Harmonizing Population, Grain, and Land: Unlocking Sustainable Land Resource Management in the Farming–Pastoral Ecotone

Abstract

As an important means of production and habitation, land is the core natural resource for people’s life and production. However, the escalating demand for land resources, along with population growth, has created a pressing challenge at the intersection of land, population, and grain. In this study, we used a combination of temporal and spatial perspectives, along with spatial analysis methods, to analyze the supply and demand of land resources in the Northeast Farming–Pastoral Ecotone (NFPE) based on the population–grain relationship. The results show that the carrying capacity of land resources in this region increased gradually and the number of people it can carry increased from 34.23 million (2000) to 127.96 million (2018). From 2000 to 2018, the land resource carrying index (LRCI) was greater than 1.125, showing a state of surplus in grain, and the LRCI increased by 0.23 per year. Most areas in this region are in a state of grain surplus, with 13 counties showing a population and grain balance, and 2 counties being overpopulated. However, the increasing trend of land resource carrying capacity of the overpopulated areas and the balanced population–grain areas are notable. The carrying capacity of land resources in the NFPE generally exhibits a positive trend with a surplus of grain; however, there are spatial variations. Areas in the south and northeast demonstrate lower change trends, while the north and southeast exhibit higher change trends. This research provides critical insights into the dynamic interplay between land, population, and grain, enabling informed decision making for sustainable development in the NFPE and offering valuable lessons for similar regions globally.

1. Introduction

Land resources are fundamental natural and strategic economic resources that are unique and stable in the long term [1]. They are essential not only for human survival and development but also for agricultural production, food security, urban and rural construction, and environmental protection, as well as for economic and social development [2,3]. Therefore, the utilization and management of land resources are of great significance for maintaining people’s livelihoods, promoting national economic and social development, and achieving sustainable economic, social, and environmental development [4,5]. As a result of the growing population and rapid urbanization, the protection and management of land resources have become increasingly more critical, and effective measures for their protection and rational utilization are required to ensure sustainable economic, social, and environmental development [6,7].

The carrying capacity of land resources is a crucial factor that affects regional economic development and ecological protection. It is an essential indicator for evaluating land resources [8]. In recent years, there has been a growing body of research conducted by scholars on the carrying capacity of land resources, leading to significant advancements in the field. Researchers are dedicated to developing comprehensive assessment methods and techniques to quantitatively evaluate and assess the carrying capacity of land resources, aiming to identify effective strategies for sustainable land use and resource management [4,9,10]. International collaboration and knowledge sharing have played a vital role in advancing the research on land resource carrying capacity, offering essential support and guidance for global sustainable development. By conducting holistic evaluations of a land’s material, energy, and ecological functions, researchers can determine the capacity of the land to sustain population and economic activities under conditions of sustainable development [11]. This research holds great significance for regional planning, land use management, and decision-making pertaining to sustainable development. The utilization of remote sensing technology and geographic information systems has further aided researchers in acquiring accurate spatial data required for assessing land resource carrying capacity, thereby enhancing the precision and credibility of their studies. Nevertheless, challenges persist in this field, including data acquisition, the selection of evaluation indicators, uncertainty analysis, and accounting for variations in carrying capacity across different scales [12]. Future research endeavors should address these challenges to enhance the reliability and applicability of land resource carrying capacity assessments, ultimately better supporting sustainable land use and resource management.

The carrying capacity of land resources refers to the ability of land to sustainably support a certain number of people in a specific area while maintaining production capacity [13,14]. It involves investigating the balance between population consumption and food production and human demand and resource supply, and reflects the ecological security status and level of development of the area [15]. The land resource carrying capacity is an essential concept for sustainable development, and the human–grain relationship is a key factor affecting the land resource carrying capacity [16]. Food is a critical material basis for human survival, and food issues are fundamental in maintaining social stability and promoting economic development [17]. With rapid population growth, decreasing cultivated land, and poor land production capacity, the conflict between limited land resources and increasing human demand for them has become more prominent [18]. The conflict between land resources, population, and food endangers regional and even national food security [19]. Therefore, quantitative analysis of the carrying capacity of land resources based on the relationship between land resources, population, and food is essential not only for ensuring food security but also for achieving regional sustainable development.

