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Review

Analysis of Research Trends and Comprehensive Utilization Solutions for Saline–Alkali Land

by
Jingyan Huang
1,2,
Yehua Shang
1,*,
Yuqi Chen
3,
Lingying Xu
3,*,
Yanping Yang
1,2 and
Xu Zhao
3,4,5
1
National Science Library, Chinese Academy of Sciences, Beijing 100049, China
2
Department of Information Resources Management, School of Economics and Management, University of Chinese Academy of Sciences, Beijing 100190, China
3
Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China
4
University of Chinese Academy of Sciences, Nanjing 211135, China
5
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China
*
Authors to whom correspondence should be addressed.
Sustainability 2025, 17(11), 5202; https://doi.org/10.3390/su17115202
Submission received: 28 April 2025 / Revised: 27 May 2025 / Accepted: 2 June 2025 / Published: 5 June 2025
(This article belongs to the Section Soil Conservation and Sustainability)
Browse Figures
Versions Notes

Abstract

:
The management and use of saline–alkaline land is a global concern and research focus. Although there is extensive long-term global research on soil salinization and improvement, systematic summaries of research progress in this field are insufficient. This study, based on the Web of Science (WOS) and incoPat database, analyzes the literature and patents on saline–alkaline land over the past 30 years, sums up research progress and current status, and proposes future directions to lay a foundation for further study. Research hotspots are mainly salt-tolerant plant growth mechanisms and gene expression under salt stress, interactions between salt-tolerant plants and microbes, soil conditioner use, remote sensing monitoring of saline–alkaline land changes, irrigation and drainage techniques, and soil nutrient status and improvement. Saline–alkaline land management research is moving toward integrated application of multiple improvement measures. Priority should be given to developing land remediation technologies and salt-tolerant plant varieties suited to different regions; studying the compatibility among technologies, plant varieties, and cultivation techniques; establishing region- and type-specific integrated management and ecological use methods; and creating comprehensive development plans to boost soil productivity and protect the ecology.

1. Introduction

Saline–alkali land is a general term for land resources characterized by saline soils, alkaline soils, and other soils with varying degrees of salinization and alkalization [1]. Saline soils contain high concentrations of soluble salts, which hinder plant growth by affecting water uptake, while alkaline soils are dominated by high pH levels and sodium content, disrupting soil structure and nutrient availability [2]. The Global Map of Salt-Affected Soils, released by the Food and Agriculture Organization of the United Nations (FAO) in 2024, indicates that over 1381 million hectares of salt-affected soils exist worldwide, accounting for 10.7% of the earth’s surface and impacting the food security of more than 2.4 billion people globally due to high salinity of irrigated soil [3]. The top 10 countries with the largest area of saline soil in the world are Australia, Argentina, Kazakhstan, Russia, the United States, Iran, Sudan, Uzbekistan, Afghanistan, and China. The total area of saline soil in these ten countries accounts for 70% of the global total saline soil area. In recent years, under the combined effect of climate change and human factors, the problem of soil salinization has become increasingly serious, and the area of salinized land has been increasing year by year [4]. The existence of saline–alkali land restricts the effective utilization of land and the sustainable development of the economy, threatens the national food production security [5,6], and poses challenges to regional economies, ecosystems, and sustainable development [7,8,9]. Therefore, the comprehensive transformation and utilization of saline–alkali land are crucial for expanding agricultural production capacity.
National policy support is an important prerequisite for the comprehensive utilization research of saline–alkali land. Many countries have introduced relevant policy initiatives to promote the governance and efficient use of saline–alkali land. For instance, Australia has implemented the National Action Plan for Salinity and Water Quality (NAP) [10], which provides financial support for measures addressing the salinity and water quality issues in agriculture, communities, and the environment. The aim is to strengthen the management of saline–alkali land and reduce the degree of salinity in drylands. In the “Soil Strategy for 2030” [11], the European Union regards salinization as a serious threat to land degradation, focusing primarily on mitigating salinization and implementing prevention and control measures for soil salinization. Middle East countries regard saline–alkali agriculture as an innovation and investment priority, developing advanced technologies such as seawater desalination, drip irrigation, and atmospheric water collection [12]. From the “11th Five-Year Plan” to the “14th Five-Year Plan”, China has implemented several key projects for saline–alkali land treatment and has researched and demonstrated key technologies for different types of saline–alkali land [13].
Academic research provides the scientific basis, technological innovations, and solutions for agricultural challenges caused by salinization. To address salinization and promote relevant fields, many international institutions specializing in saline agriculture have been established. The FAO has set up several networks and working groups focusing on salinization, such as the International Network of Salt-affected Soils (INSAS), the Water Scarcity in Agriculture Global Framework (WASAG), the Saline Agriculture Working Group (SAWG), and the Global Alliance for Climate-smart Agriculture (GACSA). These platforms facilitate the sharing and collaboration of innovative approaches to saline–alkali land management. The United States Department of Agriculture (USDA) has established the Salinity Laboratory-Agricultural Water Efficiency and Salinity Research Unit, which is internationally recognized. It aims to develop methods and management practices for assessing, predicting, and managing the movement of substances in the soil roots and solutes (such as water, salts, pesticides, and microorganisms) of arid regions. This enables sustainable and economical plant production using saline water or salt-affected soils while protecting water and soil resources. India established the Central Soil Salinity Research Institute (CSRI) of the Indian Council of Agricultural Research (ICAR) in 1969, which is dedicated to interdisciplinary research on saline management and utilization of poor-quality irrigation water in different agro-ecological zones of the country.
China has attached great importance to academic research, technological innovation, and comprehensive utilization strategy of saline–alkali land. In China, the total area of salt-affected soils is approximately 36 million hectares, ranking tenth globally [3]. The types of saline–alkali land are diverse and are distributed across a wide range of climatic and geographical regions, including tropical and temperate zones, coastal and inland areas, as well as humid and extremely arid environments. Since the 1960s, a group of scientists proposed and implemented a soil salinization management model centered on “well irrigation and well drainage”, which greatly promoted the improvement of saline–alkali land in the Huang-Huai-Hai Plain and the increase in grain production. Yao et al. [14,15,16] finely portrayed the multi-scale soil water–salt process through multiple models to use farmland management measures to regulate solute transport in a targeted manner. Zhao et al. [17] changed the traditional improvement ideas and screened out high-quality “salt-consuming” plants such as Suaeda salsa, Atriplex aucheri, and Salicornia europaea. Luo et al. [18] have developed new leguminous forage varieties of Sesbania, from which the saline–alkali-tolerant and high-yielding “Zhongkejing” series were selected. These theories and technological innovations have made significant contributions to the sustainable use of saline–alkali land.
However, in the face of a large number of international academic achievements, there remains a lack of systematic and comprehensive bibliometric analyses of global research on saline–alkali land. This hinders the accurate grasp of future research hotspots and development trends in the field of saline–alkali land. In conclusion, analyzing the research trends of saline–alkali land is of great significance for formulating more scientific and effective governance strategies and promoting the sustainable development of agricultural production. In order to clearly sort out the current situation and potential of global saline–alkali land development, this study searched the Web of Science (WOS) full-text database and the incoPat patent database and used bibliometric methods and the visualization software VOS viewer 1.6.20 to visualize and analyze the data of the papers and patents in the field of saline–alkali land in the world from 1995 to 2024, aiming at grasping the dynamics and development trends of international saline–alkali land research, summarizing the shortcomings of current research, and analyzing the future research directions. The purpose of this study is to grasp the dynamics and development trend of international research on saline–alkali land, summarize the current research deficiencies, and forecast the future research direction, so as to provide reference and inspiration for the subsequent related research.

