Climate Trends and Wheat Yield in Punjab, Pakistan: Assessing the Change and Impact

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper evaluated the influence of changes in Pakistan's climate, as well as fertilization, on winter wheat yield.

The Abstract is informative, however, in line 15, it would be more interesting to replace “has made weather patterns unpredictable” by “has made the weather patterns less predictable” or “has made the weather patterns more difficult to predict”. Also, the paragraph “The average wheat yield ranged from 1.97 t/ha to 3.29 t/ha during the growing season of 1991 to 2022.” does give a good idea on production difficulties due to the climatic factors, since there is no detailing over annual growth or decrease rates.

The chosen keywords are just bad, as they are too related to the terms used in the title.

The Introduction section fails to define what would be the rationale in studying the response of winter wheat to climate change and concomitant fertilization. The authors need to justify this, which can be done by thinking about the maintenance of certain yields over time, even with the difficulties imposed by the climate. However, note that it is a two-way street: the greater need for fertilization can balance productivity, however, it is not environmentally or economically sustainable. It is necessary to expose these ideas both in the Introduction and Discussion.

Line 96 – Figure 1 caption: Yield of what?

Section 3.1: Any discussion over increasing or decreasing trends does not make any sense if the p-value is above 0.05. Non-significant p-values indicates that there is no trend for the evaluated variable. So, only both humidities showed increasing trend and should be analyzed over wheat yield trend.

More important: As the article deals with the influence of climate change on winter wheat yield, shouldn't the variables to be analyzed as predictors of yield be selected as those that have some trend?

Section 3.2: The graphs’ font size is too small to read.

Section 3.3:

The significance of the correlation test (Figure 5) was not shown. Without the analysis of significance, it is not possible to state whether there is a correlation or not. In addition, there is a classification of correlation indexes, which was not used. Thus, mistakes were made (e.g.: “The results showed a significant positive correlation between humidity at 8 AM and fertilizer use (0.57)” – Nothing presented proves that this correlation is significant, moreover it is not strong). Still on this result (lines 261 – 265), there is not the slightest sense of what is discussed, since the value related to the fertilizer application analyzed is for the entire study region, and not by time of day. Just because there's a correlation of 0.57 doesn't mean that the higher the humidity at 8 a.m., the more fertilizer growers deliberately used. There may be correlation, but there is no cause.

The regression model does not have a lot physical logic: If rainfall, temperatures, humidities and fertilizer use are equal to zero, do you really think that you will have 0.267 t/ha of yield? If yes, you should explain why.

Lines 290 to 320: Authors explained how the yield could change with the values of every analyzed variable (e.g.: The coefficient for rainfall is -0.002 which indicates that for every unit increase in rainfall, the wheat yield is expected to decline by 0.002 t/ha, holding other variables constant) but the coefficients fitting for rainfall, min. temperature and max. temperature are not even statistically significant (as expected, by the way), and the authors did write a line about it. These variables should not be selected as predictors.

So, as expected, the model performance is not reliable (Figure 7).

Unfortunately, discussion section is poor. The authors discussed the influence of the variables over the winter wheat production, but the outlined objective is to discuss the influence of climate change over the production, the future trends and what is the role of fertilizers on it, and if something can be made regarding humidity variation due to the adopted production system. The information presented in lines 377 – 381 is just obvious

Comments on the Quality of English Language

English language is good.

Author Response

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: [The Abstract is informative, however, in line 15, it would be more interesting to replace “has made weather patterns unpredictable” by “has made the weather patterns less predictable” or “has made the weather patterns more difficult to predict”. Also, the paragraph “The average wheat yield ranged from 1.97 t/ha to 3.29 t/ha during the growing season of 1991 to 2022.” does give a good idea on production difficulties due to the climatic factors, since there is no detailing over annual growth or decrease rates. The chosen keywords are just bad, as they are too related to the terms used in the title.

Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we have changed the abstract according to your valuable suggestions, New keywords are added.

Comments 2: [The Introduction section fails to define what would be the rationale in studying the response of winter wheat to climate change and concomitant fertilization. The authors need to justify this, which can be done by thinking about the maintenance of certain yields over time, even with the difficulties imposed by the climate. However, note that it is a two-way street: the greater need for fertilization can balance productivity, however, it is not environmentally or economically sustainable. It is necessary to expose these ideas both in the Introduction and Discussion.]