The Northeast Farming–Pastoral Ecotone (NFPE) is situated in the northern part of China, where agriculture and animal husbandry intersect. This area is susceptible to ecological pattern changes caused by multiple factors, including climate change and human activities [20]. It is also a contiguous destitute area and a typical ecologically fragile region in China, where economic poverty and ecological degradation coexist, and poverty alleviation and development are separated from ecological construction [21]. The NFPE is crucial for the construction of China’s “two screens and three belts” ecological security barriers and the main implementation area for major national ecological projects, such as the Three North Shelterbelts, returning farmland to forests and grasslands, and Beijing–Tianjin sandstorm source control [22]. However, the problems of an unbalanced agricultural and animal husbandry structure and unbalanced and unsustainable development in this region have been prominent for a long time [23].

The NFPE is a region abundant in land resources with a diverse range of land use practices [24]. The NFPE is a critical region in China that faces significant challenges regarding the supply and demand of land resources [25,26]. Innovatively, this study addresses the pressing need for rational utilization of land resources in the NFPE, a region of paramount importance for national food security in China. By uniquely utilizing the relationship between population dynamics, grain production, and land resources, this research quantitatively evaluates the temporal and spatial differences in the carrying capacity of land resources over the past two decades. Through a comprehensive analysis of the supply and demand dynamics of land resources, this study seeks to provide decision support for enhancing national food security and facilitating sustainable agricultural development in the NFPE region. By leveraging this approach, we aim to contribute valuable insights and practical solutions to the ongoing challenge of harmonizing regional population growth, resource availability, and environmental preservation.

2. Materials and Methods

2.1. Study Area

The NFPE is situated at the confluence of semi-humid and semi-arid regions and is suitable for grassland and arable agriculture development. It plays an essential role as an ecological security barrier in the central and eastern parts of China [27]. The diverse ecosystems of the region, including farmland, grassland, forest, sandy land, and wetland, are distributed in a mosaic pattern and exhibit high spatial and environmental heterogeneity [28]. The average elevation of the NFPE is 475 m. Due to environmental changes and its sensitivity, the region is prone to ecological degradation, which is difficult to recover naturally, making it a typical ecologically sensitive and vulnerable area [29]. The NFPE covers four provinces, including Inner Mongolia Autonomous Region, Heilongjiang Province, Jilin Province, and Liaoning Province, and encompasses 11 cities and 64 counties (Figure 1).

2.2. Data Resources

This study uses various datasets to analyze the land resource carrying capacity in the NFPE. The research data span from 2000 to 2018. The datasets consist of demographic information, such as the total population, urban population, and rural population at the end of each year in each banner county, as well as economic statistics such as grain production, and agricultural statistics such as planted area. The data were primarily obtained from the annual statistical yearbook of Heilongjiang, Inner Mongolia, Jilin, and Liaoning [30,31,32,33].

2.3. Methods

The concept of land resource carrying capacity refers to the balance between population consumption and grain production, as well as human demand and resource supply [34]. It aims to determine the maximum population size that can be sustained based on the production potential of the land. In this study, we establish a land resource carrying index (LRCI) based on the relationship between human population and grain production to evaluate the land resource carrying capacity of the NFPE.

The population-carrying capacity of land resources is the maximum population size that can be supported by regional grain productivity, reflecting the relationship between population and grain in a certain area. The formulas used for calculating the land resource carrying capacity are as follows:

$$PLRCC=\frac{G}{G_p}$$

(1)

where $\mathrm{PLRCC}$ denotes the population-carrying capacity of land resources (persons), $G$ represents the total grain output (kg), and $G_p$ denotes the per capita grain consumption standard (kg/person). The per capita nutritional calorific value standard published by the Food and Agriculture Organization of the United Nations was used to calculate the per capita grain consumption standard. Based on China’s national conditions, many domestic experts have proposed that a per capita grain consumption of 400 kg can meet the requirements of nutritional security [35,36].

$$\mathrm{LRCI}=\frac{PLRCC}{P_a}$$

(2)

where $\mathrm{LRCI}$ is the land resource carrying index, $PLRCC$ is the population-carrying capacity of the land resource (persons), and $P_a$ is the actual population (persons).

Using the LRCI value, we divided the carrying capacity of land resources in different areas of the NFPE into the following three types: overpopulation, population–grain balance, and grain surplus. The LRCI-based land resource carrying capacity classification evaluation criteria are as follows:

(1)

Overpopulated area: LRCI is less than 0.875, with a per capita grain consumption of less than 356 kg, indicating a large grain gap and severe population overload.

(2)

Balanced population and grain area: LRCI is between 0.875 and 1.125, with a per capita grain consumption between 356 and 457 kg, indicating a balanced relationship between population and grain, but limited development potential.

(3)

Grain surplus area: LRCI is greater than 1.125, with a per capita grain consumption of more than 457 kg, indicating a surplus of grain production and development potential.

