Potential for Cropland Cultivation and Expansion Using Animal Draught Power in an Abrupt-Sunlight-Reduction Scenario with Loss of Industry

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Introduction
1. The background and rationality of the core solution for animal power have not been
clearly introduced. It is suggested to supplement the historical experience of agriculture
relying on animal power, the existing stock of animal power resources, and the
availability of animals in the absence of fuel/machinery.
2. Lack of explanation on the specific criteria for crop selection, and a brief explanation
of the reasons for crop selection should be provided in the introduction.
3. The key parameters in the research scenario were not mentioned in the introduction.
It is recommended to clearly state the core assumptions of ash injection amount, no
fertilizer application, and time range simulated in this article at the end of the
introduction or in the statement of research objectives.
4. The existing research gap description is not focused enough on the combination of
"animal power expansion+industrial loss". It is suggested to clearly point out that there
is no research evaluating the feasibility and output potential of using animal power to
maintain existing farmland and expand new farmland under the conditions of no
industry and no fuel, highlighting the unique contribution of this study.
5. There is a lack of foundation for the logical chain between "animal feed demand" and
"net available food". It is suggested to include in the research objectives a balance
between the energy demand of farming animals and the net income of human food.
6. It is not explained why the focus is on the goal of "one-third of the global
population". It is suggested to supplement the source or reasonable explanation of this
goal.
7. The last paragraph can be divided into two parts: "Research Gap" and "Summary of
Objectives and Methods of This Paper". It is recommended to first use a dedicated
paragraph to summarize the gap, and then use a clear paragraph to list the research
questions, core hypotheses, and evaluation indicators of this paper to improve
readability.
Materials and Methods
1. The correlation and regional representativeness between the crop model and the
selection of "winter wheat" have not been clearly stated. It is suggested to supplement
whether the parameters of this variety have been validated in multiple regions? If not
validated, the assumptions made to simplify the model and their impact on the results
should be explained.
2. The key physical parameters for the lack of female power are missing. It is
recommended to supplement the classic literature on animal traction and explain how
to convert traction into daily cultivable area.
3. The assumption of a steady state in animal numbers lacks reasonable justification and
is overly idealized. It should be replaced with a dynamic population model, or at least
explain the direction of the resulting bias caused by this assumption.
4. If the feasibility of cross-border transportation for animal allocation is not described,
it should be clearly stated whether it is assumed that each country only uses its own
existing animals? If so, it should be specified in the method; If international deployment
is allowed, feasibility needs to be demonstrated.
5. The "human labor" in farming tasks is not included in resource constraints. It is
recommended to supplement sensitivity analysis based on global working age
population, post disaster survival rate, and per capita working time.
6. The crop model correction factors lack empirical evidence and do not provide
literature or experimental data on the sources of inexperienced factors. They should be
clearly labeled and cited, and the uncertainty range should be discussed.
The productivity threshold of "1 t/ha" is not linked to animal energy return. It is
recommended to add a section on "Energy Balance Assessment" or at least discuss the
applicability of this threshold in animal power systems.
8. It is not explained why winter wheat was chosen instead of other staple foods, and
ecological and agronomic reasons for crop selection should be supplemented.
9. The priority of expansion sequence (wasteland → herbaceous → shrub) lacks
ecological basis. Should it be clarified whether this sequence is based on minimum
resistance or maximum output? Suggest citing relevant literature on vegetation
restoration or land reclamation.
10. Without considering the contribution of animal manure to soil fertility, the
hypothesis should be clearly stated: whether manure is collected and applied in the
field? If not included, reasons need to be explained.
11. Lack of coupling analysis between "270 working days" and seasonality. It is
suggested to supplement the comparison between cultivable days in various latitude
zones and ASRS climate simulation results.
12.The assumption of a 12% food waste rate is not completely consistent with disaster
scenarios, and relevant research on post disaster food losses should be cited or