Response 2: Agree. I have improved the introduction section according to suggestions.” Comment 3: {Section 3.1: Any discussion over increasing or decreasing trends does not make any sense if the p-value is above 0.05. Non-significant p-values indicates that there is no trend for the evaluated variable. So, only both humidities showed increasing trend and should be analyzed over wheat yield trend. More important: As the article deals with the influence of climate change on winter wheat yield, shouldn't the variables to be analyzed as predictors of yield be selected as those that have some trend?} I agree with your point but while the MK test indicated that trends in rainfall, maximum temperature, and minimum temperature are not statistically significant (p > 0.05), suggesting a lack of strong evidence for consistent long-term trends, these are the reasons to include these variables in our study: Understanding Variability: Even non-significant trends can provide a valuable understanding of the variability and stability of climatic conditions over time. By examining these trends, we can better understand the conditions under which wheat is cultivated, which is crucial for effective agricultural planning and risk management. Contextual Relevance: Including all climatic parameters ensures a comprehensive analysis that accounts for the complex interplay between different environmental factors. This holistic view is critical, as it mirrors the real-world scenario where multiple climatic factors simultaneously impact wheat yield. Baseline for Future Studies: Documenting these trends, even if they are not statistically significant, establishes a baseline for future research. As more data becomes available, future studies might reveal that trends that are currently non-significant could become significant, particularly as climate patterns continue to evolve. Agronomic Implications: Despite their statistical insignificance, these variables were included due to their known biological and agronomic impacts on wheat yield. For instance, temperature extremes can affect the phenological stages of wheat, and variability in rainfall can influence soil moisture levels crucial for wheat growth. Comment 4: { Section 3.3: The significance of the correlation test (Figure 5) was not shown. Without the analysis of significance, it is not possible to state whether there is a correlation or not. In addition, there is a classification of correlation indexes, which was not used. Thus, mistakes were made (e.g.: “The results showed a significant positive correlation between humidity at 8 AM and fertilizer use (0.57)” – Nothing presented proves that this correlation is significant, moreover it is not strong). Still on this result (lines 261 – 265), there is not the slightest sense of what is discussed, since the value related to the fertilizer application analyzed is for the entire study region, and not by time of day. Just because there's a correlation of 0.57 doesn't mean that the higher the humidity at 8 a.m., the more fertilizer growers deliberately used. There may be correlation, but there is no cause.} As per suggestion P values are added.   The regression model does not have a lot physical logic: If rainfall, temperatures, humidities and fertilizer use are equal to zero, do you really think that you will have 0.267 t/ha of yield? If yes, you should explain why.} You're right that a zero value for all predictor variables (rainfall, temperature, humidity, fertilizer use) wouldn't represent a realistic scenario for wheat production. In regression models with environmental factors, a zero intercept doesn't necessarily translate to a physically achievable yield. This could be due to factors like residual soil fertility or irrigation that contribute to a baseline yield even in the absence of the measured variables. Additionally, regression models identify statistical relationships based on the data, and the intercept might reflect limitations in capturing all relevant factors influencing yield. While the absolute value of the intercept (0.267 t/ha) might not be physically interpretable, the model's true value lies in the relationships between the predictor variables and wheat yield. These relationships tell us how changes in rainfall, temperature, humidity, and fertilizer use impact the final harvest. This problem is addressed in the study limitation section.   Comment 4: Lines 290 to 320: Authors explained how the yield could change with the values of every analyzed variable (e.g.: The coefficient for rainfall is -0.002 which indicates that for every unit increase in rainfall, the wheat yield is expected to decline by 0.002 t/ha, holding other variables constant) but the coefficients fitting for rainfall, min. temperature and max. temperature are not even statistically significant (as expected, by the way), and the authors did write a line about it. These variables should not be selected as predictors. Improvements made based on suggestions

Response 4: {Unfortunately, discussion section is poor. The authors discussed the influence of the variables over the winter wheat production, but the outlined objective is to discuss the influence of climate change over the production, the future trends and what is the role of fertilizers on it, and if something can be made regarding humidity variation due to the adopted production system. The information presented in lines 377 – 381 is just obvious}

The discussion section is improved based on suggestions. Prospects for further implications and limitation of study are added.

Added new material: Line 384-398, 413-457

Response 1:    (English language improved)

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

The manuscript currently undergoing assessment, titled "Climate Trends and Wheat Yield in Punjab, Pakistan: Assessing the Change and Impact". This study explores how climate change, and agricultural practices affect wheat production in Bahawalnagar, Pakistan. Analyzing data from 1991 to 2022, it reveals a decline in rainfall and rising temperatures alongside significant positive effects of humidity and fertilizer application (specify type if applicable) on yield. However, a concerning average annual wheat yield loss of 0.12 t/ha is attributed to climate factors. These findings emphasize the need for adapting agricultural practices to ensure food security and long-term sustainability in the region.

