Understanding Arable Land Change Patterns and Driving Forces in Major Grain-Producing Areas: A Case Study of Sichuan Province Using the PLUS Model
Round 1
Reviewer 1 Report
The theme is of enormous interest and importance because it highlights the need to find the right balance between urban expansion, food production and, more generally, the production of ecosystem services to ensure the overall sustainability of the territory.
The authors focus on the identification of driving forces that have led to a progressive loss of arable land in a strategic area for cereal production in China. This analysis is carried out using a spatial simulation model of spatial evolution of land use (PLUS). PLUS is a land use change simulation model consisting of the Soil Expansion Strategy Analysis Module (LEAS) and a multi-type of random cell automata (CARS) model [36]. LEAS extracts the part related to the expansion of changes in land use between two adjacent periods and uses the random algorithm to analyse the contribution of different determinants to the expansion of various land uses.
The model is very interesting but, in my opinion, some weaknesses emerge in the approach both research and on the methodological level.
In the design of the research are mentioned some programs / policies that have been implemented during these years (2000-2020) (eg the need to increase forestation, the need to present arable land, etc.) and that, as explained in the conclusions, have had a positive impact on the evolution of arable land. It would be appropriate to devote some space to explaining the contents of such programmes/policies and, above all, to explain what was the role of the effects of the driving forces: for example, how were they taken into account to develop e7 programmes or intervention policies?
Another aspect concerns the spatial planning process. For the reader it would be interesting to understand how spatial planning takes place in China, what are the planning tools, what kind of operational flexibility these tools have, etc. because, for example, at least in Europe, the transformations of agricultural soil (consumption and / or abandonment) are mainly influenced by territorial development policies, agricultural policies, etc.
From a methodological point of view, how were the driving forces chosen? Are they the result of an in-depth analysis of studies carried out in the past or have they been identified on the basis of random or empirical selection? Or based on data availability? Or something else? Because, as I will have the opportunity to say later, I cannot understand how some of these driving forces can act on the modification of arable land.
Specifically:
1. In the abstract and also afterwards we talk about “alternating leadership between urbanization of land and population urbanization”. Is it possible to clarify better what is meant by this concept?
· Matthew effect ... What exactly does it refer to?
· Rows 65-68 - Clarify the concept better: If we want to analyse the spread of the decrease of cultivated land pixels, we can achieve the purpose of directly analysing the driving factors of cultivated land decrease by extracting the spatial distribution of cultivated land decrease pixels between each year in the region.
· Rows 81-85 - this study will provide suggestions for exploring the path of ecological protection and coordinated development between urban expansion and grain production in the main grain-producing areas, and provide theoretical basis and decision-making reference for the rational planning, utilization, and construction of grain production bases similar to the "Tianfu Granary". I may have misinterpreted, but it doesn't seem to me that the study contains any indications in this sense but only an acknowledgment that Chinese policies have gone in this direction well before ...
· Table 1 – the acronym GDP is introduced. I think it is the Gross Domestic Product, but it is better to specify. Among other things, I would also like to explain how it was possible to reduce this value to a 1 km grid.
· Table 5 – I suggest to insert the absolute starting data (Arable Land in each province) and, moreover, the percentage share of arable land for each province ...
· The terms Arable land and farmland are often used. What is the difference between the two terms? To be clarified because it seems to me that they have the same meaning but, at least in the European context, they are two different concepts: arable land is land intended for cultivation; Farmland is land managed by farms and may also include other land uses (forest, grazing, etc.).
· Fig. 5 – You cannot appreciate the changes in the maps and, above all, you cannot read the legend and the texts in the maps. I would also recommend reporting in the maps the characteristics of land use (eg where is the urbanized, where the forests? etc.) and also the orographic characteristics ... Because otherwise it is difficult to understand what kind of territory we are facing.
· Rows 311 – 319 and fig- 6: it is certainly interesting the method of analysis of the model in which the contributions (positive and negative) of the factors are represented using a heatmap, where red represents a positive impact and blue represents a negative impact (Figure 6). At the same time, however, I have doubts about the choice of certain factors and the role they play in determining changes in arable land use. How is it possible that average temperature and precipitation (in a very limited period such as the one examined) can play a role in influencing land use changes?
