Evolution Mechanisms and Mitigation of Soil Erosion

Abstract

This Editorial paper summarizes the Special Issue entitled “Evolution of Soil and Water Erosion” in Water. This Special Issue aims to collect new knowledge on and advances in the evolution of soil and water erosion and its complex interplay with natural and human-induced factors. Five high-quality papers have been published in the Special Issue, which mainly covers new insights into the themes of erosion mechanisms and environmental drivers, erosion control and mitigation strategies and the relationship between hydraulic parameters and erosion. Overall, these studies have broadened the understanding of soil erosion and soil and water conservation, emphasizing the importance of research in this field for environmental sustainability. In future research, interdisciplinary integration into theory and methodology will play a crucial role in breakthroughs in the understanding of soil erosion and innovations in prevention and control technologies.

1. Introduction

Soil erosion is a key factor leading to soil degradation [1], and it is an environmental issue closely related to agricultural production and farmers’ livelihoods. It not only causes deterioration in water quality and loss of land resources but also negatively impacts the ecological balance of the surrounding areas, which directly affects the sustainable development of the local economy [2]. Approximately 1.5 billion people worldwide are affected by soil erosion, with developing countries being particularly impacted. In recent years, against the backdrop of climate change, population growth and intensified human activities (particularly agricultural activities), global soil erosion has become increasingly severe. For example, the area affected by soil erosion in China reached 2.6742 million square kilometers in 2021 according to data from the Ministry of Water Resources of the People’s Republic of China. The intensification of soil erosion has led to the rapid degradation of soil, a non-renewable resource, posing serious threats to food security and ecosystem services. This has led to escalating conflicts between humans and the environment, negatively impacting 80% of arable land quality and 40% of food production in agricultural areas [3]. Controlling soil erosion and improving soil quality have become some of the most important and urgent environmental practices in agricultural areas [4].

The complex interplay between climate, geology, vegetation and human interventions has shaped the present-day state of erosion in different regions of the world. To understand the evolution of soil and water erosion, it is essential to explore both the natural and human-induced factors that have contributed to this phenomenon. In recent years, the understanding of the coupling mechanisms between soil surface microtopography and erosion processes has deepened significantly [5,6]. Rapid advancements in erosion prediction models and dynamic monitoring technologies have facilitated the gradual construction of a refined knowledge system for soil erosion [7,8]. Scientific issues such as the relationship between erosion processes and water quality evolution, as well as the impact of climate change on erosion and sedimentation processes across different land-use types [9,10], have garnered significant attention, highlighting the importance of interdisciplinary researches. Against the backdrop of global change, more research is exploring the interactions between soil erosion and factors such as climate change, ecological environment quality and ecosystem services from an ecosystem perspective. Additionally, the role of public participation in soil and water conservation projects has increasingly been recognized as a critical factor in promoting sustainable management [11,12]. By integrating these cutting-edge research areas, this Special Issue aims to comprehensively reveal the mechanisms of soil and water erosion, their spatiotemporal evolution and their profound impacts on ecosystems. It seeks to provide theoretical support and practical guidance for developing scientifically sound management strategies and enhancing public engagement.

2. Review of New Advances

The Special Issue “Evolution of Soil and Water Erosion” collected five papers covering a broad range of topics that collectively advance our understanding of erosion processes. As shown in Figure 1, a word cloud was generated using the titles, keywords and abstracts of published papers to display the terms commonly used in the papers of this Special Issue. Except for the words “soil”, “water” and “erosion”, which represent the topic of this Special Issue, the most commonly used terms in the papers are “rainfall”, “land” and “runoff”. These terms indicate that precipitation and the resulting surface runoff are environmental factors closely associated with the processes of soil and water erosion, whose dynamics are widely discussed.

The collected papers are roughly clustered into three main themes: erosion mechanisms and environmental drivers (contributions 1 and 3), erosion control and mitigation strategies (contributions 4 and 5) and the relationship between hydraulic parameters and erosion (contribution 2).

Bai et al. (contribution 1) investigate the interaction between snowmelt, rainfall and the frozen soil layer in the black soil region of Northeast China. By conducting laboratory experiments with varying soil conditions, snowmelt runoff discharges and rainfall intensities, the study assesses how the presence of a frozen layer influences soil erosion during spring thaw, particularly focusing on the composite effects of combined snowmelt and rainfall. The findings are particularly valuable for improving soil erosion risk assessments in cold and temperate regions, which offer new insights that are essential for effective soil and water erosion management.