2. Data Sources and Research Methodology

In order to comprehensively reflect the research trends on saline–alkali land, this study selected the Web of Science (Clarivate Analytics, Philadelphia, PA, USA) Core Collection (SCI-Expanded) and the incoPat (Beijing Patsnap Technology Co., Ltd., Beijing, China) patent database as the data sources for analyzing research papers and patents. The Web of Science, developed by Clarivate Analytics, is a globally recognized citation database that indexes high-quality journals across disciplines and provides complete bibliographic and citation data. The incoPat database integrates over 190 million patent records from more than 170 countries and regions, including data from the Derwent World Patent Index (DWPI), and provides multilingual coverage with enriched data fields, making it a reliable source for global patent analysis. The retrieval data time period was from 1 January 1995 to 31 December 2024. Only records classified as “Article” and “Proceedings Paper” were included in the literature analysis, resulting in a total of 12,974 publications. For patent analysis, 9498 valid entries were obtained.
In the WOS Core Collection (SCI-Expanded), the search strategy for academic papers was as follows: TS = (“saline-alkali* soil” OR “saline-alkali* land” OR “salt-affected soil” OR “salt-affected land” OR “salin* soil” OR “salin* land” OR “alkali* soil” OR “alkali* land” OR “saline sodic calcareous soil” OR “saline calcareous soil” OR “sodic soil” OR “saline -sodic soil” OR “saline-sodic land” OR “soil salinity” OR “soil sodicity” OR “soil salinizat*” OR “soil sodificat*”).
In the incoPat database, using TIAB = (“saline-alkali* soil” OR “saline-alkali* land” OR “salt-affected soil” OR “salt-affected land “ OR “saline* soil” OR “saline* land” OR “alkali* soil” OR “alkali* land” OR “saline sodic calcareous soil” OR “saline calcareous soil” OR “sodic soil” OR “saline-sodic soil” OR “saline-sodic land” OR “soil salinity” OR “soil sodicity” OR “soil salinizat*” OR “soil sodificat*”) OR (TIAB = (salinity- tolerance OR salt-tolerance OR saline-tolerance OR salt-resistance OR salt-endurance OR salt-tolerant OR salinity-resistance OR saline-alkaline tolerance OR “saline-alkaline” OR “saline-alkaline soil” OR “salinization” OR “salt-stress” OR “salt-resistance”) AND IPC = (A01) as the search formula.
Based on the retrieval results of papers and patents, this paper uses a bibliometric method to conduct quantitative statistics and qualitative analysis on the research output in the field of saline–alkali land over the past nearly 30 years. This covers aspects such as the annual trend distribution, distribution of major countries and regions, analysis of research hotspots, and the trend of topic evolution. The visualization analysis was performed using VOSviewer software (version 1.6.20; Centre for Science and Technology Studies [CWTS], Leiden University, Leiden, The Netherlands) to generate keyword co-occurrence and clustering networks, highlighting research hotspots in this field. Additionally, keyword hotspot evolution maps are generated to analyze the evolution trend of research hotspots over time and explore their change patterns, so as to grasp the key direction of future research.
It is worth noting that saline–alkali land includes both natural and secondary saline–alkali soils, but because natural and human drivers of salinization are often interwoven, and both types of saline–alkali soils have value for development and utilization, this article does not make a deliberate distinction between them. Among natural factors, intensified drought due to climate change, freshwater scarcity, salinization of surface and groundwater, and rising sea levels are key drivers. Among human factors, improper irrigation practices, inadequate drainage systems, overexploitation of groundwater in coastal and inland areas, and excessive fertilizer use may all contribute to secondary salinization.

