An Integrated Methodological Framework for SoilHealth Assessment in Volcanic Island Agroecosystems: Indicator Selection, Analytical Workflows and Context-Sensitive Interpretation

Soil health assessment is increasingly used to support sustainable land management and agronomic decision-making, but generic indicator lists and universal scoring systems may be inadequate for highly reactive volcanic soils. This critical methodological review proposes an integrated methodological framework for volcanic island agroecosystems that explicitly separates analytical measurement from interpretation. The framework links assessment objectives and site context to fit-for-purpose analytical levels and classifies evidence as method-matched thresholds, local or reference benchmarks, relative or temporal comparisons, mechanistic evidence and plant–soil response validation. The reviewed evidence shows that standardized measurements do not necessarily support transferable diagnostic criteria and that volcanic-soil and andic properties can affect both analytical behavior and the functional meaning of indicator values. Rather than assigning universal scores, indicators are integrated by soil function and interpreted in relation to soil mineralogy, crop requirements, management history, and disturbance or recovery trajectories. This approach helps distinguish intrinsic volcanic-soil properties from management-induced degradation, identify functionally relevant constraints and make diagnostic confidence explicit. The framework provides a practical basis for routine monitoring, targeted diagnosis, and the development of locally validated soil health reference systems in volcanic island agriculture.