· Rows 335-339 – How is it possible, for example, that 1) the driving factors influencing the conversion of farmland into forest land are mainly altitude, temperature, GDP and population? Why? Have more in-depth analyses been done to explain why?
· Rows 342-345 – How is it possible that: 2) The driving factors affecting the conversion of cultivated land to grassland are mainly precipitation, population, and GDP distribution. Why? Have any more in-depth analyses been carried out?
· Rows 373-376: 1）From 2000 to 2020, the amount of cultivated land in Sichuan Province decreased by 3415.79 km². Although the situation of cultivated land reduction still persists, the implementation of cultivated land protection measures has led to an improvement in the situation, and the amount of cultivated land reduction has gradually decreased. What exactly are you referring to? What measures were envisaged?
· Rows 383-389 - It seems to me that the most significant data is that of the abandonment of cultivation towards forests and pastures rather than land consumption ... What is the explanation of this phenomenon in a context where the production of food (cereals) is strategic for the security of the country?
· Rows 390-395 – I ask you to explain this point better because it is not clear to me.
· Rows 396-400 – I have expressed my concerns earlier about the role of these factors in influencing arable land reduction... I ask you to give a reason for the phenomenon.
· Rows 401-404 - Explain these two concepts better: what does land urbanization mean is clear, but what is meant by population urbanization? Are you referring to the phenomena of exodus from the countryside / rural territories to the cities?
· Row 405: Currently, Sichuan Province is in a stage where population lags behind urban development. I ask you to explain this sentence better.
· Rows 465-470 - In the future, it is necessary to strictly follow the requirements of national land spatial planning, implement urban development boundaries, strictly observe ecological and farmland protection red lines, and avoid ecological protection areas and farmland falling into the dilemma of being occupied disorderly and without restraint in the competition of "dual suitability" with urban development.
· Rows 472-474 - I ask you to explain this concept better: high-low" distribution of the impact of population on the occupation of farmland by construction land.
Author Response
Dear reviewer,
First of all, I would like to express my gratitude for your valuable comments and suggested revisions to this study. After carefully reading and considering the issues you raised, I have made modifications to address the problems identified in the manuscript. I have also attempted to provide explanations for the questions that seemed unclear to you. I hope these clarifications have addressed your concerns. If there are any areas where further improvements are needed, I would greatly appreciate your valuable suggestions.
1.Regarding the relevant issues of land urbanization, population urbanization, and the impact of population on the conversion of farmland to construction land, please find the following explanations:
（1）Concerning the interpretation of "population urbanization," it is important to note that China differs from other countries in terms of its unique household registration system, land system, fiscal system, and other regulatory measures. Many Chinese scholars have found an imbalance between urban construction and urban population growth in certain regions of China. Therefore, in the context of urbanization research in China, urbanization is commonly divided into two parts: land urbanization (urban construction) and population urbanization (urban population growth). In this study, "population urbanization" refers specifically to the increase in population on newly constructed urban land, including the phenomenon you mentioned of population migration from rural areas to urban areas.
（2）In the paper, based on the analysis results of the PLUS model (Figure 6), the impact of population (pop) on the conversion of farmland to construction land (CtoB) is as follows for each period: high value of 0.196 for 2000-2005, low value of 0.053 for 2005-2010, high value of 0.135 for 2010-2015, and low value of 0.078 for 2015-2020. This demonstrates a pattern of alternating high and low values. The original expression in the text was not easily understood, and I have replaced it accordingly.
(3) From the alternating pattern of high and low values in the impact of population (pop) on the conversion of farmland to construction land (CtoB), we can deduce that population growth facilitated the conversion of farmland to construction land during the period of 2000-2005. However, the promoting effect weakened during 2005-2010. Therefore, the impact of population (pop) on the conversion of farmland to construction land (CtoB) can be characterized as a sequence of "promotion-weakening of the promoting effect-promotion-weakening of the promoting effect." Based on the actual situation, it can be inferred that the rapid population growth in Sichuan Province during 2000-2005 facilitated the expansion of urban construction land. This phase is referred to as the "stage of spatial scarcity of urban construction land" in this study, indicating a period when population urbanization outpaced land urbanization. However, from 2005 to 2010, the extensive expansion of construction land resulting from the previous phase of population growth led to land urbanization surpassing population urbanization. As a result, the promoting effect of population (pop) on the conversion of farmland to construction land (CtoB) weakened. This stage is explained as the "stage of spatial surplus of urban construction land." Similarly, we can conclude that 2010-2015 was a "stage of spatial scarcity of urban construction land" and 2015-2020 was a "stage of spatial surplus of urban construction land," indicating a phase when population urbanization lagged behind land urbanization. I have replaced some expressions in the text that were not easily understood. Thank you for your question, and I hope the above explanation addresses your concerns.
