Comparison of Crop Yield Estimates Obtained from an Historic Expert System to the Physical Characteristics of the Soil Components—A Project Report
Round 1
Reviewer 1 Report
Maybe due to inline corrections, some of tables' headings are drifted (e.g. Table 6).
L95. Amount of fertilizer is per year?
L147. Table 8. Is it Pearson correlation?
Not so 'Reference-rich'.
Author Response
Reviewer 1
Maybe due to inline corrections, some of tables' headings are drifted (e.g. Table 6).
I have adjusted the formatting of the table to improve their presentation.
L95. Amount of fertilizer is per year?
The amount of fertilizer per year required to obtain these yields is dependent on soil test P and K and nitrogen availability from organic sources available from the crop rotation or manure applications with supplemental nitrogen provided as required. This falls under the statement of best management practices.
L147. Table 8. Is it Pearson correlation?
Yes, foot note added to table.
Not so 'Reference-rich'.
I agree. This project report was not intended to be a literature review rather a report on the comparison of the historical records to soil physical properties.
Reviewer 2 Report
The main findings are novel and can be very useful as guidance for other national/regional authorities. The authors updated the crop yield estimates to soil series by looking for the best yield prediction model identified among ones using as independent variables simple physical properties, historic yields or meteo data. However, the M&M section needs some minor revision. Please find below my specific comments/suggestions:
Abstract: please refer the geographical data source of NASIS
Line 57-60 there is no link between these two paragraphs.
Line 67-68 as above. To pass from the list of the crops cultivated in West Wirginia to the project's objectives there is the need to add few sentences that describe what info (data and model) are available on the effect of soil properties on crop yield of such crops.
Table 1 Please use international units such as Mg D.M. ha-1. Does yield refers to dry matter ?
Table 3 - what does "better soil " means?
Line 88 in table 4 data on R Yreg are presented but no explanations on how these data have been calculated are presented. Please add info on R Yreg since it's not clear.
Line 97 on which data statistical analysis was conducted ?.
Line 98 which soil physical data have been used ? They are only presented at line 101. Please add info also on how these parameters have been analytically measured.
Line 103 - please rephrase, not clear
Line 105 in statistic the word "perfect" is deprecated. Please change.
Line 112 "description" is not the proper therm, it might be soil physical properties .
Line 130 Table 6 - please introduce these info on physical soil properties in the M&M section.
Line 134-135 - The regression against meteo data, as well as the availability and type of meteo data must be presented in the M&M section. This step in the regressions has not been described before in the M&M section neither in the objcetives.
Line 147 Table 8 - as above, correlation analysis has not been presented before
Line 197 - add soil "pysical" characteristic. Please also be consistent in referring to soil properties or characteristic. The two terms are used with no consistency troughout the text.
Line 206-208 this calculations should be described in the M&M and the results presented in the Result section.
Line 226 basic or physical soil properties ?
Line 253-259 this paragraph is not linked to the 18 rules listed above. Please explain the reason why here are discussed the measured data on crop yield and above the limitation's rules. The section is named "Accounting for other factors affecting expected crop production" and there is no reason to discuss the yield data here.
Author Response
Reviewer 2
The main findings are novel and can be very useful as guidance for other national/regional authorities. The authors updated the crop yield estimates to soil series by looking for the best yield prediction model identified among ones using as independent variables simple physical using as independent variables simple physical properties, historic yields or meteo data. However, the M&M section needs some minor revision. Please find below my specific comments/suggestions:
Abstract: please refer the geographical data source of NASIS
Added United States, have also identified the state of West Virginia.
Line 57-60 there is no link between these two paragraphs.
These are paragraphs introducing different topics that are pertinent to this project report and are not intended to be part of a continuing story between paragraphs.
Line 67-68 as above. To pass from the list of the crops cultivated in West Virginia to the project's objectives there is the need to add few sentences that describe what info (data and model) are available on the effect of soil properties on crop yield of such crops.
Table 1 Please use international units such as Mg D.M. ha-1. Does yield refers to dry matter ?
We are using metric tons ha-1 units of corn and hay at standard USDA units which are 85% dry matter for corn and 90% dry matter for air dry hay.
Table 3 - what does "better soil " means?
Reworded to most productive soils.
Line 88 in table 4 data on R Y reg are presented but no explanations on how these data have been calculated are presented. Please add info on R Y reg since it's not clear.
Words added in M&M to cover this.
Line 97 on which data statistical analysis was conducted?
Multiple regression was added to text.
