Spatial Heterogeneity and Driving Mechanisms of Cultivated Land Intensive Utilization in the Beibu Gulf Urban Agglomeration, China

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

GENERAL COMMENTS

I read the manuscript "Spatial Heterogeneity and Driving Mechanisms of Cultivated Land Intensive Utilization in the Beibu Gulf Urban Agglomeration, China". The authors put forward a comprehensive evaluation system of CLIU that was applied to the Beibu urban agglomeration; furthermore, they investigated the factors and driving forces affecting CLIU spatial distribution. Considering this case study's characteristics, systematically understanding CLIU spatial heterogeneity and the reasons explaining the verified spatial imbalance are, as mentioned by the authors, goals of significant importance for preserving cropland in the region and thus for assuring the area's sustainable development.

I understand the text, but there are a few concepts that could be explained better (please see specific comments). Additionally, there are some grammatical errors that need to be corrected (please see specific comments). I also had some difficulty following a few sentences (please see specific comments), so some minor editing of the English would be helpful.

The comprehensive literature review demonstrates the authors’ engagement with a challenging and topical theme, underscoring the importance of their work. However, there are few references to sources focusing on the importance of farmland protection in urban and peri-urban areas from a multifunctionality perspective (see specific comments). I also must mention concerns about the authors’ interpretation of certain cited studies’ results and of some statistical data (see specific comments), which must be addressed. The methods are suited, and the results are presented clearly and straightforwardly. While the conclusions may not be groundbreaking, overall, the manuscript provides valuable information and is scientifically sound. If the authors are willing to make major revisions, I suggest they consider the specific comments provided.

 

SPECIFIC COMMENTS

Introduction

Lines 37-38: "Cultivated land, the result of comprehensive interaction between human and nature, is an important natural resource …". Although soil is considered a natural resource, cultivated land results from losing natural habitats due to human interference and thus can hardly be called a natural resource. Instead of "… is an important natural resource…" consider "… is an important semi-natural resource …".

Lines 39-43: Instead of “It is not only the most common type of land use, but also the most essential land resource asset, and even the most precious "emerald" embedded in the vast land; this type of land ensures national food security, thus providing the material foundation required for urbanization and industrialization, as well as the ecological environment and other important functions [3].” consider something like “Being the most common type of land use, cultivated land ensures food security [3], thus providing the material foundation for urbanization and industrialization while assuring multiple other non-productive functions recognized as positive externalities and public goods, such as regulation, supporting and cultural benefits [see examples of works you can cite bellow]."

Song, X., Huang, Y., Wu, Z., Ouyang, Z., 2015. Does cultivated land function transition occur in China? J. Geogr. Sci. 25, 817–835.

Jiang, G., Wang, M., Qu, Y., Zhou, D., Ma, W., 2020. Towards cultivated land multifunction assessment in China: applying the “influencing factors-functions products-demands” integrated framework. Land Use Pol. 99.

Wang, X., Wang, D., Wu, S., Yan, Z., & Han, J. 2023. Cultivated land multifunctionality in undeveloped peri-urban agriculture areas in China: Implications for sustainable land management. J. Environ. Manag. 325, 116500.

Line 59: Instead of “… important research topics regional cropland protection …” consider “… important research topics for regional cropland protection …”.

Lines 60-63: Instead of “Continuous population growth has driven improvements in agricultural efficiency 60 [7], since intensive agricultural land management was first proposed [8], the law of di- 61 minishing land returns [9], theory of agricultural location [10], theory of labor value [11], and theory of land rental and price [12] have laid a theoretical foundation for CLIU.” consider “Continuous population growth has driven improvements in agricultural efficiency [7]. Since intensive agricultural land management was first proposed [8], the law of diminishing land returns, the theory of agricultural location [10], the theory of labor value [11], and the theory of land rental and price [12] have laid a theoretical foundation for CLIU.”

Lines 66-69: “However, 53.60 % of the counties have had agricultural land use indices lower than 0.6 [15], indicating cropland degradation via decreases in soil organic matter content [16], increases in soil acidification and salinization, and reductions in soil microorganisms [17].”

Ye et al. [15] calculated “… land-use intensity (LUI) as the ratio of actual investigated yield (per unit) of specific arable land plot to the maximum yield (per unit) of the standard farming system sub-region it belongs to.” and, based on their results, concluded that “… there is still considerable room for yield improvement as the ALUI (average land-use intensity) of ∼73.1 % counties are lower than 0.7 while the 53.60 % counties are lower than 0.6.” I do not understand how this statement can support the authors’ claim that these results indicate “… cropland degradation via decreases in soil organic matter content [16], increases in soil acidification and salinization, and reductions in soil microorganisms [17].” This claim is even harder to understand, since according to Ye et al. [15], “Counties with low ALUI are mainly distributed in northern provinces, southern Yunnan province and Hainan province (Xu et al., 2016; Liu et al., 2014b). For these areas, farming conditions are poor because of insufficient inputs and low management level (Yao et al., 2004); And limited by climatic conditions, topographic features and water resources carrying capacity, construction of high-standard agriculture is difficult and costly.” I also find difficult to understand how Zhao et al. [16] paper titled “Mirror syndrome in a Chinese hospital: Diverse causes and maternal fetal features indicates “…decreases in soil organic matter content [16], …”  and how Bian et al. [17] paper titled “A three-year experiment confirms continuous immobilization of cadmium and lead in contaminated paddy field with biochar amendment.” shows evidence of “…increases in soil acidification and salinization, and reductions in soil microorganisms [17].”