2.Explanation of the concept of the "Matthew Effect" mentioned in the abstract section:
In this study, the Matthew Effect refers to the phenomenon where higher levels of urban development result in a stronger encroachment on surrounding farmland. The basis for this conclusion is mentioned in the article, based on the analysis results of the PLUS model (Figure 6). The impact of land use intensity (LUI) on the conversion of farmland to construction land (CtoB) steadily increases in stages (0.113, 0.138, 0.201, 0.256 for the four stages from 2000 to 2020). Why does the impact of land use intensity (LUI) on the conversion of farmland to construction land (CtoB) continue to increase? We can deduce that the higher the level of urban development, the stronger the ability to encroach on surrounding farmland. In other words, urban construction land, compared to farmland, is more prone to expansion, and the expansion of urban construction land further promotes the occurrence of the "expansion" phenomenon, thus leading to the Matthew Effect.
3.Optimization of the expression of concepts in lines 65-68 of the original manuscript:
Since the PLUS model operates based on the principle of patch expansion, to analyze the driving factors of farmland reduction in this study, we can extract the regions where farmland has decreased based on land use data and analyze the expansion changes of this phenomenon of "farmland reduction." This approach aims to analyze the driving factors of farmland reduction. The modified expression for the original text, which you found difficult to understand, is: "To investigate the driving factors of farmland reduction, we can use land use data to extract the distribution data of regions where farmland has decreased. By analyzing the expansion changes of the phenomenon of 'farmland reduction' within the PLUS model, we can achieve the goal of analyzing the driving factors of farmland reduction."
4.Explanation of the significance of the research in lines 81-85 of the original manuscript:
The Chinese government has implemented numerous measures for farmland protection over the years. The mentioned finding in the conclusion of this study, where the rate of farmland reduction has decreased since 2010, confirms the effectiveness of these farmland protection measures. Currently, the local government of Sichuan Province has proposed the construction of a "granary of abundance" in the province. The summary of farmland changes in Sichuan Province over the past 20 years, presented in this study, also serves as a policy reference for the future construction of the " Tianfu Granary" in Sichuan Province.
5.Regarding the detailed explanation of the GDP concept and the supplementary method for creating the GDP kilometer grid in the text:
I have made the necessary revisions to supplement the GDP data in the text. The GDP data used in the study is sourced from the Institute of Geography, Chinese Academy of Sciences. The GDP kilometer grid data is generated through spatial interpolation, considering the spatial interaction patterns between land use types, nighttime light intensity, population density data, and GDP, all of which are closely related to human activities. According to the author's description, in the spatialization process, the distribution weights of land use types, nighttime light intensity, and population density for GDP are calculated. These weights are then standardized based on the influence of the three factors. The total weights of each county-level administrative unit are calculated, and subsequently, the unit weight proportion of GDP for each county-level administrative unit is calculated. Using raster spatial calculations, the population is spatialized by combining the population count on unit-weighted grids with the distribution map of total weights. The calculation formula is as follows:
GDPij = GDP × (Qij/Q)
Where GDPij represents the rasterized value of the grid unit after spatialization; GDP is the statistical GDP value of the county-level administrative unit where the grid unit is located; Qij is the total weight of land use types, nighttime light intensity, and population density for the grid unit; Q is the total weight of land use types, nighttime light intensity, and population density for the county-level administrative unit where the grid unit is located.
6.Modification of figures and tables:
As per your suggestion, I have made modifications to Table 5 and Figure 5.
7.Regarding the terms "Arable land" and "Farmland":
As you mentioned, the meanings of these two terms should be consistent in the text. Based on your revision suggestion, we have replaced "farmland" with "arable land" throughout the article.
