Managing Land Carrying Capacity: Key to Achieving Sustainable Production Systems for Food Security
Round 1
Reviewer 1 Report
Dear Authors
Figure 1 does not show that the city was founded on agricultural land. On the contrary, the rise of the city turned the area green. So what is this photo for?
Figure 4 - The authors recommend that the yields be controlled, but nothing comes of it. Add a comment, please
The article is submitted as a review, but should include a detailed discussion on the topic with other authors and researchers. However, the Discussion is not a discussion but a presentation of what should be. The discussion should be strengthened by quoting the views of other researchers.
There are practically no conclusions, just some generalizations (3 sentences) not resulting from the content of the article. This also needs to be corrected.
Author Response
Prof. Wang
Yan'an University, Yan'an, Shaanxi 716000, China
March 21, 2022
Dear Editor and Anonymous Reviewers:
The authors are thankful to you and anonymous reviewers valuable, detailed and professional comments on this paper.
As the corresponding author, I received an e-mail informing me that our manuscript (Ref: land-1636083, “Responses of different potato varieties to irrigation and fertilization strategies in the sandy loam soils of Northwest China”) has been reviewed, with the reviewer comments included. We were very glad to receive your e-mail. Thank you again for your letter and for giving us the opportunity to revise our manuscript. The authors are deeply grateful to all of you for your support and your careful review of our manuscript. We have studied the comments carefully and have made corrections, which we hope meet with your approval. The main corrections in the paper and the responses to the Editor's Comments and Reviewers' Comments are giving below.
Dear Authors
Figure 1 does not show that the city was founded on agricultural land. On the contrary, the rise of the city turned the area green. So, what is this photo for?
Response: Thank you very much for your valuable advice. We want to say that urban construction takes up a lot of agricultural land, but it has no real effect here. We removed Figure 1 in this revision.
Figure 4 - The authors recommend that the yields be controlled, but nothing comes of it. Add a comment, please.
Response: Thank you very much for your valuable advice. We have revised Figure 4 in this revision. We have added “Using data from thousands of field trials around the world, we found that rice, wheat, and maize yields increased with increasing nitrogen application rates at levels less than 240 kg ha-1. The yield of rice and wheat is highest when N is applied at 180-240 kg ha-1, but decreases when N is applied above this range.” in this revision.
The article is submitted as a review, but should include a detailed discussion on the topic with other authors and researchers. However, the Discussion is not a discussion but a presentation of what should be. The discussion should be strengthened by quoting the views of other researchers.
Response: Thank you very much for your valuable advice. We have revised the Discussion in this revision.
A key step in promoting sustainable agriculture is to assess the productivity of different agricultural systems around the world. Historically, the agricultural strategy was assessed based on a narrow range of standards, such as profitability or yield. In the future, the evaluation of agricultural systems should be based on environmental sustainability and the stability of food production. The stability of food production may be at risk under climate and environmental changes, as climate and the environment could be important determinants of future food production, food security and food prices (Wheeler and von Braun, 2013).
Sustainable food production is closely related to the ultimate environmental car-rying capacity (Eshel et al., 2018). All measures to increase food production should fall below environmental carrying capacity limits. For example, irrigation is an effective way to increase crop yields, but the ultimate carrying capacity of irrigated water re-sources will affect the sustainability of food production (Acevedo et al., 2018). Fertilization is another important field management measure used to improve grain yield, but the long-term damage of excessive fertilization to soil in the pursuit of high yields and stable yields will affect the sustainability of food production (Bommarco et al., 2018; Yang et al., 2018).
These processes are relevant to national and local development. Understanding such linkages or connectivity is therefore crucial to restoring soil quality and mitigating degradation. Various activities can be considered as conservation practices as they maintain or improve soil fertility or reduce soil erosion, runoff, and pesticides. These activities include management measures such as conservation tillage, soil conservation crop rotation and land improvement.
The current agricultural research results and future research direction should be clearer, that is, we must establish the environmental boundary theory of food safety production, and the critical point of “food security-environmental carrying capacity” should not be broken. It is necessary to immediately stop the overextraction of groundwater in pursuit of high yields. A “soft solution” to water shortages focuses on improving overall water productivity in agriculture (Kang et al., 2017). Innovative irrigation practices can improve water use efficiency, gain economic advantages and reduce environmental burdens (Sala et al., 2017). Drip irrigation is one of the most effective irrigation techniques worldwide (Grafton et al., 2018). Sprinkler irrigation also significantly affects crop yield under the interaction of irrigation frequency and irrigation time (Guardia et al., 2017).
