Assessing the Contribution of Citrus Orchards in Climate Change Mitigation through Carbon Sequestration in Sargodha District, Pakistan

Round 1

Reviewer 1 Report

Title: I suggest that title should be changed from “Evaluating the contribution of citrus trees in climate change mitigation through carbon sequestration in Sargodha district, Pakistan” to  “Assessing the contribution of citrus orchards in climate change mitigation through carbon sequestration in Sargodha district, Pakistan”

Abstract: Authors should focus on fruit orchards/citrus orchards rather than discussing the agroforestry or intercropping. Please mention the name of six subdivisions of district in the abstract before results. Why more carbon stock were found in shahpur due to more tree density or any other reason? Please mention here.

Keywords: Authors have used same keywords as in the title. Please use different keywords than title.

Introduction: This section is very brief and short.  Authors have given excellently global context and then discussed about fruit trees but more literature on the environmental services of fruit based agroforestry systems and/or citrus orchards should be cited. Fruit orchards not only provide good quality of fruit but also provide other benefits that any other tree can provide. Need to add two to three paragraphs on fruit trees/orchards and their role in carbon sequestration.

Material and Methods:

Why this area was selected and what is significance of citrus orchards of this area?

What is distance between six sites?

 Why quadrate size was of 0.405 ha?. Please describe?

Please discuss the cultivation practices, citrus tree age and the method that how orchard was selected? Please also give soil physic-chemical properties if measured.

Results and discussion: Why numbers of plots were different in each site? Please discuss.

Please avoid words of citrus based agroforestry system and intercropping and it is better to discuss citrus orchards. Please compare the findings with other findings for citrus and other fruit orchards.

References: Publication needs to be reformatted according to journal  for text and citation/reference style.

Author Response

Referee 2 comments

Comment 1. Title: I suggest that title should be changed from “Evaluating the contribution of citrus trees in climate change mitigation through carbon sequestration in Sargodha district, Pakistan” to  “Assessing the contribution of citrus orchards in climate change mitigation through carbon sequestration in Sargodha district, Pakistan”

Response; Thank you very much for suggesting a more appropriate title. The suggested changes have been incorporated.

Comment 2. Abstract: Authors should focus on fruit orchards/citrus orchards rather than discussing the agroforestry or intercropping. Please mention the name of six subdivisions of district in the abstract before results.

Response; Thank you very much for highlighting this point. Names of subdivisions have been incorporated.

Comment 3. Why more carbon stock were found in shahpur due to more tree density or any other reason?

Response; Thanks for pointing out this. Shahpur has more carbon due to greater tree basal diameter. The reason is also mentioned in the abstract section

Comment 4. Keywords: Authors have used same keywords as in the title. Please use different keywords than title.

Response; Thank you very much for suggesting keywords. The word used in the title has been removed from the keywords, and new keywords have also been incorporated. 

Comment 5. Introduction: This section is very brief and short.  Authors have given excellently global context and then discussed about fruit trees but more literature on the environmental services of fruit based agroforestry systems and/or citrus orchards should be cited. Fruit orchards not only provide good quality of fruit but also provide other benefits that any other tree can provide. Need to add two to three paragraphs on fruit trees/orchards and their role in carbon sequestration.

Response; Thank you very much for highlighting this important point. A new paragraph has been added in the introduction section and has been highlighted.

Comment 6. Why this area was selected, and what is the significance of citrus orchards of this area?

Response; Thank you very much for this valuable question. The significance of the area has been documented in the introduction section and also explained here. The land of this area consists of irrigated plains, and the area itself is the hub of citrus orchards in the country and plays an important role in the betterment of local dwellers in the form of income, food, and fruits. Of the total area under fruits, 29.55 percent is under citrus, and out of that, 60% citrus is present in the study area producing more than 75% of the citrus exports and providing labor days or full-time jobs for more than 75,000 people (about 57 million labor days in production and remaining in marketing sectors).

Comment 7. What is distance between the six sites?

Response; Thank you very much for your valuable question. The study was performed in a district (a hub of citrus orchards in the country) which comprised six subdivisions at the time of the study. The subdivisions/sites are adjacent to each other and have a different area under citrus orchards.

Comment 8. Why quadrate size was of 0.405 ha?. Please describe?

Response; Thank you very much for asking this. Basically, 0.405 ha is the agricultural land measuring unit in the country, which is equal to 1 acre (2.47 acre=1 ha). Citrus trees are planted in a hexagonal form on the whole acre, that’s why initially, the acre was randomly selected, and then a sub quadrat of 20*20 was laid for tree inventory and soil sampling keeping in view the literature.