8.Regarding the role of natural environmental factors such as elevation, average temperature, and precipitation in influencing land use change:
Due to their significance as environmental conditions impacting plant growth, including forests and crops, elevation, average temperature, and precipitation primarily influence land use change in three land types: forests, croplands, and grasslands. This study examines the factors affecting the transformation of croplands into other land types due to average temperature and precipitation. As mentioned in the article, the following relationships have been observed during the study period:1）In the eastern plains with higher temperatures, croplands are more likely to convert into forests compared to the northwestern regions.2）Within the same plains region, areas with higher precipitation are more prone to cropland-to-forest conversion. Similarly, in mountainous regions, croplands are more likely to transform into forests in areas with lower precipitation.3）Regions with lower precipitation are more susceptible to cropland conversion into grasslands or fallow lands.
Overall, average temperature and precipitation primarily determine the agricultural conditions in a region. Forests and grasslands have higher tolerance thresholds for average temperature and precipitation compared to croplands. Consequently, excessively high or low temperatures and precipitation can lead to the conversion of croplands into other land types. Regarding point 1), the explanation is as follows: The northwestern mountainous regions, with consistently low temperatures, are unsuitable for cultivation, resulting in fewer croplands compared to the eastern regions with milder temperatures, where cropland-to-forest conversion is more common. For point 2), the explanation is: Excessive precipitation in plains regions favors tree growth rather than crop cultivation. In mountainous areas, where precipitation is lower than in plains regions, croplands are mainly distributed in valleys with relatively better planting conditions. Therefore, areas with less precipitation lead to the abandonment of croplands, gradually transforming them into forests similar to the surrounding areas. The explanation for point 3) is similar to the previous point. In areas with lower precipitation, croplands become uncultivable, gradually transforming into grasslands similar to the surrounding areas, and eventually even into fallow lands.
9.Regarding the explanation of the impact of social and economic factors, GDP and population, on land use change:
The previous analysis focused on the influence of natural environmental factors such as elevation and temperature on the conversion of croplands to forests, as well as the effect of precipitation on cropland conversion to grasslands. In the realm of social and economic factors, GDP and population exhibit a high degree of spatial overlap. Due to the challenges associated with development in the western mountainous regions, urbanization in Sichuan Province is concentrated in the eastern plains. Consequently, the eastern regions have higher GDP and population, and the agricultural conditions are conducive to cultivation. In contrast, the less economically developed and sparsely populated western mountainous regions face unfavorable cultivation conditions, increasing the likelihood of cropland abandonment and subsequent degradation into forests and grasslands.
10.Regarding the explanation of the questions raised in lines 373-376 of the original manuscript:
The conclusion was drawn based on the calculated data of cropland area from Table 4 and Table 5. Although cropland continues to decrease, the rate of decline has been decreasing since 2010. The Chinese government has been increasingly emphasizing the importance of cropland protection. In this study, cropland protection measures mainly refer to: (1) the "18-billion-mu Cropland Protection Red Line" proposed by the Chinese government in 2013, which sets a baseline for the total amount of cropland in the country and implements cropland protection targets at the provincial level; (2) since 2014, the Chinese government has designated croplands adjacent to cities and highways as "permanent basic farmland" to prevent destruction, imposing strict penalties for activities that encroach upon or damage this permanent basic farmland; (3) based on land-use planning, the Chinese government has implemented strict control over land use, designated urban development redlines, cropland protection redlines, and ecological protection redlines, gradually curbing the occupation and destruction of cropland.
11.Regarding the explanation of the questions raised in lines 383-389 of the original manuscript:
Since 2000, the Chinese government has implemented the "Grain for Green" policy nationwide to protect the ecological environment and prevent land desertification and soil erosion. However, under the context of cropland protection, the "Grain for Green" policy undoubtedly conflicts with cropland preservation. This is one of the key points that this study attempts to summarize and analyze. As mentioned in the discussion section, in Sichuan Province, there is a relatively balanced increase and decrease in both cropland and forests. In other words, Sichuan Province has not significantly converted cropland into forests in terms of quantity. Instead, it has achieved a harmonious balance between cropland expansion in suitable areas and forest expansion in areas unsuitable for cultivation but suitable for afforestation, thereby achieving a coordinated equilibrium between ecology and agricultural production.