sensitivity analysis should be conducted for high/low waste scenarios.
13. The allocation priority rules for "crop residues" and "grains" in animal feed have not
been described. It is recommended to clearly write a decision tree or optimize the
objective function.
14. Lack of quantitative methods for uncertainty in results, it is recommended to add a
section on uncertainty assessment.
Results
1. The core quantitative conclusion in the abstract has not been clearly addressed, and
the specific number of hectares actually cultivated by animal power in the existing
cultivable area worldwide should be clearly stated; Suggest clearly stating in section 3.3
that the expandable capacity is approximately X Mha; Additional text should be
provided to describe that by the fourth year, the remaining wheat can meet
approximately X% of the global population's demand.
2. Lack of prominent display of key nodes on the time series, it is recommended to
supplement the explanation by separately listing the satisfaction rate of the fourth year
and comparing it with the abstract.
3. The order of results does not completely match the logic of the method. It is
recommended to supplement the proportion of clearing area or time for different land
types.
4. Figure 5 does not clearly distinguish between scenarios with and without trade. It is
recommended to supplement key comparative data.
5. The impact range of productivity variability on key results has not been
demonstrated. It is recommended to add a summary of the variability range.
6. The balance between animal feed demand and human food is not presented in
absolute value form. It is recommended to add a table or bar chart to directly display
the annual: total production → animal feed → human surplus → human demand
satisfaction rate.
7. There is a lack of explanation for the handling of 'unassigned work on animals', which
is not specified in the methods and not mentioned in the results, resulting in a logical
loophole.
8. The results of animal demand and allocation have not been interpreted in the main
text. It is suggested to add 1-2 key findings.
9. Not compared with other resilient food options mentioned in the introduction, it is
recommended to do so in the discussion section, but at least leave a foreshadowing in
the results.
10. Lack of sensitivity explanation on the impact of correction factors in the method. It is
suggested to add that if empirical factors are excluded, the yield in the first three years
will increase by X% without changing the overall trend.
Discussion
1. The connection with the core conclusion of the abstract is not direct enough. It is
recommended to reiterate the core findings at the beginning of the discussion and
emphasize their policy/survival significance.
2. There is a lack of discussion on the scenarios of "150 Tg soot injection" and "no
fertilizer". It is suggested to add a discussion on the uncertainty of scenario parameters
and cite literature to explain the rationality or extremism of 150 Tg.
3. The limitations of the steady-state assumption of animal population have not been
fully discussed. It is suggested to add that if the animal population decreases by X%
annually, the results need to be re evaluated, and it is pointed out that the steady-state
assumption of this study provides an "optimistic upper limit" estimate.
4. The feasibility of human labor has not been discussed, and it is suggested to increase
the limitation on the expansion speed of farmland even if there is sufficient animal
power and a lack of well-trained farmers, and to cite estimation literature on human
losses after disasters.
5. There is a lack of comparison with other resilient food schemes. It is recommended to
increase the quantitative comparison between the grain output of this scheme and the
schemes in the literature, and point out the relative advantages and disadvantages of
animal powered farming.
6. The explanation of the results of the "no trade scenario" is not deep enough, and it
should be clarified that under no trade, many countries with animal or farmland
shortages cannot be self-sufficient, while global trade can significantly alleviate regional
imbalances; It should be pointed out that under GCIL, international trade is almost
impossible to recover, so a no trade scenario is more realistic.
7. The potential contribution of animal manure to soil fertility has not been discussed. It
should be mentioned that collecting and applying animal manure can to some extent
supplement soil nutrients and increase yields. This may be a conservative assumption of
the model or a direction for future research.
8. There is a lack of reflection on the applicability of the "1 t/ha threshold". It is
suggested to discuss that in the context of post disaster hunger, even if the yield is
below 1 t/ha, as long as the energy output is greater than the animal input, it should be
included in the expansion scope. The current threshold may underestimate the potential
arable land.