In order to further explain the gap and potential of the land resource carrying capacity, we calculate the population surplus ratio (PSR).

$$\mathrm{PSR}=\frac{\left(PLRCC-P_a\right)}{PLRCC}\times 100$$

(3)

where $\mathrm{PSR}$ is the population surplus ratio (%), $PLRCC$ is the population-carrying capacity of land resources (persons), and $P_a$ is the actual population (persons). The PSR reflects the difference between the actual population and the population that can be carried by land resources, and it indicates the rationality and sustainability of the use of land resources. A positive value indicates that land resources are not fully utilized, and a negative value indicates that land resources are overutilized. The higher the absolute value of the population surplus rate, the greater the gap in land resource utilization. The linear slope of LRCI over time depicted the geographical differences and trends effectively and precisely [37]. A negative value of the slope indicates an overall decrease in land resource carrying capacity; a positive value indicates an increase in land resource carrying capacity. The linear trend slope was calculated for each county for certain periods via ArcGIS using the following formula:

$$\mathrm{slope}=\frac{n\times {{\displaystyle \sum }}_{i=1}^{n}i\times Y_i-{{\displaystyle \sum }}_{i=1}^{n}i{{\displaystyle \sum }}_{i=1}^n{Y}_i}{n\times {{\displaystyle \sum }}_{i=1}^n{i}^2-\lfloor {{\displaystyle \sum }}_{i=1}^n{i}^2\rfloor }$$

(4)

where $n$ is the study period and $Y_i$ represents the LRCI for year $i$ ($i$ = 1,2…$n$); here, $i$ is the sequence number of the year.

3. Results

3.1. Population and Food Situation in NFPE

From 2000 to 2018, the population in the NFPE exhibited a stable trend, whereas the area of cultivated land and grain production initially experienced a gradual increase before stabilizing. In 2000, the total population was 21.76 million, peaking at 24.31 million in 2009, and then subsequently maintaining a steady fluctuation. By 2018, the total population in the NFPE reached 23.62 million, with an average annual population growth of 4.67 million people (Figure 2a). The area of cultivated land in the NFPE increased from 6.33 million hectares in 2000 to 9.71 million hectares in 2018, with an average annual increase of 249,000 hectares (Figure 2b). Moreover, the grain output in the NFPE increased from 13.69 million tons in 2000 to 51.18 million tons by 2018, demonstrating an average annual growth of 2.24 million tons (Figure 2c).

Over the last two decades, the NFPE has witnessed a stable grain demand, whereas the grain output has consistently increased (Figure 2c), resulting in an upward trend in grain surplus (Figure 3). From 2000 to 2018, the annual grain demand in the region averaged 9.52 million tons, with a yearly increase of 17,529 tons (Figure 3a). The grain surplus exhibited an upward trend over this period, with an average annual surplus of 25.64 million tons and an average annual increase of 2.22 million tons (Figure 3b).

3.2. Carrying Capacity of Land Resources in NFPE

The PLRCC model was used to assess the population-carrying capacity of the land resources in the NFPE from 2000 to 2018. The findings indicate a gradual increase in the population-carrying capacity of land resources during this period. The number of individuals that could be sustained by the land resources increased from 34.23 million in 2000 to 127.96 million in 2018. The average annual population of the land was 86.44 million, with an average annual growth rate of 5.60 million (Figure 4a).

Analyzing the population-carrying capacity of land resources in each city reveals variations. Qiqihar City demonstrates the highest population-carrying capacity, with an annual average of 19.59 million, followed by Songyuan City with 15.39 million. In contrast, Chifeng City exhibits the lowest carrying capacity at 9.58 million. Moreover, Qiqihar City has the highest average annual increase in the number of people it can carry, with an annual growth of 1.64 million individuals, whereas Chifeng City has the lowest increase, averaging 0.55 million people annually (Figure 4b).

3.3. Supply and Demand of Land Resources in NFPE

Considering the recommended per capita food consumption of 400 kg for ensuring nutritional security, the grain output in the NFPE consistently exceeds the population demand. By analyzing the carrying capacity of land resources in each city, it is possible to observe that in 2000, Chifeng City, Chaoyang City, Qiqihar City, and Daqing City faced population overload, while the remaining cities were in a state of grain surplus. In 2001, Chifeng City transitioned to a grain surplus area, while the other three cities continued to experience population overload. In the subsequent year, only Qiqihar City remained in a state of population overload, with Daqing City and Chaoyang City achieving a balanced population and grain condition. In 2003, Daqing City, Qiqihar City, and Chaoyang City were again in a state of population overload, with Qiqihar City being the only city in this category in 2004. From 2005 to 2018, all cities were in a state of food abundance, except for Qiqihar City in 2007 and Chaoyang City in 2009, signifying a balance between population and grain (Figure 5).