3. Results

3.1. Annual Trend Distribution

This paper analyzed 12,974 research papers in the field of global salinization over the past 30 years (1995–2024). As shown in Figure 1, the output of global research papers in this field has generally increased. During 1995–2006, the number of papers increased slowly, and the annual number of papers was less than 200, with a slow and fluctuating increase. During the period of 2007–2015, the number of papers steadily climbed up. From 2015 to 2024, it entered a period of rapid growth, indicating that saline–alkali land research has gained increasing international attention. In 2023, the number of annual papers in this field reached a historical peak of 1493, with a compound annual growth rate of 9.52% from 1995 to 2023. In 2024, the number of papers declined slightly to 1460, but it still remained at a high level.
Global patents in the saline–alkali land field also show a general upward trend, as shown in Figure 2. From 1995 to 2024, 9498 patents were filed worldwide. Between 1995 and 2009, the number of patent applications in this field grew slowly, and the annual number of applications fluctuated within 100 pieces. From 2010 to 2017, the annual number of patent applications in this field increased rapidly and reached a historical peak of 1047 in 2017. During these eight years, 3047 patents were applied for, accounting for 32.1% of the total. This indicates that the field has received significant attention, with many researchers and enterprises actively involved in related technological innovations. Since 2017, the number of patent applications in this field has fluctuated between 700 and 1000 annually. Due to the 18-month lag between initial examination and publication, 2024’s published data are incomplete and for reference only.

3.2. Analysis of Major Countries/Areas

3.2.1. Number of Papers and Patents Published in Major Countries/Regions

Table 1 presents the major countries and regions with the output of papers and patents in the field of salinization during 1995–2024. The country attribution of each paper was determined based on the affiliation of the corresponding author, while the country of each patent was identified according to the affiliation of the first applicant. In terms of papers, China ranks first with 4973 papers, accounting for 38.33% of the total number of papers in the world, which is much higher than that of other countries. The United States and India ranked second and third with 934 and 904 papers, respectively. Australia has more than 500 papers, but remains far behind China, the US, and India. All other countries have fewer than 500 papers each. In terms of patents, the main applicant countries are China, the United States, Republic of Korea, Japan, Russia, and so on, in turn. Among them, the major countries in Asia, North America, and Europe have occupied the dominant positions. It is worth noting that China has made a cliff lead in these data, with the number of relevant patents having exceeded 8000, accounting for 92.75% of the total global patent applications in this field, far ahead of the second-ranked United States (1.92%) and third-ranked Republic of Korea (1.39%). In terms of the number of papers and patents published, China is a major scientific research output country in the field of saline–alkali land. China’s proportion of papers and patents in this field exceeds 35% globally, significantly higher than the second-ranked United States.

3.2.2. Annual Trends of Papers and Patents in Major Countries/Regions

Taking every five years as a time period, we focus on analyzing the development trends of papers and patents in major countries/regions in this field from 1995 to 2024. Judging from the time trend of paper publication (Figure 3), five countries, namely China, the United States, India, Australia, and Japan, had already carried out research related to saline–alkali land in the 1990s. The United States held a certain dominant position during the period from 1995 to 2004 and ranked first in the number of papers. China started relatively late in the research of this field, but its development has been rather rapid. Since the period from 2005 to 2009, China surpassed the United States and became the number one in the world in terms of the number of papers published. During the period from 2020 to 2024, the number of papers in China totaled 3261, which was 3.6 times the sum of the number of papers of the countries ranking second to fifth in the same period. After 2010, the rapid increase in the number of research papers in the field of saline–alkali land in China may be related to the gradual attention paid to the entire field, while China’s R&D investment in this field may have accelerated the growth of papers and patents.
From the perspective of patent application trends (Figure 4), the top five countries in turn are China, the United States, Republic of Korea, Japan, and Russia. From 1995 to 1999, the United States took the lead in patent applications in the field of saline–alkali land. After entering 2000, the number of patent applications in China rose rapidly and gradually surpassed that of the United States, rising to become the country with the largest number of patent applications in the world. During the period from 2020 to 2024, the number of patent applications in China totaled 4199, far ahead of the countries ranking second to fifth in the same period.

