Combined Application of Organic and Inorganic Fertilizers Effects on the Global Warming Potential and Greenhouse Gas Emission in Apple Orchard in Loess Plateau Region of China
, Yanting Ma 1,2, Zhiyuan Zhao 1,2, Zhaoxia Zhen 1,2, Wei Zheng 1,2,3, Ziyan Li 1,2,3 and Bingnian Zhai 1,2,3,*
Round 1
Reviewer 1 Report
Dear authors
Congratulations for your work.
Please find below some suggestions to improve the article.
Abstract –
Line 18 - and to determine and to determine
Line 18 – Change fertilization manner to fertilization management
Line 19 – Please refer to which experimental design was used
Introduction
Line 50-51 – the word “capacity” is somehow repeated
Between lines 85 -90 – Please add some notes about the types of organic fertilizers types. There is a variety of organic fertilizers that can lead to different effects on the soil, plants, and environmental responses of their application. Mention the types of fresh-raw organic fertilizers (manure, wastes, litter), compost, biochar, and digested ones (liquid and solid) among others. Types of sources (animal manure, food wastes, biowastes, organic litter others). Relate their main traits and differences with the objective of your study.
Material and methods
2.2 . Experimental Treatments and Design
Please refer to which experimental design you used. Were there any blocking factors?
2.6 Statistical analysis
Please refer which normality and homoscedasticity tests you run.
Which kind of correlation did you test? What were the alpha values?
Results
Figure 3. WFPS must be mentioned not abbreviated. Remember each figure or table must be self-explanatory.
Add the p-value that you tested in the table or figure notes.
Discussion
Line 503-504 – Please refer to archaea and bacteria. Add 2-3 references relating to methane production and archaea.
Avoid using abbreviations such as M fertilizers – Please refer to them as mineral or organic fertilizer, because it might confound the readers.
Line 520-526. Talk about anaerobic conditions and archaea methanogens in soil. Remember every soil has microsites under anaerobic conditions or aggregates.
Line 544 -545 – This statement is partially wrong “and cause an anaerobic state in the soil, which discourages the development of soil microorganisms that oxidize CH4, therefore reducing CH4 uptake”. You should talk about anaerobic archaea, please refer to the literature.
Lines 575-633 – Please add some notes about the importance of organic fertilizers in providing other macros (Mg, S, Ca) and Micronutrients (B, Zn, Mn, Fe, Cu….) to the growth and production of the apples and also for feeding soil microbes. Relate this to the gases you studied.
Conclusion
635-637 – Affect in which way?
Author Response
Please see the attached file.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Methodology seems adequate. But some details about soil collection and analyses are missing. Authors need to add those details. Some of the comments below can help them improve and address this concern and improve the MS.
Results section is very long and hard to follow because it is replete with numbers rather than general temporal trends. Authors need to reduce the size of results significantly by focusing only on the main finding of the study. Focus only on the site and treatment details because those are your objectives.
Discussion: One of the objective of the study was determine how N2O and CH4 emissions affect dryland apple orchard production. I didn’t find anything related with this either in results or discussion. A small statement though in the end is given in the conclusion.
A major objective of the study was evaluate the effects of combined organic and inorganic fertilizers on GHG emissions; however, looking at the ay discussion is designed and presented it was other way round- the effect of GHG’s emission from soil was discussed.
In my opinion, there is disconnect between objective and the discussion.
Conclusion: Line 635: You wrote “MNPK fertilizers affect soil physi-cochemical properties”. But I didn’t see any discussion on this. The discussion is always centered around GHG’s
General comments
Line 46-48: In my opinion there is contradiction here. First it was said that this particular area is dry land and then later it was mentioned that rain occurred throughout the year continuously. Please correct of explain.
Line 53: In my opinion, it would be good to mention what types (or all types) of organic fertilizers you specifically are refereeing to here since this is the main theme of your paper.
Line 54: Please note, “physical, chemical and biological”
Line 60-66: This is not related with the study objective. I don’t think this part should be in the MS. Focus only on the main theme of the paper, that is GHG’s and organic-inorganic fertilizer relationship.
Line 95-96: Please rephrase.
Line 124: I know that you have given FD and BS site full forms in abstract, but it will be good to add them here as well in the main text one more time.
Line 148: Please add the gases (CH4 and NO2) you are measuring in first sentence.
Line 175: Although you have given below the name of gases, but it will good if you can add name of concentration value of what in line 175.
Line 178: where F is the flux of CH4 and N2O, (mg m−2 h−1)
Line 178: “H” is not understandable, the sentence need rephrasing.
Line 181: (°C) should be next to T.
Same goes for N2O and CH4 conc.
Line 185: can be rephrased as “was estimated “following Liu et a. (7)”
Line 186-187: You already mentioned Liu then there is no need for this sentence here.