From a spatial perspective, the average LRCI in the NFPE during the period of 2000 to 2018 was 3.62, indicating a predominantly state of grain surplus across most areas. Only two counties in the southern region were identified as overpopulated, while thirteen counties in the south and northeast exhibited a balanced population–grain condition (Figure 6a). The LRCI from 2000 to 2018 exceeded 1.125, indicating an abundance of food resources (Figure 6b). Over the past 19 years, the LRCI displayed a positive trend of 0.23 per year. Regions in the southern and northeastern parts of the NFPE demonstrated relatively lower change trends, whereas areas in the northern and southeastern parts exhibited relatively higher change trends. The change trends in land resource carrying capacity were minimal in both the population balance area and the population overload area, while the change trend in land resource carrying capacity differed in the grain surplus areas; greater trends were observed in the majority of northern regions, whereas the southern and central regions experienced comparatively smaller changes (Figure 6b).

The average population-carrying capacity surplus rate in NFPE is 68.10%. Additionally, it shows an increasing trend, rising from 36.45% in 2000 to 81.54% in 2018, indicating an annual increase of 2.33%. From 2000 to 2009, there was a spike in volatility, followed by a slowdown in the upward trend (Figure 7b). In the majority of NFPE areas, the population-carrying capacity surplus rate is relatively high (>60%), while several counties in the south exhibit a relatively low population-carrying capacity surplus rate (0–20%), and some western and central areas have a surplus rate of 20–40%. The population surplus ratios of the overpopulated regions and the population–grain-balanced regions are both less than zero (Figure 7a). The overpopulated areas and the balanced population and grain areas exhibit a low population-carrying capacity surplus rate; however, they exhibit a relatively high increasing trend (>6%/year). Most regions with a high population-carrying surplus ratio (>60%) have a relatively low increasing trend of change (<3%/year) (Figure 7b).

4. Discussion

The land resource carrying capacity is a pivotal concept for promoting sustainable land management and development [38]. It encompasses the capacity of land to meet the needs of both humans and the ecosystems, including food production, biodiversity conservation, and environmental protection [39]. Evaluating land resource carrying capacity is crucial for effective land use planning and management. Understanding the relationship between human population and grain production is essential for analyzing the supply and demand dynamics of land resources [10]. It plays a key role in optimizing land resource utilization and ensuring food security [40]. The NFPE is a critical region in China that faces significant challenges regarding the supply and demand of land resources. Therefore, we estimated the land carrying capacity of the NFPE based on the interaction between the human population and grain supply, analyzed its temporal and spatial variations, and then discussed the dynamic balance of resource supply and consumption in this region. This study provides insights into the sustainable development of land resources based on the human–grain relationship.

4.1. Supply and Demand of Land Resources in NFPE

Between 2000 and 2018, the NFPE saw a positive development in its land resource carrying capacity. The population growth remained stable during this period, while the cultivated land area showed a consistent increase. Additionally, there was a rise in the per capita cultivated land area, and the grain yield per unit area continued to grow. These increases in cultivated land area, production capacity, and quality have led to a region with a stable and consistently high level of grain production capacity [41]. As a result, the carrying capacity of land resources has gradually increased.

In terms of spatial distribution, the majority of the NFPE experiences a grain surplus, with 13 counties in population and grain balance and 2 counties in population overload. These are the Hongshan District of Chifeng City and Lingyuan City, where the small cultivated land area and high population density in the municipal districts are the primary factors contributing to the overload. Consequently, there is a tense relationship between population and grain in these areas, and their food demand is met through trade and redistribution from other areas [42]. Addressing the issue of grain imbalance requires a long-term and systematic process that involves the collective effort and sustained attention of all stakeholders [43,44]. Agricultural productivity can be improved by promoting energy-saving and environmentally friendly agricultural production methods, as well as by adjusting the food supply structure to meet the growing demands of population and food [45,46]. Scientific and technological innovation and land management can improve agricultural production efficiency and arable land output while reducing damage to land and resources. This improves the sustainability of land productivity and capacity. The grain supply structure should be adjusted rationally, with diversified operations and planting promoted, optimizing the agricultural industrial structure and increasing food variety to meet regional and consumer demands [47].