3.2.3. Research Impact in Major Countries/Regions

Analyzing the research impact of major countries/regions in the field of saline–alkali land during 1995–2024, each paper was attributed to a country based on the affiliation of the corresponding author, and each patent was assigned according to the affiliation of the first applicant. In terms of the impact of papers from major countries (Table 2), China ranked first in the total citation frequency of papers with 106,016 citations, far ahead of the United States (31,716), which ranked second. India ranks third with 22,526 total citations. In terms of average citation frequency, Canada ranks first with 38.47 citations. The United States (33.96 citations) and Australia (33.15 citations) ranked second and third, respectively. In contrast, China’s average citation frequency is 21.32 times, which is lower than the world average (24.07 times).
Taking the papers ranked in the top 10% in terms of citation frequency in this field to represent the output of high-impact papers, there were a total of 1302 papers. Among the high-impact papers, China took a far leading position with 416 papers compared to other countries. In terms of the proportion of high-impact papers in the number of papers published by each country, the United States ranked first with a proportion of 15.95%, while China’s proportion was only 8.37%, lower than the global level.
We selected the patents with a value degree of 10 in the incoPat database as high-value patents in this field for analysis. The degree value is a patent quality indicator provided by incoPat, ranging from 1 to 10, with a score of 10 representing patents with strong technical stability, high innovation, and broad protection scope. As a result, a total of 447 high-value patents were retrieved. Judging from the patent influence of major countries (Table 3), China, the United States, and Japan ranked among the top three in terms of the number of high-value patents, accounting for 49.22%, 18.57%, and 13.65% of the total number of global high-value patents, respectively. Among them, China had the largest number of high-value patents, far higher than that of other countries, showing an obvious advantage. However, in terms of the proportion of high-value patents in the total number of patents among its own country, China’s proportion was relatively low, only 2.50%, ranking at the bottom among the top ten countries in terms of the number of high-value patents.
Although China leads the world in both the total number of publications and patents related to saline–alkali land, it still lags behind countries such as the United States, Australia, and Canada in terms of average citation frequency, the proportion of high-impact papers, and the overall value of patents. This phenomenon of “high output, low impact” is closely related to the essential logic of saline–alkali land governance advocated by China—that is, the core goal is the low-cost and rapid restoration of production functions, emphasizing practicality and systematicity. Compared to Western countries, the improvement of saline–alkali land in China is not simply about technological breakthroughs, but about quickly activating land productivity by minimizing investment. Its core lies in designing a combination of “engineering + biology + agronomy” based on different types of saline–alkali (such as soda alkali, sulfate alkali, etc.), and meeting the demand for localized low-cost solutions. These governance logics require technical solutions to be highly tailored to actual production needs, rather than pursuing theoretical innovation or technological complexity, which naturally conflicts with the scientific research evaluation system. In addition, a large number of current papers focus on fine-tuning salt control, fertile soil, and mature cultivation techniques, but these improvements have diminishing marginal benefits on actual productivity and may also make it difficult for the results to be widely cited. In the future, the influence of research can be enhanced by strengthening basic research and improving academic evaluation systems.
Beyond the high-output countries, regions such as Africa and South America have adopted innovative, context-specific strategies to address saline–alkali land challenges. In Ethiopia, integrated approaches using gypsum, biochar, organic fertilizers, and microbial technologies have been applied to improve soil conditions [19]. Sub-Saharan Africa has promoted low-cost drip irrigation systems for saline water use, enhancing crop yields while reducing salt buildup [20]. In South America, smart irrigation systems using IoT technologies and sensors are advancing precision water management [21]. These cases highlight the value of regional innovations in complementing global research and policy.

3.3. Analysis of Research Topics

3.3.1. Global Distribution of Research Topics in the Field of Saline–Alkali Land

We used the VOS viewer software to draw the keyword co-occurrence network for research papers related to the global saline–alkali land field from 1995 to 2024 and conduct clustering. The keywords with a co-occurrence frequency of more than 20 times were selected as high-frequency keywords to draw a map, and the main research topics in the saline–alkali land field were extracted from it. As can be seen from Figure 5, the number of clusters obtained from the keywords in the papers published in this field in the past nearly 30 years is 5, and the main keywords extracted from the clusters are shown in Table 4. Through the presentation of the above keyword clustering results, it can be seen that the hot topics in the saline–alkali land field in the past nearly 30 years are mainly distributed in the following aspects: (1) growth mechanism and gene expression of crops/plants under salt stress [22,23,24,25]; (2) interaction mechanism between plants and microorganisms in saline–alkali land and the application of soil amendments [26,27,28,29]; (3) remote sensing of saline–alkali land changes and environmental responses to soil salinization [30,31,32]; (4) techniques and mechanisms in saline–alkali land irrigation, drainage, and soil water–salt dynamics [33,34,35]; and (5) nutrient status and improvement of saline–alkali soil [36].