9. The impact of the "lack of experience factor" in the method on the discussion of the
results was not mentioned. It is suggested that if farmers can learn quickly, the actual
yield may be higher than the model prediction, so this result may be a conservative
estimate.
10. There is a lack of discussion on the limitations of the "residue priority" strategy in
animal feed. It is suggested to add that if the residue cannot be fully utilized, the
proportion of wheat feed will increase and the available food for humans will decrease.
11. The fate of "unassigned animals" has not been discussed, and it is suggested to add
the assumption that all unassigned animals are slaughtered for human consumption,
which would result in a higher total calorie supply. However, this part was not quantified
in this study.
12. The logical loop of "GCIL causing fuel supply interruption" in the introduction is not
closely related. It should be discussed whether a small amount of fuel reserves should
be mixed with animal power? This model assumes complete lack of fuel, and the validity
of this assumption needs to be explained.
Prospect
1. Lack of limited discussion on the key assumption of "feasibility of human labor". It is
suggested to add a section on "limitations of human labor" to discuss the impact of
labor shortage on cultivation and expansion speed, and point out that future research
needs to establish a post disaster population dynamics model that matches labor
demand.
2. The limitations of the "steady-state assumption of animal numbers" are not fully
discussed, and future research should be supplemented by simulating net food benefits
under different slaughter/retention strategies.
3. The potential and limitations of using animal manure as fertilizer have not been
discussed, and it is suggested to expand it into a separate subsection.
4. Lack of sensitivity analysis on "energy return (net food output)" suggests that future
work should evaluate the impact of different residue utilization rates on net calories.
5. Alternative strategies for "different land type cultivation sequences" have not been
considered, and it is not recommended to conduct future research to find the optimal
sequence through optimization algorithms.
4. Lack of reflection and improvement direction on the "1 t/ha threshold", it is
suggested that future research should define "cultivable land" based on energy return
on investment (EROI) rather than a fixed yield threshold.
5. The uncertainty of the "lack of farmer experience factor" was not mentioned, and it
should be supplemented that different learning curve models can be used for sensitivity
analysis in future work.
6. There is a lack of clear recognition that cross-border animal allocation is not feasible
under the "no trade scenario". Future research should focus on the allocation of animal
resources within each country, rather than global optimization.
7. The discussion on the availability of animal equipment is too optimistic. It is
suggested to supplement the investigation of the current global stock and
manufacturing capacity of animal power equipment, and set optimistic/pessimistic
scenarios.
8. The impact of extreme weather on outdoor labor and animal health has not been
discussed. Future research should couple climate models with human/animal
physiological tolerance thresholds to calculate actual available working days.
9. An important limitation of the "model crop singularity" has been overlooked:
nutritional diversity. Future work should evaluate the feasibility and comprehensive
nutritional output of animal powered planting of multiple crops (beans, tubers).
10. Future work recommendations are too general and lack specific quantitative
directions. It is recommended to provide 1-2 verifiable hypotheses.
11. It should be noted that there is no linkage with the "resilience food program"
mentioned in the introduction, and future research can explore the integrated system of
animal husbandry and these programs to form complementarity. There is currently no
involvement at all.
12. There is a lack of expansion on the scenarios of "different levels of smoke and dust
injection". Future work should cover low, medium, and high levels of smoke and dust
injection scenarios and report thresholds.
Conclusion
1. The core quantitative figures are not completely consistent with the abstract
2. The key time point of "fourth year" has not been clearly highlighted
3. The expression 'no trade scenario' may cause misunderstandings
4. Lack of a brief explanation of the dynamic process of "decreasing demand for animal
feed over time"
5. The "net energy is positive" or "sustainability" of the plan is not emphasized
6. The conclusion does not mention key uncertainties or applicable scope
7. The list of future jobs is too general and disconnected from the outlook section
8. Not forming a closed loop with the "global food security threat" mentioned in the
introduction
9. Lack of prospects for "expanding sustainable land use" or "post disaster recovery"
10 language expressions can be more refined and powerful

