Mechanistic Understanding of Leakage and Consequences and Recent Technological Advances in Improving Nitrogen Use Efficiency in Cereals
, Sandeep Kumar 2, Milan Kumar Lal 3, Dinesh Kumar 4,*, Rakesh Kumar 5, Rajendra Kumar Yadav 6, Sandeep Kumar 7, Gangadhar Nanda 8, Jogendra Singh 1, Pushpika Udawat 9, Nirmal Kumar Meena 10, Prakash Kumar Jha 11, Tatiana Minkina 12, Alexey P. Glinushkin 13, Valery P. Kalinitchenko 13,14 and Vishnu D. Rajput 12,*Round 1
Reviewer 1 Report
This paper provides a comprehensive and broad review on crop nitrogen use efficiency and factors that impact NUE, environmental N Losses, environmental consequences of N losses, and N dynamics as well as approaches for improving NUE. It has good scientific merit.
Most of the review sections only provide a general description and lack in-depth data representation and knowledge synthesis.
There are numerous errors in English grammars, phrases, and sentence structures throughout the manuscript.
Specific Comments
L47: despite lower recovery of cereals --> What does this mean?
L48: of leftover N --> What does the leftover N refers to?
L70 : for almost half of the --> for almost half of the N sources for
L82 Figure 1: --> Indicate %
L137 : leach down --> leaching
L157 : leaching down --> leaching
L164 : capacity reached to --> production capacity?
L 166: with 53.16% share --> accounting for 53.16%.
L166 : some other counties namely --> the other 4 countries, namely
L167 : also account for 13% --> account for 13%
L182 Figure 3: --> Where is Asia?
L184-194 : --> Provide references for the data
L220 Table 1: --> Head name for the 1st column in Table 1 is incorrect
L253-259 5.1: --> Very general description, need to provide in-depth data representation and knowledge synthesis
L274 : 7.6 million kg NH3 ha−1 --> this number is impossible on a per ha basis
L300 Figure 6: --> Figure 6 offers litter new information than Figure 5.
L303-319 5.4: --> Very general description, need to provide in-depth data representation and knowledge synthesis
L329-343 6.1 : --> Very general description, need to provide in-depth data representation and knowledge synthesis
L351-367 6.2: --> Very general description, need to provide in-depth data representation and knowledge synthesis
L370-381 6.3: --> Very general description, need to provide in-depth data representation and knowledge synthesis
L399-582 7. Factors affecting N dynamics in soil-plant system: --> Very general description, need to provide in-depth data representation and knowledge synthesis
L518 : WHC --> water holding capacity
L523 : the course of organic matter decomposition --> the course of organic matter decomposition
L526 : following the nutrient cycle --> what does this mean
L546 : BNF --> biological nitrogen fixation
L595-610 8.1: --> Very general description, need to provide in-depth data representation and knowledge synthesis
L612-628 8.2 : --> Very general description, need to provide in-depth data representation and knowledge synthesis
L630-342 8.3 : --> Very general description, need to provide in-depth data representation and knowledge synthesis
L676-692 8.5: --> Very general description, need to provide in-depth data representation and knowledge synthesis
L757-773 9.1: --> Very general description, need to provide in-depth data representation and knowledge synthesis
L840-845 9.5: --> Very general description, need to provide in-depth data representation and knowledge synthesis
L848-861 9.6: --> Very general description, need to provide in-depth data representation and knowledge synthesis
Author Response
Response to editor: agronomy-2163700
Title: Mechanistic understanding on leakage, consequences and recent technological advances for improving nitrogen use efficiency in cereals
We are grateful to the editor and reviewers for thoroughly reviewing our manuscript and providing valuable suggestions. We have addressed all comments as explained in detail in this response document.
Please note that the reviewer comments are in bold sky text. Our responses are in black text. The changes made in the revised manuscript file are in track change mode.
Reviewer #1:
Reviewer comment: This paper provides a comprehensive and broad review on crop nitrogen use efficiency and factors that impact NUE, environmental N Losses, environmental consequences of N losses, and N dynamics as well as approaches for improving NUE. It has good scientific merit.
Most of the review sections only provide a general description and lack in-depth data representation and knowledge synthesis.
There are numerous errors in English grammar, phrases, and sentence structures throughout the manuscript.
Author's Response: Authors would like to thank the reviewer for the efforts in reviewing our article. The manuscript has been revised as per the suggestions given.