3.3.2. Analysis of the Time Evolution of Research Topics

From the perspective of the development of topics over time, relevant research in the global saline–alkali land field had already taken shape during the period from 1995 to 2004 (Figure 6), with certain output achievements. However, the overall keyword co-occurrence network in this stage was still relatively sparse, and the research topics were relatively scattered. During this period, the research mainly focused on the physical and chemical properties, component analysis, and health status assessment of saline–alkali soils, aiming to gain a deeper understanding and systematic evaluation of the basic characteristics of saline–alkali lands. Among them, the indicators of concern mainly include soil moisture, salinity, pH, nutrient status, heavy metal content, and crop yield. In addition, besides laboratory analysis methods, remote sensing and model computational prediction methods have also emerged, which can efficiently collect large-area information and provide superior means for monitoring the dynamic changes in saline–alkali land [37]. Researchers also realized that improving the salt-tolerance ability of crops/plants was an important and effective measure for the improvement of saline–alkali soils. Relevant research focused on the adaptation mechanism and growth response of plants under salt stress environments, as well as the cultivation and quality improvement of salt-tolerant plants. Through the breeding of salt-tolerant varieties of crops such as wheat, rice, cotton, corn, and oil sunflowers, a basis was provided for increasing crop yield in saline–alkali land, which promoted the application of the biological measure of “selecting suitable varieties for specific lands”.
Between 2005 and 2014, numerous new themes emerged in the keyword co-occurrence network of published papers. The network became denser, and the distinctions among various clusters became more pronounced (Figure 7). In addition to the previously mentioned research topics, new research contents began to surface, including the interaction mechanism between plants and microorganisms in saline–alkali lands, the irrigation and drainage techniques for saline–alkali lands, and the application of soil amendments. Meanwhile, the research on remote sensing monitoring of the dynamic changes in saline–alkali lands was expanded. Some researchers utilized remote sensing and GIS technologies, in combination with geostatistical methods, to analyze the causes and influencing factors of the dynamic changes in saline–alkali lands. In particular, the related research focusing on the Yellow River Delta region gradually increased [38].
Furthermore, engineering improvement measures attracted more and more attention from researchers. These measures mainly targeted medium and severe saline–alkali land with high groundwater levels, involving the construction of drainage and irrigation facilities and land leveling. With the deepening of research, the irrigation and drainage methods were constantly evolving: from traditional flood irrigation to precise drip irrigation, and the drainage and salt removal methods shifted from open ditches to buried pipes. At the same time, the utilization of multiple water sources, such as brackish and slightly saline water for irrigation, was increased, further enhancing the drainage efficiency and salt control effect.
In terms of chemical improvement, the application of soil amendments became an important measure for saline–alkali land improvement. The research in this stage mainly focused on the application of traditional inorganic chemical amendments such as gypsum, with an emphasis on exploring their promoting effects on the growth of crops in saline–alkali lands, as well as their improvement and regulation effects on the physical and chemical properties of the soil. During this period, the improvement of soil nutrients in saline–alkali lands gradually became the research focus of scientific researchers. The keywords related to relevant research mainly concentrated on major elements such as organic carbon, nitrogen, phosphorus, and potassium, indicating that to achieve efficient and comprehensive utilization of saline–alkali lands, solving the problem of soil nutrient limitation is crucial.
The keyword co-occurrence network constructed between 2015 and 2024 exhibits distinct clustering features, and the hotspots have closer connections (Figure 8). During this stage, research on the molecular mechanism of salt tolerance has become a hot topic. Researchers are increasingly focusing on the genetic level of plant salt and alkali tolerance [39]. Uncovering salt-tolerant genes and understanding the molecular mechanisms of plant salt tolerance have become major challenges in breeding salt-tolerant varieties. In 2024, Chinese scientists first discovered the main alkali-controlling gene AT1 and its mechanism of action in the salt-tolerant crop sorghum [40]. Through genetic modification, the grain yield of sorghum increased by 20.1%, the whole-plant biomass for silage increased by nearly 30.5%, and the yield of foxtail millet also rose by 19.5%. In the saline–alkali land of Da’an, Jilin Province, the annual yield increase in different crops ranged from 22.4% to 27.8%. This shows significant application prospects in the comprehensive utilization of saline–alkali land improvement.
Moreover, new salt-tolerant varieties have emerged continuously, such as “Zhongmu No. 1”, “Zhongmu No. 3”, and “Zhongmu No. 4” bred with Cangzhou alfalfa as the parent [41]. However, from the perspective of crop physiological growth, simply improving salt and alkali tolerance through genetic modification to increase yield is far from enough. The balance between soil nutrient supply and demand is equally crucial. Therefore, during this period, the relationships among salt tolerance, nutrient absorption capacity, and soil fertility status (especially nitrogen) have become increasingly intertwined [42]. Compared with the period from 2005 to 2014, research on organic soil amendments and their applications in saline–alkali lands has gradually increased. The research mainly involves the interaction mechanisms at the macro and micro levels between soil amendments such as compost, vermicompost, and biofertilizers, and soil aggregates, soil nutrients, soil microorganisms, and soil water [43,44,45]. Among them, biochar and humic acid, as multi-beneficial soil conditioners, have gradually become the focus of researchers.
New methods for the dynamic monitoring of soil salinization have continued to emerge, including the use of deep learning-based remote sensing methods for processing information about saline–alkali lands [46]. New progress has also been made in the optimization of irrigation and drainage techniques for saline–alkali lands. The application of new technologies such as computer technology [47], monitoring technology [32], and communication technology [48,49] enables real-time dynamic monitoring of soil moisture, salinity, nutrients, and other data, which is expected to achieve refined management of crop irrigation in saline–alkali land, a precise supply of water and fertilizers, and maximizing crop yield.
In summary, in the past three decades, rich progress has been made globally in the field of saline–alkali land research. Research on saline–alkali land management and utilization has evolved from a single measure to the direction of extending the comprehensive utilization of multiple improvement measures. These studies revolve around themes such as remote sensing monitoring of the dynamic changes in saline–alkali lands, the breeding of salt-tolerant plants, the application of soil amendments, the optimization of irrigation and drainage techniques, and the expansion and enhancement of soil nutrient capacity. New methods keep emerging. In terms of biological improvement, the technology for salt-tolerant breeding has been continuously upgraded, the application of transgenic breeding technology has been expanding, and gene editing technology has also begun to gain prominence. In terms of chemical improvement, there is a wide variety of soil amendments for saline–alkali lands. The research focus has shifted from inorganic substances to organic substances, gradually developing toward emerging modifier materials and comprehensive utilization of multiple improvement measures. In terms of physical improvement measures, hydraulic improvement technologies mainly include subsurface drainage and water-saving and salt-controlling techniques. With the introduction of new technologies such as computer technology and laser technology, it promotes the development of irrigation and drainage technology toward automation and intelligence.

