Soil Quality Monitoring: An Undeniable Necessity

Background and Objectives: Soil integrity is facing serious challenges worldwide due to multiple pollution sources, including industrial effluents, municipal and domestic waste, agricultural chemicals, and pathogenic organisms. According to the Food and Agriculture Organization (FAO), roughly one-third of the global soil resource is affected by varying degrees of degradation, with annual economic losses estimated to exceed €50 billion. To safeguard soil functions, continuous and systematic monitoring of soil properties is essential. Despite growing awareness of its importance, a consolidated review of global soil monitoring experiences has been lacking. This study addresses this gap through a structured literature review.
 

 



Methodology: This research used databases such as Science Direct and Scopus. The review is divided into two main sections: the first discusses the advantages and necessity of soil monitoring networks, and the second examines the experiences of several countries, including Europe, China, Canada, Japan, New Zealand, Latin America, and Iran.
 
Results: Many countries have established soil monitoring programs; however, considerable differences exist in the approaches used. These include observation density, frequency of sampling, sampling depths, measured parameters, and analytical techniques. Such diversity complicates comparisons across regions and highlights the need for harmonized protocols. In China, the initial nationwide agricultural soil survey in 1958 aimed to evaluate soil fertility and guide crop production using 13 chemical and physical parameters. A subsequent survey in 1979 expanded the analysis to include nutrient status, trace elements, and chemical composition, resulting in detailed provincial soil maps. Presently, China operates 107 national and provincial monitoring sites. Canada launched soil monitoring and the selection of benchmark sites in 1989. Sites were chosen to represent major soil zones or agro-ecological regions, typical physiographic units, and dominant agricultural production systems. Soil parameters were classified based on sensitivity and systematically measured at each site. Japan initiated a nationwide soil identification and performance monitoring program in 1999 across 5,500 sites. In 2008, a national program for monitoring soil carbon content and management practices added approximately 3,500 sites to the network. New Zealand implemented two soil quality monitoring initiatives between 1995 and 2001 to evaluate methodologies and provide data for sustainable land use reporting. Over 500 sites were assessed using seven core indicators encompassing physical, chemical, and biological soil properties. Iran’s soil monitoring program began in 2011 in three phases, covering 18.5 million hectares across 3,278 sites. Sampling depths were 0–30 and 30–60 cm for croplands and 0–30, 30–60, and 60–90 cm for orchards. The second phase focused on approximately 10% of sites as reference locations for detailed biological, chemical, and physical measurements. By 2025, the third phase will cover all provinces and monitoring sites nationwide.

 



Conclusion: Comparative evaluation of national soil monitoring programs demonstrates that, despite their widespread implementation, these initiatives continue to face notable constraints, including technical challenges, incomplete soil datasets, and limited continuity in financial support. Variability in selected indicators and monitoring strategies reflects differences in environmental conditions, land management practices, and institutional capacities among countries. While such heterogeneity is context-dependent, it restricts data interoperability and limits the potential for broader regional and global assessments. The findings emphasize the necessity of developing an integrated and flexible framework that allows for methodological harmonization while accommodating local ecological and managerial conditions. Establishing consistent criteria for indicator selection, sampling design, and analytical procedures would enhance data comparability and strengthen long-term soil assessments. Existing monitoring infrastructures provide a valuable foundation for advancing sustainable land management; however, their effectiveness depends on systematic coordination and long-term commitment. Overall, sustained and well-designed soil monitoring systems are critical for tracking changes in soil condition, supporting adaptive management strategies, and informing policy decisions. Strengthening collaboration among monitoring networks and adopting standardized yet adaptable methodologies can significantly improve the reliability of soil information, thereby contributing to soil conservation efforts, agricultural sustainability, and broader environmental objectives.