Line 98 which soil physical data have been used? They are only presented at line 101. Please add info also on how these parameters have been analytically measured.
Citations were added that give the description of metadata with words added to tell what soil physical measures were used.
Line 103 - please rephrase, not clear
I rephased the sentence.
Line 105 in statistic the word "perfect" is deprecated. Please change.
I changed the wording in this sentence.
Line 112 "description" is not the proper term, it might be soil physical properties.
I changed the wording in this sentence.
Line 130 Table 6 - please introduce these info on physical soil properties in the M&M section.
Reworded in table to line up with what was given in M&M.
Line 134-135 - The regression against meteo data, as well as the availability and type of meteo data must be presented in the M&M section. This step in the regressions has not been described before in the M&M section neither in the objectives.
Citations and wording added to M&M.
Line 147 Table 8 - as above, correlation analysis has not been presented before
As above citations and wording added to M&M.
Line 197 - add soil "physical" characteristic. Please also be consistent in referring to soil properties or characteristic. The two terms are used with no consistency trough out the text.
We made this change.
Line 206-208 this calculation should be described in the M&M and the results presented in the
This is part of the discussion relative to updating the expected crop yields. The research section was on the relationship between historic crop yields and soil physical characteristics.
Result section.
Line 226 basic or physical soil properties?
Reworded.
Line 253-259 this paragraph is not linked to the18 rules listed above. Please explain the reason why here are discussed the measured data on crop yield and above the limitation's rules. The section is named "Accounting for other factors affecting expected crop production "and there is
affecting expected crop production and there is no reason to discuss the yield data here.
The description of the rules used to limit yields being added to the NASIS database (due to excessive slope and stoniness) is appropriate for the discussion. Having this in the discussion is logical, it is not a part of the materials and methods dealing with the statistical analysis of historic yields and soil physical properties.
Reviewer 3 Report
The research entitled, “Comparison of Crop Yield Estimates Obtained from A Historic Expert System to the Physical Characteristics of the Soil Components – A Project Report”. The manuscript is within the Agronomy Journal but should be extensively revised before publication. Some of the methods need some clarification, especially in relation to the study area and statistical analysis used. At its current version, the authors provide no information on how they conducted the soil survey, which makes it difficult to contextualize the results since we do not know the variance models used. Tables in the Results section also need improvements. The Discussion was not well discussed; it seems the interpretation of the results as it was not consulted with the results of other studies. Thus, I would suggest the authors discuss this in detail to make that clearer.
Below are comments.
Title: not sure what is meant by ‘Expert’ here. What is ‘Expert System? And Why Physical Characteristics of the Soil? Why not chemical or a combination of both?
Abstract:
Lines 14-17: You have indicated a sort of background on factors affecting crop yields, but you didn’t say anything about why you were interested (the research gap) to conduct this work on your current topic.
I’d suggest you indicate the research gap after the aforementioned lines.
Lines 17-19: ‘The aim of … ‘this objective is not in line with your objective mentioned in the introduction part. Please recheck it. In addition, please specify the study area. Tip: NASIS of what? (location).
Line 19: …National Soil Information system (NASIS) is general. Please make it more clear? NASIS of where (country).
Lines 20-21: … over 60% of the variation in corn and hay yields. I couldn’t get this information in the result section. And compared to what this variation was obtained?
Lines 28-29: Do you think that the current study (only on limited crops) is sufficient to be used as expected crop yields for West Virginia soil?
Lines 31-32: Keywords: Can you list them in alphabetical order?
Introduction
Line 36: What are ‘best management practices? Make it clearer.
Line 43: In the United States many countries…, do you mean in the ‘world’ or what. Please make it clear.
Lines 62-67: I’d suggest moving these sentences under the material and methods section, in ‘Description of the Study Site’. Instead, I suggest you include the innovative point or research gap of your study in this paragraph. Because I’m not convinced why you initiated this project on the current topic.
Line 70: … I’d suggest changing ‘ not currently having published to ‘ not researched yet’.
Lines 72-73: How updated crop yields predicting soil physical properties alone will be used as fertilization recommendations? I think it's more logical if the prediction was from soil chemical properties or the combination of both physical and chemical properties. Please recheck it.
Overall, the introduction is somewhat shallow. For example, which and how did soil physical properties impact expected crop yield? What do the previous reports show regarding this issue? These and other related information need to be introduced.
Materials and Methods
I’d suggest you a separate description of the Study area (West Virginia) as 2.1. just by including all important information such as a description of the climate, location, soil, crops are grown, etc. However, in its current version, the authors provide no detailed information about the study site.
