Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

# land-2780042
Manuscript Title: Spatio-Temporal Distribution Pattern and Fragmentation Driving Mechanism of Paddy Field and Dryland in the Urban Agglomeration in the Middle Reaches of the Yangtze River from 1990 to 2020

Having carefully evaluated the manuscript, I would like to commend the authors for their rigorous work. I would like to offer some feedback for the authors' consideration during the revision process.

Abstract and Title:

- Keywords need re-finding best explain the study!

Introduction:

- The structure of the introduction lacks necessary coherence and needs to be rewritten. Do it by using a funnel essay structure. In short, explain the topic, broaden its scope, and narrow it down.

- Provide a literature as research background to shows the evolution of the studies and state of the art.

- Please provide further elaboration on the various approaches to assessing the landscape change dynamic and fragmentation analysis in the introductory section.

- Prior to stating the objective, a summary of previous research would help in highlighting the significant aspects of the research.

- Provide the closure statement, indicating what exactly your research hits and showing how important the study is.

Study area:

- It is better to provide some description on the range of precipitation and temperature changes, main population centers, dominant land use type, … in the study area section.

Research Methodology:

- Equation 6 contains undefined variables such as K, T, Sa, and Sb.

- Regarding the land use dynamic degree, it would be advantageous to explain on the methodology and the specific index employed in literature (Land use change dynamics assessment in the…), as a similar study.

- Ensure the accuracy of Equation 7 by providing some valid sources.

- Clarify the process of calculating landscape metrics. Provide insight into the rationale guiding the selection of particular landscape metrics among a multitude of options. Additionally, specify the software utilized for these calculations, e.g., landscape change assessment and its prediction in a mountainous gradient...

- Include detailed explanations concerning entropy weights within the research methodology section.

Results and discussion

- In interpreting the results, please avoid repetitive presentation of tabled data in textual form. Instead, focus on translating and discussing the reasons behind the changes in results (lines 406 to 440 or other relevant sections could be presented more briefly).

- Explain whether, over time, the impact of driving forces on changes in paddy and dry lands has undergone alterations.

- Provide a brief explanation regarding the ecological environment resulting from the conversion of cultivated land into natural areas (forest).

- Has the fragmentation caused by the expansion of paddy fields led to a reduction in the fragmentation of natural lands and subsequently affected the ecological integrity of these natural areas? Briefly mention its effects in this regard.

- One of the important factors as a driving force for land changes and expansion is the level of willingness and readiness of the farmers to develop agricultural fields, which may vary during time based on the social context of the region. This can be mentioned in the final conclusions.

Conclusions:

- Make some practical suggestion regarding the minimizing the negative impacts of increased fragmentations of PF and DLs.

- Make an overall projection/prediction regarding the future trend in PF and DL extent based on the findings.

Comments on the Quality of English Language

The manuscript's English level is good, but some minor revisions are needed, which can be addressed by revising the manuscript.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper outlines fragmentation of specific land uses within cultivated land areas in a region in China. The broad problems associated with land use fragmentation are noted before focusing on paddy rice areas and dryland agriculture in a rapidly industrialising and urbanising region. Based on government land use data, several measures of fragmentation, rates of change, and loci of change, were applied to each of the two selected land uses. Of these, paddy rice represented approximately 70% of the total area used for paddy and dryland cultivation. The locations of these two uses differed considerably, with both recording the greatest rate of change in the period since 2000 (paddy from 2010-2020 and dryland from 2000-2010). City-by-city data for land use changes were presented; and it was noted that the gravity centre for dryland cultivation shifted further than for paddy rice. The importance of interacting variables in explaining change was emphasised, along with the importance of elevation and slope as contributing fragmentation drivers.

General comments

The paper refers overwhelmingly to Chinese literature sources, many of which I am not familiar with but which are outlined in the paper.

The paper is focused on reporting and making recommendations about land use fragmentation in China. In order to identify the contribution of the paper to new research knowledge, there should be a clear statement indicating the relevance and importance of its findings to other countries.

Most of my comments below are related to specific statements or clarification of expression which would improve the quality of the manuscript.

Specific comments

The title is far too long and needs condensing. A suggested shorter title (although still not concise) would be ‘Spatio-temporal fragmentation of paddy rice and dryland farming in a Yangtse River region, 1990 to 2020’.