Comments for author File: Comments.pdf

Author Response

The reply to Reviewer 1's review report is attached below.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Your models, the use of draft animals and expansion of crop production would work in New Zealand because it gets sufficient rain. Irrigation is not required. In dry parts of the world, such as the Australian outback and the Western United States dryland farming does not work. It may be possible for the authors models to work in the eastern United States which gets much more rain. Severe drought in the Western United States has forced farmers to reduce the amount of land when they can plant become wells are running dry.

Line 34:  replace the word bolide with fiery meteor or asteroid

Line 186–201: add my comments about problems with crop expansion in arid (dry) parts of the world.

Line 408: gasoline diesel fuel has limited life span. Diesel will deteriorate in 12 to 24 months in gasoline may deteriorate in 3 to 6 months. It may last up to 12 months in a sealed container. You also need to discuss the use of coal. The United States and China have abundant amounts of coal which can be used to generate electric power. Coal does not deteriorate. Natural gas, which is mostly methane could also be used. It does not deteriorate and it can be used indefinitely. Natural gas can be used to power vehicles and generate electric power. Countries that have abundant coal or natural gas may become more resilient.

Line 476: countries that are import dependent for fuel that has sufficient rainfall from crop expansions may have better outcomes compared to the arid parts of the world.

Line 646: conclusions- should discuss how areas of the world that has sufficient rainfall would have a better outcome than very aired countries

Author Response

The reply to Reviewer 2's review report is attached below.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Manuscript ID: sustainability-4367313

Type of manuscript: Article

Title: Cropland cultivation and expansion using animal draught power in an abrupt-sunlight-reduction scenario with loss of industry

 

This study evaluates whether animal draught power could sustain agriculture during an abrupt-sunlight-reduction scenario combined with global industrial collapse. Results suggest existing cattle and horses could cultivate over 700 Mha of cropland and expand an additional 160 Mha, producing enough wheat to meet more than one-third of global calorie needs by the fourth year.

Comments:

The title does not communicate the paper's key finding, the feasibility of maintaining food production using animal draught power. The title should clearly identify the disaster scenario, emphasize the paper's focus on agricultural potential, and preserve the technical term “animal draught power.” I therefore recommend the following title: “The Potential of Animal Draught Power for Cropland Cultivation and Expansion in Abrupt Sunlight Reduction Scenarios with Global Catastrophic Industry Loss."

 

 

 

Comments

• Generally, the authors assume that animals, people, and equipment can be moved wherever needed. However, a GCIL scenario would likely involve severe transportation disruptions or collapse. This assumption should be explicitly justified and discussed.

 

• Lines 15–20: The abstract reports specific outputs but does not explain why wheat was selected, why 150 Tg soot was selected, and why 1 t/ha was used as the viability threshold.
• Lines 20–21: The statement "making outdoor agriculture and cropland expansion viable and sustainable methods" is stronger than the presented results support. The paper demonstrates physical feasibility but does not demonstrate sustainability.
• Lines 176–177: The assumption that "the number of ploughs and harrows in a country is assumed to be the same as the number of draught animal pairs" is not acceptable. The authors assume that hundreds of millions of animal pairs and hundreds of millions of functional ploughs are immediately available without supporting evidence. This assumption may invalidate the cultivation analysis.
• Lines 391–392: Another important assumption concerns animal training. Although supporting citations are provided, additional documentation is needed regarding training duration, failure rates, behavioral issues, and skilled labor requirements.
• Lines 405–406: The phrase "it has been confirmed" requires clarification. Specify by whom it was confirmed and provide an appropriate citation, or remove the statement.
• Lines 413–415: The statement "using animals for labour prevents their culling" is speculative and requires supporting evidence or citations.
• Lines 554–564: The comparison with another study may be misleading because the studies rely on different assumptions, land areas, and production systems.

 

 

Review the whole manuscript for grammar and spelling issues. Here are some examples:

• Lines 13–14: Replace "animal draught as a power source" With "animal draught power"
• Lines 59–60: Replace "would cause 21% reduction in wheat production" With "would cause a 21% reduction in wheat production"
• Lines 145–146: Replace "This model considers draught animals are used" With "This model assumes that draught animals are used."
• Line 150: Replace "assumes steady state" With "assumes a steady state"
• Line 170: Use either American or British English consistently throughout the manuscript (e.g., labor/labour).
• Lines 264–265: Replace "and total around 3.3 kg" With "and totals around 3.3 kg"
• Line 281: Replace "wheat used to feed to meet animals" With "wheat used to meet animals' feed requirements"
• Line 340: Replace "animal's diets" with "animals' diets." The plural possessive form is required because Figure 4 refers to multiple animals.
• Line 569: Replace "under-estimate" With "underestimate"

Author Response

The reply to Reviewer 3's review report is attached below.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for your reply. It has cleared up all my doubts. I believe it has reached the publication standards. Congratulations!