Exploring Crop Production Strategies to Mitigate Greenhouse Gas Emissions Based on Scenario Analysis

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study examines mitigating greenhouse gas emissions through optimising agricultural production layouts in the three northeastern provinces of China. It aims to explore strategies to achieve carbon reduction in the agricultural sector while ensuring food security using scenario analysis. The structure is clear and well organized. The topic is suitable for the journal Land. However, there still are some comments to further improve the manuscript as follows.

1. The article contains some issues with imprecise word choices and grammatical inconsistencies, such as "GHG emissions" and "greenhouse gas emissions". Please standard the related terminologies.

2. Certain transitions between paragraphs lack fluidity, particularly in the “2. study area and data source” section. It is recommended that well-crafted transitional sentences be introduced to strengthen the logical progression between paragraphs and enhance the overall coherence and academic rigour of the manuscript.

3. Some sentence should be improved. For example, it’s better to adjust the sentence structure by moving "as major crop production bases" after the subject.

4. In the article, several titles use title case capitalization, such as “Study Area and Data Source,” while some others (e.g., “Study area”) do not follow this capitalization style.

5. The colour scheme of Figure 4 appears overly complex. The authors should adjust the colour scheme to highlight key content.

6. The formulas in the method section are described to some extent but lack detailed explanations of key parameters. Please add the related contents.

7. There is considerable redundancy in the manuscript, such as repeated descriptions of scenario analysis results across multiple sections.

Author Response

We first want to thank reviewer #1 for his/her careful reading of our manuscript. In total, the reviewer had 7 comments on our manuscript. We have responded and incorporated the revisions into our revised manuscript.

Comment 1:

The article contains some issues with imprecise word choices and grammatical inconsistencies, such as "GHG emissions" and "greenhouse gas emissions". Please standard the related terminologies.

Response:

Thanks for your comments. We have checked the entire manuscript and found that there are two ways of expressing “GHG emissions” and “greenhouse gas emissions” in the manuscript. We have modified all the related terminologies in the revised manuscript.

 

Comment 2:

(2) Certain transitions between paragraphs lack fluidity, particularly in the “2. study area and data source” section. It is recommended that well-crafted transitional sentences be introduced to strengthen the logical progression between paragraphs and enhance the overall coherence and academic rigour of the manuscript.

Response:

Thanks for your comments. We have carefully checked the sentence structure of the article and added conjunctions between sentences and transition phrases between paragraphs to improve the overall logic and readability. In particular, we have strengthened the transitions between paragraphs in the “2. study area and data source” section. The modified paragraphs are shown in the current manuscript.

 

Comment 3:

(3) Some sentence should be improved. For example, it’s better to adjust the sentence structure by moving "as major crop production bases" after the subject.

Response:

Thank you very much for your suggestion. We have already made changes to address the issues you have pointed out. In addition, we have also made modifications to other similar issues in the article.

Line 73-74, Page 2:

China is a major agricultural country and has a responsibility to ensure food security while reducing GHG emissions.

 

Comment 4:

(4)In the article, several titles use title case capitalization, such as “Study Area and Data Source,” while some others (e.g., “Study area”) do not follow this capitalization style.

Response:

Thank you very much for your suggestion. We have made revisions based on the issues you pointed out. We found that the main issue was the inconsistency in the title of Section 2 compared to other sections. This has now been corrected, and the formatting of the section titles throughout the manuscript has been unified.

 

Comment 5:

(5) The colour scheme of Figure 4 appears overly complex. The authors should adjust the colour scheme to highlight key content.

Response:

Thank you for your valuable feedback. We have revised Figure 4 to simplify the colour scheme and ensure that key content is more prominently highlighted. The updated version of Figure 4 is provided below. We hope this revision improves clarity and aligns with your suggestions.

Fig. 4.  Direct and indirect GHG emissions during 2011-2022.

 

Comment 6:

(6) The formulas in the method section are described to some extent but lack detailed explanations of key parameters. Please add the related contents.