Line 18 – ‘…two specific land use types…’

Line 18 – delete ‘and more’

Line 31 – ‘…than a single…’

Line 33 – ‘…urbanisation relating to cultivated…’

Line 36 – the last 10 words in that line do not constitute key words – please re-consider

Line 43-44 – ‘…by construction and ecological uses has led…’

Line 98 – ‘…effects of a driving factor…’

Line 99 – ‘tors[40]. These latter are complex,…’

Line 127 – ‘driving factors and their possible interactions that have…’

Line 135 – ‘development in a grain-producing area…’

Line 144 – ‘…west China and extending over north and south…’

Line 167 – ‘Paddy fields are…’

Line 168 – ‘…irrigated in normal years…’

Lines 167-172 – More clarity is needed about the definitions of ‘paddy rice fields’ and ‘dryland cultivation’. It is stated that ‘paddy fields…can be irrigated in normal years’ and that dryland cultivation areas ‘can be irrigated in a normal year.’ If both paddy rice and dryland cultivation areas can be irrigated in normal years, what is the difference between them? Does it relate to the types of crops grown rather than the irrigation potential? Or some other factor? And how are ‘paddy irrigation’ and ‘dryland irrigation’ areas identified in the government data base (on crop type reflectance)? I am not familiar with the details of the Chinese definitions of these terms and there are probably other readers who would be in my position. Clarification would be helpful.

Line 179 – ‘The gravity…..model reflects the…’

Line 190 – ‘amount of paddy field’ – does ‘amount’ refer to ‘area’, or ‘% of x’?

Lines 199-200 – ‘…of the data [55].’

Line 212 – ‘…dynamic degree quantifies….change in the quantity of…’ Is ‘area’ meant here, rather than ‘quantity’? Need to be precise.

Line 223 – ‘…we can identify the rate…’

Lines 227-243 – this paragraph would be better placed in the Introduction, as it includes an overview of evaluating fragmentation.

Lines 249-250 – ‘…dimensionless, by uniformly transforming the positive….indicators into positive standardised…’

Line 256 – ‘…step, the entropy…’

Line 257 – ‘…metrics. This method can…’

Line 263 – remove comma after [63]

Line 266 – where is VIF defined?

Lines 272-273 – ‘…evaluation model, as follows: …’

Line 283 – ‘…the spatial pattern of…’

Line 288 – ‘…and spatial factors for…’

Line 291 – ‘…are described in Table 2.’

In Table 2, column 2 – ‘Driving factors’ – col.2, category 2, ‘Per capita …..of rural residents’

Line 294 – ‘The geodetector model…’

Line 303 – ‘…is that it can detect…’

Line 305 – ‘…in the geodetector model…’

Line 303 – ‘…as well as the variance for the…’

Line 330 – ‘The paddy field areas are distributed…’

Line 334 – ‘the continuous decline in cultivated land…’

Figure 3 – gravity centre points (top RHS diagram) would be better placed on the main map below, as this would be more effective in representing where the shifts have occurred.

Figure 4 – same comment as for Figure 3.

Line 381 – ‘3.1.3 Dynamics Change in the Areas of Paddy Field and Dryland’

Line 385 – ‘…change of these land uses at the…’

Line 390 – ‘…of paddy fields in’

Line 391 – ‘…province is slow; the city with…’

Lines 393-394 – ‘…change in dryland areas was generally greater than for paddy fields during….’

Line 395 – ‘between -8.59% and 3.51%.....between -3.09% and 31.06%.’

Line 397 – ‘…higher than most of the cities in the remaining…provinces, and Xiangyang…’

Lines 399-400 – ‘…Changsha (Hunan province) and Ezhou and Xiantao (Hubei province) have higher…’

Line 401 – ‘…dryland areas in Hunan…’

Line 403 – ‘land areas has rebounded…’

Line 404 – ‘where their number has remained…’

Lines 448-458 – To improve logic in this paragraph – place lines 456-458 after PFF in line 448. Noted below (using original line numbers):

Line 448 – ‘…values than PFF. High value zones of DLF….’

Line 449 – ‘…most severe DLF and PFF. High value zones of PFF….’

Line 451 – ‘…which include the hilly…’

Line 453 – ‘…the MAYRUA, namely the Dongting…’

Line 454 – ‘Paddy fields…’

Line 455 – ‘…topography, where the density of paddy field patches is higher than in plains [64].’ (to line 448) – ‘High-value… ’

Line 459 – ‘In terms of temporal changes, PFF and DLF…’

Line 464 – ‘…paddy fields only…’

Line 484 – ‘…and 0.7208 respectively, and for slope were 0.8226 and 0.7164 respectively.’

Line 521 – when referring to ‘better soil’, is this a result of cultivation (anthropogenic) or pre-cultivation (natural) soil properties?