Today, food consumption has become more diversified, and solely considering grains has limitations. Neglecting the contribution of meat, eggs, milk, and other food sources in the NFPE can impact the land resource carrying capacity. In addition, China’s per capita grain levels, food consumption structure, and dietary nutrition structure have changed. The food structure has evolved beyond its sole reliance on grains, encompassing a diverse range of sources such as meat, eggs, milk, vegetables, fruits, and other food items [48]. In the future, to explore the carrying capacity of land resources based on the relationship between population and food, we need to comprehensively consider various types of food and changes in the food structure. This will help us seek adaptive strategies for the sustainable use of land resources, improve the resource- and environmental carrying capacity, and provide scientific support for the sustainable and high-quality development of the NFPE.

4.2. The Factors Affecting the Land Resources’ Carrying Capacity

The carrying capacity of land resources is influenced by many factors including natural environmental factors, socioeconomic factors, land use patterns, ecological environment factors, environmental protection strategies, and sustainable development strategies [10,49]. Natural environmental factors such as climate, soil fertility, land type, and water resources affect the carrying capacity of land resources. The carrying capacity of land resources is also influenced by many socioeconomic factors, including population size and structure, urbanization, economic development level, technological innovation level, agricultural productivity, and policies and regulations [50]. These factors play a vital role in shaping the potential of land resources to sustain human activities and development. Furthermore, land use patterns, encompassing the type of land, the method of land use, and land management practices significantly impact the carrying capacity of land resources [51]. Ecological and environmental factors, such as biodiversity and ecological balance, are also essential considerations in determining the carrying capacity of land resources. In addition, environmental protection policies and sustainable development strategies can regulate land use and mitigate the adverse effects of human activities on the environment, influencing the overall capacity of land resources [52].

4.3. The Sustainable Use of Land Resources

Land serves as the fundamental basis for agricultural production, and the efficient utilization of land resources is of the utmost importance in enhancing agricultural productivity and ensuring food security [53]. Additionally, land resources form the basis of both urban and rural development, encompassing housing and infrastructure construction. Effectively managing land resources is crucial for promoting the coordinated growth of urban and rural areas [54]. Furthermore, land resources play a pivotal role in facilitating industrial development and enhancing competitiveness by accommodating production plants, storage facilities, logistics distribution centers, and other industrial purposes. However, it is equally important to prioritize environmental protection while utilizing land resources. This can be achieved through the rational planning and development of land, ensuring the preservation of the ecological environment and natural resources, and minimizing environmental pollution and ecological damage [55]. Ultimately, the use of land resources should be balanced, considering its economic, social, and environmental consequences, to achieve sustainable development. To achieve a sustainable use of land resources, we need to focus on land management and planning, promote ecological agriculture, strengthen land protection, develop circular economy, and enhance land monitoring and evaluation. The scientific planning and management of land resources is crucial for a sustainable use [56]. The government should formulate rational land use policies and plans to ensure the appropriate allocation and utilization of land resources. Ecological agriculture is a sustainable way to use land resources, which protects soil, water, air quality, and biodiversity through reasonable agricultural production methods to achieve sustainable agricultural development. Strengthening land protection will prevent over-exploitation and irrational use of land resources, maintain the stability of land ecosystems, and protect people’s livelihoods and the natural environment. By advocating for resource recycling and actively minimizing waste and pollution, we can strive towards the objective of a sustainable utilization of land resources. Additionally, through the implementation of scientific land monitoring and evaluation, we can obtain timely information on the utilization status and dynamics of land resources. This enables us to develop sound land use plans and policies that promote rational and sustainable practices for the utilization of land resources [57].

5. Conclusions

The formulation of China’s land use policy is a comprehensive process that takes into account economic, social, and environmental factors. Government departments initiate this process by establishing the background and objectives of the land use policy. Subsequently, they engage experts, research institutions, and stakeholders to conduct thorough research and consultations. These activities aim to gain a comprehensive understanding of land resource conditions, identify existing problems, and determine the needs of various stakeholders. This study focused on the NFPE and incorporated temporal and spatial perspectives, along with spatial analysis methods, to visualize the spatial–temporal pattern characteristics of the land resource carrying capacity of the NFPE. The analysis investigated the supply and demand of land resources, leading to the following conclusions: Between 2000 and 2018, the land resource carrying capacity in the NFPE increased gradually, and the grain output consistently exceeded the population demand. The trend is upward. Spatial differences in the land resource-carrying capacity are evident, with most areas presenting a surplus of food. Furthermore, 13 counties in the south and northeast have a balanced relationship between population and food, whereas 2 counties in the south experience population overload. The change trend in the LRCI varied across different regions, with a small change in parts of the south and northeast, and a significant change in parts of the north and southeast. Notably, the overpopulated areas and the population–grain balanced areas exhibited a minimal change in the LRCI, whereas the grain surplus area exhibited a different change trend.