Response:

Thanks for your comments. This paper has been supplemented with information on all the parameters that need to be added to the formulae and made into a table as shown below.

 

 

 

Appendix A Emission factors for GHG emissions

Agricultural activity			Value	Unit
Direct emissions	Crop Stover Burning	Yield Stover Ratio Rice	0.98	/
		Yield Stover Ratio Wheat	1.43	/
		Yield Stover Ratio Corn	1.66	/
		Yield Stover Ratio Soybean	1.40	/
		Yield Stover Ratio Tuber	0.70	/
		Heilongjiang burning ratio	0.21	/
		Jilin burning ratio	0.21	/
		Liaoning burning ratio	0.16	/
		Emission factor of Crop residue open burning	3.23 0.008	g CH4/kg g N2O/kg
	Rice cultivation	growth period	130	day
		Emission factor	2	mg CH4 /(m2 * h)
	Cropland emission	Emission factor	0.01	kg N2O-N/ kg N
Indirect emissions	Nitrogen fertiliser	Emission factor	1.53	kg CO2/kg
	Phosphate fertiliser	Emission factor	1.63	kg CO2/kg
	Potassic fertiliser	Emission factor	0.66	kg CO2/kg
	Pesticide	Emission factor	16.35	kg CO2/kg
	Electricity	Emission factor	0.85	kg CO2/KWh
	Machinery use	Emission factor	0.18	kg/kW
	Agricultural film	Emission factor	5.18	kg/kg

 

Comment 7:

(7) There is considerable redundancy in the manuscript, such as repeated descriptions of scenario analysis results across multiple sections.

Response:

Thank you for pointing out the issue of repeated descriptions in the manuscript, particularly in Section 4.3 "Results of Scenario Analysis." We have carefully reviewed the manuscript and streamlined the content to avoid repetition. Specifically, the statements in Section 4.3 have been condensed, and overlapping content introduced in Section 3.2 "Projections and Planning Optimization for 2030" and parts of the discussion section have been removed. The modified paragraphs are shown in the current manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This paper employs a macro-level analysis to assess the balance between food security and environmental protection through adjustments in agricultural production structures. Notably, the "Sustainable Optimization" scenario achieves significant GHG reductions by altering crop planting layouts without compromising crop yields. This methodological framework provides a novel theoretical basis for optimising agricultural production layouts, addressing the limitations of previous studies that primarily emphasised single mitigation measures. Despite the article’s many strengths, some revisions need to be considered before formal publication:

(1)      The introduction lacks depth. A more detailed analysis of the region's unique role in national agriculture and environmental contexts is recommended. For example, emphasising the significance of black soil resources and the region's contribution to major crop production at the national level could better justify the selection of the study area and enhance the robustness of the research rationale.

(2)      As for the study area section, line 128-150 should be move to the literature review, not the introduction of the study area. Please considered and revise it.

(3)      The formulas presented in the methodology section are partially described but require further parameterisation to improve clarity and applicability. all parameters should be illustrated clearly in the manuscript.

(4)      Some figures can be further improved. There are two repeating figure South China Sea in Figure 1.

(5)      The connection between the figures and the related results should be clearly articulated to emphasise the role of the figures in supporting the narrative of the article.

(6)      In the results section, the language can be further improved, such as “If broken down into individual cities in the study area, the GHG emission……” in line 313-316. Please check the whole manuscript. Moreover, the manuscript contains several grammatical errors that should be addressed to ensure clarity and professionalism. The authors should carefully proofread the manuscript, focusing on correcting grammatical issues to enhance the overall quality.

Author Response

We first want to thank reviewer #2 for his/her careful reading of our manuscript. In total, the reviewer had 6 comments on our manuscript. We have responded and incorporated the revisions into our revised manuscript.

Comment 1:

(1) The introduction lacks depth. A more detailed analysis of the region's unique role in national agriculture and environmental contexts is recommended. For example, emphasising the significance of black soil resources and the region's contribution to major crop production at the national level could better justify the selection of the study area and enhance the robustness of the research rationale.