Specific Comments
Reviewer comment: L47: despite lower recovery of cereals --> What does this mean?
Author's Response: Since, cereals have lower recovery of nitrogen, hence continuously higher application of N fertilizers may not be utilized by cereals and accumulate in soil which may affect the environmental health.
Reviewer comment: L48: of leftover N --> What does the leftover N refers to?
Author's Response: Leftover N refers to the portion of N which is left in soil after uptak by crops or unutilized N remained in soil after crop harvest.
Reviewer comment: L70 : for almost half of the --> for almost half of the N sources for
Author's Response: Incorporated, please refer to L73.
Reviewer comment: L82 Figure 1: --> Indicate %
Author's Response: Incorporated, please refer to L85.
Reviewer comment: L137 : leach down --> leaching
Author's Response: Corrected, please refer to L140.
Reviewer comment: L157 : leaching down --> leaching
Author's Response: Deteled 'down', please refer to L160.
Reviewer comment: L164 : capacity reached to --> production capacity?
Author's Response: Corrected, please refer to L167.
Reviewer comment: L 166: with 53.16% share --> accounting for 53.16%.
Author's Response: Corrected, please refer to L169.
Reviewer comment: L166 : some other counties namely --> the other 4 countries, namely
Author's Response: Corrected, please refer to L170.
Reviewer comment: L167 : also account for 13% --> account for 13%
Author's Response: Corrected, please refer to L171.
Reviewer comment: L182 Figure 3: --> Where is Asia?
Author's Response: The author would like to thank the reviewer for the concern. We have missed the information of Asia. Which has been now included in Fig. 3
Reviewer comment: L184-194 : --> Provide references for the data
Author's Response: Added refernce (Ladha et al 2016)
Reviewer comment: L220 Table 1: --> Head name for the 1st column in Table 1 is incorrect
Author's Response: Corrected, please refer to Table 1.
Reviewer comment: L253-259 5.1: --> Very general description, need to provide in-depth data representation and knowledge synthesis
Author's Response: Corrected, provided data representations. please refer to L269-274.
Reviewer comment: L274 : 7.6 million kg NH3 ha−1 --> this number is impossible on a per ha basis
Author's Response: Authors have cited this literature from Mahmud, Kishan, Dinesh Panday, Anaas Mergoum, and Ali Missaoui. "Nitrogen losses and potential mitigation strategies for a sustainable agroecosystem." Sustainability 13, (2021): 2400.
Reviewer comment: L300 Figure 6: --> Figure 6 offers litter new information than Figure 5.
Author's Response: Figure 6 is about different factors affecting nitrogen dynamics in soil, where as figure 5 was about Interactions between nitrogen dynamics and environmental factors. So author request to consider both figure as such.
Reviewer comment: L303-319 5.4, 6.1, 6.2, 6.3 --> Very general description, need to provide in-depth data representation and knowledge synthesis
Author's Response: Corrected, and added some more desired information. Please refer to L333-339. Moreover, as per the suggestion of the esteemed reviewer, we have incorporated all necessary information that is available in the literature in the appropriate places. We are highly thankful to the reviewer for the crucial and professional comments regarding the improvement of the manuscript.
Reviewer comment: L399-582 7. Factors affecting N dynamics in soil-plant system: --> Very general description, need to provide in-depth data representation and knowledge synthesis
Author's Response: Kindly refer point no. 7.1.1 to 7.1.7., 7.2.1 to 7.2.3. Authors are requested to consider as given detail point-wise description.
Reviewer comment: L518 : WHC --> water holding capacity
Author's Response: Corrected, please refer to L542.
Reviewer comment: L523 : the course of organic matter decomposition --> the course of organic matter decomposition
Author's Response: Revised, please refer to L546.
Reviewer comment: L526 : following the nutrient cycle --> what does this mean
Author's Response: It refers to that incorporation of crop residues to soil undergoes microbial decomposition and mineralization process wherein nutrients from crop residue converted into available form which is further taken up by next growing crop on the same soil and so on.
Reviewer comment: L546 : BNF --> biological nitrogen fixation
Author's Response: Revised, please refer to L570.