Line192: Since you already have abbreviated the GHG in initial sentences, you can use it elsewhere without using expanded form throughout the paper.
Line 199 and 203: Redundant. Please remove.
Line 200: expanded form of GWP is not required since it was explained in previous sentence.
Line 207: Crop yield and N2O conc emission coefficient is same thing? If yes, How?
Line 212: “According to soil agrochemical analysis methodologies”; what are these; probably a reference would suffice.
Line 212: How many total soil samples; how may replicates from each treatment.
Basic soil characteristics? And what are standard basic ones?
Section 2.4: Soil: Details about soil samples processing prior to analyses and posterior to collection is missing.
Line 213-214: You here are referring to Walkey-Black method. It is used for organic carbon estimation. Organic matter calculation from it is empirical.
Line 214: Kjeldahl is for total Nitrogen (not available) which also includes organic bound one and peptides. Also it is automated or not.
Lin 215-: This need rephrasing. You estimated Nitrate and Ammonical-nitrogen as well. First explain the procedure of extraction and then go for machine analyses.
Line 216: Please add size fraction (I am assuming it is seived to <2mm). Also add filter details.
Line 217: suggestion--- continuous flow AutoAnalyzer 3 - AA3 analytical system (company details)
Line 219: repetitive dm−3; been is not required.
Line 222: ombining?
cm3? Why not ml – a standard unit of measurement? You mean adjusted to pH 7?
Line 223: I would say this is exchangeable K not available. And this is quite uncommon way of treating soil for K analysis.
Line: 224: details of atomic absorption spectrometer.
Line 225: Please define- Analyzing samples of 225 organic fertilizer (Goat manure) were determined for what?
Line 227: Soil pH is pH in H2O or KCl or other solution.
General comment: either move goat manure analyses above or below soil analyses. All soil analyses must come in flow one by one.
Line 248: which post hoc test did you use?
Since you are using two different tests here, one for samples having normal distribution and other non-normal distribution you need to add which parameter is tested with anova and which ones ae tested with kruskal-wallis.
Also, add details of normality test.
Line 250: Which Correlations
What do you mean by impact factors? Please use simple language for easy understanding.
Line 256-263: Did you study these parameters in your study or they are collated from nearby meteorological stations. Because how these parameters were studied in the field was not discussed in the methodology, in fact if they were collected. If not collected originally, then you can move this section to method. Also this seems not directly linked to the objective of the study, and in my opinion figures related with this part can be moved to supplementary section
Line 264: at 20 cm soil depth
Line 265-: In this you are comparing the WFPS between sessions but relative units are not properly addressed. Low when and what is the lowest.
Also, lowest were not encountered in rainy period, lowest were before and after rainy period.
No rain during rainy season? What does that mean?
Also, if you are comparing it with seasonal temperature, then figure 3 must include temp. as well probably in the background on second axis.
Line 292: remove period.
Section 3.2: In my opinion you should give only general trend from 208-2019 and main statistical results mentioning difference among sites and treatments. The raw number description is making hard to understand the results. If anyone wants to know more about the values they can look at the graphs and figure to extract more information.
Line 326: This is not required because in succeeding lines you are again describing them in different sites and treatments.
Line 349-352: I think this part is not required here; probably belongs to discussion.
Line 481: I don’t think correlations are strong although they are significant. They are moderate except a few according to biplots in figure 8. In most of the subsets dispersion in th data is very high and the way data is projected it shows that a good number of data points are projected outside 95 percentile CI limit.
In addition to that, this whole figure is hard to understand. What are the values given in four sides of the figure? I assume these are conc. values and each of that is highly specific unit. If authors are correlating only two GHG parameters with others parameters then again this figure is confusing because it has too many sub figures which is not required because they are not the focus.
Line 503: methanogen are methane producing microorganisms. So, the second part of this sentence is not required. Also, this statement if not supported by citation.
line 506-507: I am not able to understand how this is related to your results.
CH4 uptake by what, microorganisms, plants. How did u measure this? I thought you measured the CH4 release. Are u referring to soil as CH4 sink?
524-525: This is recommendation not discussion.
Spelling: please run spell check. There are a few special mistakes.
Tables
Check alignments.
Table no. 3 and 4: I am not able to understand this table especially average and then in last rows year-wise split. If year specific trends are given separately and then their average are also given then what is 2019-2020 in last three rows. If authors decided to give average of all the treatments in last three row then again it doesn’t make any sense.
A, d, c d: post hic test results. Please rephrase their description in the table. These are post hoc test results in column and the lowercase letters shows significant difference between treatments (P value).
Figures
Fig. 3 and others: X-axis must include year separately for each year
Author Response
Please see the attached file.
Author Response File: Author Response.pdf
