Environmental Effects on Soybean (Glycine Max (L.) Merr) Production in Central and South Germany

Round 1

Reviewer 1 Report

Overall comment:

• Major revision of overall writing is needed
• The rationale of this study is bit weak and additional discussion is needed
• Discussion part needs more analyses and explanations. For e.g. what is the importance of varietal correlation matrix with the climatic parameters? How can it affect the crop production and eventually the adaptability? Why there is negative correlation between protein and oil content in soybean? Why drought stress increase protein content and reduce oil content? and many more.

Line # 2: Please include the scientific name of soybean

Line # 19: Which variety? All 13 varieties that were used in this study? Are the numbers (i.e. dry matter, oil content, and seed yield) average of 13 varieties, 9 locations, and 2 years. Please explain it clearly.

Line # 19: Please use the superscript and subscript consistently

Line # 38: I think word ‘safety’ fits better than ‘protection’

Line # 47: Unclear. Please re-write the sentence “Soybean needs a minimum temperature sum for ripening; for example, >2400 Crop Heat Units (CHU) for MG 000 varieties “

Line # 48: “Flower bud initiation and flowering (beginning of reproductive development) is determined by latitude (first with respect to temperature and second, day length) of the growing area”- very generalized statement. Please change it or remove it

Line # 51: Please replace “big” with “significant”. What is the extent of loss here (XX%)?

Line # 54: Remove gap between 40-44%

Line # 58-59: “There is evidence that warm temperature (min 20°C) during the growing period increases the protein content of soybean, or that a positive correlation exists between temperature and protein content at temperatures below 28°C”-Confusing sentence. Please re-write it

Line # 61: Protein or soy protein? Please try to be consistent

Line # 66: demands of soy protein for ……….

Line # 68: The flow of the writing needs to be improved.

Line # 71: “Regions where soybean with a high protein content cannot be successfully grown would be better suited for oil production”- Please explain how? Is it only due to insufficient rainfall? Do all the adverse soybean producing areas in Germany have insufficient rainfall and can only promote oil production?

Line # 88: Please indicate how many years were considered to calculate the long-term means

Line # 91: Please explain cfu

Line # 91: What is N²?

Line # 91: 400g 100kg–1 of seeds: Please use 400g per 100kg of seeds

Line # 95: Please use superscript consistently

Line # 92: Replace “sowing rate” with “seed rate”

Table 2: Please include duration of the varieties (days required to reach maturity)

Line # 111: Please explain R8 (e.g. Reproductive stage 8)

Line # 113: subscript for H2O and superscript ha-1. Please make sure to correct all these issues.

Table 3: Use different symbols

Line # 119 and 121: Please explain PWV consistently e.g. total precipitation over entire vegetation period

Line # 125: Is global radiation similar to the solar radiation value in Germany?

Line # 178: 0.5 or 0.05? (You might write it as α<0.05)

Line # 184, 196: Normally, acronyms can not be used to start a sentence. Please address it in the entire manuscript.

Table 7: The ‘mean’ in the table 7: What does it indicate? For an example mean of 2016 (-0.04) and 2017 (0.14) can not be 0.18. Also, why are you using mean in Pearson correlation coefficient? Please describe your data elaborately.

Is it the average of 2016 and 2017 data? Explain

Table 6 and 7: I don’t understand the idea of providing table 6 and 7 separately. You can just report table 6 or 7 with statistical significance

Line # 209: P<0.05 or <0.01 should be sufficient

Figure 2a: You can remove the figure 2a as it has no significance or definite trend

Author Response

Response to Reviewer 1 Comments

Dear reviewer, thank you very much for your time, which you took to make the valuable professional comments and remarks.

The English check was carried out by a native speaker from the USA, who completed her PhD in Agronomy at the University of Hohenheim.

We will reply to your comments afterwards in red marked text.