12.Regarding the explanation of the questions raised in lines 465-470 of the original manuscript regarding changes in cropland landscape patterns:
This conclusion is based on the analysis of dynamic changes in cropland landscape patterns (Figure 4). The analysis indicates that from 2000 to 2010, there was a decrease in the quantity of cropland but an increase in its aggregation in Sichuan Province. This suggests that small patches of cropland were occupied during this period. From 2010 to 2020, there was an increase in the quantity of cropland along with an increase in fragmentation. This implies that contiguous cropland experienced fragmentation. The rise in the Landscape Shape Index (LSI) indicates irregular shape changes in croplands, while the Clumpy Index.
Thank you again for your valuable suggestions for changes and the time you spent.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Analysis of arable land change characteristics and driving
forces in major grain producing areas based on PLUS model- Sichuan Province as an example
The purpose of this study is to examine the characteristics and factors influencing changes in cropland in Sichuan Province. The researchers aim to provide an overview of the current status of cropland coordination, ecosystem protection, and urban expansion in the region, as well as offer suggestions for the sustainable use and conservation of arable land resources. The study utilizes ArcGIS spatial analysis and the PLUS model as research methods.
The findings of the study are as follows:
1. The cropland area in Sichuan Province has been continuously decreasing over the past 21 years. However, the implementation of arable land protection policies has effectively mitigated this decline.
2. Apart from Chengdu, the reduction in arable land in each city in Sichuan Province has gradually balanced out, ensuring the development of both major and lagging cities.
3. The concept of "dual suitability" highlights the conflict between urban development and agricultural land use. Additionally, the expansion of construction lands driven by urban development has further disadvantaged croplands in competition for land resources.
4. The urban development process in Sichuan Province exhibits a pattern of alternating leadership between land urbanization and population urbanization. This implies that as urban development occupies cropland, it affects the balance between urbanization and agricultural land.
However, there are certain modification which are to be done in order improve the clarity, organization, and precision of the manuscript, making it more informative and accessible to readers.
Reviewer’s Comments
· Change the title of the manuscript to “Understanding Arable Land Change Patterns and Driving Forces in Major Grain Producing Areas: A Case Study of Sichuan Province using the PLUS Model"
· Introduction:
The introduction provides a good overview of the importance of food security, the challenges posed by decreasing arable land resources in China, and the significance of studying cultivated land changes in Sichuan Province. However, there are a few areas where improvements can be made to enhance the clarity and organization of the introduction:
1. The introduction lacks a clear and concise statement of the research objectives or research questions that this study aims to address. Including a specific research objective or a set of research questions will provide a clear focus for the study.
2. Some of the statements in the introduction could benefit from additional references or citations to support the claims made. For example, the statement that "China's arable land resources have been decreasing continuously" (referring to [3]) could be strengthened by citing specific studies or reports that demonstrate this trend.
3. The introduction mentions the exploration of spatiotemporal evolution rules and influencing factors of cultivated land as a way to improve regional agricultural development. However, it would be helpful to provide a brief explanation or context regarding why understanding these factors is important and how it relates to the study's objectives.
4. The comparison between the geographic detector model and the PLUS model could be expanded upon to highlight the advantages or unique features of the PLUS model that make it suitable for the study's objectives. Additionally, providing a brief overview of the improved PLUS model used in this study would help readers understand its relevance and contribution to the research.
5. The introduction poses several research questions related to cultivated land changes, coordinated development, and the conflict between urban expansion and cultivated land. While these questions are valuable, it would be helpful to prioritize and clearly state the main research questions that will be addressed in this study.
6. The introduction briefly mentions the implications of the study for ecological protection and coordinated development but could expand on these points. Providing specific examples or potential outcomes of the study's findings will highlight the practical significance of the research.
· Results and Analysis
1. Provide more specific details about the methods used for data extraction and analysis. Specify the ArcGIS tools and techniques employed to extract the distribution of cultivated land and count the number of cultivated land pixels. Clarify how the cultivated land area was calculated for each year.
2. Include units of measurement consistently throughout the Results section. Make sure to specify the unit of measurement for cultivated land area (e.g., km2) consistently when presenting the results.
3. Provide statistical significance or confidence intervals for the reported changes in cultivated land area. If available, include statistical tests or measures of uncertainty to support the statements made about the decrease in cultivated land area over time.
4. Clarify the meaning of terms and abbreviations used. For example, explain the abbreviation "km2" as "square kilometers" upon first use and define any specialized terms, such as "dynamic changes" or "rate of cultivated land reduction," to ensure readers can understand the context.
