have a few comments:
General comments:
The Tittle and Abstract correspond to the content of manuscript. The introduction provides the most important information about the nitrogen and nutrient cycles, which depend on the crops used. The authors showed that it is critical to investigate strategies to balance nitrogen surpluses and deficits between early and late seasons in order to sensibly reduce overall nitrogen rates and increase nitrogen use efficiency while maintaining high yields for both crops.
In the Materials and Methods there is no broader description of the soil. In subchapter 2.4 only soil density is determined, while in subchapter 2.1 the authors present the determinations of chemical properties of soils without specifying the method used to determine them. The methodology should be sorted out. What method was used to determine total nitrogen in the soil? The Results and Discussion were well described, correct conclusions were also drawn. References are correctly cited in order. There is no reference in the text to two items of literature 15 and 16 in the list of literature. I don’t feel qualified to judge about The English language an style, but in the text there are sometimes sentences that are too long that make it difficult to understand. Figures and Tables have correct numbers and signatures. Figures should be enlarged because they are a bit illegible
Detailed comments
- Too little information on the properties of the soils used in the study
- The methods of determining nitrogen in soil should be supplemented
- Supplement the citation of 15 and 16 literature items
- Increase the readability of graphs and drawings by enlarging them
Good luck
Sincerely yours
Reviewer
Comments for author File: Comments.pdf
Author Response
Comments 1: Too little information on the properties of the soil used in the study.
Response 1: Thank you for pointing this out. We agree with all these comments. This experiment was a long-term field trial initiated from 2019. Due to the relatively short duration of this experiment, the current paper mainly focused on crop yield and soil nitrogen, other information on the properties of the soil will be published in the further research. Thanks for your understanding.
Comments 2: The methods of determining nitrogen in soil should be supplemented.
Response 2: Thank you for pointing this out. We agree with all these comments. We have added the corresponding explanation in the article, line 129-133.
Comments 3: Supplement the citation of 15 and 16 literature items.
Response 3: Thank you for pointing this out. We agree with all these comments. We have carefully examined the relevant literature, and in this manuscript, these two documents are quoted only for their corresponding calculation formulas.
Comments 4: Increase the readability of graphs and drawings by enlarging them.
Response 4: Thank you for pointing this out. We agree with all these comments. We have made the font bold in all the tables and figure in the article and deleted the white space in the combined chart.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe results of the research don't have a practical significance for agricultural producers tending to achieve a more sustainable and resilient agriculture.Such crop rotation as rice-wheat can't achieve a non-deficit balance of soil organic carbon and it has many negative consequences on the environment,including global warming.Authors have not mentioned such consequences and how to avoid them.
Author Response
Comments 1: The results of the research don't have a practical significance for agricultural producers tending to achieve a more sustainable and resilient agriculture. Such crop rotation as rice-wheat can't achieve a non-deficit balance of soil organic carbon and it has many negative consequences on the environment, including global warming. Authors have not mentioned such consequences and how to avoid them.
Response 1: Thank you for pointing this out. Rice-wheat rotation is the major planting system of Jiangsu Province in China. High input of nitrogen fertilizer to achieve high yield is very common in such cropping rotation, whereas nitrogen fertilizer is often overused without considering the environmental risks caused by the redundancy of nitrogen fertilizers. This study was conducted based on the perspective of maintaining soil nitrogen balance and ensuring crop yield. We are also concerning about the impact on the environment, which will be discussed in the following articles. In addition, the suitable nitrogen application amount proposed at present is lower than the application level of nitrogen fertilizer in large-scale agricultural production, especially in the local area. The results of this study have a positive effect on optimizing nitrogen application and reducing environmental pollution. Anyway, we valued your impartial opinions, we have further discussed this in the manuscript.
Round 2
Reviewer 1 Report
Comments and Suggestions for Authorsagronomy-3551723-peer-review-v2
Line 110 Add units
Line 180 Clarify if mean separation was performed within a line (rice N rate) and evaluation year
line 221 Is it Table 5 insted of 6?
Line 225 Why in table 4 mean separation was performed within a line, and in Table 5, it was performed within a column.
line 288 Clarify if mean separation was performed within a line (rice N rate) and evaluation year
line 304 Column
line 330 Clarify if mean separation was performed within a line (rice N rate) and evaluation year
line 337 Column
Comments for author File: Comments.pdf
Author Response
Comments 1: Line 110 Add units.
Response 1: Thank you for pointing this out. We added units to the text to make it easier to read.
Comments 2: Line 180 Clarify if mean separation was performed within a line (rice N rate) and evaluation year.
Response 2: Thank you for pointing this out. We have added a comparison of years.
Comments 3: line 221 Is it Table 5 instead of 6.
Response 3: Thank you for pointing this out. We change Table 6 to Table 5 in the paper
Comments 4: Line 225 Why in table 4 mean separation was performed within a line, and in Table 5, it was performed within a column.
Response 4: Thank you for pointing this out. All the comparisons in this paper are based on the same nitrogen application rate in the current season. In this paper, the nitrogen application rate in wheat season is vertically arranged, so it is compared in one column.
Comments 5: Line 288 Clarify if mean separation was performed within a line (rice N rate) and evaluation year.
Response 5: Thank you for pointing this out. We have added a comparison of years.
Comments 6: Line 304 Column.
Response 6: Thank you for pointing this out. We corrected the spelling mistakes.
Comments 7: line 330 Clarify if mean separation was performed within a line (rice N rate) and evaluation year.
Response 7: Thank you for pointing this out. We have added a comparison of years.
Comments 8: Line 337 Column.
Response 8: Thank you for pointing this out. We corrected the spelling mistakes.