However, I have some questions based on what is stated in this manuscript. This study investigates climate trends and their impact on wheat production in Bahawalnagar, Pakistan. It employs the Mann-Kendall test to assess trends and regression analysis to identify factors influencing yield. The study reveals a decline in rainfall, increasing temperatures, and positive correlations between humidity and fertilizer application with yield. However, some p-values for temperature trends are non-significant, and the discussion section could benefit from a more concise explanation of the potential mechanisms behind humidity's positive effect. The discussion section can be condensed by focusing on statistically significant trends and elaborating on the plausible reasons behind humidity's positive correlation with yield (e.g., dew formation). Consider clarifying the contrasting findings on rainfall's impact (positive vs. negative depending on timing/intensity) for a broader audience.

 

 

Congratulations to the authors for their commendable work on this subject.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Moderate editing of English language required. 

Author Response

Thanks for your valuable suggestions. The discussion section is improved based on your suggestions. Line 384-397 and line 413-457.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Accept

Author Response

Thanks for reviewing my Article.

Reviewer 4 Report

Comments and Suggestions for Authors

1. It is necessary to present the instruments and equipment used in the study.

2. It is necessary to present the results of statistical processing of the adequacy of the developed mathematical model for predicting yield.

3. It is necessary to present the relevance of the study more clearly.

4. It is necessary to reflect the prospects for further implementation of the research results obtained.

Author Response

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: [ It is necessary to present the instruments and equipment used in the study.

Response 1: This study relies entirely on secondary data obtained from various sources. Therefore, information regarding the specific instruments used for data collection might not be readily available. As per your valuable suggestions data sources are clearly mentioned in the study.  Lines 167-178 include the data information.

Comments 2: [It is necessary to present the results of statistical processing of the adequacy of the developed mathematical model for predicting yield.]

Response 2: Agree. We have mentioned the results of statistical processing of the adequacy in Line 290-299. Comments 3: {It is necessary to present the relevance of the study more clearly}. Response 3: The relevance of the study has been added in the introduction section as per suggestions in lines 81-102. Comments 4: {It is necessary to reflect the prospects for further implementation of the research results obtained.}. Response 4: Prospects for further implementation of the results have been added in discussion section as per your valuable suggestions in lines 427-440.

4. Response to Comments on the Quality of English Language

Response 1:    (English language re-checked by native speaker)

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

For this second round of review, the keywords are still repeating terms of the title, which is not interesting for indexing.

The article’s Introduction section still fails to define what would be the rationale in studying the response of winter wheat to climate change and concomitant fertilization. The authors only cited studies about the influence of climate variables and fertilization on winter wheat production but did not explain why fertilization should be included in a study about climate trends. In my last review, I explained how it can be tied, and the authors just did not do it.

Directly: the material and methods should explain how climate variables were selected. Once again: why were climate variables that have no trend used in the analysis? I understand that the authors will not change the analyzes already carried out, so I ask for an explanation for this. Information on lines 444 to 447 can do this but, pay attention: “Their inclusion was based on biological and agronomic considerations but might limit the interpretability of the findings” – so, you have to discuss the limitation, and you did not do it.

Regarding the significant positive correlation between humidity at 8 AM and fertilizer use, the authors did not change what was pointed out. The value related to the fertilizer application analyzed is for the entire study region, and not by time of day so, again: just because there's a correlation of 0.57 doesn't mean that the higher the humidity at 8 a.m., the more fertilizer growers deliberately used. There may be a correlation, but there is no cause. Is there any information about the time of the day the fertilizers were applied in most farms? I don’t think so. Discussion on lines 385 – 399 does not explain this.

Anything was discussed about the actual soundness of the regression model intercept, that was previously asked.

Lines 370 – 375: Table 2 shows that there is no significative trend for maximum and minimum temperatures. Also, these climatic variables coefficients, at the regression analysis, were not significant too. You must discuss your findings based on the statistics.

The statement “This study suggests that fertilizer application can be a tool for adapting to climate change and maintaining the yield of wheat. However, long-term solutions require a combination of strategies including sustainable fertilizer use and development of climate-resilient wheat varieties” should be the main line of discussion of the entire article, but the authors did not define this in the Introduction section, as previously asked.

I really did not understand section 4.1. Where did this discussion come from? Which presented data take you into this discussion? Also, the presentation, using topics, is just bad.

The limitations of the study should not be in the “Discussion” section, because there is no discussion, just statements. Some must be on Material and Methods and some at the Conclusions:

Lines 448 to 450 – Material and Methods

Lines 451 to 453 – Conclusion (could be on discussion, if actually discussed).