According to crop water demand physiology and soil conditions, precision irrigation, including irrigation amount, irrigation time, irrigation frequency, and irrigation times, can be used. However, the difficulty in implementing widespread precision irrigation is encouraging farmers to accept higher water prices due to improved equipment systems. The application on a large scale requires farmers to gain more knowledge about the wider environmental benefits and economic advantages of pre-cision irrigation. Farmers generally lack the incentives and means to understand crop water use, actual irrigation applications and crop responses to different water management practices, all of which affect the current level of water efficiency on their farms. The water use efficiency of agricultural water management will remain unknown, and farmers will have little incentive to adopt more effective practices. Sustained knowledge exchange is necessary so that all stakeholders share a greater share of the responsibility for addressing the critical points of crop production and the ultimate carrying capacity of water resources.
Precise fertilization techniques should be applied in agriculture. The system of fertilization is determined according to the nutrient physiology of crops and soil con-ditions, such as the time, amount, proportion, times and quantity of fertilization (Wang et al., 2019). The processes of water and fertilization should be coupled. The target yield is determined according to the growth status of crops and the yield of the previous season. According to crop nutrition theory data, the fertilization formula is formulated. The formula should be adjusted according to soil conditions. The ratio between the amount of fertilizer absorbed and the amount of fertilizer applied under drip irrigation can be used to calculate the amount of fertilizer applied under drip irrigation.
The use of mulch and other mulch materials can retain soil moisture, reduce soil evaporation, inhibit weed growth, affect soil microorganisms, control soil structure and temperature, and provide aesthetic benefits. The selection of suitable mulch mate-rials should be combined with effective fertilizer management strategies. In addition, crop types, crop management methods and climatic conditions are important factors affecting suitable mulching materials and nitrogen management strategies. Reducing pests and weeds is essential for crop management in the field and can further improve fertilizer use efficiency. A better understanding of the interactions between major nutrients and other nutrients, as well as mulching, may help to understand the im-portance of a balanced supply of fertilizers, thereby improving plant growth, water use efficiency, fertilizer use efficiency and yield.
Biotechnological methods have the potential to increase crop yields under dif-ferent environmental pressures. Molecular breeding, genetic engineering, and their combination with conventional breeding make crops better able to withstand changes in salinity, drought, temperature and solar radiation (Fang and Xiong, 2015; Ding et al., 2019). With current and emerging technologies such as rapid RNAi (rapid gene recognition), target gene replacement cycles, marker-assisted selection, chromosome engineering, genome-wide selection and nano-biological technology, designers are developing and improving the functions of crops that can be used for natural resources, such as water, soil nutrients, carbon and nitrogen in the atmosphere, more efficiently than ever before (Keurentjes et al., 2006; Schauer et al., 2006). The benefit of crop improvement brings more benefits than improving grain production, which can reduce the value of the environmental limit bearing capacity. Farmers supported by low-yield land will receive unexpected benefits, including economic benefits, social welfare, and ecological benefits. In addition, the production of crops can be improved by the indirect manipulation of the quantitative trait locus (QTL) to control the genetic variation in the characteristics and physiological mechanisms of biomass production and its distribution.
To ensure global food security, a new green revolution in agricultural productivity is needed to dramatically increase crop yields and the supply of food. This goal re-quires an integrated, multifaceted, and sustainable approach that will increase pro-duction per unit area and optimize the resource use efficiency of crops. The successful and acceptable application of biotechnology to crop breeding will be essential to pro-vide the required stepwise increases in production.
Diversified cropping systems (farmland biodiversity and ecosystem services) are an effective way to balance food production and environmental impacts. In the future, agricultural research and innovation need to focus on resource efficiency, production stability, minimizing environmental impacts, buffering extreme events and adapting to local conditions.
Reliable food production and distribution determine the availability of food, and both are key factors in achieving food security. A major problem is the worldwide distribution of food; for example, poverty-stricken areas have major food shortages, while other areas have an increasingly obese population. A partial solution would be the achievement of an equitable distribution of food resources.