4. Research Trend Conclusions

This paper systematically reviews and analyzes the development trends in the global saline–alkali land field from 1995 to 2024 by using the bibliometric method. It analyzes the trends of papers and patents, major countries and regions, main research institutions, research hotspots, and the evolution trends of research topics. The conclusions are as follows:
(1)
From the perspective of annual trend distribution, the development of papers in the saline–alkali land field from 1995 to 2024 has gone through three stages: gradual exploration, steady development, and rapid growth. Meanwhile, the development trend of patents has experienced three phases: slow growth, rapid climb, and fluctuating development. The research output in the global saline–alkali land field shows an upward trend, attracting the attention of an increasing number of scholars and possessing great development potential.
(2)
In terms of research strength, at the national level, major countries involved in saline–alkali land research have all made arrangements for scientific research and innovation in this field. China, the United States, India, Australia, and other countries have made outstanding contributions to saline–alkali land research. China is a major country in terms of scientific research output in the saline–alkali land field, ranking first in both the number of papers and patents, demonstrating strong scientific research productivity. However, China needs to pay attention to enhancing its research influence. At the institutional level, universities and research institutes are the main contributors of papers in this field, among which the Chinese Academy of Sciences has a far-leading number of publications. Institutions such as the Chinese Academy of Sciences, the Indian Council of Agricultural Research, China Agricultural University, and the Chinese Academy of Agricultural Sciences are the backbone forces in saline–alkali land research.
(3)
From the perspective of research topics, the research hotspots in the global saline–alkali land field in the past nearly 30 years have concentrated on the following five directions: the growth mechanism and gene expression of salt-tolerant plants under salt stress; the interaction mechanism between plants and microorganisms in saline–alkali land and the application of soil amendments; the remote sensing monitoring of the dynamic changes in saline–alkali land and the environmental responses to soil salinization; the irrigation and drainage techniques for saline–alkali land and the dynamic regulation mechanism of soil water and salt; and the nutrient status and improvement of saline–alkali soil. With the passage of time, research in the field of saline–alkali land has made rich progress. Technologies for improving saline–alkali land, such as biology, chemistry, and physics, are constantly being updated and iterated. The research on the genetic mechanism of salt-tolerant plants, the application of emerging soil amendments such as biochar, and the automation and intelligence development of irrigation and drainage techniques have gradually become research hotspots in the saline–alkali land field, attracting wide attention.
The research trends of saline–alkali land from 1990 to 2030 can generally be divided into five stages, as shown in Figure 9. The 1990s were the stage of basic exploration and initial management, with main research topics including the physicochemical properties of saline–alkali soils, analysis of soil components, irrigation improvement measures, and plant salt-tolerance studies. The 2000s marked the stage of research expansion, during which new research content such as the interaction mechanisms between plants and microorganisms in saline–alkali land and chemical soil conditioners began to emerge. Meanwhile, dynamic remote sensing monitoring of saline–alkali land also started to gain attention. The 2010s were the stage of technological deepening, with continuous development of engineering improvement measures such as precision irrigation, subsurface drainage for salt removal, and brackish water irrigation. New types of soil conditioners kept emerging, and research on improving the fertility of saline–alkali soils began to receive more attention. The 2020s were the stage of research innovation, with breakthroughs in the molecular mechanisms of salt tolerance in plants and the continuous emergence of new salt-tolerant plant varieties. Research on organic soil conditioners also kept innovating. With the development of artificial intelligence technology, dynamic monitoring of saline–alkali land became faster and more accurate. Looking ahead to the 2030s, saline–alkali land research will develop toward comprehensive utilization and intelligentization. Comprehensive utilization of saline–alkali land will develop in both the direction of “adapting crops to the land” and “adapting the land to the crops” to increase the output of saline–alkali land and ensure food security. Meanwhile, the monitoring, assessment, management, and utilization of saline–alkali land will move toward intelligent and precise management.

