Multidimensional Assessment as an Integral Basis for Soil Health Diagnostics: A Review

— This article examines methodological issues and modern approaches to defining soil health. Since the 1990s, this concept has expanded beyond agricultural potential to reflect the role of soil in the sustainable development of ecosystems. Modern approaches focus on a comprehensive assessment of physical, chemical, and biological characteristics; however, the practical application of existing environmental risk assessment standards remains limited. The development of a triad methodology with a multi-level distribution of methods—from simple to complex, including analysis of the mechanisms of action of factors and changes in soil genetic material—emphasizes its adaptability to specific goals and scenarios. Based on the triad methodology, a method for assessing the quality of humic remediants for soils contaminated with heavy metals is proposed. Changes in key indicators are analyzed: the transfer of heavy metals to adjacent environments, the growth of higher plants, and the characteristics of the soil microbiome. It is found that humic preparations (nanomagnetitohumate and lignohumate) reduce the ecotoxicity of urban soils and influence the ecophysiological parameters of the biota. The primary factor in their remediation effect when applied at concentrations of 0.0025–0.01 wt % is the biological activity, not toxicant binding. Synthesizing the latest data and advances in physical, chemical, and soil biological assessment within an open and flexible triadic framework creates a robust scientific foundation for developing promising methods for multidimensional soil health diagnostics.