The environment for agricultural production, trade and consumption is more dynamic and unpredictable. Knowledge, information, and technology are increasingly generated, disseminated and applied through the private sector. There are changes in the ability to utilize knowledge developed elsewhere or for other purposes. The knowledge structure of the agricultural sector is undergoing major changes in many countries. Agricultural development increasingly takes place in the context of globalization. Based on a historical view of the assumptions of environmental constraints on food production over the past few decades and looking into the future, we analyze the types of interdisciplinary research required to improve productivity.
Past experience in using global generalizations of the state of the planet and future trajectories have proven unsatisfactory. The sustainability paradigm is suffering a general insufficiency of problem-solving power (González-Márquez and Toledo, 2020). Those analysts go on to state they are seeing an accumulation of anomalies (problems that resist solution under the sustainability paradigm) and in their commentary they sound an alarm to warn the scientific community about the possibility of a paradigm crisis in sustainability science. We also presented empirical, quantitative data that might be interpreted as demonstrating that the scientific community is losing trust in the paradigm.
There are real problems that are faced by individuals and societies around the world which stem from population numbers in specific locations, resource utilization, and current imperfect technologies and policies. Nevertheless, despite the challenges, food production is growing as fast as population demand, life expectancy is increasing around the world and the planet is getting greener (Piao et al., 2020; Walker et al., 2021) and many new technological advances in agriculture are developing rapidly (Walker and Buhler, 2020) including gene editing (Gao, 2021) and new laser biotechnology (Klimek-Kopyra et al., 2021). This is not to say that broad metrics cannot be useful and there are some interesting new approaches (Kraemer et al., 2020) but they need to demonstrate real world applicability and usefulness.
There are practically no conclusions, just some generalizations (3 sentences) not resulting from the content of the article. This also needs to be corrected.
Response: Thank you very much for your valuable advice. We have revised the conclusions to “Solutions to ensure the maximum food safety and water resources could include the following methods. First, less water can be used for irrigation, such as by using drip irrigation with film mulch, irrigating only in the critical period of crop physiological water demand or using underground drip irrigation with special crops. Second, more drought-resistant crops can be grown in areas with groundwater depletion, and drought-resistant crop varieties can be bred all over the world; additionally, targeted measures, such as metering and regulation of groundwater pumping, can be implemented. Third, food production can be coordinated and managed domestically and globally, such as by adjusting the main production grain regions to alleviate the intensification of groundwater depletion for irrigation, optimizing high water consumption crops in humid and semihumid areas, planting drought-resistant crops in arid and semiarid regions, and exporting the grain yield to countries with less food.
Increasing the food production of limited land resources with environmentally sustainable development is an even greater challenge. It is therefore necessary to assess the impact of urbanization on farmland expansion at the global, national, and subnational levels to identify potential conflict areas and conflict-forming strategies to identify more sustainable forms of urban expansion.
To achieve sustainable development, it is necessary to plan effective agricultural production systems, taking into account resource management and respecting natural services. Energy input-output analysis is often used to evaluate the relationship be-tween the efficiency of production systems and environmental impacts, but the bearing capacity of the environment is often neglected. Some researchers have used environ-mental assessment approaches, such as ecological footprint, material flow analysis, ecological network analysis, life cycle analysis, and energy and renewable energy, to assess environmental performance at different scales, focusing on sustainability analysis.” in this revision.
This advice is very valuable for us to improve the quality of the manuscript. We have tried our best to delete the repeat part in the results. We also revised the discussion part in this revision, please check it. Thank you again for your valuable advice.
We particularly appreciate your valuable advice.
Once again, thank you very much for your comments and suggestions.
Kind regards,
Prof. Xiukang Wang
Phone: +86-911-2332030
Fax: +86-911-2332030
Email: [email protected]
Author Response File: 
Author Response.pdf
Reviewer 2 Report
see the attached pdf file
Comments for author File: Comments.pdf
Author Response
Prof. Wang
Yan'an University, Yan'an, Shaanxi 716000, China
March 21, 2022
Dear Editor and Anonymous Reviewers:
The authors are thankful to you and anonymous reviewers valuable, detailed and professional comments on this paper.