• Major revision of overall writing is needed

• The rationale of this study is bit weak and additional discussion is needed
• Discussion part needs more analyses and explanations. For e.g. what is the importance of varietal correlation matrix with the climatic parameters? How can it affect the crop production and eventually the adaptability? Why there is negative correlation between protein and oil content in soybean? Why drought stress increase protein content and reduce oil content? and many more. Thanks for your ideas and hints. The chapter Discussion was worked on and deepened. The differences in results between the maturity groups (we did not go explicitly to the varieties because they are short-lived) were constantly presented and discussed. As the different responses to environmental parameters are different, we have also proposed a scheme for the adaptation of the varieties of the corresponding maturity group to the growing conditions (dry/wet and so on) in Germany. We have also actively addressed the negative correlation between protein and oil content. We have taken a closer look at the effects of drought on quality traits.

Line # 2: Please include the scientific name of soybean - the scientific name was included

Line # 19: Which variety? All 13 varieties that were used in this study? Are the numbers (i.e. dry matter, oil content, and seed yield) average of 13 varieties, 9 locations, and 2 years. Please explain it clearly. Thank you for this helpful clue, this statement is now clearly explained

Line # 19: Please use the superscript and subscript consistently – has been controlled, it is consistent

Line # 38: I think word ‘safety’ fits better than ‘protection’ –replaced

Line # 47: Unclear. Please re-write the sentence “Soybean needs a minimum temperature sum for ripening; for example, >2400 Crop Heat Units (CHU) for MG 000 varieties “The sentence was rewritten to make clear that it is the heat sum in the growing season

Line # 48: “Flower bud initiation and flowering (beginning of reproductive development) is determined by latitude (first with respect to temperature and second, day length) of the growing area”- very generalized statement. Please change it or remove it. The sentence has been re-written

Line # 51: Please replace “big” with “significant”. What is the extent of loss here (XX%)? was replaced and % of losses entered

Line # 54: Remove gap between 40-44%, thanks, done

Line # 58-59: “There is evidence that warm temperature (min 20°C) during the growing period increases the protein content of soybean, or that a positive correlation exists between temperature and protein content at temperatures below 28°C”-Confusing sentence. Please re-write it. The confusion was removed, and the sentence was rewritten

Line # 61: Protein or soy protein? Please try to be consistent – decided to use “protein”

Line # 66: demands of soy protein for ……done

Line # 68: The flow of the writing needs to be improved. The sentence has been rewritten to emphasize the comparable productivity of organic and conventional cultivated soybean.

Line # 71: “Regions where soybean with a high protein content cannot be successfully grown would be better suited for oil production”- Please explain how? Is it only due to insufficient rainfall? Do all the adverse soybean producing areas in Germany have insufficient rainfall and can only promote oil It is an outlook into the future. The idea in the statement is not only to aim at the production of soybean protein, but also to consider oil production. Soybean seed contain approximately 20% oil and can be cultivated biologically in comparison to oilseed rape (Brassica napus) and sunflower (Helianthus annuus) in Germany much more efficiently. Some soybean varieties have above average high oil content (genetically assessed) and if you grow them in the selected areas, you could benefit more from oil production than from protein production.

Line # 88: Please indicate how many years were considered to calculate the long-term means – The number of years is now added in brackets

Line # 91: Please explain cfu - colony forming units, was complemented

Line # 91: What is N²? nitrogen, has been replaced

Line # 91: 400g 100kg–1 of seeds: Please use 400g per 100kg of seeds – thanks, great idea

Line # 95: Please use superscript consistently - done

Line # 92: Replace “sowing rate” with “seed rate” - done

Table 2: Please include duration of the varieties (days required to reach maturity) - This information is not available in the official German Descriptive List of varieties: cereals, maize oil and fiber crops, leguminous, beet root and catch crops. The standard maturity assessment is performed in by rating from 1-9

Line # 111: Please explain R8 (e.g. Reproductive stage 8) done

Line # 113: subscript for H2O and superscript ha-1. Please make sure to correct all these issues  - was corrected on “14% moisture of seed”

Table 3: Use different symbols thanks for useful hint, has been changed, same table 6 and 7

Line # 119 and 121: Please explain PWV consistently e.g. total precipitation over entire vegetation period changed

Line # 125: Is global radiation similar to the solar radiation value in Germany? no, it was meant solar radiation

Line # 178: 0.5 or 0.05? (You might write it as α<0.05) we meant p<0.05, corrected

Line # 184, 196: Normally, acronyms can not be used to start a sentence. Please address it in the entire manuscript. Thanks, the entire manuscript has been corrected for this error

Table 7: The ‘mean’ in the table 7: What does it indicate? For an example mean of 2016 (-0.04) and 2017 (0.14) can not be 0.18. Also, why are you using mean in Pearson correlation coefficient? Please describe your data elaborately.