Line 91: Instead of “…; under the guidance of the SDGs framework, …” consider “…; under the guidance of the DSG´s framework, …”.

Line 97: Instead of “… prerequisites: increased input, increased yield; …” consider “… premises: increased production …”.

Lines151: Instead of “Another approach considers that the CLIU results in energy flow be- 150 tween water resources, energy, and food [10], natural conditions can influence CLIU” consider “Another approach considers that the CLIU results in energy flow between water resources, land, and food [10]; natural conditions can influence CLIU.”

Lines 152-156: Chen et al., which is written in the text “Chen et- al.”, corresponds to reference [43], not reference [42], as mentioned in the text. Was the mentioned framework developed by Ringler et al. [43]?

Line 161: Please clarify what you mean by “The analyses of the driving…”.

Line 167: Please clarify what you mean by “… the corresponding impacts of external land conservation and natural conditions on it”.

Line 226: Instead of “… driving factor …”, consider “… driving factors …”.

Figure 1: Regarding the legend of Aspect, instead of “low: -1”, consider “low: 1”.

Line 232: Instead of “… influencing factor ….” consider “… influencing factors …”.

Line 248: Is it “ 2.3.1. Construction of A Comprehensive Evaluation System” or “ 2.3.1. Construction of a Comprehensive Evaluation System”?

Line 287: Instead of “… humanistic factors …” consider “… anthropogenic factors …”, as well as in Table 2.

Line 343: Instead of “… When G is the Gini coefficient, ….” consider “… Where G is the Gini coefficient, …”.

Figure 2: In the legend is it “not intensity” or “nonintensive”?

Lines 456-459 and line 529: This kind of information should be stated in the Material and Methods section. The different software packages used, mentioning the versions employed, are expected to be mentioned in the Material and Methods section.

Figure 6: In the box “Low carbon and environmentally”, what do you mean? Environmentally is an adverb. Environmentally what? I suppose that on the top right side, instead of “Global remediation,” the text should read “Global remediation.”

In Figures 8-1, 8-2, 9-1 and 9-2, in the captions replace “… period 2017-2020” with “… period 2017-2021.”

Lines 704-705: “Overall, the rice purchase price, fertilizer application, and cultivated land area of the Beibu Gulf urban agglomeration showed a decreasing trend, while the consumer price index of residents showed an increasing trend.” Generally, the rice purchase price decreased from 2017 to 2019 but not from 2019 to 2021; on the other hand, the PCI increased from 2017 to 2019 but declined from 2019 to 2021. So, how can these opposite coupled tendencies explain a continuous decline in fertilizer application and cultivated size from 2017 to 2021?

Lines 782-789: This text summarizes information already known. Why this repetition here? This section may start in line 789 by stating something like, “Due to data limitations, several aspects need to be ameliorated by future research. First, ...”. Alternatively, instead of forming a relatively small section, the limitations could be included in the final part of the Conclusions.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This paper examines the spatial heterogeneity of cultivated land intensive utilization (CLIU) and its driving mechanisms in the Beibu Gulf urban agglomeration, conducting a systematic analysis of the land use status in this region. The topic is forward-looking and has high practical value. The paper employs various quantitative analysis methods to comprehensively and deeply discuss the level of CLIU, the degree of spatial imbalance, the influencing factors, and the spatial heterogeneity. The research results have good academic significance and decision-making reference value. However, there are still areas that can be further improved, and the following evaluation and revision suggestions are provided:

The literature review is relatively comprehensive, covering the relevant theories, evaluation methods, and influencing factors of CLIU, which provides good support for the theoretical basis and research design of this study. However, the elaboration and analysis of some key concepts can be further deepened and systematized. For example, the connotation of "CLIU", the relevant theoretical basis, and the research progress at home and abroad can be further improved.

The paragraphs in the paper are too long, which is very unfriendly to the reading experience of readers. The author should strive to make the paragraphs more concise and focused.

The reliability and stability of the weighted multi-factor evaluation method used in the paper to quantify the CLIU need to be objectively evaluated, as the evaluation results will have a significant impact on the conclusions.

The review of existing research should be more objective and focused, taking into account the rich literature on CLIU evaluation and influencing factors, rather than making vague statements about the lack of systematic research.

The interpretation of some data indicators and the analysis of the results can be further deepened, such as the in-depth discussion of the spatial non-stationary characteristics of some key influencing factors and the analysis of their causes.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This paper attempts to explore the spatial heterogenous of CLIU and its driving forces, based on the empirical evidence from China. My main concern is that this paper lacks a theoretical framework. What are your main arguments in this research? The scientific contribution is vague. It follows with my detailed comments.