Reviewer comment: L595-610 8.1, 8.2, 8.3, 8.5, 9.1, 9.5, 9.6: --> Very general description, need to provide in-depth data representation and knowledge synthesis
Author's Response: As per the suggestion of the esteemed reviewer, we have incorporated all necessary information that is available in the literature in the appropriate places. We are highly thankful to the reviewer for the crucial and professional comments regarding the improvement of the manuscript. Kindly see the respective section where the necessary correction was made.
Author Response File: 
Author Response.doc
Reviewer 2 Report
Optimizing the use of nitrogen from fertilizers by crop plants is very important due to the economic and ecological aspects.
The economic aspect is the reduction of fertilization costs and obtaining high yields with good biological value.
The ecological aspect is the reduction of pollution of the natural environment - soil, water and air.
Striving to optimize the use of nitrogen from fertilizers, one must first understand its cycle in the environment (fertilizer-soil-plant).
I highly appreciate the authors' approach to the subject of nitrogen transformations in the soil, the causes and mechanisms of its losses and their limitations. However, after careful examination of the manuscript, I have a few remarks, which I present below.
General note
Please include tables and figures in the order of their description in the text of the manuscript. In addition, tab.5 should have No. 3, while tab.3 should have Nr.5
Detailed notes
Keywords (line 60).
I propose a change to: nitrogen in the environment, nitrogen fertilizers, cereals, optimization of nitrogen fertilization
Chapter 5.1. Soil erosion and surface runoff (line 252)
The information provided is too general. I propose to expand this part of the manuscript. Provide available figures.
Chapter 6.1. Groundwater contamination and nitrate pollution
The authors included - Figure 7: Molecular breeding for enhancing NUE in cereals (lines 345-348), which was not discussed in the text of the manuscript.
Chapter 6.3. GHG emission (line 383) . This chapter should have No. 6.4.
Chapter 7.1.7. Amount and Type N Fertilizers (line 490). I believe that this chapter should be expanded to include organic fertilizers and fertilizers containing N in the form of NO3-.
Chapter 8.1 Genetic approaches (line 595) . Note as to 5.1.
Author Response
Reviewer #2:
Comments and Suggestions for Authors: Optimizing the use of nitrogen from fertilizers by crop plants is very important due to the economic and ecological aspects. The economic aspect is the reduction of fertilization costs and obtaining high yields with good biological value.
The ecological aspect is the reduction of pollution of the natural environment - soil, water and air.
Striving to optimize the use of nitrogen from fertilizers, one must first understand its cycle in the environment (fertilizer-soil-plant).
I highly appreciate the authors' approach to the subject of nitrogen transformations in the soil, the causes and mechanisms of its losses and their limitations. However, after careful examination of the manuscript, I have a few remarks, which I present below.
Author's Response: Authors are thankful to the reviewer for critically reviewing this article. We have incorporated the suggested remarks in the revised manuscript.
Reviewer General Note: Please include tables and figures in the order of their description in the text of the manuscript. In addition, tab.5 should have No. 3, while tab.3 should have Nr.5
Author's Response: Changed the Table number. Also, relocated Table 4 to 5 and vice versa.
Detailed Notes
Reviewer comment:: Keywords (line 60). I propose a change to: nitrogen in the environment, nitrogen fertilizers, cereals, optimization of nitrogen fertilization
Author's Response: We have replaced the nitrogen with nitrogen fertilizers in keywords. Please refers to line 60.
Reviewer comment: Chapter 5.1. Soil erosion and surface runoff (line 252). The information provided is too general. I propose to expand this part of the manuscript. Provide available figures.
Author's Response: Corrected, some additional information added. please refer to L270-275.
Reviewer comment: Chapter 6.1. Groundwater contamination and nitrate pollution
The authors included - Figure 7: Molecular breeding for enhancing NUE in cereals (lines 345-348), which was not discussed in the text of the manuscript.
Author's Response: The author would like to thank the reviewer for the suggestion. We have removed the figure and placed it in the appropriate place.
Reviewer comment: Chapter 6.3. GHG emission (line 383) . This chapter should have No. 6.4.
Author's Response: Corrected. Please refers to line 407.
Reviewer comment: Chapter 7.1.7. Amount and Type N Fertilizers (line 490). I believe that this chapter should be expanded to include organic fertilizers and fertilizers containing N in the form of NO3-.
Author's Response: We have improved the line according to the suggestion of the reviewer.
Reviewer comment: Chapter 8.1 Genetic approaches (line 595) . Note as to 5.1.