5. Consider providing more comprehensive conclusions and summarizing the main findings of the study. Emphasize the key insights and implications of the results for understanding the spatiotemporal changes in cultivated land in Sichuan Province.
6. Ensure consistent formatting and citation style throughout the section. Check the numbering and order of tables, figures, and citations to ensure they align correctly with the text and are properly referenced.
· Conclusion and discussion.
1. Why is conclusion part of manuscript before discussion? The discussion section is generally placed before the conclusion section in a scientific manuscript for several reasons: Interpretation of results, better addressing limitations and alternative explanations, and for logical flow.
2. Page 15, L 410-413. Write the text as “The management of cultivated land has shown improvement, and to achieve the development goal of maintaining a relatively stable amount of cultivated land as outlined in the 'Sichuan Province Land Spatial Planning (2020-2035)', it is recommended to maintain the strictest land protection system.”
3. Page 15, L 419-420. Write the text as “Over the past decade, apart from Chengdu, the occupation of cultivated land in other cities has shown a tendency towards balance.”
4. Page 15, L 428-429. Write the text as “This can be attributed to the implementation of the 'Grain for Green' project, which has been vigorously promoted in Sichuan Province since 1999.”
· References are not properly written. Follow a consistent citation style and format.
Comments for author File: Comments.pdf
English writing needs to be improved.
Author Response
Dear reviewer,
First of all, I would like to express my gratitude for your valuable comments and suggested revisions to this study. After carefully reading and considering the issues you raised, I have made modifications to address the problems identified in the manuscript. I have also attempted to provide explanations for the questions that seemed unclear to you. I hope these clarifications have addressed your concerns. If there are any areas where further improvements are needed, I would greatly appreciate your valuable suggestions.
1.Modification regarding the research topic:
In accordance with your suggestions, we have made revisions to the title of the paper.
2.Modification regarding the introduction:
Your suggestions are of utmost importance. Taking into consideration your proposed modifications, we have revised the expression of the research objective in the introduction. We have provided citation references for statements such as "reduction in cultivated land." The overview of the enhanced PLUS model has been refined by incorporating additional content to elucidate the rationale behind its selection in the study. Furthermore, as per your request, we have supplemented the significance of analyzing the spatiotemporal patterns and influencing factors of cultivated land and the practical implications of the research.
3.Issue of unified measurement units:
We have achieved uniformity in the measurement units of area throughout the manuscript, employing km² as the standardized unit. An elucidation has been provided at the initial mention of "km²." Additionally, we have provided detailed explanations for the meanings of "dynamic changes" and "rate of cultivated land reduction."
4.Regarding the details of data extraction and analysis methods, as well as the statement on "reduction in cultivated land":
The ArcGIS software was utilized to extract the distribution of cultivated land in Sichuan Province from 2000 to 2020. Simultaneously, based on the land use data and its classification according to land types, a statistical tool was employed to obtain the number of pixels representing "cultivated land." The pixel size of the land use data was 30m*30m, and by combining this information with the total number of cultivated land pixels, the cultivated land area for each year was calculated.
In this study, the calculation of cultivated land area was based on the land use data provided by the Resource and Environment Science and Data Center, with a classification accuracy of 90%. The conclusion of "reduction in cultivated land area" was derived from the calculation of pixel area for cultivated land in each year (Table 4). In addition to the precision of the data itself, it was previously mentioned that the classification accuracy of the land use data used in the study exceeded 90%. This paper further validated the accuracy of area calculation. Based on official statistical data, the approximate area of Sichuan Province is 486,000 km². By conducting pixel-based statistical calculations for the years 2000, 2010, and 2020, the calculated areas for Sichuan Province were determined as 486,118.93 km², 486,049.55 km², and 486,044.65 km², respectively, with differences below 0.02%. This confirms that the method of calculating area using ArcGIS through pixel statistics is relatively accurate.
5.Regarding the modifications in the conclusion and discussion section:
Taking your suggestions into consideration, we have reorganized the sequence of the conclusion and discussion section. Furthermore, we have enhanced the content of the conclusion, providing a more comprehensive summary of the main findings of our study. We emphasize the crucial insights and implications of the results for understanding the spatiotemporal changes in cultivated land in Sichuan Province.