Lines 454 to 456 - Conclusion (could be on discussion, if actually discussed).

Lines 457 to 459 – Conclusion.

 

Thus, unfortunately, the discussion is still poor.

Comments on the Quality of English Language

The quality of English language is ok.

Author Response

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: [For this second round of review, the keywords are still repeating terms of the title, which is not interesting for indexing.]

Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we have updated the keywords.

Comments 2: [The article’s Introduction section still fails to define what would be the rationale in studying the response of winter wheat to climate change and concomitant fertilization. The authors only cited studies about the influence of climate variables and fertilization on winter wheat production but did not explain why fertilization should be included in a study about climate trends. In my last review, I explained how it can be tied, and the authors just did not do it.]

Response 2: We have thoroughly improved the introduction, and clearly explain the hypothesis and objectives in the introduction section.  We have added an explanation why fertilization should be included in the study. The updated text has been highlighted in lines from 86 to 110. Comments 3: [Directly: the material and methods should explain how climate variables were selected. Once again: why were climate variables that have no trend used in the analysis? I understand that the authors will not change the analyzes already carried out, so I ask for an explanation for this. Information on lines 444 to 447 can do this but, pay attention: “Their inclusion was based on biological and agronomic considerations but might limit the interpretability of the findings” – so, you have to discuss the limitation, and you did not do it.] Response 3: In the material and method section we have added how climate variables are selected in lines from 178-182. Comments 4: [Regarding the significant positive correlation between humidity at 8 AM and fertilizer use, the authors did not change what was pointed out. The value related to the fertilizer application analyzed is for the entire study region, and not by time of day so, again: just because there's a correlation of 0.57 doesn't mean that the higher the humidity at 8 a.m., the more fertilizer growers deliberately used. There may be a correlation, but there is no cause. Is there any information about the time of the day the fertilizers were applied in most farms? I don’t think so. Discussion on lines 385 – 399 does not explain this.] Response 4: as per your valuable suggestion this correlation makes no sense we have deleted these lines and discussed the correlation between wheat yield and other parameters only. Comments 5: [Anything was discussed about the actual soundness of the regression model intercept, that was previously asked.] Response 5: Thanks for your suggestion we have added the discussion about intercept value in lines 316-319. Comments 6: [Lines 370 – 375: Table 2 shows that there is no significative trend for maximum and minimum temperatures. Also, these climatic variables coefficients, at the regression analysis, were not significant too. You must discuss your findings based on the statistics.] Response 6: Thanks for your suggestions, we have discussed the results based on statistics, About temperature we have added new literature based on our results in lines 372-378 and in lines 409-415. Comments 7: {The statement “This study suggests that fertilizer application can be a tool for adapting to climate change and maintaining the yield of wheat. However, long-term solutions require a combination of strategies including sustainable fertilizer use and development of climate-resilient wheat varieties” should be the main line of discussion of the entire article, but the authors did not define this in the Introduction section, as previously asked.] Response 7: We have addressed this comment and added the section about fertilizer in introduction section as mentioned in previous comment 2.   Comments 8: [I really did not understand section 4.1. Where did this discussion come from? Which presented data take you into this discussion? Also, the presentation, using topics, is just bad.] Response 8: Thanks for pointing out this mistake we have removed this section.   Comments 9: [The limitations of the study should not be in the “Discussion” section, because there is no discussion, just statements. Some must be on Material and Methods and some at the Conclusions.] Response 9: We have added these lines in the relevant section based on your valuable suggestions: We have added your suggested line in material and methods section 183-185. Other material is added in the conclusion section in 448-453.

Thank you for your continued feedback. We appreciate your time and attention to our manuscript. We believe these revisions enhance clarity and comprehensiveness.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

The manuscript has been improved, in the view of the authors, if this research brings an economic improvement in the area of interest, I agree with its publication in the present form. In the future, however, a different approach is needed, with climate data and production data obtained from my point of view does not present any degree of novelty so these data are published in SUSTAINABILITY. I appreciate the work and effort put into the collection and statistical processing of the data.

 

Congratulations to the authors for their commendable work on this subject.

 

Comments on the Quality of English Language

Minor editing of English language required. 

 

 

Author Response

Thank you for your continued feedback. We appreciate your time and attention to our manuscript. 

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

The authors answered all the queries presented in R2, and improved the manuscript following the suggestions made.

Comments on the Quality of English Language

There minor editing issues throughout the text.

Author Response

Dear Reviewer! 

Thank you for considering our manuscript. We appreciate the time and valuable feedback provided.