Study on the Law of Nitrogen Transfer and Conversion and Use of Fertilizer Nitrogen in Paddy Fields under Water-Saving Irrigation Mode
Round 1
Reviewer 1 Report
The authors compared three irrigation modes : W0 (conventional irrigation), W1 (thin and wet irrigation), and W2 (intermitted irrigation) and demonstrated that the leaching loss amount of fertilizer nirogen in the W1 and W2 modes are decreased compared to W0 mode.
The proposed study is interesting, the results will contributing to solved ecological questions and could provides novel information if we consider that the protecting water resources from nitrate-nitrogen (NO3-N) contamination is the main factor causing nitrogen pollution in aquatic environment and is also an important public health concern and a major national environmental issue in China.
The subject of the paper is well suited for this journal even though has been extensively studied over the past years. I think the interpretation of data drawn by the authors are reasonable.
I only have a couple minor concerns which would be incorporated to finalize the manuscript.
Minor points:
1) In the paragraph : 2.3 Methos : I found this paragraph « to skinny » The authors should be more detailed in the methods description and should adding appropriate references (e.g. Kjeldahl method)
2) There are many editing errors in the text, please be careful and correct (e.g. Page 4 lane 151 (W1,W1), Page4 lane 155 « of of » )
3) In the paragraph 3. Results and Discussion. Page 5 lane 173 « The results of this study were consistent with those of other related studies ». I found this sentence to generic, please provide more examples and references
Author Response
Point1: In the paragraph : 2.3 Methos : I found this paragraph « to skinny » The authors should be more detailed in the methods description and should adding appropriate references (e.g. Kjeldahl method)
Response 1: We have revised the article as required.
Using large tonnage and high precision quality comparator to weigh the barrel evaporator, the water consumption of rice can be obtained by the difference between the front and back periods. The bottom of the barrel evaporator was equipped with a drainage device. The tap was regularly opened to drain water. The water samples were collected at intervals of the 1st, 3rd, 6th, 10th days after each fertilization and one day before the next fertilization or harvest, and the amount of water leakage during the two sampling periods was weighed. The NO3--N concentration was measured by ultraviolet spectrophotometry method. N15 isotope with 10% abundance was used in this study, and the labeling and content of N15 isotope were analyzed by mass spectrometry method. NH3 volatilization was collected by PVC tube ventilation method. NH3 volatilization collection device was placed in the middle of barrel evaporator. Samples were taken on the 1st day and 5th day after the application of base fertilizer, tiller fertilizer and jointing-booting fertilizer. The samples were sent to the laboratory for elution and nitrogen content detection. NH3 volatilization was determined by distillation titration. Plants were sampled once per growth period, which required representativeness.Soil samples were collected before soaking fields and after the off-test. Nitrogen content in plant and soil was determined by Kjeldahl method.
Point2: There are many editing errors in the text, please be careful and correct (e.g. Page 4 lane 151 (W1,W1), Page4 lane 155 « of of » )
Response 2: We have revised the article as required.
Point3: In the paragraph 3. Results and Discussion. Page 5 lane 173 « The results of this study were consistent with those of other related studies ». I found this sentence to generic, please provide more examples and references
Response 3: We have revised the article as required.
Research by scholars at home and abroad showed that, in farmland ecosystem, NO3--N leaching depends on precipitation (or irrigation) and NO3--N concentration. When the NO3--N concentration is high and the amount of water infiltrated below the root zone is large, the NO3--N leaching is serious, and a factor is limited, and the NO3--N leaching will be significantly reduced. In humid and semi-humid areas, NO3--N usually accumulates in the core soil layer, and then leaches into groundwater gradually. In arid and semi-arid areas, NO3--N in soil migrates downward with water due to the infiltration of natural precipitation or irrigation water. This study showed that water-saving irrigation mode can reduce NO3--N leaching loss by reduced leakage and NO3--N concentration. The results of this study were consistent with studies of Hay [25] and Parfitt [26]
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This manuscript is very well written and presents important research into the effects of water-saving methods of rice production on nitrogen utilization. I recommend publication. I have included minor comments in the attached file.
Comments for author File: Comments.pdf
Author Response
Point1: Page 2, Line 50: Change ‘field’ to ‘fields’.
Response1: It has been revised in the article.
Point2: Page 2, Line 86: Change ‘this paper carried on research of nitrogen’s fate’ to ‘this paper presents research on nitrogen’s fate’.
Response2: It has been revised in the article.
Point3: Page 2, Line 87: Change ‘did innovative research’ to ‘reports on innovative research’.
Response3: It has been revised in the article.
Point4: Page 3, Line 117: I am not familiar with the term ‘plum rain season’. Is the word ‘plum’ correct?
Response4: The word plum is correct.
Point5: Page 3, Line 121: Change ‘were shown in Table 1’ to ‘are shown in Table 1’.
Response5: I think the past statements use more appropriate.
Point6: Page 3, Line 128: The word ‘three’ is misspelled.
Response6: It has been revised in the article.
Point7: Page 8, Line 227: Delete the word ‘basically’.
Response7: It has been revised in the article.
Point8: Page 8, Line 254: Delete the word ‘obviously’.
Response8: It has been revised in the article.
Point9:Page 10, Lines 313-316: In Table 3 there was no significant difference in NH3 volatilization betweentreatments W0 and W1. Please check this and other statements to make sure that the entire statementis accurate in terms of significant differences.
Response9: It has been revised in the article.
Point10:Page 13, Line 439: I could not find reference 32 cited in the text. Please check.
Response10: We have added the 32 references to this paper.
Author Response File: Author Response.pdf