Is it the average of 2016 and 2017 data? Explain

Table 6 and 7: I don’t understand the idea of providing table 6 and 7 separately. You can just report table 6 or 7 with statistical significance

Table 6 shows only the significant correlations and Table 7 all correlations. Since the weather conditions were different in the two years (which was also described in the discussion), our aim in presenting the two tables was to show these differences in the correlations over years and maturity groups. in Table 7, each correlation was calculated in a separate data set for the respective year, and the mean values in the table are the calculated Pearson correlations over two test years. It is not simply average from two numbers. With this information caption of the table was added. More illustrative example of the necessity and informational value of the two tables is the correlation between precipitation and solar radiation.

From the above table we can see that in 2016 varieties from MG 00 have positively and significantly correlated with solar radiation and varieties from MG 000 have not. in 2017 the values of correlations over two years from MG 00 and MG 00 are comparable, both significant and positive but different. This data can be found in table 7. In table 6 we find again a positive correlation between seed yield and solar radiation, calculated across two trial years, five locations, and 13 varieties from two maturity groups (MG 00 and MG 000) at the same time and it is almost as high as mw from table 7.

Line # 209: P<0.05 or <0.01 should be sufficient - has now been fitted  

Figure 2a: You can remove the figure 2a as it has no significance or definite trend –the graphic in figure 2a has no significance or definite trend, but it’s the finding too. We believe that such a result is still important to make the placement of the varieties in the growing areas efficient according to the different uses of soybean. Above all, it is important that the graphs show the reactions of the respective varieties each maturity groups.

Author Response File: Author Response.docx

Reviewer 2 Report

Review – Agronomy 978454

Title

The title of a manuscript is too broad with respect to variability in weather conditions in Germany.

This study presents data to certain localities, but not to the whole Germany. 

Abstract

The introductory part of the Abstract requires correction. The hypothesis of study is described instead of clearly presented.

L 20/21: This relationship is well recognized in all oil, and starchy crops.

L 26/26: The abstract should be closed by a conclusion. This is not a conclusion, but only statement.

Introduction

In general, Introduction is too focusing on basic phenological and enviromental data.

L 30-41: In accordance to the current knowlege about climatic regions in Europe, Germany covers three environmental zones from Continetal to Atlantic North. References no. 1, 6, and 7 do not inform on so called climate change.

Jongman, R.H.G., Bunce, R,G.H., Metzger, M.J., Mucher, C.A., Howard, D.C., Mateus, V.L. Objectives and applications of a statistical environmental stratification of Europe. Landsc. Ecol. 2006, 21, 409-429.

L 75-78: The presented hypotheses are poorly supported by documented materials. In fact, they can be validated based on literature study.

Materials and methods

There are not shown any data on soil fertility, i.e. the content of available P, K, Mg, Ca, and Mo. All these nutrients are important for both N2 fixations by soybean and yield and its characteristics. There are literaturę data on the Nmin content, and its effects on soybean growth and formation of yield components, and grain quality characteristics.

Results

Table 6.

The impact of precipitation on soybean characteristics is clearly shown in Table 6, taking into account the relationships between precipitation during flowering-seed filling and protein yield. It has been also proved that the higher protein content in seeds of legume crops, subsequently  results in the lower content of crude oil.

Table 7.

The effect of years on the presented soybean characteristics was significantly strong to define the impact of environmental factors. Hence, the shown year-means do not help a reader to make its own evaluation of the studied factors. The most striking are coefficients for means, describing the content of crude oil.

Figures 1 and 2 repeats data presented in respective tables. They should be moved to the supplementary material.