The method of data collection was not clearly indicated. For instance, lines 75-77 describe the source of data (obtained as of 2020), and similarly, lines 77-79 about the source of data (obtained over 1959-1997). Here the gap between 1997 and 2020 is about 22 years. So, to extend yield from (1959-1997) to 2020 or vice versa, what standard approach (model) you have used?
Line 79: If you have used a soil survey, please specify the type, sample size, and approach used.
Table1: what is N in the second column? Sample size? If so, the table caption should specify, and also include what statistical analysis was used. What is mixed hay?
Tables3 and 4: Please indicate the sample size used and in addition, please includes measures of variability in front of mean values presented here.
Results
Table 5: please state what regression analysis the R2, SDreg, and AAPE values refers to, and could you mention your base to classify drainage into moderately well, somewhat poorly, poorly, and very poorly? Or your own finding? If so, you need to explain them well.
Line 127: Can we know the significance level of this soil's physical properties on yields?
Table 6: similar comments to Table 5 above.
Line 133: I’d suggest you change ‘Expected crop yield not directly related to climatic growing conditions’ into ‘Relationship between crop yield and climatic conditions. In addition, these climatic growing conditions (climatic variables) were not introduced in ‘the Materials and Methods section.
Table 8: please indicate what statistical analysis was used for comparisons and specify it in the table captions.
Lines 165-175: (1) I’d suggest you move this part to the Methods section, and (2) please indicate the standard (any reference) you have used for these calculations or approaches.
Discussion
Lines 194-196: any evidence to back up this claim?
Lines 197-198: Can you provide an example that makes similar to your results and others (cited in line 198)?
Lines 204-216: this paragraph seems more about result interpretation, not discussion, so I’d suggest you move this paragraph under the result section.
Table11: if the values in each column are mean, please provide a measure of variability.
Table12: similar comments to Table 11 above.
Lines 229-251: Did you use all these rules in your current report? Why do you prefer to mention them in the discussion section? I’d suggest you introduce them under the methods section.
Overall, the discussion is not well discussed, and then I’d suggest the authors to consult further research results from previous studies in the scope of their current topic.
Author Response
Reviewer 2
The main findings are novel and can be very useful as guidance for other national/regional authorities. The authors updated the crop yield estimates to soil series by looking for the best yield prediction model identified among ones using as independent variables simple physical using as independent variables simple physical properties, historic yields or meteo data. However, the M&M section needs some minor revision. Please find below my specific comments/suggestions:
Abstract: please refer the geographical data source of NASIS
Added United States, have also identified the state of West Virginia.
Line 57-60 there is no link between these two paragraphs.
These are paragraphs introducing different topics that are pertinent to this project report and are not intended to be part of a continuing story between paragraphs.
Line 67-68 as above. To pass from the list of the crops cultivated in West Virginia to the project's objectives there is the need to add few sentences that describe what info (data and model) are available on the effect of soil properties on crop yield of such crops.
Table 1 Please use international units such as Mg D.M. ha-1. Does yield refers to dry matter ?
We are using metric tons ha-1 units of corn and hay at standard USDA units which are 85% dry matter for corn and 90% dry matter for air dry hay.
Table 3 - what does "better soil " means?
Reworded to most productive soils.
Line 88 in table 4 data on R Y reg are presented but no explanations on how these data have been calculated are presented. Please add info on R Y reg since it's not clear.
Words added in M&M to cover this.
Line 97 on which data statistical analysis was conducted?
Multiple regression was added to text.
Line 98 which soil physical data have been used? They are only presented at line 101. Please add info also on how these parameters have been analytically measured.
Citations were added that give the description of metadata with words added to tell what soil physical measures were used.
Line 103 - please rephrase, not clear
I rephased the sentence.
Line 105 in statistic the word "perfect" is deprecated. Please change.
I changed the wording in this sentence.
Line 112 "description" is not the proper term, it might be soil physical properties.
I changed the wording in this sentence.
Line 130 Table 6 - please introduce these info on physical soil properties in the M&M section.
Reworded in table to line up with what was given in M&M.
Line 134-135 - The regression against meteo data, as well as the availability and type of meteo data must be presented in the M&M section. This step in the regressions has not been described before in the M&M section neither in the objectives.
Citations and wording added to M&M.
Line 147 Table 8 - as above, correlation analysis has not been presented before
As above citations and wording added to M&M.