Response:

Thanks for your comments. Thank you for your feedback. We fully agree that the introduction lacked depth in analysing the regional agricultural and environmental context. As a national granary and a critical area for agricultural emission reduction, the three northeastern provinces of China hold significant importance. The original manuscript touched upon the unique characteristics and global significance of black soil resources, as well as some descriptions of the specific features of the research region.

Building on this foundation, we have further refined the discussion. We emphasized that black soil is a globally rare and highly fertile soil type. Additionally, by integrating the climatic and geographical characteristics of the northeastern provinces, we further analysed the impacts of high-intensity agricultural practices on energy inputs, fertilizer use, and greenhouse gas emissions.

Line 85-102, Page 2-3:

In the global context of climate change mitigation, the sustainability of agriculture in the three northeastern provinces, as a national “granary”, is closely linked to the health of the regional ecological environment. The black soil of Northeast China is rich in organic carbon reserves, a type of highly fertile soil that is rare worldwide and ideal for agricultural use [19]. Although the relatively limited area covered by black soil globally, it accounts for a substantial portion of global crop production. Statistics show that black soil regions produce more than 50% of the world’s sunflowers and millet, 30% of wheat, 26% of soybeans, and 16% of corn [20]. Therefore, studying the relationship between agricultural distribution and GHG emissions in Northeast China and exploring sustainable agricultural production models is of great significance.

The climatic and geographical characteristics of the three northeastern provinces also bring dual pressures on agricultural production and environmental protection. Agriculture in the northeast region is characterized by high intensification, which leads to the centralization of energy input, fertilizer use and GHG emissions [21]. With climate change, the northward movement of agricultural centres has also increased the pressure on agricultural production in the northeast [22]. Against the background of the national emission reduction strategy, the three northeastern provinces are not only a core area of food security, but also an important battleground for agricultural emission reduction.

 

Comment 2:

(2) As for the study area section, line 128-150 should be move to the literature review, not the introduction of the study area. Please considered and revise it.

Response:

Thanks for your comments. This section has been incorporated into the literature review part of the introduction.

Line 103-123, Page 3:

To address these environmental challenges, policies that support low-carbon agriculture, including subsidies for black soil conservation and the promotion of low-carbon technologies, have encouraged sustainable practices like conservation tillage and precision fertilisation [23-25]. Moreover, studies confirm that optimising nitrogen management, integrating straw incorporation, and adopting precision agriculture can significantly reduce emissions and enhance resource efficiency.

Based on these advancements, researchers have proposed various low-carbon agricultural management practices tailored to the specific conditions of Northeast China. For instance, Chen, et al. [26] conducted a life-cycle assessment and identified nitrogen fertiliser application as a key factor influencing GHG emissions from major crops. In a similar vein, Guo et al. [11] demonstrated that reducing the planting area of high-carbon-emission crops and optimising crop structures significantly support the development of low-carbon agriculture. Additionally, Wang et al. [25] evaluated the balance between crop production potential and GHG reduction through scenario analysis, providing scientific guidance for policy formulation. These studies collectively highlight the effectiveness of practices such as optimised nitrogen management, straw incorporation, conservation tillage, and precision agriculture in reducing emissions and improving resource use efficiency [27]. In addition, remote sensing monitoring and life cycle assessment techniques in recent years have provided important support for agricultural production, especially for quantifying agricultural GHG emissions from crop cultivation and productions [28].

 

Comment 3:

(3) The formulas presented in the methodology section are partially described but require further parameterisation to improve clarity and applicability. all parameters should be illustrated clearly in the manuscript.

Response:

Thanks for your comments. This paper has been supplemented with information on all the parameters that need to be added to the formulae and made into a table as shown below.