5. Suggestions for Future Development of Saline–Alkali Land Improvement and Comprehensive Utilization

The rapid development of research on saline–alkali soil has made important contributions to the utilization of land resources, improvement of cultivated land quality, and increase in grain production. However, from the research results of this article, there are still many challenges in the study of saline–alkali soil. Suggestions for the efficient utilization of saline–alkali land resources in the future can be further explored from the following aspects, as shown in Figure 10.
(1)
Emphasize policy support at the national level. Policy-makers should guide the research directions and priorities of saline–alkali land through policies, provide sufficient financial support for scientific research, optimize the allocation of scientific research resources to strengthen interdisciplinary integration and cooperation among universities, research institutes, and enterprises in the aspects of industry–university–research, and enhance the cooperation among government officials, scientific researchers, and farmers to achieve the publicity, popularization, and application of scientific research achievements.
(2)
Deepen the governance model of zoning, classification, and differentiated strategies for saline–alkali land. There are numerous saline–alkali areas in the world. There are significant differences in climate, parent material, topography, hydrology, and human management models among these regions, resulting in strong heterogeneity in the formation causes of saline–alkali land, types of saline–alkali soil, and obstacle-causing characteristics. Therefore, in-depth investigations into the specific characteristics of saline–alkali land in each region and the implementation of governance based on zoning, classification, and differentiated strategies in line with local conditions can not only effectively save resources but also maximize the improvement benefits.
(3)
Promote the combination of “selecting suitable plants for specific lands” and “selecting suitable lands for specific plants” to achieve simultaneous progress in reducing saline–alkali obstacles and enhancing plant stress tolerance. To reduce saline–alkali obstacles, a strategy that combines prevention, control, and treatment should be mainly adopted. Advanced technologies such as remote sensing, machine learning, and big data analysis play an increasingly important role in accurately monitoring and predicting saline–alkali land dynamics. In practical applications, remote sensing monitoring integrates hyperspectral satellite imagery, UAV-based data, and ground observations through AI-driven models to build dynamic databases and quantitatively assess the degree of land salinization. Meanwhile, artificial intelligence, with its ability to integrate multi-source heterogeneous data and model complex nonlinear patterns, is reshaping the paradigm of salinization trend prediction, enabling more timely and targeted responses to potential degradation risks. Through the innovation of irrigation and drainage techniques and agronomic techniques, explore more efficient control measures. Comprehensively apply a variety of improvement methods in physical, chemical, biological, and agricultural machinery engineering aspects (screen and effectively combine technical measures such as inorganic amendments, organic amendments, and microbial inoculation improvement) to achieve effective treatment of saline–alkali lands. In terms of enhancing plant stress tolerance, focus on in-depth research on the molecular mechanisms of plant salt tolerance, breed stress-tolerant crops/plants adapted to saline–alkali environments, and further improve their stress resistance and high yield through genetic improvement. In addition, enhancing the interaction between plants and microorganisms and promoting the protective and facilitating effects of microorganisms on plants are also important ways to strengthen the salt-tolerance ability of plants. Through these comprehensive means, ultimately achieve the coordinated improvement of effective treatment of saline–alkali lands and plant stress tolerance.
(4)
Prioritize the health management of saline–alkali soils. The health management of saline–alkali soils is the key link connecting obstacle reduction and stress-tolerance adaptation. It involves multiple aspects, including enhancing nutrient capacity, promoting carbon sequestration and emission reduction, optimizing soil aggregate structure, increasing biodiversity, and strengthening multifunctionality. Improving the soil health status of saline–alkali lands is a necessary condition for ensuring increased and high yields of crops and improving ecological benefits.
With the rapid development of saline–alkali land improvement technology, major countries in saline–alkali land should leverage their disciplinary advantages, develop new technology research, optimize saline–alkali land improvement technology according to local conditions, and play an important role in achieving sustainable development of saline–alkali land resources and increasing food production.

Author Contributions

Conceptualization, Y.S., Y.Y. and X.Z.; methodology, Y.S., J.H. and Y.Y.; validation, Y.S. and J.H.; formal analysis, J.H.; investigation, J.H. and Y.S.; resources, Y.Y. and Y.S.; data curation, J.H.; writing—original draft preparation, J.H. and Y.C.; writing—review and editing, Y.S. and L.X.; visualization, J.H. and Y.S.; supervision, Y.Y. and X.Z.; project administration, Y.Y. and X.Z.; funding acquisition, Y.Y. and X.Z. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Special Project for Strategic Research and Decision Support System Construction of Chinese Academy of Sciences, grant number GHJ-ZLZX-2025-05, Strategic Priority Research Program of the Chinese Academy of Sciences, grant number XDA0440000, and National Natural Science Foundation of Jiangsu Province, grant number BK20242107.