Line 197 - add soil "physical" characteristic. Please also be consistent in referring to soil properties or characteristic. The two terms are used with no consistency trough out the text.
We made this change.
Line 206-208 this calculation should be described in the M&M and the results presented in the
This is part of the discussion relative to updating the expected crop yields. The research section was on the relationship between historic crop yields and soil physical characteristics.
Result section.
Line 226 basic or physical soil properties?
Reworded.
Line 253-259 this paragraph is not linked to the18 rules listed above. Please explain the reason why here are discussed the measured data on crop yield and above the limitation's rules. The section is named "Accounting for other factors affecting expected crop production "and there is
affecting expected crop production and there is no reason to discuss the yield data here.
The description of the rules used to limit yields being added to the NASIS database (due to excessive slope and stoniness) is appropriate for the discussion. Having this in the discussion is logical, it is not a part of the materials and methods dealing with the statistical analysis of historic yields and soil physical properties.
Reviewer 3
The research entitled, “Comparison of Crop Yield Estimates Obtained from A Historic Expert System to the Physical Characteristics of the Soil Components – A Project Report”. The manuscript is within the Agronomy Journal but should be extensively revised before publication. Some of the methods need some clarification, especially in relation to the study area and statistical analysis used. At its current version, the authors provide no information on how they conducted the soil survey, which makes it difficult to contextualize the results since we do not know the variance models used. Tables in the Results section also need improvements. The Discussion was not well discussed; it seems the interpretation of the results as it was not consulted with the results of other studies. Thus, I would suggest the authors discuss this in detail to make that clearer.
Below are comments.
Title: not sure what is meant by ‘Expert’ here. What is ‘Expert System? And Why Physical Characteristics of the Soil? Why not chemical or a combination of both?
The reviewer needs to look up the definitions of Expert Systems. This paper was first submitted to a special issue of Agronomy dealing with crop modelling and climate change. Expert Systems are a topic area within computer modelling. This project is dealing only with soil physical characteristics effects on crop yields under best management practices. Our work on soil fertility is reported elsewhere.
Abstract:
Lines 14-17: You have indicated a sort of background on factors affecting crop yields, but you didn’t say anything about why you were interested (the research gap) to conduct this work on your current topic. I’d suggest you indicate the research gap after the aforementioned lines.
This comment was answered in line 16.
Lines 17-19: ‘The aim of … ‘this objective is not inline with your objective mentioned in the introduction part. Please recheck it. In addition, please specify the study area. Tip: NASIS of what? (location).
Reworded introduction and added NASIS area.
Line 19: …National Soil Information system (NASIS) is general. Please make it more clear? NASIS of where (country).
Did this.
Lines 20-21: … over 60% of the variation in corn and hay yields. I couldn’t get this information in the result section. And compared to what this variation was obtained?
Reworded to specify variation reported in table 5.
Lines 28-29: Do you think that the current study(only on limited crops) is sufficient to be used as expected crop yields for West Virginia soil?
Yes, this study includes historical yields for all crops normally grown on all of the soils mapped in West Virginia soil surveys.
Lines 31-32: Keywords: Can you list them in alphabetical order?
The Keywords are listed in hierarchical order as they relate to this paper. I may have missed it if the editors expect them to be listed alphabetically.
EDITOR which way do you want them listed?
Introduction
Line 36: What are ‘best management practices? Make it clearer.
BMPs are now defined in the M&M section.
Line 43: In the United States many countries…,do you mean in the ‘world’ or what. Please make it clear.
In the United States the political subdivisions within most states are counties. In Louisiana they are called parishes. Since not all counties have published soil surveys, we stated many.
Lines 62-67: I’d suggest moving these sentences under the material and methods section, in ‘Description of the Study Site’. Instead, I suggest you include the innovative point or research gap of your study in this paragraph. Because I’m not convinced why you initiated this project on the current topic.
The objectives were stated in lines 70-74. Keep in mind that this is a project report and not a scientific article.
Line 70: … I’d suggest changing ‘ not currently having published to ‘not researched yet’
having published to not researched yet.
No, that would be incorrect. NRCS soil scientists conduct soil surveys, describe the soils, and publish the results of the surveys. They do no conduct research. The soils lab within USDA conducts physical descriptions of the soils and that information is archived in NASIS.
Lines 72-73: How updated crop yields predicting soil physical properties alone will be used as fertilization recommendations? I think it's more logical if the prediction was from soil chemical properties or the combination of both physical and chemical properties. Please recheck it.