Discussion

In general, discussion is too descriptive, instead of being conclusive. There are not explained physiological mechanisms of soybean positive or negative response to environmental factors.

L 216-225: These parts should be moved to the introductory part of the manuscript.

L226-231: This part belongs to the Results section.

L 287-295: This an example of a typical comparative discussion, and the conclusion is well known.

The entire discussion is too wordy. This chapter should be more concessive and conclusive.

Author Response

Response to Reviewer 2 Comments

Dear reviewer, thank you very much for your time, which you took to make the valuable professional comments and remarks.

The English check was carried out by a native speaker from the USA, who completed her PhD in Agronomy at the University of Hohenheim.

We will reply to your comments afterwards in red marked text.

Title

The title of a manuscript is too broad with respect to variability in weather conditions in Germany. This study presents data to certain localities, but not to the whole Germany. The title was fitted -central and south Germany

Abstract

The introductory part of the Abstract requires correction. The hypothesis of study is described instead of clearly presented. The abstract has been better fitted to the results obtained and conclusion.

L 20/21: This relationship is well recognized in all oil, and starchy crops. Yes, they are. Depending on crop and weather conditions in the year of cultivation the values vary a little bit.

L 26/26: The abstract should be closed by a conclusion. This is not a conclusion, but only statement. thanks for the hint, this sentence was rephrased to reflect the contents of conclusion – “In growing areas with heat periods during ripening, the protein content tends to be higher and in areas with a high solar radiation during flowering, the protein content tends to be reduced.”

Introduction

In general, Introduction is too focusing on basic phenological and enviromental data. We need this introduction to the topic to be able to provide the reactions of the soybeans from the field trials

L 30-41: In accordance to the current knowlege about climatic regions in Europe, Germany covers three environmental zones from Continetal to Atlantic North. References no. 1, 6, and 7 do not inform on so called climate change. Thanks a lot for the reference to source, in this paper are more specific references to climate change ; this source has been included in the manuscript and incorporated

Jongman, R.H.G., Bunce, R,G.H., Metzger, M.J., Mucher, C.A., Howard, D.C., Mateus, V.L. Objectives and applications of a statistical environmental stratification of Europe. Landsc. Ecol. 2006, 21, 409-429.

L 75-78: The presented hypotheses are poorly supported by documented materials. In fact, they can be validated based on literature study. The results on the topic are mostly from South or North America and therefore cannot be transferred one to one to the cultivation conditions in Germany. There are hardly any literature sources about the findings in our country and therefore these hypotheses were made.

Materials and methods

There are not shown any data on soil fertility, i.e. the content of available P, K, Mg, Ca, and Mo. All these nutrients are important for both N2 fixations by soybean and yield and its characteristics. There are literaturę data on the Nmin content, and its effects on soybean growth and formation of yield components, and grain quality characteristics. This study focused on the environmental impact of (temperature, precipitation, solar radiation) on soybean production. To avoid the complexity of the study, the nutrients were not explicitly investigated. We have to suppose that the trials were adequately supplied with nutrients because they were trial locations from plant breeders and state trial stations

Results

Table 6.

The impact of precipitation on soybean characteristics is clearly shown in Table 6, taking into account the relationships between precipitation during flowering-seed filling and protein yield. It has been also proved that the higher protein content in seeds of legume crops, subsequently results in the lower content of crude oil. It was also found, comparable to the existing study results, that protein and oil contents correlate negatively and significantly

Table 7.

The effect of years on the presented soybean characteristics was significantly strong to define the impact of environmental factors. Hence, the shown year-means do not help a reader to make its own evaluation of the studied factors. The most striking are coefficients for means, describing the content of crude oil. Since the weather conditions in all test years were so different for all locations, this detailed presentation (for each year and the calculated results from two years) was chosen. In the same way, one can fully see that the soybean seed properties are so sensitive to extreme conditions (dry stress or above average precipitation), as in the case of the oil content.