Comment 9. Please discuss the cultivation practices, citrus tree age and the method that how orchard was selected? Please also give soil physic-chemical properties if measured

Response; Thank you very much for asking this valuable question. As the whole district, all sub-division has citrus orchards. In each subdivision, all the rural union councils were visited. From each rural union council, citrus orchards were randomly selected for sampling age ranging between 4 to 18 years (also mentioned in the methodology). Soil sampling was done to measure the soil carbon stock, not the physicochemical properties, as measuring physicochemical properties was not the objective.

Comment 10. Why numbers of plots were different in each site? Please discuss

Response; Thank you very much for asking this. As each subdivision has a different agricultural area and has different is under citrus orchards as well. Subdivisions with a greater area under citrus orchards have more plots to be measured for sampling.  

Comment 11. Please avoid words of citrus-based agroforestry system and intercropping and it is better to discuss citrus orchards. Please compare the findings with other findings for citrus and other fruit orchards.

Response; Thank you very much for suggesting the suitable word to be used. The suggested word and other findings have been incorporated in the discussion section.

Comment 12. References: Publication needs to be reformatted according to journal for text and citation/reference style.

Response; Thank you very much for highlighting this. The references have been formatted according to the journal format.

Reviewer 2 Report

Reviewer’s comments

This study investigated the above and below-ground biomass and soil carbon of a citrus-based intercropping system in six sites (subdivisions) of District Sargodha, South-east Pakistan. The results not only help us better understand the current carbon stock and CO₂ mitigation potential of an agroforestry system, but also enriches our knowledge on carbon storage potential of citrus-based agroforestry systems under a sub-humid climate. The findings are innovative to the reader, and the manuscript is organized in a good shape. I suggest the manuscript be accepted after minor revision

 

Abstract

1) The text gives reasonable research background and significance. The method is practical and data are sound. Results and conclusion are useful in deepening the understanding of the carbon storage potential of fruit-based agroforestry systems.

Line 26: in ‘The surface soil (0-15 cm) has greater bulk density’, I suggest the author using past tense. Change ‘has’ to ‘had’.

 

Introduction

The section gives a suitable literature review and adequate background of the research by listing recently published literature. From the introduction, the readers knew, although the carbon capturing prospective of agroforestry systems have been well studied by researchers around the globe, information about citrus-based agroforestry systems under local climatic conditions is limited, indicating the importance of this study. The objectives are clear and elaborate.

Line 35: Use ‘in the past few decades’.

Lines 61-62: Use scientific notation with one figure to the left of the decimal point. For example, change ‘total production of 239550 tons’ into 2.4 × 10⁵ t.

 

Material and methods

Line 107: Below-ground biomass was calculated by dividing the above-ground biomass by which coefficient? Please specify the detailed coefficient.

Line 113: Delete a space between ‘depth’ and ‘Overall’.

 

Results and discussion

Line 134: Use superscript for 14.55 Mg ha-1 to 21.43 Mg ha -1. The same below for R2=0.91. Please check it throughout the manuscript.

 

4. Conclusions

Line 164: Use subscript for CO2.

 

References 

References should be presented in correct format as MDPI requested, such as using Abbreviated Journal Name. Year should be used in bold type, and Volume in an italic font.

Comments for author File: Comments.pdf

Author Response

Referee 2 comments

Sr.No	Comments	RESPONSE
1	Line 26: in ‘The surface soil (0-15 cm) has greater bulk density’, I suggest the author using past tense. Change ‘has’ to ‘had’.	Thank you very much for suggesting to use the past tense. The suggested change has been made.
2	Line 35: Use ‘in the past few decades’.	Thank you very much for suggesting a suitable sentence. The suggested sentence has been incorporated.
3	Use scientific notation with one figure to the left of the decimal point. For example, change ‘total production of 239550 tons’ into 2.4 × 105 t.	Thanks for pointing out this. I have corrected the figure as suggested.
4	Line 107: Below-ground biomass was calculated by dividing the above-ground biomass by which coefficient? Please specify the detailed coefficient.	Thank you very much for highlighting this important point. Below ground biomass is generally considered 24% of above-ground biomass in citrus trees. The suggested changes have been incorporated into the text.
5	Delete a space between ‘depth’ and ‘Overall’.	Thank you very much for highlighting the mistake. The space between depth and overall has been deleted
6	Use superscript for 14.55 Mg ha-1 to 21.43 Mg ha -1. The same is below for R2=0.91. Please check it throughout the manuscript.	Thank you for mentioning these mistakes. The suggested changes have been made in the text
7	Line 164: Use subscript for CO2.	Thanks for pointing out this. The suggested change has been incorporated in the text.
8	References should be presented in correct format as MDPI requested, such as using Abbreviated Journal Name. Year should be used in bold type, and Volume in an italic font.	References have been corrected to MDPI format.

Author Response File: Author Response.pdf

Reviewer 3 Report

Good field work and a clear presentation of the results.

Author Response

Good fieldwork and a clear presentation of the results.

Thank you for your encouraging comments, we really appreciate your suggestions to the editor to accept our research work