Data Availability Statement

No new data were created or analyzed in this study. Data sharing is not applicable to this article.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. The development trends of papers in the field of saline–alkali land from 1995 to 2024.
Figure 1. The development trends of papers in the field of saline–alkali land from 1995 to 2024.
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Figure 2. The development trends of patents in the field of saline–alkali land from 1995 to 2024.
Figure 2. The development trends of patents in the field of saline–alkali land from 1995 to 2024.
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Figure 3. Research paper development trends in saline–alkali land in major countries from 1995 to 2024. (Note: since the number of papers varies greatly in different time periods, the vertical axis uses a logarithmic scale with base 10 for the convenience of display).
Figure 3. Research paper development trends in saline–alkali land in major countries from 1995 to 2024. (Note: since the number of papers varies greatly in different time periods, the vertical axis uses a logarithmic scale with base 10 for the convenience of display).
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Figure 4. Patent development trends in saline–alkali land in major countries from 1995 to 2024. (Note: since the number of patents varies greatly in different time periods, the vertical axis uses a logarithmic scale with base 10 for the convenience of display.).
Figure 4. Patent development trends in saline–alkali land in major countries from 1995 to 2024. (Note: since the number of patents varies greatly in different time periods, the vertical axis uses a logarithmic scale with base 10 for the convenience of display.).
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Figure 5. Global distribution of paper topics in the field of saline–alkali land from 1995 to 2004.
Figure 5. Global distribution of paper topics in the field of saline–alkali land from 1995 to 2004.
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Figure 6. Global hot topics in the field of saline–alkali land from 1995 to 2004.
Figure 6. Global hot topics in the field of saline–alkali land from 1995 to 2004.
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Figure 7. Global hot topics in the field of saline–alkali land from 2005 to 2014.
Figure 7. Global hot topics in the field of saline–alkali land from 2005 to 2014.
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Figure 8. Global hot topics in the field of saline–alkali land from 2015 to 2024.
Figure 8. Global hot topics in the field of saline–alkali land from 2015 to 2024.
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Figure 9. The temporal evolution of research on saline–alkali land from the 1990s to the 2030s.
Figure 9. The temporal evolution of research on saline–alkali land from the 1990s to the 2030s.
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Figure 10. Efficient utilization strategies of saline–alkali land resources.
Figure 10. Efficient utilization strategies of saline–alkali land resources.
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Table 1. Distribution of the top 10 countries/regions by papers and patents in the field of saline–alkali land from 1995 to 2024.
Table 1. Distribution of the top 10 countries/regions by papers and patents in the field of saline–alkali land from 1995 to 2024.
RankingDistribution of Papers by Country/RegionDistribution of Patents by Country/Region
Country/RegionNumber of PapersPercentage of Papers/%Country/RegionNumber of PatentsProportion of Patents/%
1China497338.33China880992.75
2The United States9347.20The United States1821.92
3India9046.97Republic of Korea1321.39
4Australia5924.56Japan1281.35
5Iran4843.73Russia550.58
6Pakistan4833.72Australia350.37
7Spain3652.81India280.29
8Egypt3262.51Germany270.28
9Brazil2882.22Spain170.18
10Italy2571.98Uzbekistan90.09
Table 2. Paper influence of major countries in the field of saline–alkali land from 1995 to 2024.
Table 2. Paper influence of major countries in the field of saline–alkali land from 1995 to 2024.
RankingCountry/RegionTotal Citation FrequencyAverage Citation Frequency Per PaperNumber of High-Impact PapersProportion of High-Impact Papers in Total Publications
1China106,01621.324168.37
2The United States31,71633.9614915.95
3India22,52624.929910.95
4Australia19,62633.159315.71
5Spain10,78429.553810.41
6Pakistan10,09620.9469.52
7Iran925119.11377.64
8Egypt900627.633611.04
9Italy783530.493413.23
10Canada711738.472312.43
Table 3. Patent influence of major countries in the field of saline–alkali land from 1995 to 2024.
Table 3. Patent influence of major countries in the field of saline–alkali land from 1995 to 2024.
RankingCountry/RegionNumber of High-Value PatentsProportion of High-Value Patents in Total PatentsProportion of High-Value Patents in Total National Patents/ %
1China22049.222.50
2The United States8318.5745.60
3Japan6113.6547.66
4Republic of Korea235.1517.42
5Germany194.2570.37
6Australia122.6834.29
7India71.5725.00
8Spain71.5741.18
9Belgium61.3485.71
10The United Kingdom30.6737.50
Table 4. Keyword cluster co-occurrence table.
Table 4. Keyword cluster co-occurrence table.
ClusterResearch TopicRepresentative Keywords
1Growth mechanism and gene expression of crops/plants under salt stresssalt stress, gene expression, salinity tolerance, proteomics, plant growth, photosynthesis, osmoregulation, antioxidant, seed yield, wheat, zea mays, rice
2Interaction mechanism between plants and microorganisms in saline–alkali land and the application of soil amendmentshalophytes, phytoremediation, microbial diversity, bacterial diversity, arbuscular mycorrhizal fungi, enzyme activity, organic fertilizer, soil amendment, biochar
3Remote sensing of saline–alkali land changes and environmental responses to soil salinizationsoil salinization, climate change, ecological restoration, carbon sequestration, coastal wetland, mangrove, salt marsh, Yellow River Delta, Songnen plain, digital soil mapping, GIS, Landsat, remote sensing
4Techniques and mechanisms in saline–alkali land irrigation, drainage, and soil water–salt dynamicsdrip irrigation, wastewater, irrigation, groundwater, soil water content, water use efficiency, water quality, nitrate, salt accumulation
5Nutrient status and improvement of saline–alkali soilmicronutrients, iron, sodium, potassium, calcium, nitrogen, phosphorus
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Huang, J.; Shang, Y.; Chen, Y.; Xu, L.; Yang, Y.; Zhao, X. Analysis of Research Trends and Comprehensive Utilization Solutions for Saline–Alkali Land. Sustainability 2025, 17, 5202. https://doi.org/10.3390/su17115202

AMA Style

Huang J, Shang Y, Chen Y, Xu L, Yang Y, Zhao X. Analysis of Research Trends and Comprehensive Utilization Solutions for Saline–Alkali Land. Sustainability. 2025; 17(11):5202. https://doi.org/10.3390/su17115202

Chicago/Turabian Style

Huang, Jingyan, Yehua Shang, Yuqi Chen, Lingying Xu, Yanping Yang, and Xu Zhao. 2025. "Analysis of Research Trends and Comprehensive Utilization Solutions for Saline–Alkali Land" Sustainability 17, no. 11: 5202. https://doi.org/10.3390/su17115202

APA Style

Huang, J., Shang, Y., Chen, Y., Xu, L., Yang, Y., & Zhao, X. (2025). Analysis of Research Trends and Comprehensive Utilization Solutions for Saline–Alkali Land. Sustainability, 17(11), 5202. https://doi.org/10.3390/su17115202

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