Figures 1 and 2 repeats data presented in respective tables. They should be moved to the supplementary material. we have checked, in the tables 6 and 7 the correlations between environmental impacts and seed properties of soybean are shown. In the figures we have exclusively visualized the correlations between seed properties among each other, for example protein and oil content.

Discussion

In general, discussion is too descriptive, instead of being conclusive. There are not explained physiological mechanisms of soybean positive or negative response to environmental factors. The topic of the study was worked on for agricultural reasons. The plant physiology on the molecular level was not investigated here. According to the reviewer’s comment, we have added some aspects of the physiological background. .

L 216-225: These parts should be moved to the introductory part of the manuscript. This information was moved in introduction.

L226-231: This part belongs to the Results section. This information is shown in detail in tables of the results chapter. We seize this information here and interpreted it, as a transition to the following paragraphs. If possible, we would like to leave this information unchanged here.

L 287-295: This an example of a typical comparative discussion, and the conclusion is well known. After a strong modification of the discussion, also the conclusion has been adapted as suggested.

The entire discussion is too wordy. This chapter should be more concessive and conclusive. We have changed the discussion and made it more conclusive and coherent.

Author Response File: Author Response.docx

Reviewer 3 Report

Title: Authors used four locations in Germany. If the four locations represent Germany the title is OK, if not you need to change.

Line 32-36: authors described the importance of soybean as food and feed. As we know soybean is derived from East Asia and Asian have been eating soybeans for a long time. The importance of soybean as food material has not known recently.

At Materials and Method

• No explain about how to plant soybeans. Did you use furrow plot or scatter block?
• How to estimate protein yield and oil yield? Need to describe.
• Line 113: Check H2O.

Table 4: analysis results showed that significant different for protein and oil content among varieties but no different for protein yield and oil yield. Assume that content and yield are closely correlated. Any reason for this result?

Table 5: Need to analysis between MGs. Authors just showed mean with SD. Without proper analysis author cannot describe clearly for traits.

Line 210-211: many research reports demonstrated the negative correlation between protein and yield. But this manuscript showed that no significant correlation between two traits. Need to discussion about this.

Conclusion

The results from this study were obtained in four regions of Germany. Therefore, the application of this result need to be described in four regions of Germany. Need to edit conclusion.  

Author Response

Response to Reviewer 3 Comments

Dear reviewer, thank you very much for your time, which you took to make the valuable professional comments and remarks.

The English check was carried out by colleague native speaker from the USA, who completed her PhD in Agronomy at the University of Hohenheim.

We will reply to your comments afterwards in red marked text.

Title: Authors used four locations in Germany. If the four locations represent Germany the title is OK, if not you need to change. The title was fitted -central and south Germany

Line 32-36: authors described the importance of soybean as food and feed. As we know soybean is derived from East Asia and Asian have been eating soybeans for a long time. The importance of soybean as food material has not known recently. Soybean is currently grown for feed in Germany, but there is also some production for tofu making. We think that there is a future market for soybean as food because of the increasing demand for vegetarian and vegan diets.

At Materials and Method

• No explain about how to plant soybeans. Did you use furrow plot or scatter block? The sowing method for each trial is now presented in table 1
• How to estimate protein yield and oil yield? Need to describe. thanks, done.
• Line 113: Check H2O.was corrected on 14%moisture

Table 4: analysis results showed that significant different for protein and oil content among varieties but no different for protein yield and oil yield. Assume that content and yield are closely correlated. Any reason for this result? Protein yield as well as oil yield was calculated by multiplying seed yield and corresponding protein or oil content. So, both were derived from seed yield and correlated together very closely – we calculated r=0,84 (across two trial years, five locations, and 13 varieties from two maturity groups). At the same time, according to the results of variance analysis, the variety does not significantly influence the seed yield.

Table 5: Need to analysis between MGs. Authors just showed mean with SD. Without proper analysis author cannot describe clearly for traits. In table 5 the yields and seed ingredients are presented to indicate the level of the traits, so that reader is able to classify the results. The SD helps to determine the range of all values, that there are mean values over all varieties of each MG. Generally, the data are statistically evaluated as presented in the sub-chapter data analysis.