 

 

 

Appendix A Emission factors for GHG emissions

Agricultural activity			Value	Unit
Direct emissions	Crop Stover Burning	Yield Stover Ratio Rice	0.98	/
		Yield Stover Ratio Wheat	1.43	/
		Yield Stover Ratio Corn	1.66	/
		Yield Stover Ratio Soybean	1.40	/
		Yield Stover Ratio Tuber	0.70	/
		Heilongjiang burning ratio	0.21	/
		Jilin burning ratio	0.21	/
		Liaoning burning ratio	0.16	/
		Emission factor of Crop residue open burning	3.23 0.008	g CH4/kg g N2O/kg
	Rice cultivation	growth period	130	day
		Emission factor	2	mg CH4 /(m2 * h)
	Cropland emission	Emission factor	0.01	kg N2O-N/ kg N
Indirect emissions	Nitrogen fertiliser	Emission factor	1.53	kg CO2/kg
	Phosphate fertiliser	Emission factor	1.63	kg CO2/kg
	Potassic fertiliser	Emission factor	0.66	kg CO2/kg
	Pesticide	Emission factor	16.35	kg CO2/kg
	Electricity	Emission factor	0.85	kg CO2/KWh
	Machinery use	Emission factor	0.18	kg/kW
	Agricultural film	Emission factor	5.18	kg/kg

 

Comment 4:

(4) Some figures can be further improved. There are two repeating figure South China Sea in Figure 1.

Response:

Thanks for your comments. We have revised Figure 1 by removing the redundant section of the South China Sea. The current version of the Figure 1 is as follows.

Figure 1:

Figure 1. Location of three northeastern provinces in Northeast China

 

Comment 5:

(5) The connection between the figures and the related results should be clearly articulated to emphasise the role of the figures in supporting the narrative of the article.

Response:

Thanks for your comments. It is no doubt that your comments are very important for the article. We have made the images and tables in the articles more closely related to the content of the article. Instead of just adding a picture and table number after a point. This strengthens the interpretation of the pictures and tables and thus the overall article. For example:

Line333-334，355, 375-377, Page 11-12:

Over the past decade, Figure 4 illustrates that agricultural production in the three northeastern provinces has undergone exciting changes in GHG emissions.

Figure 5 shows that, from 2011 to 2016, the intensity of GHG emissions in crop production areas increased in three cities: …

However, in the comparison of the BU scenario with other scenarios in Table 3 and Figure 7, it can be seen that, despite this increase, GHG emissions are expected to decline only moderately, by 8.8%, reaching 25.26 million tons.

…

 

Comment 6:

(6) In the results section, the language can be further improved, such as “If broken down into individual cities in the study area, the GHG emission……” in line 313-316. Please check the whole manuscript. Moreover, the manuscript contains several grammatical errors that should be addressed to ensure clarity and professionalism. The authors should carefully proofread the manuscript, focusing on correcting grammatical issues to enhance the overall quality.

Response:

Thanks for your comments. We have noted the grammatical issues here. Thank you very much for your careful reading and comments. The grammatical problem has been corrected. We have also checked and corrected any other language issues that may be present in the article.

Line 344-348, Page 11:

The GHG emission levels of each city have declined, with the most significant decrease observed in Heilongjiang Province. Along with the changing trends in crop production, the calculation results show that an increase in grain production does not necessarily imply an increase in GHG emissions.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

This paper is interesting and try to address an important environmental problem in the context of agriclture and GHG emmissions. However there are some issues which needs to be addressed before the paper is accepted for publicaiton. Please find my comments below. 

1. The introduction section is written well but some important details of crops in missing. You can add some recent literature there. Some suggestions are here https://www.mdpi.com/2072-4292/14/12/2843

2. Please put information in Section 2.2 in a table to have a better read. 

3. Please provide more information on how the scenarios were devised in Table 1

4. Draw a proper methodology diagram to show the step by step process of the study to show an overall workflow. 

5. The results and other sections are written well. \

However, existing research has rarely addressed the

14
dynamic simulation and scenario-based analysis about optimised agricultural layouts and their 15
impact on GHG emission

Author Response

We first want to thank reviewer #3 for his/her careful reading of our manuscript. In total, the reviewer had 5 comments on our manuscript. We have responded and incorporated the revisions into our revised manuscript.