6.Regarding the verification of numbering and other aspects related to figures and tables:
We have diligently examined the figures and tables in the manuscript and conducted further checks on the correspondence of the numbering. We appreciate your meticulous suggestions.
7.Regarding the optimization of expressions in the text:
Referring to your suggestions, we have replaced the expressions that needed improvement as you pointed out.
8.Regarding the modification of the reference citation format:
We have revised the format of the references in accordance with the requirements specified by the journal.
Thank you again for your time and your valuable suggestions.
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper uses ArcGIS spatial analysis and PLUS modeling to explore the characteristics and the driving factors that may lead to land change. The manuscript is well-structured, and the methodology employed is well-described and sound. A few amendments for improvement are mainly structural and include the following:
1. Mention the research innovativeness in the introductory section and why it could interest international readers. Are there any specific policy recommendations (if any) that may be generalized to a broader context?
2. The Conclusion is not a discussion. Accordingly, delete and write only one paragraph giving the study's main results (with data), its significance, and its novelty versus actual knowledge.
Author Response
Dear reviewer,
First of all, I would like to express my gratitude for your valuable comments and suggested revisions to this study. After carefully reading and considering the issues you raised, I have made modifications to address the problems identified in the manuscript. I have also attempted to provide explanations for the questions that seemed unclear to you. I hope these clarifications have addressed your concerns. If there are any areas where further improvements are needed, I would greatly appreciate your valuable suggestions.
1.Regarding the aspect of supplementing research to attract international readers' interest and providing specific policy recommendations that can be extended to a broader context:
Taking your suggestions into account, we have included relevant content in the conclusion and discussion sections. The Chinese government has made significant policy attempts in the protection of cultivated land, such as the "Red Line of 1.8 Billion Mu of Cultivated Land" and the "Permanent Basic Farmland" policy. By connecting these concrete policies, we have summarized the model of coordinated development between cultivated land protection and ecological conservation in Sichuan Province, which serves as a major grain-producing region. We have demonstrated the necessity of implementing certain policies. For example, due to more severe encroachment on cultivated land in peri-urban areas, it is crucial to establish a red line for cultivated land protection in these areas. Furthermore, Sichuan Province, as a major grain-producing region, prioritizes allocating development rights to its primary large city within the region, while restricting other cities from occupying cultivated land, thus ensuring the primary agricultural function of the grain-producing region. We have supplemented these contents in the paper, aiming to provide references for the construction of grain-producing regions in other areas.
2.Regarding the modifications in the conclusion section:
Based on your suggestions, we have added an analysis of the significance of the research findings and the conclusions derived from their connection to the real-world situation. We have made detailed revisions in the paper to address this.
Thank you again for your time and your valuable suggestions.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The paper is improved thanks to suggestions and additions made by the authors.
On a general level, however, I note that, compared to some observations made, the authors have responded only in the cover letter but I would suggest to insert part of their answers directly into the text just to improve the reading. I refer, in particular, to points 4, 5, 8, 9, 10 and 11 of the cover letter.
Specifically, I believe that:
1. In Figure 3, land use changes are not perceptible in the map. I would suggest increasing the size or using more prominent colors or, at least, highlighting the zooms more:
2. in Figure 5 you do not appreciate the changes and, above all, you can not read the legend and the texts within the maps. I would recommend highlighting the reductions with a more noticeable color: not green but red?
3. Separate discussion and conclusions: instead of making a single paragraph (4. Conclusion and Discussion) I would make two separate and revise the numbering of the points which is incorrect. In any case, point 5) of the conclusions (4.2) is not reflected in the discussion of the results (4.1) where it only talks about land use changes but not about the determining factors and, therefore, I would recommend that it be included in the discussion;
4. Finally, pay attention to the numbers in the text and tables by entering the comma (for thousands) and the point for decimals. Also, for surfaces, always report 4 decimal places for uniformity.
Author Response
Dear Reviewers：
Thank you for your careful review of this study and for your further valuable comments and suggestions for revision, we have made the following changes to the article:
(1) Points 4, 5, 8, 9, 10 and 11 of the cover letter have been placed in the article to facilitate the reader's understanding of the study. (2) We have revised Figures 3 and 5 to make the information in the figures clear. (3) We have revised the structure of the article in the '4. Conclusion and Discussion' section and have added missing content to the Conclusion.
Thank you again for your suggestions.