As the corresponding author, I received an e-mail informing me that our manuscript (Ref: land-1636083, “Responses of different potato varieties to irrigation and fertilization strategies in the sandy loam soils of Northwest China”) has been reviewed, with the reviewer comments included. We were very glad to receive your e-mail. Thank you again for your letter and for giving us the opportunity to revise our manuscript. The authors are deeply grateful to all of you for your support and your careful review of our manuscript. We have studied the comments carefully and have made corrections, which we hope meet with your approval. The main corrections in the paper and the responses to your Comments are giving below.
The article clearly indicates the approach followed to address the issues discussed through review of literature (review article). Though its agricultural production boundary theory.
Response: Thank you very much for your recommendation. Thank you for sparing your precious time to help me improve the quality of my paper.
The title needs revision to ensure reflection of what is presented in text.
Response: Thank you very much for your valuable advice. We have revised the title to “Managing land carrying capacity: key to achieving sustainable production systems for food security” in this revision.
The abstract has no mention about small farmers
Response: Thank you very much for your valuable advice. We have revised the title to “Many previous studies have estimated the carrying capacity and feasible planetary boundaries for humankind. However, less attention has been given to how we will sustainably feed 9 billion people in 2050 and beyond. Here, we review the major natural resources that limit food production and discuss possible options, measures, and strategies to sustainably feed a human population of 9 billion in 2050 and beyond. Currently, food production greatly depends on external inputs, e.g., irrigation water and fertilizers, but these approaches are not sustainable. Due to the unbalanced distribution of global natural resources and large regional differences, urbanization expansion causes important areas to face more serious arable land resource shortages. Hence, sustainably feeding 9 billion people in 2050 and beyond remains an immense challenge for humankind, and this challenge requires novel planning and better decision-making tools. Importantly, the measures and strategies employed must be region/country-specific because of the significant differences in the socioeconomic characteristics and natural environmental carrying capacity in different parts of the world. Considering the impact of unexpected extreme events (e.g., a global pandemic and war) in the future, the food trade and translocation of goods will also face challenges, and the strategies and decision-making processes employed must consider the possible influences at both regional and global scales.” in this revision.
The main parts present only the global/macro level resources and their effect on crop production along with the ultimate carrying capacity. There is no any link to small farmers
Response: Thank you very much for your valuable advice. We have revised the title to “Managing land carrying capacity: key to achieving sustainable production systems for food security” in this revision.
The key issues in the text are (i) Major resources that affect food production, (ii) Carrying capacity of these resources, (iii) impact on food security, and (iv) global population growth.
Response: Thank you very much for your help. I have made modifications according to your suggestions. Thank you very much for your valuable advice, which is very helpful to improve the quality of my paper.
Thus, the title needs to be revised to reflect these issues.
Response: Thank you very much for your valuable advice. We have revised the title to “Managing land carrying capacity: key to achieving sustainable production systems for food security” in this revision.
The aggregate look of developed and developing countries in terms of the key issues discussed (resources and limitation in carrying capacity) may reduce the relevance of the arguments made. Even there is considerable different in resources and carrying capacity discussed for crop production among the developing countries. For example, one can recommend the same way in terms of resources and carrying capacity for crop production between north African countries and southern African countries.
Response: Thank you very much for your advice. What you said is very reasonable. We have tried our best to revise our paper. Thank you again for your help.
In addition, it is expected to somehow present a conceptual framework so that one can understand how the main natural resources indicated are related with (i) ultimate bearing capacity of natural resources, (ii) how they affect crop production thereby food security, and (iii) the population growth that is estimated to be 9 billion by 2050. This also demands relooking the structure of the article.
Response: Thank you very much for your advice. We have tried our best to revise our paper in this revision. I would like to ask for your help, and we will cooperate with you in the next article according to this idea. Thank you again for your guidance.
This advice is very valuable for us to improve the quality of the manuscript. We have tried our best to delete the repeat part in the results. We also revised the discussion part in this revision, please check it. Thank you again for your valuable advice.
We particularly appreciate your valuable advice.
Once again, thank you very much for your comments and suggestions.
Kind regards,
Prof. Xiukang Wang
Phone: +86-911-2332030
Fax: +86-911-2332030
Email: [email protected]
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Dear Author
The article has been corrected. I have no comments on the submitted article.
Reviewer 2 Report
I am glad that the author has addressed the concerns raised