Author's Response: We have improved the section according to the suggestion of reveiwer 1 and 2
Author Response File: Author Response.doc
Reviewer 3 Report
The manuscript by Yadav et al. provide a comprehensive review of approaches to improve the nitrogen use efficiency (NUE), focussing on agronomic and genetic approaches. The authors provide an introductory review for N fluxes in agriculture and different definitions of NUE concepts. I understand the spin the authors have given to the manuscript, specifically on mechanistic processes.
I think that this review paper tries to focus on everything while avoiding to focus on anything really. This is particularly true for the first “section” of the manuscript related to N fluxes. There are too many repetitions and the organization/structure could definitely improve – the size of the paper would also substantially decrease. The text generally does not read well (which is a key aspect of review papers) with some vague expressions; the use of expressions like “substantial” without providing anything factual is more common that it should. The section related to ways to improve the NUE reads better and I have not much to say about this part (although there are different reviews focussing on either agronomic practices or genetic approaches).
For these reasons, my vote is for rejection. This would change provided the authors are able to tighten the structure and the way the text flows. Please see my other comments here attached.
Comments for author File: 
Comments.pdf
Author Response
Reviewer #3:
Comments and Suggestions for Authors: The manuscript by Yadav et al. provide a comprehensive review of approaches to improve the nitrogen use efficiency (NUE), focussing on agronomic and genetic approaches. The authors provide an introductory review for N fluxes in agriculture and different definitions of NUE concepts. I understand the spin the authors have given to the manuscript, specifically on mechanistic processes.
I think that this review paper tries to focus on everything while avoiding to focus on anything really. This is particularly true for the first "section" of the manuscript related to N fluxes. There are too many repetitions and the organization/structure could definitely improve – the size of the paper would also substantially decrease. The text generally does not read well (which is a key aspect of review papers) with some vague expressions; the use of expressions like "substantial" without providing anything factual is more common that it should. The section related to ways to improve the NUE reads better and I have not much to say about this part (although there are different reviews focussing on either agronomic practices or genetic approaches).
For these reasons, my vote is for rejection. This would change provided the authors are able to tighten the structure and the way the text flows. Please see my other comments here attached.
Author's Response: Authors express their gratitudes to reviewer for reviewing this article critically. We have incorporated your valuable suggestions and improved this manuscript.
Reviewer comment: 1. Introduction: The introduction can be improved. I feel it doesn't read too well, there is some overlap in topics and the need to improve the NUE (ie, the main justification) could be tightened up
Author's Response: As per the suggestion of reviewers 1, 2 and 3 we have improved the introduction section and removed the overlap portion.
Reviewer comment: L64-66 – Awkward way to start a paper. I'd suggest (i) to start about the future food demand which requires an increase of about 60% in agricultural production, (ii) avoid using 'augmentation' and (iii) the global food demand (in the future) may not necessarily be only tied with an increase in food production, but also with reduced food losses&waste.
Author's Response: Modified as per suggestion. Please refer L64-66.
Reviewer comment: L70 – '(…) almost half of global food production (…)', is this here introduced as common knowledge?
Author's Response: We have corrected sentence. It reveals that around 50% of the global N requirement for foodgrains production is supplied through synthetic/ chemical fertilizers.
Reviewer comment: L82 – Source? Year? Please highlight the unit (%)
Author's Response: We added unit (%) in the figure title.
Reviewer comment: L84-85 – You mean "(…) [11-15], cereal crops play (…)".
Author's Response: We agree with the suggestion of the reviewer. The suggestion modfification has been made in the section.
Reviewer comment: L88-89 – You already state this previously, e.g., l70
Author's Response: Authors did not find this repetition. Requested to consider this.
Reviewer comment: L95-l97 – I think you could improve the text before introducing the need to improve NUE (ie, improve the justification). There are several global studies that provide some values for gaseous and water losses and this could provide some more substance to this justification. Furthermore, I'd like to see highlighted that NUE improving techniques (whichever they may be) are not common across all continents.
Author's Response: Authors improved the manuscript as per suggestion. Requested to consider this
Reviewer comment: L137 – Refrain to use "That's".
Author's Response: Replaced with Therefore, please refer to L142.
Reviewer comment: L153 – If this equation tries to be as comprehensive as possible, you're missing nitrate (and to a much lesser extent, ammonium) input from irrigation water.