Line 210-211: many research reports demonstrated the negative correlation between protein and yield. But this manuscript showed that no significant correlation between two traits. Need to discussion about this. Yes. For example, in cereals there is clearly a negative correlation between yield and protein content. The protein content in cereals is – compared to soybean – quite low, and carbohydrates are high. In soybean, the most important ingredients oil and protein have another relation to each other. There is no clear message about the correlations from existing literature: some studies show a negative correlation, others report a positive one. Over the years and growing areas there are big differences. We now discuss this point more detailed.

Conclusion

The results from this study were obtained in four regions of Germany. Therefore, the application of this result need to be described in four regions of Germany. Need to edit conclusion. The results were obtained from four regions. Today, these four regions represent the soybean growing areas in Germany. In the north of the country, the ripening and harvesting of soybeans is very difficult. We have considered your comment and revised the conclusion according your suggestion.

Round 2

Reviewer 1 Report

The author tried to respond my comments, however, numerous issues (both technical and non-technical) can still be found in the manuscript. Also, when addressing the comments of the reviewers, you must mention the line # and page # for changes. It was hard for me to find line # in this revised manuscript.

English and overall writing has been improved, but still several mistakes can be found. You need to re-structure most of the sentences and in often cases your sentences were not flowing well. You need to connect paragraphs in your manuscript.

Overall comment:

• The rationale of this study still needs to be developed. The introduction suggests that we already know protein and oil content in soybean are negatively correlated, high temperature during growing season of soybean promotes oil production, precipitation can be negatively or positively related with soybean oil and protein content. Therefore, what is the merit of this study? What unique research/knowledge is it offering to the scientific community.

Line # 57: I think ‘mature’ is better than ‘ripen’

Line # 62: “On average, soybean seeds contain 1]-25% oil” -Please verify the number. What is this?

Line # 64: Please specify the range instead of ‘somewhat’

Line # 67: Please insert to (> 20°C to <28°C)

Table 1. Please put standard deviations

Line # 98: Correct gram spelling

Line # 99: space between ‘per100kg’

Line # 110: How the threshold was calculated for disease infestation in soybean? What kind of diseases occurred during soybean production season? Were the diseases same in both 2016 and 2017?

Table # 2: Duration of the varieties

Line # 118: Does soybean have real full maturity stage?

Line # 125: This is not way to write scientific papers. Please spell out max to maximum

Table 6 and 7: Table 7 showing elaborated results while table 6 is showing the overall results. These two tables are very much related, and one should be removed. Please note that keeping both tables are literally duplication of your own data.

Line # 239: “The early maturing varieties of MG 000 were more sensitive to increases in precipitation in the period R4-R6 than MG 00 varieties”-How respiration is related to the precipitation response? Please explain it clearly.

Line # 281: “If water deficiency occurred at R5-R6, soybean seeds did not fully develop and did not reach their variety-specific size [41,48,50,51]. The transfer processes of nutrients and thus seed quality were impaired [15,46], and the assimilates could not be completely converted into oil and protein [51].”-It means that the draught or water deficiency results lower seed oil content in soybean. Then please explain how seed oil is negatively correlated with precipitation.

I totally cannot understand the statement. You just mentioned that water deficiency resulted lower oil content in soybean and in the second sentence you said, ‘seed oil is negatively correlated with precipitation’. Look at your data and statement: it should be positively correlated. If increase of X also increases Y then they are positively correlated. Please re-write the statement.  

Figure 2a must be removed. You got a R2 value of 0.08 (8%) which does not mean any relationship at all. Just mention very weak relation between protein content and seed yield was observed in the text. Providing all the data does not enrich your paper, just present the data which is meaningful.

Author Response

Dear reviewer,

thank you very much for your time, which you took to make valuable professional and logical comments and remarks, which contribute to the flowing consistency of the manuscript

We have looked at each comment thoroughly and responded to each one factually to implement the changes.

Best regards

Author Response File: Author Response.docx

Reviewer 2 Report

I accept the present form of a manuscript. 

Author Response

Dear reviewer,

thank you very much for your time and effort.

Best regards