Estimation of Maize (Zea mays L.) Yield Per Harvest Area: Appropriate Methods

Round 1

Reviewer 1 Report

Most of my concerns have been addressed in the revised version of the manuscript.  A few issues remain.  See below.

Remote sensing technology is used in various disciplines. Nevertheless, readers of this review may not be familiar with the terms used in the Remote sensing section. Add a statement defining remote sensing. Also, provide the meaning of vegetation index.  Additionally, indicate to the audience that vegetation indices are derived from the remotely-sensed data.    Thoroughly check manuscript for grammatical and punctuation errors. Abstract Line 22 after small plots of land; place in parenthesis (less than 1 ha) Figure 2. More detailed information is needed for the Figure caption.

General changes

Line 105: Replace ‘it’ with another word, revise the sentence. The paragraph discusses the maize density affect on plant growth and yield.  Lines 105 – 128: Paragraph is too long.  Divide paragraph into 2 separate paragraphs, lines 105 -120 (high plant density); lines 120 – 128. Lines 133 – 152: Paragraph is too long.  Divide paragraph into 3 separate paragraphs, lines 133 - 137; lines 138 – 146 (at harvest); and lines 146 – 152.  Line 163: Move ‘after harvest’ to end of sentence. Lines 172 – 173: Change ‘through’ to ‘though’ and delete ‘in presence’. Line 194: Change ‘It’ to Crop Yield Line 224: Add the word ‘to’ after exposed…exposed to Line 268: Change ‘framer’ to farmer. Line 300: References listed, should 9 come before 72. Lines 320 – 342: Paragraph is too long. Suggestion for splitting it into 2 paragraphs; Lines 320 – 337 (stop at efficiency) paragraph 1, Lines 337 – 342 paragraph 2. Lines 364 – 365: First letter in caps resolution imaging spectroradiometer. Lines 386: Delete “F.” Lines 391: Change ‘Color’ to color; also check font of Color-infrared (790, 660, 550 nm)

Author Response

Dear Reviewer,

Thank you for your relevant comments. The corrections have been incorporated. Kindly find attached the improve version.

Best regards

Author Response File: Author Response.docx

Reviewer 2 Report

The work was a revised version of the previous work already reviewed

The manuscript has been significantly improved with respect to the first version, but before its publication needs of some other little improvements:

captions of TAB 1 and TAB 2: Please comment also the presence of the map in the caption of the table;

row 388-392. This sentences must be rewritten; it is not clear.

Captions of figure 2. The caption does not explain well what the figure represents. Please rewrite the caption of figure 2 with more details

After these minor corrections, that could be checked directly by the Editor, the work could be accepted for the publication.

Some minor corrections will be made directly on the text on the doc file.

Comments for author File: Comments.docx

Author Response

Dear Reviewer,

Thank you for your relevant comments. The corrections were incorporated. Kindly find attached the improved version.

best regards

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Overall, the manuscript has been revised as requested by this reviewer. 

Currently, the Remote Sensing section needs to be revised. In paragraph one of that section, the appropriate information has been provided; however, the sentences do not fit together---lack cohesion.  Also as indicated previously (Remote Sensing Section) some paragraphs are too long.  Lines 399-402 needs to be revised.  Those lines do not flow well with the other sentences in the paragraph. 

Figure 2. More information is needed in the Figure caption—additional information to what is already written.  (1) What does the close-up in B represent? (2) Does the green area in section 2 of the figure represent agricultural land? (3) Green, brown, and yellow areas---Are they related to changes in cropland? If yes, then insert information into figure caption. 

Overall, edit the text.  

Author Response

Dear Reviewer

Thank you for your relevant comments. Your suggestions were incorporated in the main document. Kindly see attached the latest version of the manuscript.

Best regards

Liliane Tandzi

Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Overall Comments: The manuscript is a review paper discussing yield estimation methods and yield gaps between maize potential and attainable yield.