Author's Response: This equation was standardized by Di, H.J. and Cameron, K.C. (2002). Therefore, the authors could not be able to modify this. Authors requested to consider this .
Reviewer comment: L163 – "Further, FAO (…) ".
Author's Response: Revised. Please refer to L167.
Reviewer comment: L164 – capacity reached to or is?
Author's Response: Corrected, please refer to L170.
Reviewer comment: L184-185 – Needs source – although I agree
Author's Response: Relevant source has already been cited, please refer to L189-190.
Reviewer comment: L206-l214 – I am familiar with these concepts and definitions, but other readers may are not. I suggest that you create a list of acronyms with units at least. Edit: only mentioning this in l222- 223 is insufficient for other readers.
Author's Response: Yes, it has been given in Table no 02.
Reviewer comment: Table 1 – Unclear what column 1 is meant to say
Author's Response: Revised, please see Table 1.
Reviewer comment: L228 – I wouldn't say NUE is necessarily a measurement but more like a proxy
Author's Response: Yes, replace word "measurement" by representation. Please refer L234-240.
Reviewer comment: L229 – That is one definition, as you say in l232-234. There are several, which makes this sometimes hard to understand. Please refer to Congreves et al 2021 for a comprehensive review of NUE definitions.
Congreves KA, Otchere O, Ferland D, Farzadfar S, Williams S and Arcand MM (2021) Nitrogen Use Efficiency Definitions of Today and Tomorrow. Front. Plant Sci. 12:637108. doi: https://doi.org/10.3389/fpls.2021.637108
Author's Response: Yes, refered suggested paper. Please refer L239-242
Reviewer comment: Table 2 – PNB, as implied, is a balance and this is a ratio. PNB is related with the gross nitrogen balance (and its variations per Leip et al., 2011). This is typically what in the modelling community is the de facto NUE.
Leip, A., Britz, W., Weiss, F., & de Vries, W. (2011). Farm, land, and soil nitrogen budgets for agriculture in Europe are calculated with CAPRI. Environmental Pollution, 159(11), 3243–3253. https://doi.org/10.1016/j.envpol.2011.01.040
Author's Response: The authors agree with the suggestion of the esteemed reviewer. We have incorporated the suggested modifications in table 2.
Reviewer comment: L245-250 – Could be interesting to provide global values (e.g., Beusen et al (2016) and Uwizeye et al (2020) for N losses to the water, and Uwizeye et al (2020), Crippa et al (2021) and the EDGAR database for N losses to the air).
Crippa, M., Solazzo, E., Guizzardi, D. et al. Food systems are responsible for a third of global anthropogenic GHG emissions. Nat Food 2, 198–209 (2021). https://doi.org/10.1038/s43016- 021-00225-9
Uwizeye, A., de Boer, I.J.M., Opio, C.I. et al. Nitrogen emissions along global livestock supply chains. Nat Food 1, 437–446 (2020). https://doi.org/10.1038/s43016-020-0113- y
Beusen, A. H. W., Bouwman, A. F., van Beek, L. P. H., Mogollón, J. M., & Middelburg, J. J. (2016). Global riverine N and P transport to ocean increased during the 20th century despite increased retention along the aquatic continuum. Biogeosciences, 13(8), 2441–2451. https://doi.org/10.5194/bg-13-2441-2016
Author's Response: Authors improved the manuscript as per suggestions. Requested to consider this.
Reviewer comment: L253-l255 – Provide a range for these N losses (see works by Panagos)
Author's Response: : Corrected, provided data representations. please refer to L271-276.
Reviewer comment: L257 – “(...) soil erosion depends on (...)”.
Author's Response: Corrected, please refer to L268.
Reviewer comment: L270-272 – There are several other driving factors for this. I'd avoid saying this unless you want to expand. Just say in the beginning of the section that there are large variations of these N losses and their importance in the agricultural N cycle across the globe and that this is due to different reasons (pedoclimatic, socioeconomic, cultural, etc).
Author's Response: Yes, Reviewer has righlty pointed out. But this is also one of the main reason in developing countries which was given by author. Authors will take care suggestion of reviewer.
Reviewer comment: L274 – 7.6 million kg N-NH3 per ha??
Author's Response: Yes, this information was collected from one manuscript, authored by Hasanuzzaman et al., 2018 [52].