Fertilizer recommendations are based on soil test chemical extraction and expected crop yield. The updated expected crop yields are used in this recommendation system.
Overall, the introduction is somewhat shallow. For example, which and how did soil physical properties impact expected crop yield? What do the previous reports show regarding this issue? These and other related information need to be introduced.
This is covered in the introduction with citations to seven relevant references. This is a concise introduction to the topic.
Materials and Methods
I’d suggest you a separate description of the Study area (West Virginia) as 2.1. just by including all important information such as a description of the climate, location, soil, crops are grown, etc. However, in its current version, the authors provide no detailed information about the study site.
The method of data collection was not clearly indicated. For instance, lines 75-77 describe the source of data (obtained as of 2020), and similarly, lines 77-79 about the source of data (obtained over 1959-1997). Here the gap between 1997 and 2020 is about 22 years. So, to extend yield from (1959-1997) to 2020 or vice versa, what standard approach (model) you have used?
It appears that the reviewer does not know or understand how soil surveys are conducted and archived within the United States. This system is described within these lines with references and links to the appropriate archives. The objective of this project as described is to update the yields observes between 1959-1997 to yields being obtained in 2020.
Line 79: If you have used a soil survey, please specify the type, sample size, and approach used.
The term “soil survey” as used by NRCS refers to the observation, description, and mapping of soils across the landscape of a specified county or counties. Again this has been referenced.
Table1: what is N in the second column? Sample size? If so, the table caption should specify, and also include what statistical analysis was used. What is mixed hay?
Reworded caption and foot note and defined mixed hay.
Tables3 and 4: Please indicate the sample size used and in addition, please includes measures of variability in front of mean values presented here.
Sample size does not relate to table 3 since these are estimates of average yield over a 3-5 year period for planning purposes. Table 4 has sample size noted as site years with the relevant SD.
Results
Table 5: please state what regression analysis the R2, SD reg, and AAPE values refers to, and could you mention your base to classify drainage into moderately well, somewhat poorly, poorly, and very poorly? Or your own finding? If so, you need to explain them well.
This is described in the M&M section. Drainage classes are those defined by USDA/NRCS as cited in the references.
Line 127: Can we know the significance level of this soil's physical properties on yields?
This is the statistical significance of the analysis.
Table 6: similar comments to Table 5 above.
This is described in the M&M section. Drainage classes are those defined by USDA/NRCS as cited in the references.
Line 133: I’d suggest you change ‘Expected crop yield not directly related to climatic growing conditions’ into ‘Relationship between crop yield and climatic conditions. In addition, these climatic growing conditions (climatic variables) were not introduced in ‘the Materials and Methods section.
I prefer the current title. Crop yield is related to climatic conditions. However, here we have the story to tell of why crop yield does not respond to climate as expected. In West Virginia elevation controls temperature and rainfall with contradictory impacts on growth as shown in the tables. These variables are part of the metadata references in the M&M.
Table 8: please indicate what statistical analysis was used for comparisons and specify it in the
was used for comparisons and specify it in the table captions.
Added as requested.
Lines 165-175: (1) I’d suggest you move this part to the Methods section, and (2) please indicate the standard (any reference) you have used for these calculations or approaches.
This is best presented as part of the discussion and uses standard coefficients as used by NRCS and WVU Extension and defined for the reader.
Discussion
Lines 194-196: any evidence to back up this claim?
Line numbers have changed with the addition of text requested by reviews. I don’t know what claim the reviews is addressing. If referring to claims in what are now lines 183-186 these are standard well accepted results seen in the field.
Lines 197-198: Can you provide an example that makes similar to your results and others (cited in line 198)?
Line numbers have changed with the addition of text requested by reviews. These are calculations based on nationally recognized coefficients used by WVU Extension and NRCS for planning purposes in the field.
Lines 204-216: this paragraph seems more about result interpretation, not discussion, so I’d suggest you move this paragraph under the result section.
I think they should stay in the discussion.
Table11: if the values in each column are mean, please provide a measure of variability.
These values are quintile averages. We could include a SD on these averages but that is misleading since they would be SD values within quintiles versus SD withing a population.
Table12: similar comments to Table 11 above.
These values are quintile averages. We could include a SD on these averages but that is misleading since they would be SD values within quintiles versus SD withing a population.
Lines 229-251: Did you use all these rules in your current report? Why do you prefer to mention them in the discussion section? I’d suggest you introduce them under the methods section.
Overall, the discussion is not well discussed, and then I’d suggest the authors to consult further research results from previous studies in the scope of their current topic.