It remains unclear why to explore the spatial heterogeneity of CLIU and the driving factors from a scientific perspective. It is a cheap argument on the three knowledge gaps in terms of the research objective, research level, and research content, which are not convincing. Why did earlier studies ignore these three points? What are the consequences?

In the analytical framework, the authors did not account for their choices of the four criteria (reasonable investment intensity, balanced utilization degree, output efficiency, and sustainable utilization status) and related variables. Why not other criteria? What are their theoretical underpins? What are their interrelationships? Besides, these four criteria are normative. For instance, what is (un)reasonable, what is (un)balanced, what is efficient, what is (un)sustainable? In addition, why did you choose these 14 variables? How did you determine the weight of these variables?

What does the theory of human-environment relationships mean? Why do you use this theory? There are lots of 'whys' in choosing the natural and humanistic factors.

What are your new findings? Are these in contrast to existing research? And why?

It is hard to follow the storyline. The language needs extensive editing.

Comments on the Quality of English Language

No

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors appropriately considered the suggestions regarding minor aspects, but unfortunately, they did not satisfactorily address either of my primary concerns, which I refer to below. 

 

Lines 62-63: “However, 53.60 % of the counties have had agricultural land use indices lower than 0.6 [17], indicating cropland degradation via decreases in soil organic matter content [18], increases in soil acidification and salinization, and reductions in soil microorganisms [19].”

 

As previously mentioned, Ye et al. [17] results, as implicitly admitted by the authors in their response (transcribed below), do not indicate “… cropland degradation via decreases in soil organic matter content [18], increases in soil acidification and salinization, and reductions in soil microorganisms [19].” Also, I still do not understand how Zhao et al. [18] paper titled “Mirror syndrome in a Chinese hospital: Diverse causes and maternal fetal features” shows any sign of “…decreases in soil organic matter content [18], …” and how Bian et al. [19] paper titled “A three-year experiment confirms continuous immobilization of cadmium and lead in contaminated paddy field with biochar amendment.” provides any evidence of “…increases in soil acidification and salinization, and reductions in soil microorganisms [19]. Thus, I suggest replacing “However, 53.60 % of the counties have had agricultural land use indices lower than 0.6 [17], indicating cropland degradation via decreases in soil organic matter content [18], increases in soil acidification and salinization, and reductions in soil microorganisms [19].” with something like “However, 53.60 % of the counties have had agricultural land use indices lower than 0.6 [17], indicating that the current efficiency of cultivated land utilization needs further improvement”.

 

Authors’ response: These data are the evaluation results of existing literature on the intensive use of cultivated land, which belong to the content of the literature review section. The purpose of listing these results in this article is to illustrate that the current efficiency of cultivated land utilization needs further improvement, and conducting research on the spatiotemporal heterogeneity and driving forces of intensive use of cultivated land can provide policy suggestions and reference for improving the efficiency of cultivated land utilization.

 

Lines 675-677: “Overall, the rice purchase price, fertilizer application, and cultivated land area of the Beibu Gulf urban agglomeration showed a decreasing trend, while the consumer price index of residents showed an increasing trend.” As I previously mentioned “Generally, the rice purchase price decreased from 2017 to 2019 but not from 2019 to 2021; on the other hand, the PCI increased from 2017 to 2019 but declined from 2019 to 2021. So, how can these opposite coupled tendencies explain a continuous decline in fertilizer application and cultivated size from 2017 to 2021? “

 

Authors’ response: After our research, we found that the purchase price of the Beibu Gulf urban agglomeration decreased from 2017 to 2019; PCI increased from 2017 to 2019, but decreased from 2019 to 2021. Despite fluctuations in rice purchase prices, fertilizer application, and cultivated land area in the Beibu Gulf urban agglomeration between 2017 and 2021.

 

“Despite fluctuations in rice purchases prices, fertilizer application, and cultivated land area in the Beibu Gulf urban agglomeration between 2017 and 2021.” Something needs to be added here since this is an incomplete sentence. No explanation whatsoever was given to the previously asked question. For example, one can hypothesize that the recent recovery of the rice purchase price, accompanied by a drop in the CPI, was not enough to regain farmers' confidence and thus reverse the trend towards a decrease in fertilizer application and cultivated land size decline. Moreover, the authors maintained in the revised version of the manuscript a statement that, in the face of the presented data, needs to be corrected: “Overall, the rice purchase price, fertilizer application, and cultivated land area of the Beibu Gulf urban agglomeration showed a decreasing trend, while the consumer price index of residents showed an increasing trend.” In fact, the opposite happened from 2019 to 2021.

 

Besides properly addressing these major issues, a careful reading of the text is necessary to avoid typos such as the following. 

 

Lines 440-441: “According to the principal components of the driving factorsresult, five principal component factors were extracted, for a cumulative contribution rate of 83.11% (Table 4).” Replace “factorsresult” with factors”.

 

Comments on the Quality of English Language

Minor editing of English language required.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have made significant strides in addressing both of my primary concerns. Consequently, the manuscript's quality has notably improved, making it suitable for publication in Sustainability.