Reviewer comment: L311 – An irrigated condition? Rephrase
Author's Response: Rephrased, please refer to L327.
Reviewer comment: L315 – How much is substantial? Please refer some values or delete this sentence.
Author's Response: Deleted sentence, please refer to L330-332.
Reviewer comment: L334 – Biodiversity loss is preferrable to 'fish death'.
Author's Response: Replaced by "Biodiversity loss". please refer to L356.
Reviewer comment: L351-l355 – Sentence doesn't read well.
Author's Response: Revised, please refer to L373-375.
Reviewer comment: L361 – Which chemicals? I understand this is long review, but you sometimes use vague expressions that you need to fix. Last time I'll highlight them; need to check them thoroughly next time.
Author's Response: Revised and added chemicals names i.e., unionized ammonia, formation of hydrogen sulphide. Please refer to L384.
Reviewer comment: L363 – The estimates from whom?
Author's Response: The relevant literatures have been cited in the Figure 4 [41–43], please refer to L221 for Figure 4 and L364-366 for text (Figure 4). It was indicated in the Figure 4.
Reviewer comment: L385 – From which source? Again, last time I'll do this as well.
Author's Response: The relevant literatures have been cited from [73]. Direct sources are cultivation of crops, livestock and deforestation. Please refer to L409-410.
Reviewer comment: L747 – Wouldn't this be rather 8.1 (currently section 9) because it includes ways to improve NUE (section 8)? Furthermore, I propose that 8.XX-8.XX be in a large subsection focussing only on genetic approaches (eg, 8.1 Genetic approaches) and then you could further divide it accordingly (eg, 8.1.1 Molecular breeding approaches). Likewise for Agronomic practices (e.g., 8.2 Agronomic practices).
Author's Response: We would like to inform the reviewer that we have improved the section 8 and 9 as per the suggestion and recommendation of reviewer 1, 2, and 3.
Reviewer comment: L944 – “levels
Author's Response: Revised, please refer to L1074.
Reviewer comment: L944 – What is "leading machine model"? You mean machine learning? If yes, please specify the algorithm (eg, random forests, XGBoost).
Author's Response: Yes, it was machine learning model. For modelling and optimization, it was used XGBoost by reference paper author Gril et al 2021.
Author Response File: Author Response.doc
Reviewer 4 Report
It is a rather good review paper that summarises all the up-to date knowledge about the topic. However, there are some points in the text that should be clarified, corrected or improved. I also recommend editing of the whole text by a native speaking english. All my comments are included in the attached pdf file.
Comments for author File: Comments.pdf
Author Response
Reviewer #4:
Comments and Suggestions for Authors:
It is a rather good review paper that summarises all the up-to date knowledge about the topic. However, there are some points in the text that should be clarified, corrected or improved. I also recommend editing of the whole text by a native speaking english. All my comments are included in the attached pdf file.
Author's Response: Authors are thanful to the reviewer for his excellent reviewing this manuscript and for giving valuable suggestions for improvement.
Reviewer comment: what' s the meaning of "leakage" in the title? I cannot understand it.
Author's Response: It means the loss of nitrogen to the environment by various mechanisms like leaching, volatilization, greenhouse gas emission, etc.
Reviewer comment: L84-87, You must unify the two sentences.
Author's Response: Revised, please refer to L87-90.
Reviewer comment: L122, delete + in N2.
Author's Response: Deleted, please refer to L126.
Reviewer comment: L137, leaching
Author's Response: Done, please refer to L141.
Reviewer comment: L155, where
Author's Response: Done, please refer to L160.
Reviewer comment: L177, delete for
Author's Response: Deleted, please refer to L182.
Reviewer comment: L200, to be included
Author's Response: Corrected, please refer to L205.
Reviewer comment: L201, to measure it...
Author's Response: Changed accoridng to the suggestion.
Reviewer comment: L208-209, there is no syntax
Author's Response: Corrected, please refer to L215.
Reviewer comment: L209-214, You should explain what AE, PPF, PE and ARE are also in the text and not only in Table 1.
Author's Response: Explained in text, please refer to L229-L231.
Reviewer comment: L216, for the three
Author's Response: Revised, please refer to L223.
Reviewer comment: L250, summarized in Fig. 2.
Author's Response: Corrected, please refer to L261.
Reviewer comment: L266, NH3
Author's Response: Done, please refer to L279.