Koulibaly et al. (contribution 2) investigate the most effective hydraulic parameters for assessing the erosive force of water on rock masses in unlined dam spillways. The study finds that water pressure, particularly pressure head and flow velocity, are the most relevant indicators of water’s erosive force, as opposed to shear stress and energy dissipation. By analyzing erosional events over 100 study sites, the paper provides a systematic approach to selecting hydraulic parameters that can better represent the erosive potential of water, offering practical insights for improving spillway design and reducing erosion in hydraulic engineering projects.

Wang et al. (contribution 3) examine the interactions between various rainfall types and land use in influencing water erosion in the red soil region of southern China. The study identifies high-intensity rainfall as the primary driver of both runoff and soil erosion, with land use playing a significant role in modifying these effects. Shrubland is found to substantially mitigate both runoff and soil erosion, whereas land uses such as grassland and cropland are more susceptible to erosion under intense rainfall conditions. The research emphasizes the importance of enhanced vegetation coverage in mitigating the degree of erosion and underscores the critical need for region-specific land management strategies that account for both rainfall intensity and land use, offering valuable insights for effective erosion control in this ecologically vulnerable area.

Stefanović et al. (contribution 4) report a case study assessing the long-term impact of erosion control works (ECWs) on soil erosion in the Ćelije reservoir watershed in Serbia. The findings show a significant reduction in soil erosion and sediment transport over 54 years, with specific gross erosion decreasing by more than 50%. The study also reveals a strong correlation between the success of erosion control efforts and decreased sedimentation, providing key insights into the effectiveness of ECWs in large watershed management projects. The paper contributes to the knowledge of long-term erosion control strategies and their role in mitigating soil degradation in river basins.

Cao et al. (contribution 5) evaluate the effectiveness of no-tillage (NT) and mulching (NTS) practices in reducing water-induced soil erosion in the agricultural area of China. The study finds that both NT and NTS significantly reduce soil loss compared to conventional tillage with reductions of 48% and 64%, respectively. The effectiveness of these measurements varies spatially, being more practical in southern China because of the high precipitation amount and steep terrain, while the benefits are moderate but notable in the flatter northern regions. The paper identifies precipitation amount and slope as key factors influencing the patterns of erosion, especially in regions with steep terrain and high precipitation amounts. By performing a comprehensive national assessment, the study emphasizes the potential of NT and NTS for mitigating soil erosion and provides constructive recommendations for their broader implementation to combat soil degradation. It highlights the need to balance ecological benefits with economic considerations, particularly advocating for targeted adoption in northern China to achieve sustainable agricultural practices.

3. Summary and Recommendations for Future Directions

Soil erosion is a major environmental issue that leads to soil degradation, reduces land productivity and severely threatens sustainable development. Understanding the evolutionary mechanisms of soil erosion is of paramount importance for ecological function assessment and water–soil resource management. This Special Issue presents cutting-edge research in key areas of soil erosion, covering the characteristics of soil erosion in different regions, the relationship between soil erosion, hydrological parameters and vegetation cover, as well as practices for erosion mitigation and soil and water conservation. These studies explore erosion and hydrological processes from multiple perspectives, providing important insights for the control and prevention of soil erosion and land degradation in various regions.

Future studies should focus on promoting interdisciplinary integration between soil and water conservation and other fields, such as hydrology, environmental science, human geography and social sciences. This integration will be crucial for studying the mechanisms of soil erosion evolution and its prevention and control measures under increasingly complex climatic and underlying surface conditions. For example, the observation of runoff sediment processes and the application of sediment transport models can provide an intuitive reflection of surface soil erosion, clarifying the evolution of runoff sediment at different spatial scales and their driving mechanisms. Runoff plot experiments and multi-model analyses can reveal the relationship and influencing factors of slope erosion and hydrological connectivity at different spatial scales, thus quantifying sediment transport paths and spatial patterns and identifying key areas for soil and water conservation. Additionally, the use of remote sensing to retrieve soil parameters and isotopic tracers can provide a comprehensive evaluation of soil erosion patterns, enabling the precise investigation and monitoring of land degradation. In conclusion, it is hoped that future interdisciplinary collaboration and innovative technologies will further enhance the effectiveness of soil erosion control, providing more practical and feasible solutions for global sustainable development and environmental protection.