Introduction
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.
Approach
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 using databases such as ScienceDirect 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 Iran, China, Canada, Japan, New Zealand, Europe, and Latin America.
Key Findings
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 covers all provinces and monitoring sites nationwide.
Discussion and Implications
A comparative analysis of soil monitoring initiatives reveals several challenges: technical limitations, gaps in soil data, and insufficient long-term funding. Indicators for soil quality assessment differ across countries due to variations in climate, land use, management priorities, and scientific capacity. While these differences reflect ecological and managerial diversity, they underscore the urgent need for a coordinated framework to standardize indicator selection, sampling methodologies, and data analysis procedures.
The existence of structured monitoring programs indicates growing recognition of soil monitoring as a key instrument for sustainable land management and enhanced agricultural productivity. Integrating monitoring networks with standardized protocols enables long-term evaluation, cross-country comparisons, and informed decision-making for soil conservation and improvement.
Conclusion
In conclusion, well-planned, continuous, and methodologically rigorous soil monitoring provides the foundation for maintaining soil health and managing natural and agricultural ecosystems sustainably. Such coordinated efforts generate valuable insights, support evidence-based land management strategies, and contribute to achieving global environmental and agricultural goals. |