Reviewer comment: L288, ammonium
Author's Response: Not changed. Since ammonical N will be more suitable as compared to ammonium N.
Reviewer comment: L289, chrematistics? what's this?
Author's Response: It indicates the water disposal chemistry and behaviour in the soil system.
Reviewer comment: L319, discussed in section...
Author's Response: Corrected, please refer to L335.
Reviewer comment: L342, 10 ppm means 10 mg NO3 L-1. Why you refer to 50 mg NO3 L-1?
Author's Response: Corrected, please refer to L343.
Reviewer comment: L371, geo surface?
Author's Response: It refers to the earth surface.
Reviewer comment: L377, delete in.
Author's Response: Deleted, please refer to L401.
Reviewer comment: L384, 6.4.
Author's Response: Corrected, please refer to L407.
Reviewer comment: L395, ..contribute to the global...
Author's Response: Corrected, please refer to L420.
Reviewer comment: L403, That's why efficient...
Author's Response: Corrected, please refer to L429.
Reviewer comment: L408, from crop to crop
Author's Response: Revised, please refer to L433.
Reviewer comment: L438-439, A sentence without syntax.
Author's Response: Revised, please refer to L464-466.
Reviewer comment: L439, in relation to.
Author's Response: Revised, please refer to L466.
Reviewer comment: L440, Also, a sentence without syntax.
Author's Response: Revised, please refer to L467.
Reviewer comment: L486, is
Author's Response: Revised, please refer to L513.
Reviewer comment: L518, you must explain what WHC is.
Author's Response: Revised, please refer to L545.
Reviewer comment: L522-523, ?
Author's Response: Corrected, please refer to L550.
Reviewer comment: L546, what is BNF?
Author's Response: Revised, please refer to L574.
Reviewer comment: L553-557, Be careful of the syntax.
Author's Response: Revised, please refer to L581-582.
Reviewer comment: L576-577, ?
Author's Response: Revised, please refer to L605.
Reviewer comment: L663, deleted
Author's Response: We have improved the section.
Reviewer comment: L674, SNP ?
Author's Response: Explained, please refer to L779.
Reviewer comment: L678-679, Why you start sentences with "Which"? This sentence cannot stand alone.
Author's Response: Revised, please refer to L784.
Reviewer comment: L698-699, Why you start sentences with "While"? This sentence cannot stand alone.
Author's Response: Revised, please refer to L804.
Reviewer comment: L783, delete the
Author's Response: Deleted, please refer to L871.
Reviewer comment: L785, Why you mention a specific instrument? Aren' t there similar devices in the market?
Author's Response: This instrument is most widely adopted and popular among users and also cited in the several literatures. Further, it has rapid, accurate and non-destructive measurement. Therefore, we mentioned name of this instrument.
Reviewer comment: L798, Japanese
Author's Response: Corrected, please refer to L916.
Reviewer comment: L799, the Philippines to monitor...what do you mean here?
Author's Response: It indicates the LCC tool developed by IRRI, Philippines is used to monitor the relative leaf greenness which gives N content in plant, thus farmers can apply N to the crops as per need.
Reviewer comment: L925, N2O
Author's Response: Corrected, please refer to L1055.
Reviewer comment: L933, write another word instead of "betterment". There is no such a word!
Author's Response: Corrected, please refer to L1064.
Reviewer comment: L944, levels
Author's Response: Corrected, please refer to L1074.
Reviewer comment: L945, soil electrical conductivity
Author's Response: Revised, please refer to L1075.
Reviewer comment: L948, fertilization
Author's Response: Corrected, please refer to L1079.
Reviewer comment: L978, fertilizer
Author's Response: Corrected, please refer to L1109.
Reviewer comment: L1008, what' s this?
Author's Response: It is Sesbania and local name is Dhaincha. Name changed, please refer to L1140.
Reviewer comment: L1055, what do you mean by "wet season rice"?
Author's Response: It is the rice sown in the Kharif/Monsoon season/ June-July months.
Reviewer comment: L1071, residues
Author's Response: Corrected, please refer to L1202.
Reviewer comment: L1087, particular
Author's Response: Corrected, please refer to L1220.
Reviewer comment: L1107, have not been fully explored
Author's Response: Corrected, please refer to L1241.
Author Response File: Author Response.doc
Round 2
Reviewer 4 Report
The authors have corresponded positively to my comments.