Lines 521-523 – more explanation is needed as to why eroded soils are more suitable for paddy rice than others. Eroded soils are generally less fertile than non-eroded soils, so the juxtaposition of ‘better soil’ and eroded hilly areas seems inconsistent.

Lines 534-537 – please clarify. Does ‘land occupation’ refer to occupation by urbanisation/ industrialisation? This sentence needs to be re-written as its intention is unclear.

Lines 546-547 – ‘…speed of change shows that…’

Line 552 – ‘…and water bodies, and dryland…’

Lines 576-577 – ‘…commonality and individual characteristics.’

Lines 586-587 – ‘…that of DLF. The Jianghan Plain….’

Line 591 – ‘and waterlogging[93]. The rise…’

Line 600-601 – ‘…to effectively optimising the CLF…’

Line 603 – ‘persed pattern of cultivated land…’

Line 607 – ‘…areas with more suitable topography…’

Line 624 – ‘…farmland [45,64,96]. Government-led land….’

Line 630 – place resolution of RS in Methods section as well. As is noted, lack of precision may result in under-estimation of fragmentation, which is reasonably likely as fragmentation has been recognised at the lower resolution used in this study. It may also be useful for the non-Chinese audience to be provided with average sizes (areas) of field/occupation/ownership in order that readers are able to consider field patterns in relation to the 1 km resolution used in the study.

Line 639 – possible addition – ‘…driving mechanisms to include a greater emphasis on local and regional differences in already-identified key parameters.’

Line 650 – ‘the economic and policy context…’ what level of government is being referred to – national? regional? or other administrative?

Lines 655-656 – ‘high-value’, or ‘high change’?

Line 660 – ‘…the strongest influence on PFF is grain output and paddy field slope…’ Logically it would seem that grain output depends on paddy area, not the other way around. Please clarify how grain output controls PFF.

Comments on the Quality of English Language

See above - minor English expression changes are listed in Comments to authors.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Overall and Major Comments

In this paper, the center of gravity transfer model, standard deviation ellipse model and land use dynamic model were used to study the spatial and temporal changes of paddy field and dry land distribution in the middle reaches of the Yangtze River in the past 30 years. The PFF and DLF evaluation system based on landscape pattern index was constructed, and the spatio-temporal changes of paddy field and dryland fragmentation were studied by entropy weight method. After that, geographic detectors were used to explore the driving factors of this change, and the influence of single driving factor and the interaction of two driving factors on the fragmentation of paddy field and dryland was studied.

In short, this paper uses a variety of methods to study the spatio-temporal changes of paddy field and dryland from different angles. If some problems are solved, the paper can be considered and accepted.

Specific Comments

(1)   Page 2, Line 90:It is suggested to add "name of author + think" in "Among the many research directions".

(2)   Page 3, Line 111:It is suggested that "a number of existing" be changed to "the name of the author of the cited document".

(3)   Page 3, Line 114:It is recommended to add the full name of MAYRUA after "such as the MAYRUA".

(4)   Page 4, Line 150:It is suggested to add "scale and north pointer" to the map of China in Figure 1.

(5)   Page 5, Line 218:Formula (6) is incorrectly written.

(6)   Page 6, Line 221-225:Recommendations "By calculating...... at the administrative scale. "Read another paragraph.

(7)   Page 6, Line 265:The result of adding "The results of the multicollinearity tes" is recommended.

(8)   Page 8, Line 309:Proposed to replace "Formula (8)" with "Formula (9)"

(9)   Page 8, Line 322-329:It is suggested to add the content "The biggest difference between paddy field and dry field in 2000".

(10)  Page 9, Line 351:It is recommended to change "(1)-(7)" to "(1)-(6)".

(11)  Page 15, Line 448:It is suggested to add "The spatio-temporal changes of the fragmentation of paddy field and dryland land are shown in Figure 6" before "Overall".

(12)  Page 15, Line 461:Indicate what "over the past 20 years" is.

(13)  Page 17, Line 497:"0.9271" in "(1990.0.9271)" is not the highest in 1990, whether it is written incorrectly.

(14)  Page 19, Line 548: It is proposed to replace "A related study concluded" with "the name of the author of the cited literature".

(15)  Page 20, Line 588:It is suggested that "The relevant studies" should be replaced by "research by an author".

(16)  Page 20, Line 597:It is suggested that the words "previous studies" be changed to "the name of the author of the cited literature".

(17)  Page 20, Line 613:It is suggested that "in other" be changed to "the name of the author of the reference".

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Hello,

Through a careful consideration, the authors have addressed the comments provided by the referees in an acceptable way. Therefore, the paper can be accepted for publication.