Diagnostic Limitations in Soil Health Frameworks for Tropical Perennial Systems: A Critical Review and Implications for Regenerative Agriculture in Southeast Asia

Tropical perennial systems in Southeast Asia, including oil palm, rubber, and cocoa, are established on highly weathered soils under monsoonal climates that differ fundamentally from temperate systems for which most soil health frameworks were developed. Growing certification, environmental, social, and governance (ESG) reporting, and regenerative agriculture requirements demand demonstrable soil health outcomes, yet the diagnostic infrastructure needed to generate and verify such outcomes remains limited. Existing approaches rely on episodic, indicator-based assessment that captures static conditions rather than functional state, applying benchmarks from dissimilar agroecological contexts with limited basis for resolving system readiness, biological constraint, or functional trajectory. This creates a persistent diagnostic gap between measurement and decision-making, disproportionately affecting smallholders required to meet compliance frameworks calibrated for fundamentally different systems. This critical review synthesizes literature on conventional soil testing, indicator-based frameworks, monitoring programs, and biological diagnostics to identify the structural origins of this gap. Soil health surveillance is identified as a review-derived diagnostic logic, i.e., longitudinal, function-oriented, and crop-calibrated, integrative across chemical, physical, and biological dimensions, and tiered from field-level screening to longitudinal datasets supporting monitoring, reporting, and verification (MRV) reporting. Empirical calibration, context-specific threshold development, and longitudinal validation at the individual system scale are identified as research priorities for operationalizing governance-ready soil health assessment in tropical perennial agriculture.