The Introduction provided the necessary background on why the review paper was written. The yield terms were defined in this section. 

Simulation models and remote sensing techniques are too expensive and not accurate for estimating yields on small plots. This reviewer does not disagree with the statement. The statement would be much stronger if dollar values were used to support it.     

The manuscript contains several tables summarizing country specific information related to maize. Add a figure or figures showing the location of the countries in the tables. The figure(s) would be helpful to readers in comparing the different geographic locations.

The appropriate number of tables were used in the manuscript. For tables 1 and 2, revise the table heading. Include “maize” in the heading.    

Numerous grammatical and punctuation errors throughout the manuscript.

Throughout the manuscript the word plant is used. At times, it would be better to replace “plant” with the word “maize”.          

Specific Comments By Section

Keywords

Maize is used in the title of the manuscript; consider using another word in keywords section to replace maize. Consider changing “maize” to “corn” in keywords section.

Introduction

Good job in defining the yield terms.

Plant Density and Kernel Number

Lines 84-125: Paragraph is too long; divide it into two or more paragraphs. Line 109: change logging to lodging.

Yield Simulation

Lines 299-331: Paragraph is too long; divide it into two or more paragraphs.

Remote sensing

Lines 333-371 is a long paragraph; separate the paragraph into two or more paragraphs. Line 356: replace flowering with tasseling. Lines 370-371: Add literature to support the statement or better explain. This reviewer agrees with the statement, justify it. Lines 370-371: What do you mean by small plot size production? Insert value for plot size; for example, 5 ha or less. Just an example. 

Yield gap between potential yield and actual yield

Lines 387-388: Table 3 does provide good information. Discuss information in that Table in the Yield gap section. Discuss in terms of the trends observed for current trend, potential trend, and yield gap.

References

Check format of references. Make sure that references are in the format required by the journal. Numerous punctuation errors. Change “&” to and.

Figure

Figure 1. Change the word “plant” to “maize”.  

Tables

Table 1. Plant density – is that plant density per hectare, please be more specific. First letter of calcareous should be capital.  Table 3. Change 6.37 to 6.4 and 3.37 to 3.4.

Author Response

Dear Reviewer,

Thank you very much for your relevant comments. Kindly find the revised document attached.

Best regards

Author Response File: Author Response.docx

Reviewer 2 Report

Definitions about yield potential and potential yield are confusing, as well as other definitions about experimental, economic or actual yield. Since the paper is a review about estimation of maize yield, concepts must to be clear and defined adequately.

The review's contribution to the field is not significant.

Author Response

Dear Reviewer,

Thank you for your comments.

Kindly see attached the revised version of the manuscript.

Best regards

Author Response File: Author Response.docx

Reviewer 3 Report

The work reported a review on how to estimate the corn yield. The paper is sufficient innovative. The English, in general, is correct, but nevertheless there are some typing errors. I advise checking carefully the text.

In my opinion, the tables presented in the paper must be improved a new table must be added. 

In particular:

Table 1: Could be interesting to insert also the average yield of different counties;

Table 2: This table can be deleted: in my opinion, it is not relevant for the work.

Table 3: The table could be improved inserting the system used for the estimation of potential yield and the number of the equation used (only when is pertinent).

I advise to insert two new tables:

a) a new table where you describe some characteristics of the models described in the text for the yield simulation (nome of the model, the parameters used by the model, citation)

b) a new table that resumes the bibliography present in the text will be appreciated

I suggest the authors to insert some experimental photos of different remote sensing data.

Other little changes:

line 9: substitute astract with abstract;

line 26: substitute potential with potential yield; realized with attainable yield or harvest yield.

line 94 and 95: I advise to delete the table 2 and the relative sentence

line 171 and other equations: please the equations must be numbered;

line 240: please substitutes with 15% instead of 150g/kg

line 388. please rewrite the sentence: It is not clear.

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

Thank you very much for your relevant comments.

Kindly see attached the revised version.

Best regards

Author Response File: Author Response.docx