Comment 1:

(1) The introduction section is written well but some important details of crops in missing. You can add some recent literature there. Some suggestions are here https://www.mdpi.com/2072-4292/14/12/2843

Response:

Thanks for your comments. Your suggestions were very useful. We have read the articles you recommended and enriched our introduction section. The detailed revisions has been include in the current manuscript.

Line 120-123, Page 3:

In addition, remote sensing monitoring and life cycle assessment techniques in recent years have provided important support for agricultural yield, especially for quantifying agricultural GHG emissions from crop cultivation and productions [28].

 

28. Khan, S.N.; Li, D.; Maimaitijiang, M. A geographically weighted random forest approach to predict corn yield in the US corn belt. Remote Sensing 2022, 14, 2843.

Comment 2:

(2) Please put information in Section 2.2 in a table to have a better read.

Response:

Thanks for your comments. We have organized the main points from 2.2 into a table for inclusion in the article. We strongly agree that this enhances the readability of the article.

Table 1 Data Source

Data Type	Description	Data Source
Crop Production and Agricultural Input Data	Sown area and total production (rice, soybeans, wheat, corn, and tubers) Nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, pesticides, agricultural film, and use of agricultural machinery	China Agricultural Yearbook (https://data.cnki.net/yearBook); Heilongjiang Provincial Statistical Yearbook (https://tjj.hlj.gov.cn/tjj/); Jilin Provincial Statistical Yearbook (http://tjj.jl.gov.cn/tjsj/tjnj/); Liaoning Provincial Statistical Yearbook (https://tjj.ln.gov.cn/tjj/tjxx/xxcx/tjnj/)
National Statistical Data	National agricultural-related statistics	China Statistical Yearbook (https://www.stats.gov.cn/sj/ndsj/)
Administrative Boundary Data	The administrative boundary data for China	Resource and Environmental Sciences Data Platform (https://www.resdc.cn/)

 

Comment 3:

(3) Please provide more information on how the scenarios were devised in Table 1.

Response:

Thanks for your comments. The scenario categorization in the article has been described in greater detail. The statement has been refined to make the categorization approach and the underlying principles more explicit.

Line 265-286, Page 7:

Three scenarios, as shown in Table 2, — Business as Usual (BU), Sustainable Optimisation (SO), and Ecological Priority (EP)—explored the balance between food security and the ecological impact of an optimal planting structure and layout. The BU scenario assumes maintaining the planting structure of 2022 to verify GHG emissions and the stability of food production under unchanged conditions. The basis for this scenario lies in the region's historical cropping patterns and current food production policy requirements, while ensuring that the total production does not fall below the 2022 level. The SO scenario optimizes the crop layout by limiting the excessive expansion of dominant crops while ensuring that the production levels of all crop types are not lower than those in 2022. The design logic of this scenario is based on balancing food security and ecological protection, allowing for moderate adjustments to the cropping structure to improve diversity and resource use efficiency. The EP scenario optimizes the crop production structure to ensure that by 2030, the production of all crops is at least 85% of the 2022 level, and the total production does not fall below the 2022 level. To ensure the scientific validity and practical feasibility of the simulation results, the following constraints were established in this study: (1) The Sown area in each city will not increase. (2) The planting area of non-dominant crops should not decrease significantly. (3) The total crop yield within the study area must not fall below the production level of 2022. (4) By 2030, the yield of each type of crop within the study area should not experience a significant decrease. The reason for setting these constraints is to adhere to the historical cropping structure of the region and be as closely aligned as possible with the traditional farming practices of local farmers. This approach is also essential for ensuring the feasibility of the study results.

 

Comment 4:

(4) Draw a proper methodology diagram to show the step by step process of the study to show an overall workflow.

Response:

Thank you for your valuable suggestion. We have created a Graphical Abstract to illustrate the main research content and research objectives of this study.

 

Comment 5:

(5) The results and other sections are written well.

Response:

Thank you for your positive feedback on the results and other sections of the manuscript. We are glad that these parts were well-received. Your comments encourage us to maintain and further improve the quality of our work.

 

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for considering my comments. In my opinion the manuscript is not better and can be published in Land