These are the rules being used in applying expected yields to soils on the landscape in the field. This is the discussion of how the research component is being applied in the field.
Keep in mind that this is a project report where we have used statistical analysis to relate soil physical characteristics to expected crop yield and using currently observed crop yields to update expected crop yields.
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
Crop yield is affected by a variety of factors such as soil, climate, and field management. Among them, soil property factors are one of the key influencing factors. Soil organic matter content is considered by many experts to be the dominant factor causing spatial heterogeneity in crop yield. Empirical methods for estimating crop yield using soil attributes have a long history. With advances in agricultural technology, qualitative improvements in crop yields have occurred. The earlier estimation of crop yield based on soil attributes and related parameters need to be updated in time to meet the practical needs.
This report, using West Virginia as an example, aims to compare historic expected crop yields to soil physical characteristics and to update expected yields in the National Soils Information System (NASIS). It is relevant and fits the research content of the journal and is suitable for publication.
Reviewer 2 Report
First of all, I would like to congratulate you on the work that is being presented. However, in order to show the time needed for the elaboration and presentation of the present research, in my opinion, it is necessary to make corrections. I think the results could be improved in terms of how they are presented, because at the moment the reader is lost and forced to return to the tables that are gathered at the beginning of each chapter.
In the discussion I could not find a real comparison with other types of research that has been conducted both for the study area or for similar areas, but also no comparison with similar or the same methodology followed by other researchers. I only read an extension of the results and not a discussion chapter.
Regarding the chapter on conclusions, I believe that improvement is needed so that the result is clear to the reader.
Finally I found some spelling mistakes which I think that with a careful reading can be eliminated.
Reviewer 3 Report
The manuscript "Comparison of Crop Yield Estimates Obtained from A Historic Expert System to the Physical Characteristics of the Soil Components – A Project Report." deals with the relationship of yield and soil properties and gives insight into yield changes. In the submitted report it has been showing the possibility to predict yield based on available data from various sources. This study is reporting on a relevant topic and that is of interest to a wider scientific audience. The original idea is interesting and appears that the manuscript has not been successful in developing and verifying the aim of the study because doesn’t explain the timeframe and confuses with terms like BMP, good management practice, reasonable management practice, historic yield …that hasn’t been properly explained. It is also unclear what the report is intended - who is the beneficiary? In general, this report cannot add merit to current knowledge
Specific comments
Line: 36-39 In this section the authors introduce the soil characteristics as a major factor in crop yield performance and support it with appropriate literature. However, the following discussion has completely overlooked the role of climatic conditions (although discussed later) and crop management practices - tillage. One could say that crop yield depends on a complex interaction of multiple conditions among which in some years particular soil properties could appear to limit higher yield performance. So my suggestion is that this observation can be part of the conclusion if data show soil properties effects on yield in this study.
LINE 75-76: historic expected yield needs further explanation. How many years were included in that period and from which year this period begins? Also, it could be the average yield of expected yield based on recommendation strategy (for instance fertilization is based on expected yields to calculate nutrient loss). It is not clear which data has been used
Table 1. Which period was taken as reference for presenting the corn yield and does these periods (presented in Table 1, Table 2 and Table 3)matching
LINE 79: BMP should be elaborated better in the materials and methods sections. It is mentioned before as some “recommended cropping strategy” however it is not sufficiently explained to be understandable for readers. Also what about crop rotation for corn, any information on that
LINE 92-93: …”To test the use of soil physical descriptions….” Please be more specific which soil physical characteristic was used in this project and how they were obtained in this study
LINE 95-96: Which statistical package was used for testing the yield against soil properties?
LINE 128-129: For which period/Year GDD, FFD, ET etc was calculated to be used for describing the yield. Usually, it requires a certain period of time in order to get reliable results because of temporal effects. In addition to that if you use mean temp/precipitation then you need long-term yield data as well and how the yield was obtained and selected was not clear and understandable. How reliable are Extension Service yield data? And are they replicated or not?
LINE 218: what “reasonable management situations” refers to what
LINE 219-238: How these rules were established? In the previous paragraph author listed “Topography, soil, and management factors” were used. However, using “soil” is a broad term in agronomy and must be specified. Are they tested somehow?
LINE 248-249 “These updated expected yields were evaluated by NRC fields staff who suggested modifications based on local experience.” This part was not previously discussed or explained in the paper that NRC staff use they experience to suggest modification. It raises additional questions about how many NRC staff how experienced are how they were selected…
